ltk

stb_truetype.c (149573B)

---

 // stb_truetype.h - v1.26 - public domain
 // authored from 2009-2021 by Sean Barrett / RAD Game Tools
 //
 // =======================================================================
 //
 //    NO SECURITY GUARANTEE -- DO NOT USE THIS ON UNTRUSTED FONT FILES
 //
 // This library does no range checking of the offsets found in the file,
 // meaning an attacker can use it to read arbitrary memory.
 //
 // =======================================================================
 
 #include <math.h>
 #include <stdlib.h>
 #include <assert.h>
 #include <string.h>
 #include "stb_truetype.h"
 
 //////////////////////////////////////////////////////////////////////////////
 //////////////////////////////////////////////////////////////////////////////
 ////
 ////   INTEGRATION WITH YOUR CODEBASE
 ////
 ////   The following sections allow you to supply alternate definitions
 ////   of C library functions used by stb_truetype, e.g. if you don't
 ////   link with the C runtime library.
 
 typedef unsigned char   stbtt_uint8;
 typedef signed   char   stbtt_int8;
 typedef unsigned short  stbtt_uint16;
 typedef signed   short  stbtt_int16;
 typedef unsigned int    stbtt_uint32;
 typedef signed   int    stbtt_int32;
 typedef char stbtt__check_size32[sizeof(stbtt_int32)==4 ? 1 : -1];
 typedef char stbtt__check_size16[sizeof(stbtt_int16)==2 ? 1 : -1];
 #define STBTT_ifloor(x)   ((int) floor(x))
 #define STBTT_iceil(x)    ((int) ceil(x))
 #define STBTT_sqrt(x)      sqrt(x)
 #define STBTT_pow(x,y)     pow(x,y)
 #define STBTT_fmod(x,y)    fmod(x,y)
 #define STBTT_cos(x)       cos(x)
 #define STBTT_acos(x)      acos(x)
 #define STBTT_fabs(x)      fabs(x)
 #define STBTT_malloc(x,u)  ((void)(u),malloc(x))
 #define STBTT_free(x,u)    ((void)(u),free(x))
 #define STBTT_assert(x)    assert(x)
 #define STBTT_strlen(x)    strlen(x)
 #define STBTT_memcpy       memcpy
 #define STBTT_memset       memset
 
 ///////////////////////////////////////////////////////////////////////////////
 ///////////////////////////////////////////////////////////////////////////////
 ////
 ////   IMPLEMENTATION
 ////
 ////
 
 #ifndef STBTT_MAX_OVERSAMPLE
 #define STBTT_MAX_OVERSAMPLE   8
 #endif
 
 #if STBTT_MAX_OVERSAMPLE > 255
 #error "STBTT_MAX_OVERSAMPLE cannot be > 255"
 #endif
 
 typedef int stbtt__test_oversample_pow2[(STBTT_MAX_OVERSAMPLE & (STBTT_MAX_OVERSAMPLE-1)) == 0 ? 1 : -1];
 
 #ifndef STBTT_RASTERIZER_VERSION
 #define STBTT_RASTERIZER_VERSION 2
 #endif
 
 #ifdef _MSC_VER
 #define STBTT__NOTUSED(v)  (void)(v)
 #else
 #define STBTT__NOTUSED(v)  (void)sizeof(v)
 #endif
 
 //////////////////////////////////////////////////////////////////////////
 //
 // stbtt__buf helpers to parse data from file
 //
 
 static stbtt_uint8 stbtt__buf_get8(stbtt__buf *b)
 {
    if (b->cursor >= b->size)
       return 0;
    return b->data[b->cursor++];
 }
 
 static stbtt_uint8 stbtt__buf_peek8(stbtt__buf *b)
 {
    if (b->cursor >= b->size)
       return 0;
    return b->data[b->cursor];
 }
 
 static void stbtt__buf_seek(stbtt__buf *b, int o)
 {
    STBTT_assert(!(o > b->size || o < 0));
    b->cursor = (o > b->size || o < 0) ? b->size : o;
 }
 
 static void stbtt__buf_skip(stbtt__buf *b, int o)
 {
    stbtt__buf_seek(b, b->cursor + o);
 }
 
 static stbtt_uint32 stbtt__buf_get(stbtt__buf *b, int n)
 {
    stbtt_uint32 v = 0;
    int i;
    STBTT_assert(n >= 1 && n <= 4);
    for (i = 0; i < n; i++)
       v = (v << 8) | stbtt__buf_get8(b);
    return v;
 }
 
 static stbtt__buf stbtt__new_buf(const void *p, size_t size)
 {
    stbtt__buf r;
    STBTT_assert(size < 0x40000000);
    r.data = (stbtt_uint8*) p;
    r.size = (int) size;
    r.cursor = 0;
    return r;
 }
 
 #define stbtt__buf_get16(b)  stbtt__buf_get((b), 2)
 #define stbtt__buf_get32(b)  stbtt__buf_get((b), 4)
 
 static stbtt__buf stbtt__buf_range(const stbtt__buf *b, int o, int s)
 {
    stbtt__buf r = stbtt__new_buf(NULL, 0);
    if (o < 0 || s < 0 || o > b->size || s > b->size - o) return r;
    r.data = b->data + o;
    r.size = s;
    return r;
 }
 
 static stbtt__buf stbtt__cff_get_index(stbtt__buf *b)
 {
    int count, start, offsize;
    start = b->cursor;
    count = stbtt__buf_get16(b);
    if (count) {
       offsize = stbtt__buf_get8(b);
       STBTT_assert(offsize >= 1 && offsize <= 4);
       stbtt__buf_skip(b, offsize * count);
       stbtt__buf_skip(b, stbtt__buf_get(b, offsize) - 1);
    }
    return stbtt__buf_range(b, start, b->cursor - start);
 }
 
 static stbtt_uint32 stbtt__cff_int(stbtt__buf *b)
 {
    int b0 = stbtt__buf_get8(b);
    if (b0 >= 32 && b0 <= 246)       return b0 - 139;
    else if (b0 >= 247 && b0 <= 250) return (b0 - 247)*256 + stbtt__buf_get8(b) + 108;
    else if (b0 >= 251 && b0 <= 254) return -(b0 - 251)*256 - stbtt__buf_get8(b) - 108;
    else if (b0 == 28)               return stbtt__buf_get16(b);
    else if (b0 == 29)               return stbtt__buf_get32(b);
    STBTT_assert(0);
    return 0;
 }
 
 static void stbtt__cff_skip_operand(stbtt__buf *b) {
    int v, b0 = stbtt__buf_peek8(b);
    STBTT_assert(b0 >= 28);
    if (b0 == 30) {
       stbtt__buf_skip(b, 1);
       while (b->cursor < b->size) {
          v = stbtt__buf_get8(b);
          if ((v & 0xF) == 0xF || (v >> 4) == 0xF)
             break;
       }
    } else {
       stbtt__cff_int(b);
    }
 }
 
 static stbtt__buf stbtt__dict_get(stbtt__buf *b, int key)
 {
    stbtt__buf_seek(b, 0);
    while (b->cursor < b->size) {
       int start = b->cursor, end, op;
       while (stbtt__buf_peek8(b) >= 28)
          stbtt__cff_skip_operand(b);
       end = b->cursor;
       op = stbtt__buf_get8(b);
       if (op == 12)  op = stbtt__buf_get8(b) | 0x100;
       if (op == key) return stbtt__buf_range(b, start, end-start);
    }
    return stbtt__buf_range(b, 0, 0);
 }
 
 static void stbtt__dict_get_ints(stbtt__buf *b, int key, int outcount, stbtt_uint32 *out)
 {
    int i;
    stbtt__buf operands = stbtt__dict_get(b, key);
    for (i = 0; i < outcount && operands.cursor < operands.size; i++)
       out[i] = stbtt__cff_int(&operands);
 }
 
 static int stbtt__cff_index_count(stbtt__buf *b)
 {
    stbtt__buf_seek(b, 0);
    return stbtt__buf_get16(b);
 }
 
 static stbtt__buf stbtt__cff_index_get(stbtt__buf b, int i)
 {
    int count, offsize, start, end;
    stbtt__buf_seek(&b, 0);
    count = stbtt__buf_get16(&b);
    offsize = stbtt__buf_get8(&b);
    STBTT_assert(i >= 0 && i < count);
    STBTT_assert(offsize >= 1 && offsize <= 4);
    stbtt__buf_skip(&b, i*offsize);
    start = stbtt__buf_get(&b, offsize);
    end = stbtt__buf_get(&b, offsize);
    return stbtt__buf_range(&b, 2+(count+1)*offsize+start, end - start);
 }
 
 //////////////////////////////////////////////////////////////////////////
 //
 // accessors to parse data from file
 //
 
 // on platforms that don't allow misaligned reads, if we want to allow
 // truetype fonts that aren't padded to alignment, define ALLOW_UNALIGNED_TRUETYPE
 
 #define ttBYTE(p)     (* (stbtt_uint8 *) (p))
 #define ttCHAR(p)     (* (stbtt_int8 *) (p))
 #define ttFixed(p)    ttLONG(p)
 
 static stbtt_uint16 ttUSHORT(stbtt_uint8 *p) { return p[0]*256 + p[1]; }
 static stbtt_int16 ttSHORT(stbtt_uint8 *p)   { return p[0]*256 + p[1]; }
 static stbtt_uint32 ttULONG(stbtt_uint8 *p)  { return (p[0]<<24) + (p[1]<<16) + (p[2]<<8) + p[3]; }
 static stbtt_int32 ttLONG(stbtt_uint8 *p)    { return (p[0]<<24) + (p[1]<<16) + (p[2]<<8) + p[3]; }
 
 #define stbtt_tag4(p,c0,c1,c2,c3) ((p)[0] == (c0) && (p)[1] == (c1) && (p)[2] == (c2) && (p)[3] == (c3))
 #define stbtt_tag(p,str)           stbtt_tag4(p,str[0],str[1],str[2],str[3])
 
 static int stbtt__isfont(stbtt_uint8 *font)
 {
    // check the version number
    if (stbtt_tag4(font, '1',0,0,0))  return 1; // TrueType 1
    if (stbtt_tag(font, "typ1"))   return 1; // TrueType with type 1 font -- we don't support this!
    if (stbtt_tag(font, "OTTO"))   return 1; // OpenType with CFF
    if (stbtt_tag4(font, 0,1,0,0)) return 1; // OpenType 1.0
    if (stbtt_tag(font, "true"))   return 1; // Apple specification for TrueType fonts
    return 0;
 }
 
 // @OPTIMIZE: binary search
 static stbtt_uint32 stbtt__find_table(stbtt_uint8 *data, stbtt_uint32 fontstart, const char *tag)
 {
    stbtt_int32 num_tables = ttUSHORT(data+fontstart+4);
    stbtt_uint32 tabledir = fontstart + 12;
    stbtt_int32 i;
    for (i=0; i < num_tables; ++i) {
       stbtt_uint32 loc = tabledir + 16*i;
       if (stbtt_tag(data+loc+0, tag))
          return ttULONG(data+loc+8);
    }
    return 0;
 }
 
 static int stbtt_GetFontOffsetForIndex_internal(unsigned char *font_collection, int index)
 {
    // if it's just a font, there's only one valid index
    if (stbtt__isfont(font_collection))
       return index == 0 ? 0 : -1;
 
    // check if it's a TTC
    if (stbtt_tag(font_collection, "ttcf")) {
       // version 1?
       if (ttULONG(font_collection+4) == 0x00010000 || ttULONG(font_collection+4) == 0x00020000) {
          stbtt_int32 n = ttLONG(font_collection+8);
          if (index >= n)
             return -1;
          return ttULONG(font_collection+12+index*4);
       }
    }
    return -1;
 }
 
 static int stbtt_GetNumberOfFonts_internal(unsigned char *font_collection)
 {
    // if it's just a font, there's only one valid font
    if (stbtt__isfont(font_collection))
       return 1;
 
    // check if it's a TTC
    if (stbtt_tag(font_collection, "ttcf")) {
       // version 1?
       if (ttULONG(font_collection+4) == 0x00010000 || ttULONG(font_collection+4) == 0x00020000) {
          return ttLONG(font_collection+8);
       }
    }
    return 0;
 }
 
 static stbtt__buf stbtt__get_subrs(stbtt__buf cff, stbtt__buf fontdict)
 {
    stbtt_uint32 subrsoff = 0, private_loc[2] = { 0, 0 };
    stbtt__buf pdict;
    stbtt__dict_get_ints(&fontdict, 18, 2, private_loc);
    if (!private_loc[1] || !private_loc[0]) return stbtt__new_buf(NULL, 0);
    pdict = stbtt__buf_range(&cff, private_loc[1], private_loc[0]);
    stbtt__dict_get_ints(&pdict, 19, 1, &subrsoff);
    if (!subrsoff) return stbtt__new_buf(NULL, 0);
    stbtt__buf_seek(&cff, private_loc[1]+subrsoff);
    return stbtt__cff_get_index(&cff);
 }
 
 // since most people won't use this, find this table the first time it's needed
 static int stbtt__get_svg(stbtt_fontinfo *info)
 {
    stbtt_uint32 t;
    if (info->svg < 0) {
       t = stbtt__find_table(info->data, info->fontstart, "SVG ");
       if (t) {
          stbtt_uint32 offset = ttULONG(info->data + t + 2);
          info->svg = t + offset;
       } else {
          info->svg = 0;
       }
    }
    return info->svg;
 }
 
 static int stbtt_InitFont_internal(stbtt_fontinfo *info, unsigned char *data, int fontstart)
 {
    stbtt_uint32 cmap, t;
    stbtt_int32 i,numTables;
 
    info->data = data;
    info->fontstart = fontstart;
    info->cff = stbtt__new_buf(NULL, 0);
 
    cmap = stbtt__find_table(data, fontstart, "cmap");       // required
    info->loca = stbtt__find_table(data, fontstart, "loca"); // required
    info->head = stbtt__find_table(data, fontstart, "head"); // required
    info->glyf = stbtt__find_table(data, fontstart, "glyf"); // required
    info->hhea = stbtt__find_table(data, fontstart, "hhea"); // required
    info->hmtx = stbtt__find_table(data, fontstart, "hmtx"); // required
    info->kern = stbtt__find_table(data, fontstart, "kern"); // not required
    info->gpos = stbtt__find_table(data, fontstart, "GPOS"); // not required
 
    if (!cmap || !info->head || !info->hhea || !info->hmtx)
       return 0;
    if (info->glyf) {
       // required for truetype
       if (!info->loca) return 0;
    } else {
       // initialization for CFF / Type2 fonts (OTF)
       stbtt__buf b, topdict, topdictidx;
       stbtt_uint32 cstype = 2, charstrings = 0, fdarrayoff = 0, fdselectoff = 0;
       stbtt_uint32 cff;
 
       cff = stbtt__find_table(data, fontstart, "CFF ");
       if (!cff) return 0;
 
       info->fontdicts = stbtt__new_buf(NULL, 0);
       info->fdselect = stbtt__new_buf(NULL, 0);
 
       // @TODO this should use size from table (not 512MB)
       info->cff = stbtt__new_buf(data+cff, 512*1024*1024);
       b = info->cff;
 
       // read the header
       stbtt__buf_skip(&b, 2);
       stbtt__buf_seek(&b, stbtt__buf_get8(&b)); // hdrsize
 
       // @TODO the name INDEX could list multiple fonts,
       // but we just use the first one.
       stbtt__cff_get_index(&b);  // name INDEX
       topdictidx = stbtt__cff_get_index(&b);
       topdict = stbtt__cff_index_get(topdictidx, 0);
       stbtt__cff_get_index(&b);  // string INDEX
       info->gsubrs = stbtt__cff_get_index(&b);
 
       stbtt__dict_get_ints(&topdict, 17, 1, &charstrings);
       stbtt__dict_get_ints(&topdict, 0x100 | 6, 1, &cstype);
       stbtt__dict_get_ints(&topdict, 0x100 | 36, 1, &fdarrayoff);
       stbtt__dict_get_ints(&topdict, 0x100 | 37, 1, &fdselectoff);
       info->subrs = stbtt__get_subrs(b, topdict);
 
       // we only support Type 2 charstrings
       if (cstype != 2) return 0;
       if (charstrings == 0) return 0;
 
       if (fdarrayoff) {
          // looks like a CID font
          if (!fdselectoff) return 0;
          stbtt__buf_seek(&b, fdarrayoff);
          info->fontdicts = stbtt__cff_get_index(&b);
          info->fdselect = stbtt__buf_range(&b, fdselectoff, b.size-fdselectoff);
       }
 
       stbtt__buf_seek(&b, charstrings);
       info->charstrings = stbtt__cff_get_index(&b);
    }
 
    t = stbtt__find_table(data, fontstart, "maxp");
    if (t)
       info->numGlyphs = ttUSHORT(data+t+4);
    else
       info->numGlyphs = 0xffff;
 
    info->svg = -1;
 
    // find a cmap encoding table we understand *now* to avoid searching
    // later. (todo: could make this installable)
    // the same regardless of glyph.
    numTables = ttUSHORT(data + cmap + 2);
    info->index_map = 0;
    for (i=0; i < numTables; ++i) {
       stbtt_uint32 encoding_record = cmap + 4 + 8 * i;
       // find an encoding we understand:
       switch(ttUSHORT(data+encoding_record)) {
          case STBTT_PLATFORM_ID_MICROSOFT:
             switch (ttUSHORT(data+encoding_record+2)) {
                case STBTT_MS_EID_UNICODE_BMP:
                case STBTT_MS_EID_UNICODE_FULL:
                   // MS/Unicode
                   info->index_map = cmap + ttULONG(data+encoding_record+4);
                   break;
             }
             break;
         case STBTT_PLATFORM_ID_UNICODE:
             // Mac/iOS has these
             // all the encodingIDs are unicode, so we don't bother to check it
             info->index_map = cmap + ttULONG(data+encoding_record+4);
             break;
       }
    }
    if (info->index_map == 0)
       return 0;
 
    info->indexToLocFormat = ttUSHORT(data+info->head + 50);
    return 1;
 }
 
 STBTT_DEF int stbtt_FindGlyphIndex(const stbtt_fontinfo *info, int unicode_codepoint)
 {
    stbtt_uint8 *data = info->data;
    stbtt_uint32 index_map = info->index_map;
 
    stbtt_uint16 format = ttUSHORT(data + index_map + 0);
    if (format == 0) { // apple byte encoding
       stbtt_int32 bytes = ttUSHORT(data + index_map + 2);
       if (unicode_codepoint < bytes-6)
          return ttBYTE(data + index_map + 6 + unicode_codepoint);
       return 0;
    } else if (format == 6) {
       stbtt_uint32 first = ttUSHORT(data + index_map + 6);
       stbtt_uint32 count = ttUSHORT(data + index_map + 8);
       if ((stbtt_uint32) unicode_codepoint >= first && (stbtt_uint32) unicode_codepoint < first+count)
          return ttUSHORT(data + index_map + 10 + (unicode_codepoint - first)*2);
       return 0;
    } else if (format == 2) {
       STBTT_assert(0); // @TODO: high-byte mapping for japanese/chinese/korean
       return 0;
    } else if (format == 4) { // standard mapping for windows fonts: binary search collection of ranges
       stbtt_uint16 segcount = ttUSHORT(data+index_map+6) >> 1;
       stbtt_uint16 searchRange = ttUSHORT(data+index_map+8) >> 1;
       stbtt_uint16 entrySelector = ttUSHORT(data+index_map+10);
       stbtt_uint16 rangeShift = ttUSHORT(data+index_map+12) >> 1;
 
       // do a binary search of the segments
       stbtt_uint32 endCount = index_map + 14;
       stbtt_uint32 search = endCount;
 
       if (unicode_codepoint > 0xffff)
          return 0;
 
       // they lie from endCount .. endCount + segCount
       // but searchRange is the nearest power of two, so...
       if (unicode_codepoint >= ttUSHORT(data + search + rangeShift*2))
          search += rangeShift*2;
 
       // now decrement to bias correctly to find smallest
       search -= 2;
       while (entrySelector) {
          stbtt_uint16 end;
          searchRange >>= 1;
          end = ttUSHORT(data + search + searchRange*2);
          if (unicode_codepoint > end)
             search += searchRange*2;
          --entrySelector;
       }
       search += 2;
 
       {
          stbtt_uint16 offset, start, last;
          stbtt_uint16 item = (stbtt_uint16) ((search - endCount) >> 1);
 
          start = ttUSHORT(data + index_map + 14 + segcount*2 + 2 + 2*item);
          last = ttUSHORT(data + endCount + 2*item);
          if (unicode_codepoint < start || unicode_codepoint > last)
             return 0;
 
          offset = ttUSHORT(data + index_map + 14 + segcount*6 + 2 + 2*item);
          if (offset == 0)
             return (stbtt_uint16) (unicode_codepoint + ttSHORT(data + index_map + 14 + segcount*4 + 2 + 2*item));
 
          return ttUSHORT(data + offset + (unicode_codepoint-start)*2 + index_map + 14 + segcount*6 + 2 + 2*item);
       }
    } else if (format == 12 || format == 13) {
       stbtt_uint32 ngroups = ttULONG(data+index_map+12);
       stbtt_int32 low,high;
       low = 0; high = (stbtt_int32)ngroups;
       // Binary search the right group.
       while (low < high) {
          stbtt_int32 mid = low + ((high-low) >> 1); // rounds down, so low <= mid < high
          stbtt_uint32 start_char = ttULONG(data+index_map+16+mid*12);
          stbtt_uint32 end_char = ttULONG(data+index_map+16+mid*12+4);
          if ((stbtt_uint32) unicode_codepoint < start_char)
             high = mid;
          else if ((stbtt_uint32) unicode_codepoint > end_char)
             low = mid+1;
          else {
             stbtt_uint32 start_glyph = ttULONG(data+index_map+16+mid*12+8);
             if (format == 12)
                return start_glyph + unicode_codepoint-start_char;
             else // format == 13
                return start_glyph;
          }
       }
       return 0; // not found
    }
    // @TODO
    STBTT_assert(0);
    return 0;
 }
 
 STBTT_DEF int stbtt_GetCodepointShape(const stbtt_fontinfo *info, int unicode_codepoint, stbtt_vertex **vertices)
 {
    return stbtt_GetGlyphShape(info, stbtt_FindGlyphIndex(info, unicode_codepoint), vertices);
 }
 
 static void stbtt_setvertex(stbtt_vertex *v, stbtt_uint8 type, stbtt_int32 x, stbtt_int32 y, stbtt_int32 cx, stbtt_int32 cy)
 {
    v->type = type;
    v->x = (stbtt_int16) x;
    v->y = (stbtt_int16) y;
    v->cx = (stbtt_int16) cx;
    v->cy = (stbtt_int16) cy;
 }
 
 static int stbtt__GetGlyfOffset(const stbtt_fontinfo *info, int glyph_index)
 {
    int g1,g2;
 
    STBTT_assert(!info->cff.size);
 
    if (glyph_index >= info->numGlyphs) return -1; // glyph index out of range
    if (info->indexToLocFormat >= 2)    return -1; // unknown index->glyph map format
 
    if (info->indexToLocFormat == 0) {
       g1 = info->glyf + ttUSHORT(info->data + info->loca + glyph_index * 2) * 2;
       g2 = info->glyf + ttUSHORT(info->data + info->loca + glyph_index * 2 + 2) * 2;
    } else {
       g1 = info->glyf + ttULONG (info->data + info->loca + glyph_index * 4);
       g2 = info->glyf + ttULONG (info->data + info->loca + glyph_index * 4 + 4);
    }
 
    return g1==g2 ? -1 : g1; // if length is 0, return -1
 }
 
 static int stbtt__GetGlyphInfoT2(const stbtt_fontinfo *info, int glyph_index, int *x0, int *y0, int *x1, int *y1);
 
 STBTT_DEF int stbtt_GetGlyphBox(const stbtt_fontinfo *info, int glyph_index, int *x0, int *y0, int *x1, int *y1)
 {
    if (info->cff.size) {
       stbtt__GetGlyphInfoT2(info, glyph_index, x0, y0, x1, y1);
    } else {
       int g = stbtt__GetGlyfOffset(info, glyph_index);
       if (g < 0) return 0;
 
       if (x0) *x0 = ttSHORT(info->data + g + 2);
       if (y0) *y0 = ttSHORT(info->data + g + 4);
       if (x1) *x1 = ttSHORT(info->data + g + 6);
       if (y1) *y1 = ttSHORT(info->data + g + 8);
    }
    return 1;
 }
 
 STBTT_DEF int stbtt_GetCodepointBox(const stbtt_fontinfo *info, int codepoint, int *x0, int *y0, int *x1, int *y1)
 {
    return stbtt_GetGlyphBox(info, stbtt_FindGlyphIndex(info,codepoint), x0,y0,x1,y1);
 }
 
 STBTT_DEF int stbtt_IsGlyphEmpty(const stbtt_fontinfo *info, int glyph_index)
 {
    stbtt_int16 numberOfContours;
    int g;
    if (info->cff.size)
       return stbtt__GetGlyphInfoT2(info, glyph_index, NULL, NULL, NULL, NULL) == 0;
    g = stbtt__GetGlyfOffset(info, glyph_index);
    if (g < 0) return 1;
    numberOfContours = ttSHORT(info->data + g);
    return numberOfContours == 0;
 }
 
 static int stbtt__close_shape(stbtt_vertex *vertices, int num_vertices, int was_off, int start_off,
     stbtt_int32 sx, stbtt_int32 sy, stbtt_int32 scx, stbtt_int32 scy, stbtt_int32 cx, stbtt_int32 cy)
 {
    if (start_off) {
       if (was_off)
          stbtt_setvertex(&vertices[num_vertices++], STBTT_vcurve, (cx+scx)>>1, (cy+scy)>>1, cx,cy);
       stbtt_setvertex(&vertices[num_vertices++], STBTT_vcurve, sx,sy,scx,scy);
    } else {
       if (was_off)
          stbtt_setvertex(&vertices[num_vertices++], STBTT_vcurve,sx,sy,cx,cy);
       else
          stbtt_setvertex(&vertices[num_vertices++], STBTT_vline,sx,sy,0,0);
    }
    return num_vertices;
 }
 
 static int stbtt__GetGlyphShapeTT(const stbtt_fontinfo *info, int glyph_index, stbtt_vertex **pvertices)
 {
    stbtt_int16 numberOfContours;
    stbtt_uint8 *endPtsOfContours;
    stbtt_uint8 *data = info->data;
    stbtt_vertex *vertices=0;
    int num_vertices=0;
    int g = stbtt__GetGlyfOffset(info, glyph_index);
 
    *pvertices = NULL;
 
    if (g < 0) return 0;
 
    numberOfContours = ttSHORT(data + g);
 
    if (numberOfContours > 0) {
       stbtt_uint8 flags=0,flagcount;
       stbtt_int32 ins, i,j=0,m,n, next_move, was_off=0, off, start_off=0;
       stbtt_int32 x,y,cx,cy,sx,sy, scx,scy;
       stbtt_uint8 *points;
       endPtsOfContours = (data + g + 10);
       ins = ttUSHORT(data + g + 10 + numberOfContours * 2);
       points = data + g + 10 + numberOfContours * 2 + 2 + ins;
 
       n = 1+ttUSHORT(endPtsOfContours + numberOfContours*2-2);
 
       m = n + 2*numberOfContours;  // a loose bound on how many vertices we might need
       vertices = (stbtt_vertex *) STBTT_malloc(m * sizeof(vertices[0]), info->userdata);
       if (vertices == 0)
          return 0;
 
       next_move = 0;
       flagcount=0;
 
       // in first pass, we load uninterpreted data into the allocated array
       // above, shifted to the end of the array so we won't overwrite it when
       // we create our final data starting from the front
 
       off = m - n; // starting offset for uninterpreted data, regardless of how m ends up being calculated
 
       // first load flags
 
       for (i=0; i < n; ++i) {
          if (flagcount == 0) {
             flags = *points++;
             if (flags & 8)
                flagcount = *points++;
          } else
             --flagcount;
          vertices[off+i].type = flags;
       }
 
       // now load x coordinates
       x=0;
       for (i=0; i < n; ++i) {
          flags = vertices[off+i].type;
          if (flags & 2) {
             stbtt_int16 dx = *points++;
             x += (flags & 16) ? dx : -dx; // ???
          } else {
             if (!(flags & 16)) {
                x = x + (stbtt_int16) (points[0]*256 + points[1]);
                points += 2;
             }
          }
          vertices[off+i].x = (stbtt_int16) x;
       }
 
       // now load y coordinates
       y=0;
       for (i=0; i < n; ++i) {
          flags = vertices[off+i].type;
          if (flags & 4) {
             stbtt_int16 dy = *points++;
             y += (flags & 32) ? dy : -dy; // ???
          } else {
             if (!(flags & 32)) {
                y = y + (stbtt_int16) (points[0]*256 + points[1]);
                points += 2;
             }
          }
          vertices[off+i].y = (stbtt_int16) y;
       }
 
       // now convert them to our format
       num_vertices=0;
       sx = sy = cx = cy = scx = scy = 0;
       for (i=0; i < n; ++i) {
          flags = vertices[off+i].type;
          x     = (stbtt_int16) vertices[off+i].x;
          y     = (stbtt_int16) vertices[off+i].y;
 
          if (next_move == i) {
             if (i != 0)
                num_vertices = stbtt__close_shape(vertices, num_vertices, was_off, start_off, sx,sy,scx,scy,cx,cy);
 
             // now start the new one
             start_off = !(flags & 1);
             if (start_off) {
                // if we start off with an off-curve point, then when we need to find a point on the curve
                // where we can start, and we need to save some state for when we wraparound.
                scx = x;
                scy = y;
                if (!(vertices[off+i+1].type & 1)) {
                   // next point is also a curve point, so interpolate an on-point curve
                   sx = (x + (stbtt_int32) vertices[off+i+1].x) >> 1;
                   sy = (y + (stbtt_int32) vertices[off+i+1].y) >> 1;
                } else {
                   // otherwise just use the next point as our start point
                   sx = (stbtt_int32) vertices[off+i+1].x;
                   sy = (stbtt_int32) vertices[off+i+1].y;
                   ++i; // we're using point i+1 as the starting point, so skip it
                }
             } else {
                sx = x;
                sy = y;
             }
             stbtt_setvertex(&vertices[num_vertices++], STBTT_vmove,sx,sy,0,0);
             was_off = 0;
             next_move = 1 + ttUSHORT(endPtsOfContours+j*2);
             ++j;
          } else {
             if (!(flags & 1)) { // if it's a curve
                if (was_off) // two off-curve control points in a row means interpolate an on-curve midpoint
                   stbtt_setvertex(&vertices[num_vertices++], STBTT_vcurve, (cx+x)>>1, (cy+y)>>1, cx, cy);
                cx = x;
                cy = y;
                was_off = 1;
             } else {
                if (was_off)
                   stbtt_setvertex(&vertices[num_vertices++], STBTT_vcurve, x,y, cx, cy);
                else
                   stbtt_setvertex(&vertices[num_vertices++], STBTT_vline, x,y,0,0);
                was_off = 0;
             }
          }
       }
       num_vertices = stbtt__close_shape(vertices, num_vertices, was_off, start_off, sx,sy,scx,scy,cx,cy);
    } else if (numberOfContours < 0) {
       // Compound shapes.
       int more = 1;
       stbtt_uint8 *comp = data + g + 10;
       num_vertices = 0;
       vertices = 0;
       while (more) {
          stbtt_uint16 flags, gidx;
          int comp_num_verts = 0, i;
          stbtt_vertex *comp_verts = 0, *tmp = 0;
          float mtx[6] = {1,0,0,1,0,0}, m, n;
 
          flags = ttSHORT(comp); comp+=2;
          gidx = ttSHORT(comp); comp+=2;
 
          if (flags & 2) { // XY values
             if (flags & 1) { // shorts
                mtx[4] = ttSHORT(comp); comp+=2;
                mtx[5] = ttSHORT(comp); comp+=2;
             } else {
                mtx[4] = ttCHAR(comp); comp+=1;
                mtx[5] = ttCHAR(comp); comp+=1;
             }
          }
          else {
             // @TODO handle matching point
             STBTT_assert(0);
          }
          if (flags & (1<<3)) { // WE_HAVE_A_SCALE
             mtx[0] = mtx[3] = ttSHORT(comp)/16384.0f; comp+=2;
             mtx[1] = mtx[2] = 0;
          } else if (flags & (1<<6)) { // WE_HAVE_AN_X_AND_YSCALE
             mtx[0] = ttSHORT(comp)/16384.0f; comp+=2;
             mtx[1] = mtx[2] = 0;
             mtx[3] = ttSHORT(comp)/16384.0f; comp+=2;
          } else if (flags & (1<<7)) { // WE_HAVE_A_TWO_BY_TWO
             mtx[0] = ttSHORT(comp)/16384.0f; comp+=2;
             mtx[1] = ttSHORT(comp)/16384.0f; comp+=2;
             mtx[2] = ttSHORT(comp)/16384.0f; comp+=2;
             mtx[3] = ttSHORT(comp)/16384.0f; comp+=2;
          }
 
          // Find transformation scales.
          m = (float) STBTT_sqrt(mtx[0]*mtx[0] + mtx[1]*mtx[1]);
          n = (float) STBTT_sqrt(mtx[2]*mtx[2] + mtx[3]*mtx[3]);
 
          // Get indexed glyph.
          comp_num_verts = stbtt_GetGlyphShape(info, gidx, &comp_verts);
          if (comp_num_verts > 0) {
             // Transform vertices.
             for (i = 0; i < comp_num_verts; ++i) {
                stbtt_vertex* v = &comp_verts[i];
                stbtt_vertex_type x,y;
                x=v->x; y=v->y;
                v->x = (stbtt_vertex_type)(m * (mtx[0]*x + mtx[2]*y + mtx[4]));
                v->y = (stbtt_vertex_type)(n * (mtx[1]*x + mtx[3]*y + mtx[5]));
                x=v->cx; y=v->cy;
                v->cx = (stbtt_vertex_type)(m * (mtx[0]*x + mtx[2]*y + mtx[4]));
                v->cy = (stbtt_vertex_type)(n * (mtx[1]*x + mtx[3]*y + mtx[5]));
             }
             // Append vertices.
             tmp = (stbtt_vertex*)STBTT_malloc((num_vertices+comp_num_verts)*sizeof(stbtt_vertex), info->userdata);
             if (!tmp) {
                if (vertices) STBTT_free(vertices, info->userdata);
                if (comp_verts) STBTT_free(comp_verts, info->userdata);
                return 0;
             }
             if (num_vertices > 0 && vertices) STBTT_memcpy(tmp, vertices, num_vertices*sizeof(stbtt_vertex));
             STBTT_memcpy(tmp+num_vertices, comp_verts, comp_num_verts*sizeof(stbtt_vertex));
             if (vertices) STBTT_free(vertices, info->userdata);
             vertices = tmp;
             STBTT_free(comp_verts, info->userdata);
             num_vertices += comp_num_verts;
          }
          // More components ?
          more = flags & (1<<5);
       }
    } else {
       // numberOfCounters == 0, do nothing
    }
 
    *pvertices = vertices;
    return num_vertices;
 }
 
 typedef struct
 {
    int bounds;
    int started;
    float first_x, first_y;
    float x, y;
    stbtt_int32 min_x, max_x, min_y, max_y;
 
    stbtt_vertex *pvertices;
    int num_vertices;
 } stbtt__csctx;
 
 #define STBTT__CSCTX_INIT(bounds) {bounds,0, 0,0, 0,0, 0,0,0,0, NULL, 0}
 
 static void stbtt__track_vertex(stbtt__csctx *c, stbtt_int32 x, stbtt_int32 y)
 {
    if (x > c->max_x || !c->started) c->max_x = x;
    if (y > c->max_y || !c->started) c->max_y = y;
    if (x < c->min_x || !c->started) c->min_x = x;
    if (y < c->min_y || !c->started) c->min_y = y;
    c->started = 1;
 }
 
 static void stbtt__csctx_v(stbtt__csctx *c, stbtt_uint8 type, stbtt_int32 x, stbtt_int32 y, stbtt_int32 cx, stbtt_int32 cy, stbtt_int32 cx1, stbtt_int32 cy1)
 {
    if (c->bounds) {
       stbtt__track_vertex(c, x, y);
       if (type == STBTT_vcubic) {
          stbtt__track_vertex(c, cx, cy);
          stbtt__track_vertex(c, cx1, cy1);
       }
    } else {
       stbtt_setvertex(&c->pvertices[c->num_vertices], type, x, y, cx, cy);
       c->pvertices[c->num_vertices].cx1 = (stbtt_int16) cx1;
       c->pvertices[c->num_vertices].cy1 = (stbtt_int16) cy1;
    }
    c->num_vertices++;
 }
 
 static void stbtt__csctx_close_shape(stbtt__csctx *ctx)
 {
    if (ctx->first_x != ctx->x || ctx->first_y != ctx->y)
       stbtt__csctx_v(ctx, STBTT_vline, (int)ctx->first_x, (int)ctx->first_y, 0, 0, 0, 0);
 }
 
 static void stbtt__csctx_rmove_to(stbtt__csctx *ctx, float dx, float dy)
 {
    stbtt__csctx_close_shape(ctx);
    ctx->first_x = ctx->x = ctx->x + dx;
    ctx->first_y = ctx->y = ctx->y + dy;
    stbtt__csctx_v(ctx, STBTT_vmove, (int)ctx->x, (int)ctx->y, 0, 0, 0, 0);
 }
 
 static void stbtt__csctx_rline_to(stbtt__csctx *ctx, float dx, float dy)
 {
    ctx->x += dx;
    ctx->y += dy;
    stbtt__csctx_v(ctx, STBTT_vline, (int)ctx->x, (int)ctx->y, 0, 0, 0, 0);
 }
 
 static void stbtt__csctx_rccurve_to(stbtt__csctx *ctx, float dx1, float dy1, float dx2, float dy2, float dx3, float dy3)
 {
    float cx1 = ctx->x + dx1;
    float cy1 = ctx->y + dy1;
    float cx2 = cx1 + dx2;
    float cy2 = cy1 + dy2;
    ctx->x = cx2 + dx3;
    ctx->y = cy2 + dy3;
    stbtt__csctx_v(ctx, STBTT_vcubic, (int)ctx->x, (int)ctx->y, (int)cx1, (int)cy1, (int)cx2, (int)cy2);
 }
 
 static stbtt__buf stbtt__get_subr(stbtt__buf idx, int n)
 {
    int count = stbtt__cff_index_count(&idx);
    int bias = 107;
    if (count >= 33900)
       bias = 32768;
    else if (count >= 1240)
       bias = 1131;
    n += bias;
    if (n < 0 || n >= count)
       return stbtt__new_buf(NULL, 0);
    return stbtt__cff_index_get(idx, n);
 }
 
 static stbtt__buf stbtt__cid_get_glyph_subrs(const stbtt_fontinfo *info, int glyph_index)
 {
    stbtt__buf fdselect = info->fdselect;
    int nranges, start, end, v, fmt, fdselector = -1, i;
 
    stbtt__buf_seek(&fdselect, 0);
    fmt = stbtt__buf_get8(&fdselect);
    if (fmt == 0) {
       // untested
       stbtt__buf_skip(&fdselect, glyph_index);
       fdselector = stbtt__buf_get8(&fdselect);
    } else if (fmt == 3) {
       nranges = stbtt__buf_get16(&fdselect);
       start = stbtt__buf_get16(&fdselect);
       for (i = 0; i < nranges; i++) {
          v = stbtt__buf_get8(&fdselect);
          end = stbtt__buf_get16(&fdselect);
          if (glyph_index >= start && glyph_index < end) {
             fdselector = v;
             break;
          }
          start = end;
       }
    }
    if (fdselector == -1) stbtt__new_buf(NULL, 0);
    return stbtt__get_subrs(info->cff, stbtt__cff_index_get(info->fontdicts, fdselector));
 }
 
 static int stbtt__run_charstring(const stbtt_fontinfo *info, int glyph_index, stbtt__csctx *c)
 {
    int in_header = 1, maskbits = 0, subr_stack_height = 0, sp = 0, v, i, b0;
    int has_subrs = 0, clear_stack;
    float s[48];
    stbtt__buf subr_stack[10], subrs = info->subrs, b;
    float f;
 
 #define STBTT__CSERR(s) (0)
 
    // this currently ignores the initial width value, which isn't needed if we have hmtx
    b = stbtt__cff_index_get(info->charstrings, glyph_index);
    while (b.cursor < b.size) {
       i = 0;
       clear_stack = 1;
       b0 = stbtt__buf_get8(&b);
       switch (b0) {
       // @TODO implement hinting
       case 0x13: // hintmask
       case 0x14: // cntrmask
          if (in_header)
             maskbits += (sp / 2); // implicit "vstem"
          in_header = 0;
          stbtt__buf_skip(&b, (maskbits + 7) / 8);
          break;
 
       case 0x01: // hstem
       case 0x03: // vstem
       case 0x12: // hstemhm
       case 0x17: // vstemhm
          maskbits += (sp / 2);
          break;
 
       case 0x15: // rmoveto
          in_header = 0;
          if (sp < 2) return STBTT__CSERR("rmoveto stack");
          stbtt__csctx_rmove_to(c, s[sp-2], s[sp-1]);
          break;
       case 0x04: // vmoveto
          in_header = 0;
          if (sp < 1) return STBTT__CSERR("vmoveto stack");
          stbtt__csctx_rmove_to(c, 0, s[sp-1]);
          break;
       case 0x16: // hmoveto
          in_header = 0;
          if (sp < 1) return STBTT__CSERR("hmoveto stack");
          stbtt__csctx_rmove_to(c, s[sp-1], 0);
          break;
 
       case 0x05: // rlineto
          if (sp < 2) return STBTT__CSERR("rlineto stack");
          for (; i + 1 < sp; i += 2)
             stbtt__csctx_rline_to(c, s[i], s[i+1]);
          break;
 
       // hlineto/vlineto and vhcurveto/hvcurveto alternate horizontal and vertical
       // starting from a different place.
 
       case 0x07: // vlineto
          if (sp < 1) return STBTT__CSERR("vlineto stack");
          goto vlineto;
       case 0x06: // hlineto
          if (sp < 1) return STBTT__CSERR("hlineto stack");
          for (;;) {
             if (i >= sp) break;
             stbtt__csctx_rline_to(c, s[i], 0);
             i++;
       vlineto:
             if (i >= sp) break;
             stbtt__csctx_rline_to(c, 0, s[i]);
             i++;
          }
          break;
 
       case 0x1F: // hvcurveto
          if (sp < 4) return STBTT__CSERR("hvcurveto stack");
          goto hvcurveto;
       case 0x1E: // vhcurveto
          if (sp < 4) return STBTT__CSERR("vhcurveto stack");
          for (;;) {
             if (i + 3 >= sp) break;
             stbtt__csctx_rccurve_to(c, 0, s[i], s[i+1], s[i+2], s[i+3], (sp - i == 5) ? s[i + 4] : 0.0f);
             i += 4;
       hvcurveto:
             if (i + 3 >= sp) break;
             stbtt__csctx_rccurve_to(c, s[i], 0, s[i+1], s[i+2], (sp - i == 5) ? s[i+4] : 0.0f, s[i+3]);
             i += 4;
          }
          break;
 
       case 0x08: // rrcurveto
          if (sp < 6) return STBTT__CSERR("rcurveline stack");
          for (; i + 5 < sp; i += 6)
             stbtt__csctx_rccurve_to(c, s[i], s[i+1], s[i+2], s[i+3], s[i+4], s[i+5]);
          break;
 
       case 0x18: // rcurveline
          if (sp < 8) return STBTT__CSERR("rcurveline stack");
          for (; i + 5 < sp - 2; i += 6)
             stbtt__csctx_rccurve_to(c, s[i], s[i+1], s[i+2], s[i+3], s[i+4], s[i+5]);
          if (i + 1 >= sp) return STBTT__CSERR("rcurveline stack");
          stbtt__csctx_rline_to(c, s[i], s[i+1]);
          break;
 
       case 0x19: // rlinecurve
          if (sp < 8) return STBTT__CSERR("rlinecurve stack");
          for (; i + 1 < sp - 6; i += 2)
             stbtt__csctx_rline_to(c, s[i], s[i+1]);
          if (i + 5 >= sp) return STBTT__CSERR("rlinecurve stack");
          stbtt__csctx_rccurve_to(c, s[i], s[i+1], s[i+2], s[i+3], s[i+4], s[i+5]);
          break;
 
       case 0x1A: // vvcurveto
       case 0x1B: // hhcurveto
          if (sp < 4) return STBTT__CSERR("(vv|hh)curveto stack");
          f = 0.0;
          if (sp & 1) { f = s[i]; i++; }
          for (; i + 3 < sp; i += 4) {
             if (b0 == 0x1B)
                stbtt__csctx_rccurve_to(c, s[i], f, s[i+1], s[i+2], s[i+3], 0.0);
             else
                stbtt__csctx_rccurve_to(c, f, s[i], s[i+1], s[i+2], 0.0, s[i+3]);
             f = 0.0;
          }
          break;
 
       case 0x0A: // callsubr
          if (!has_subrs) {
             if (info->fdselect.size)
                subrs = stbtt__cid_get_glyph_subrs(info, glyph_index);
             has_subrs = 1;
          }
          // FALLTHROUGH
       case 0x1D: // callgsubr
          if (sp < 1) return STBTT__CSERR("call(g|)subr stack");
          v = (int) s[--sp];
          if (subr_stack_height >= 10) return STBTT__CSERR("recursion limit");
          subr_stack[subr_stack_height++] = b;
          b = stbtt__get_subr(b0 == 0x0A ? subrs : info->gsubrs, v);
          if (b.size == 0) return STBTT__CSERR("subr not found");
          b.cursor = 0;
          clear_stack = 0;
          break;
 
       case 0x0B: // return
          if (subr_stack_height <= 0) return STBTT__CSERR("return outside subr");
          b = subr_stack[--subr_stack_height];
          clear_stack = 0;
          break;
 
       case 0x0E: // endchar
          stbtt__csctx_close_shape(c);
          return 1;
 
       case 0x0C: { // two-byte escape
          float dx1, dx2, dx3, dx4, dx5, dx6, dy1, dy2, dy3, dy4, dy5, dy6;
          float dx, dy;
          int b1 = stbtt__buf_get8(&b);
          switch (b1) {
          // @TODO These "flex" implementations ignore the flex-depth and resolution,
          // and always draw beziers.
          case 0x22: // hflex
             if (sp < 7) return STBTT__CSERR("hflex stack");
             dx1 = s[0];
             dx2 = s[1];
             dy2 = s[2];
             dx3 = s[3];
             dx4 = s[4];
             dx5 = s[5];
             dx6 = s[6];
             stbtt__csctx_rccurve_to(c, dx1, 0, dx2, dy2, dx3, 0);
             stbtt__csctx_rccurve_to(c, dx4, 0, dx5, -dy2, dx6, 0);
             break;
 
          case 0x23: // flex
             if (sp < 13) return STBTT__CSERR("flex stack");
             dx1 = s[0];
             dy1 = s[1];
             dx2 = s[2];
             dy2 = s[3];
             dx3 = s[4];
             dy3 = s[5];
             dx4 = s[6];
             dy4 = s[7];
             dx5 = s[8];
             dy5 = s[9];
             dx6 = s[10];
             dy6 = s[11];
             //fd is s[12]
             stbtt__csctx_rccurve_to(c, dx1, dy1, dx2, dy2, dx3, dy3);
             stbtt__csctx_rccurve_to(c, dx4, dy4, dx5, dy5, dx6, dy6);
             break;
 
          case 0x24: // hflex1
             if (sp < 9) return STBTT__CSERR("hflex1 stack");
             dx1 = s[0];
             dy1 = s[1];
             dx2 = s[2];
             dy2 = s[3];
             dx3 = s[4];
             dx4 = s[5];
             dx5 = s[6];
             dy5 = s[7];
             dx6 = s[8];
             stbtt__csctx_rccurve_to(c, dx1, dy1, dx2, dy2, dx3, 0);
             stbtt__csctx_rccurve_to(c, dx4, 0, dx5, dy5, dx6, -(dy1+dy2+dy5));
             break;
 
          case 0x25: // flex1
             if (sp < 11) return STBTT__CSERR("flex1 stack");
             dx1 = s[0];
             dy1 = s[1];
             dx2 = s[2];
             dy2 = s[3];
             dx3 = s[4];
             dy3 = s[5];
             dx4 = s[6];
             dy4 = s[7];
             dx5 = s[8];
             dy5 = s[9];
             dx6 = dy6 = s[10];
             dx = dx1+dx2+dx3+dx4+dx5;
             dy = dy1+dy2+dy3+dy4+dy5;
             if (STBTT_fabs(dx) > STBTT_fabs(dy))
                dy6 = -dy;
             else
                dx6 = -dx;
             stbtt__csctx_rccurve_to(c, dx1, dy1, dx2, dy2, dx3, dy3);
             stbtt__csctx_rccurve_to(c, dx4, dy4, dx5, dy5, dx6, dy6);
             break;
 
          default:
             return STBTT__CSERR("unimplemented");
          }
       } break;
 
       default:
          if (b0 != 255 && b0 != 28 && b0 < 32)
             return STBTT__CSERR("reserved operator");
 
          // push immediate
          if (b0 == 255) {
             f = (float)(stbtt_int32)stbtt__buf_get32(&b) / 0x10000;
          } else {
             stbtt__buf_skip(&b, -1);
             f = (float)(stbtt_int16)stbtt__cff_int(&b);
          }
          if (sp >= 48) return STBTT__CSERR("push stack overflow");
          s[sp++] = f;
          clear_stack = 0;
          break;
       }
       if (clear_stack) sp = 0;
    }
    return STBTT__CSERR("no endchar");
 
 #undef STBTT__CSERR
 }
 
 static int stbtt__GetGlyphShapeT2(const stbtt_fontinfo *info, int glyph_index, stbtt_vertex **pvertices)
 {
    // runs the charstring twice, once to count and once to output (to avoid realloc)
    stbtt__csctx count_ctx = STBTT__CSCTX_INIT(1);
    stbtt__csctx output_ctx = STBTT__CSCTX_INIT(0);
    if (stbtt__run_charstring(info, glyph_index, &count_ctx)) {
       *pvertices = (stbtt_vertex*)STBTT_malloc(count_ctx.num_vertices*sizeof(stbtt_vertex), info->userdata);
       output_ctx.pvertices = *pvertices;
       if (stbtt__run_charstring(info, glyph_index, &output_ctx)) {
          STBTT_assert(output_ctx.num_vertices == count_ctx.num_vertices);
          return output_ctx.num_vertices;
       }
    }
    *pvertices = NULL;
    return 0;
 }
 
 static int stbtt__GetGlyphInfoT2(const stbtt_fontinfo *info, int glyph_index, int *x0, int *y0, int *x1, int *y1)
 {
    stbtt__csctx c = STBTT__CSCTX_INIT(1);
    int r = stbtt__run_charstring(info, glyph_index, &c);
    if (x0)  *x0 = r ? c.min_x : 0;
    if (y0)  *y0 = r ? c.min_y : 0;
    if (x1)  *x1 = r ? c.max_x : 0;
    if (y1)  *y1 = r ? c.max_y : 0;
    return r ? c.num_vertices : 0;
 }
 
 STBTT_DEF int stbtt_GetGlyphShape(const stbtt_fontinfo *info, int glyph_index, stbtt_vertex **pvertices)
 {
    if (!info->cff.size)
       return stbtt__GetGlyphShapeTT(info, glyph_index, pvertices);
    else
       return stbtt__GetGlyphShapeT2(info, glyph_index, pvertices);
 }
 
 STBTT_DEF void stbtt_GetGlyphHMetrics(const stbtt_fontinfo *info, int glyph_index, int *advanceWidth, int *leftSideBearing)
 {
    stbtt_uint16 numOfLongHorMetrics = ttUSHORT(info->data+info->hhea + 34);
    if (glyph_index < numOfLongHorMetrics) {
       if (advanceWidth)     *advanceWidth    = ttSHORT(info->data + info->hmtx + 4*glyph_index);
       if (leftSideBearing)  *leftSideBearing = ttSHORT(info->data + info->hmtx + 4*glyph_index + 2);
    } else {
       if (advanceWidth)     *advanceWidth    = ttSHORT(info->data + info->hmtx + 4*(numOfLongHorMetrics-1));
       if (leftSideBearing)  *leftSideBearing = ttSHORT(info->data + info->hmtx + 4*numOfLongHorMetrics + 2*(glyph_index - numOfLongHorMetrics));
    }
 }
 
 STBTT_DEF int  stbtt_GetKerningTableLength(const stbtt_fontinfo *info)
 {
    stbtt_uint8 *data = info->data + info->kern;
 
    // we only look at the first table. it must be 'horizontal' and format 0.
    if (!info->kern)
       return 0;
    if (ttUSHORT(data+2) < 1) // number of tables, need at least 1
       return 0;
    if (ttUSHORT(data+8) != 1) // horizontal flag must be set in format
       return 0;
 
    return ttUSHORT(data+10);
 }
 
 STBTT_DEF int stbtt_GetKerningTable(const stbtt_fontinfo *info, stbtt_kerningentry* table, int table_length)
 {
    stbtt_uint8 *data = info->data + info->kern;
    int k, length;
 
    // we only look at the first table. it must be 'horizontal' and format 0.
    if (!info->kern)
       return 0;
    if (ttUSHORT(data+2) < 1) // number of tables, need at least 1
       return 0;
    if (ttUSHORT(data+8) != 1) // horizontal flag must be set in format
       return 0;
 
    length = ttUSHORT(data+10);
    if (table_length < length)
       length = table_length;
 
    for (k = 0; k < length; k++)
    {
       table[k].glyph1 = ttUSHORT(data+18+(k*6));
       table[k].glyph2 = ttUSHORT(data+20+(k*6));
       table[k].advance = ttSHORT(data+22+(k*6));
    }
 
    return length;
 }
 
 static int stbtt__GetGlyphKernInfoAdvance(const stbtt_fontinfo *info, int glyph1, int glyph2)
 {
    stbtt_uint8 *data = info->data + info->kern;
    stbtt_uint32 needle, straw;
    int l, r, m;
 
    // we only look at the first table. it must be 'horizontal' and format 0.
    if (!info->kern)
       return 0;
    if (ttUSHORT(data+2) < 1) // number of tables, need at least 1
       return 0;
    if (ttUSHORT(data+8) != 1) // horizontal flag must be set in format
       return 0;
 
    l = 0;
    r = ttUSHORT(data+10) - 1;
    needle = glyph1 << 16 | glyph2;
    while (l <= r) {
       m = (l + r) >> 1;
       straw = ttULONG(data+18+(m*6)); // note: unaligned read
       if (needle < straw)
          r = m - 1;
       else if (needle > straw)
          l = m + 1;
       else
          return ttSHORT(data+22+(m*6));
    }
    return 0;
 }
 
 static stbtt_int32 stbtt__GetCoverageIndex(stbtt_uint8 *coverageTable, int glyph)
 {
    stbtt_uint16 coverageFormat = ttUSHORT(coverageTable);
    switch (coverageFormat) {
       case 1: {
          stbtt_uint16 glyphCount = ttUSHORT(coverageTable + 2);
 
          // Binary search.
          stbtt_int32 l=0, r=glyphCount-1, m;
          int straw, needle=glyph;
          while (l <= r) {
             stbtt_uint8 *glyphArray = coverageTable + 4;
             stbtt_uint16 glyphID;
             m = (l + r) >> 1;
             glyphID = ttUSHORT(glyphArray + 2 * m);
             straw = glyphID;
             if (needle < straw)
                r = m - 1;
             else if (needle > straw)
                l = m + 1;
             else {
                return m;
             }
          }
          break;
       }
 
       case 2: {
          stbtt_uint16 rangeCount = ttUSHORT(coverageTable + 2);
          stbtt_uint8 *rangeArray = coverageTable + 4;
 
          // Binary search.
          stbtt_int32 l=0, r=rangeCount-1, m;
          int strawStart, strawEnd, needle=glyph;
          while (l <= r) {
             stbtt_uint8 *rangeRecord;
             m = (l + r) >> 1;
             rangeRecord = rangeArray + 6 * m;
             strawStart = ttUSHORT(rangeRecord);
             strawEnd = ttUSHORT(rangeRecord + 2);
             if (needle < strawStart)
                r = m - 1;
             else if (needle > strawEnd)
                l = m + 1;
             else {
                stbtt_uint16 startCoverageIndex = ttUSHORT(rangeRecord + 4);
                return startCoverageIndex + glyph - strawStart;
             }
          }
          break;
       }
 
       default: return -1; // unsupported
    }
 
    return -1;
 }
 
 static stbtt_int32  stbtt__GetGlyphClass(stbtt_uint8 *classDefTable, int glyph)
 {
    stbtt_uint16 classDefFormat = ttUSHORT(classDefTable);
    switch (classDefFormat)
    {
       case 1: {
          stbtt_uint16 startGlyphID = ttUSHORT(classDefTable + 2);
          stbtt_uint16 glyphCount = ttUSHORT(classDefTable + 4);
          stbtt_uint8 *classDef1ValueArray = classDefTable + 6;
 
          if (glyph >= startGlyphID && glyph < startGlyphID + glyphCount)
             return (stbtt_int32)ttUSHORT(classDef1ValueArray + 2 * (glyph - startGlyphID));
          break;
       }
 
       case 2: {
          stbtt_uint16 classRangeCount = ttUSHORT(classDefTable + 2);
          stbtt_uint8 *classRangeRecords = classDefTable + 4;
 
          // Binary search.
          stbtt_int32 l=0, r=classRangeCount-1, m;
          int strawStart, strawEnd, needle=glyph;
          while (l <= r) {
             stbtt_uint8 *classRangeRecord;
             m = (l + r) >> 1;
             classRangeRecord = classRangeRecords + 6 * m;
             strawStart = ttUSHORT(classRangeRecord);
             strawEnd = ttUSHORT(classRangeRecord + 2);
             if (needle < strawStart)
                r = m - 1;
             else if (needle > strawEnd)
                l = m + 1;
             else
                return (stbtt_int32)ttUSHORT(classRangeRecord + 4);
          }
          break;
       }
 
       default:
          return -1; // Unsupported definition type, return an error.
    }
 
    // "All glyphs not assigned to a class fall into class 0". (OpenType spec)
    return 0;
 }
 
 // Define to STBTT_assert(x) if you want to break on unimplemented formats.
 #define STBTT_GPOS_TODO_assert(x)
 
 static stbtt_int32 stbtt__GetGlyphGPOSInfoAdvance(const stbtt_fontinfo *info, int glyph1, int glyph2)
 {
    stbtt_uint16 lookupListOffset;
    stbtt_uint8 *lookupList;
    stbtt_uint16 lookupCount;
    stbtt_uint8 *data;
    stbtt_int32 i, sti;
 
    if (!info->gpos) return 0;
 
    data = info->data + info->gpos;
 
    if (ttUSHORT(data+0) != 1) return 0; // Major version 1
    if (ttUSHORT(data+2) != 0) return 0; // Minor version 0
 
    lookupListOffset = ttUSHORT(data+8);
    lookupList = data + lookupListOffset;
    lookupCount = ttUSHORT(lookupList);
 
    for (i=0; i<lookupCount; ++i) {
       stbtt_uint16 lookupOffset = ttUSHORT(lookupList + 2 + 2 * i);
       stbtt_uint8 *lookupTable = lookupList + lookupOffset;
 
       stbtt_uint16 lookupType = ttUSHORT(lookupTable);
       stbtt_uint16 subTableCount = ttUSHORT(lookupTable + 4);
       stbtt_uint8 *subTableOffsets = lookupTable + 6;
       if (lookupType != 2) // Pair Adjustment Positioning Subtable
          continue;
 
       for (sti=0; sti<subTableCount; sti++) {
          stbtt_uint16 subtableOffset = ttUSHORT(subTableOffsets + 2 * sti);
          stbtt_uint8 *table = lookupTable + subtableOffset;
          stbtt_uint16 posFormat = ttUSHORT(table);
          stbtt_uint16 coverageOffset = ttUSHORT(table + 2);
          stbtt_int32 coverageIndex = stbtt__GetCoverageIndex(table + coverageOffset, glyph1);
          if (coverageIndex == -1) continue;
 
          switch (posFormat) {
             case 1: {
                stbtt_int32 l, r, m;
                int straw, needle;
                stbtt_uint16 valueFormat1 = ttUSHORT(table + 4);
                stbtt_uint16 valueFormat2 = ttUSHORT(table + 6);
                if (valueFormat1 == 4 && valueFormat2 == 0) { // Support more formats?
                   stbtt_int32 valueRecordPairSizeInBytes = 2;
                   stbtt_uint16 pairSetCount = ttUSHORT(table + 8);
                   stbtt_uint16 pairPosOffset = ttUSHORT(table + 10 + 2 * coverageIndex);
                   stbtt_uint8 *pairValueTable = table + pairPosOffset;
                   stbtt_uint16 pairValueCount = ttUSHORT(pairValueTable);
                   stbtt_uint8 *pairValueArray = pairValueTable + 2;
 
                   if (coverageIndex >= pairSetCount) return 0;
 
                   needle=glyph2;
                   r=pairValueCount-1;
                   l=0;
 
                   // Binary search.
                   while (l <= r) {
                      stbtt_uint16 secondGlyph;
                      stbtt_uint8 *pairValue;
                      m = (l + r) >> 1;
                      pairValue = pairValueArray + (2 + valueRecordPairSizeInBytes) * m;
                      secondGlyph = ttUSHORT(pairValue);
                      straw = secondGlyph;
                      if (needle < straw)
                         r = m - 1;
                      else if (needle > straw)
                         l = m + 1;
                      else {
                         stbtt_int16 xAdvance = ttSHORT(pairValue + 2);
                         return xAdvance;
                      }
                   }
                } else
                   return 0;
                break;
             }
 
             case 2: {
                stbtt_uint16 valueFormat1 = ttUSHORT(table + 4);
                stbtt_uint16 valueFormat2 = ttUSHORT(table + 6);
                if (valueFormat1 == 4 && valueFormat2 == 0) { // Support more formats?
                   stbtt_uint16 classDef1Offset = ttUSHORT(table + 8);
                   stbtt_uint16 classDef2Offset = ttUSHORT(table + 10);
                   int glyph1class = stbtt__GetGlyphClass(table + classDef1Offset, glyph1);
                   int glyph2class = stbtt__GetGlyphClass(table + classDef2Offset, glyph2);
 
                   stbtt_uint16 class1Count = ttUSHORT(table + 12);
                   stbtt_uint16 class2Count = ttUSHORT(table + 14);
                   stbtt_uint8 *class1Records, *class2Records;
                   stbtt_int16 xAdvance;
 
                   if (glyph1class < 0 || glyph1class >= class1Count) return 0; // malformed
                   if (glyph2class < 0 || glyph2class >= class2Count) return 0; // malformed
 
                   class1Records = table + 16;
                   class2Records = class1Records + 2 * (glyph1class * class2Count);
                   xAdvance = ttSHORT(class2Records + 2 * glyph2class);
                   return xAdvance;
                } else
                   return 0;
                break;
             }
 
             default:
                return 0; // Unsupported position format
          }
       }
    }
 
    return 0;
 }
 
 STBTT_DEF int  stbtt_GetGlyphKernAdvance(const stbtt_fontinfo *info, int g1, int g2)
 {
    int xAdvance = 0;
 
    if (info->gpos)
       xAdvance += stbtt__GetGlyphGPOSInfoAdvance(info, g1, g2);
    else if (info->kern)
       xAdvance += stbtt__GetGlyphKernInfoAdvance(info, g1, g2);
 
    return xAdvance;
 }
 
 STBTT_DEF int  stbtt_GetCodepointKernAdvance(const stbtt_fontinfo *info, int ch1, int ch2)
 {
    if (!info->kern && !info->gpos) // if no kerning table, don't waste time looking up both codepoint->glyphs
       return 0;
    return stbtt_GetGlyphKernAdvance(info, stbtt_FindGlyphIndex(info,ch1), stbtt_FindGlyphIndex(info,ch2));
 }
 
 STBTT_DEF void stbtt_GetCodepointHMetrics(const stbtt_fontinfo *info, int codepoint, int *advanceWidth, int *leftSideBearing)
 {
    stbtt_GetGlyphHMetrics(info, stbtt_FindGlyphIndex(info,codepoint), advanceWidth, leftSideBearing);
 }
 
 STBTT_DEF void stbtt_GetFontVMetrics(const stbtt_fontinfo *info, int *ascent, int *descent, int *lineGap)
 {
    if (ascent ) *ascent  = ttSHORT(info->data+info->hhea + 4);
    if (descent) *descent = ttSHORT(info->data+info->hhea + 6);
    if (lineGap) *lineGap = ttSHORT(info->data+info->hhea + 8);
 }
 
 STBTT_DEF int  stbtt_GetFontVMetricsOS2(const stbtt_fontinfo *info, int *typoAscent, int *typoDescent, int *typoLineGap)
 {
    int tab = stbtt__find_table(info->data, info->fontstart, "OS/2");
    if (!tab)
       return 0;
    if (typoAscent ) *typoAscent  = ttSHORT(info->data+tab + 68);
    if (typoDescent) *typoDescent = ttSHORT(info->data+tab + 70);
    if (typoLineGap) *typoLineGap = ttSHORT(info->data+tab + 72);
    return 1;
 }
 
 STBTT_DEF void stbtt_GetFontBoundingBox(const stbtt_fontinfo *info, int *x0, int *y0, int *x1, int *y1)
 {
    *x0 = ttSHORT(info->data + info->head + 36);
    *y0 = ttSHORT(info->data + info->head + 38);
    *x1 = ttSHORT(info->data + info->head + 40);
    *y1 = ttSHORT(info->data + info->head + 42);
 }
 
 STBTT_DEF float stbtt_ScaleForPixelHeight(const stbtt_fontinfo *info, float height)
 {
    int fheight = ttSHORT(info->data + info->hhea + 4) - ttSHORT(info->data + info->hhea + 6);
    return (float) height / fheight;
 }
 
 STBTT_DEF float stbtt_ScaleForMappingEmToPixels(const stbtt_fontinfo *info, float pixels)
 {
    int unitsPerEm = ttUSHORT(info->data + info->head + 18);
    return pixels / unitsPerEm;
 }
 
 STBTT_DEF void stbtt_FreeShape(const stbtt_fontinfo *info, stbtt_vertex *v)
 {
    STBTT_free(v, info->userdata);
 }
 
 STBTT_DEF stbtt_uint8 *stbtt_FindSVGDoc(const stbtt_fontinfo *info, int gl)
 {
    int i;
    stbtt_uint8 *data = info->data;
    stbtt_uint8 *svg_doc_list = data + stbtt__get_svg((stbtt_fontinfo *) info);
 
    int numEntries = ttUSHORT(svg_doc_list);
    stbtt_uint8 *svg_docs = svg_doc_list + 2;
 
    for(i=0; i<numEntries; i++) {
       stbtt_uint8 *svg_doc = svg_docs + (12 * i);
       if ((gl >= ttUSHORT(svg_doc)) && (gl <= ttUSHORT(svg_doc + 2)))
          return svg_doc;
    }
    return 0;
 }
 
 STBTT_DEF int stbtt_GetGlyphSVG(const stbtt_fontinfo *info, int gl, const char **svg)
 {
    stbtt_uint8 *data = info->data;
    stbtt_uint8 *svg_doc;
 
    if (info->svg == 0)
       return 0;
 
    svg_doc = stbtt_FindSVGDoc(info, gl);
    if (svg_doc != NULL) {
       *svg = (char *) data + info->svg + ttULONG(svg_doc + 4);
       return ttULONG(svg_doc + 8);
    } else {
       return 0;
    }
 }
 
 STBTT_DEF int stbtt_GetCodepointSVG(const stbtt_fontinfo *info, int unicode_codepoint, const char **svg)
 {
    return stbtt_GetGlyphSVG(info, stbtt_FindGlyphIndex(info, unicode_codepoint), svg);
 }
 
 //////////////////////////////////////////////////////////////////////////////
 //
 // antialiasing software rasterizer
 //
 
 STBTT_DEF void stbtt_GetGlyphBitmapBoxSubpixel(const stbtt_fontinfo *font, int glyph, float scale_x, float scale_y,float shift_x, float shift_y, int *ix0, int *iy0, int *ix1, int *iy1)
 {
    int x0=0,y0=0,x1,y1; // =0 suppresses compiler warning
    if (!stbtt_GetGlyphBox(font, glyph, &x0,&y0,&x1,&y1)) {
       // e.g. space character
       if (ix0) *ix0 = 0;
       if (iy0) *iy0 = 0;
       if (ix1) *ix1 = 0;
       if (iy1) *iy1 = 0;
    } else {
       // move to integral bboxes (treating pixels as little squares, what pixels get touched)?
       if (ix0) *ix0 = STBTT_ifloor( x0 * scale_x + shift_x);
       if (iy0) *iy0 = STBTT_ifloor(-y1 * scale_y + shift_y);
       if (ix1) *ix1 = STBTT_iceil ( x1 * scale_x + shift_x);
       if (iy1) *iy1 = STBTT_iceil (-y0 * scale_y + shift_y);
    }
 }
 
 STBTT_DEF void stbtt_GetGlyphBitmapBox(const stbtt_fontinfo *font, int glyph, float scale_x, float scale_y, int *ix0, int *iy0, int *ix1, int *iy1)
 {
    stbtt_GetGlyphBitmapBoxSubpixel(font, glyph, scale_x, scale_y,0.0f,0.0f, ix0, iy0, ix1, iy1);
 }
 
 STBTT_DEF void stbtt_GetCodepointBitmapBoxSubpixel(const stbtt_fontinfo *font, int codepoint, float scale_x, float scale_y, float shift_x, float shift_y, int *ix0, int *iy0, int *ix1, int *iy1)
 {
    stbtt_GetGlyphBitmapBoxSubpixel(font, stbtt_FindGlyphIndex(font,codepoint), scale_x, scale_y,shift_x,shift_y, ix0,iy0,ix1,iy1);
 }
 
 STBTT_DEF void stbtt_GetCodepointBitmapBox(const stbtt_fontinfo *font, int codepoint, float scale_x, float scale_y, int *ix0, int *iy0, int *ix1, int *iy1)
 {
    stbtt_GetCodepointBitmapBoxSubpixel(font, codepoint, scale_x, scale_y,0.0f,0.0f, ix0,iy0,ix1,iy1);
 }
 
 //////////////////////////////////////////////////////////////////////////////
 //
 //  Rasterizer
 
 typedef struct stbtt__hheap_chunk
 {
    struct stbtt__hheap_chunk *next;
 } stbtt__hheap_chunk;
 
 typedef struct stbtt__hheap
 {
    struct stbtt__hheap_chunk *head;
    void   *first_free;
    int    num_remaining_in_head_chunk;
 } stbtt__hheap;
 
 static void *stbtt__hheap_alloc(stbtt__hheap *hh, size_t size, void *userdata)
 {
    if (hh->first_free) {
       void *p = hh->first_free;
       hh->first_free = * (void **) p;
       return p;
    } else {
       if (hh->num_remaining_in_head_chunk == 0) {
          int count = (size < 32 ? 2000 : size < 128 ? 800 : 100);
          stbtt__hheap_chunk *c = (stbtt__hheap_chunk *) STBTT_malloc(sizeof(stbtt__hheap_chunk) + size * count, userdata);
          if (c == NULL)
             return NULL;
          c->next = hh->head;
          hh->head = c;
          hh->num_remaining_in_head_chunk = count;
       }
       --hh->num_remaining_in_head_chunk;
       return (char *) (hh->head) + sizeof(stbtt__hheap_chunk) + size * hh->num_remaining_in_head_chunk;
    }
 }
 
 static void stbtt__hheap_free(stbtt__hheap *hh, void *p)
 {
    *(void **) p = hh->first_free;
    hh->first_free = p;
 }
 
 static void stbtt__hheap_cleanup(stbtt__hheap *hh, void *userdata)
 {
    stbtt__hheap_chunk *c = hh->head;
    while (c) {
       stbtt__hheap_chunk *n = c->next;
       STBTT_free(c, userdata);
       c = n;
    }
 }
 
 typedef struct stbtt__edge {
    float x0,y0, x1,y1;
    int invert;
 } stbtt__edge;
 
 
 typedef struct stbtt__active_edge
 {
    struct stbtt__active_edge *next;
    #if STBTT_RASTERIZER_VERSION==1
    int x,dx;
    float ey;
    int direction;
    #elif STBTT_RASTERIZER_VERSION==2
    float fx,fdx,fdy;
    float direction;
    float sy;
    float ey;
    #else
    #error "Unrecognized value of STBTT_RASTERIZER_VERSION"
    #endif
 } stbtt__active_edge;
 
 #if STBTT_RASTERIZER_VERSION == 1
 #define STBTT_FIXSHIFT   10
 #define STBTT_FIX        (1 << STBTT_FIXSHIFT)
 #define STBTT_FIXMASK    (STBTT_FIX-1)
 
 static stbtt__active_edge *stbtt__new_active(stbtt__hheap *hh, stbtt__edge *e, int off_x, float start_point, void *userdata)
 {
    stbtt__active_edge *z = (stbtt__active_edge *) stbtt__hheap_alloc(hh, sizeof(*z), userdata);
    float dxdy = (e->x1 - e->x0) / (e->y1 - e->y0);
    STBTT_assert(z != NULL);
    if (!z) return z;
 
    // round dx down to avoid overshooting
    if (dxdy < 0)
       z->dx = -STBTT_ifloor(STBTT_FIX * -dxdy);
    else
       z->dx = STBTT_ifloor(STBTT_FIX * dxdy);
 
    z->x = STBTT_ifloor(STBTT_FIX * e->x0 + z->dx * (start_point - e->y0)); // use z->dx so when we offset later it's by the same amount
    z->x -= off_x * STBTT_FIX;
 
    z->ey = e->y1;
    z->next = 0;
    z->direction = e->invert ? 1 : -1;
    return z;
 }
 #elif STBTT_RASTERIZER_VERSION == 2
 static stbtt__active_edge *stbtt__new_active(stbtt__hheap *hh, stbtt__edge *e, int off_x, float start_point, void *userdata)
 {
    stbtt__active_edge *z = (stbtt__active_edge *) stbtt__hheap_alloc(hh, sizeof(*z), userdata);
    float dxdy = (e->x1 - e->x0) / (e->y1 - e->y0);
    STBTT_assert(z != NULL);
    //STBTT_assert(e->y0 <= start_point);
    if (!z) return z;
    z->fdx = dxdy;
    z->fdy = dxdy != 0.0f ? (1.0f/dxdy) : 0.0f;
    z->fx = e->x0 + dxdy * (start_point - e->y0);
    z->fx -= off_x;
    z->direction = e->invert ? 1.0f : -1.0f;
    z->sy = e->y0;
    z->ey = e->y1;
    z->next = 0;
    return z;
 }
 #else
 #error "Unrecognized value of STBTT_RASTERIZER_VERSION"
 #endif
 
 #if STBTT_RASTERIZER_VERSION == 1
 // note: this routine clips fills that extend off the edges... ideally this
 // wouldn't happen, but it could happen if the truetype glyph bounding boxes
 // are wrong, or if the user supplies a too-small bitmap
 static void stbtt__fill_active_edges(unsigned char *scanline, int len, stbtt__active_edge *e, int max_weight)
 {
    // non-zero winding fill
    int x0=0, w=0;
 
    while (e) {
       if (w == 0) {
          // if we're currently at zero, we need to record the edge start point
          x0 = e->x; w += e->direction;
       } else {
          int x1 = e->x; w += e->direction;
          // if we went to zero, we need to draw
          if (w == 0) {
             int i = x0 >> STBTT_FIXSHIFT;
             int j = x1 >> STBTT_FIXSHIFT;
 
             if (i < len && j >= 0) {
                if (i == j) {
                   // x0,x1 are the same pixel, so compute combined coverage
                   scanline[i] = scanline[i] + (stbtt_uint8) ((x1 - x0) * max_weight >> STBTT_FIXSHIFT);
                } else {
                   if (i >= 0) // add antialiasing for x0
                      scanline[i] = scanline[i] + (stbtt_uint8) (((STBTT_FIX - (x0 & STBTT_FIXMASK)) * max_weight) >> STBTT_FIXSHIFT);
                   else
                      i = -1; // clip
 
                   if (j < len) // add antialiasing for x1
                      scanline[j] = scanline[j] + (stbtt_uint8) (((x1 & STBTT_FIXMASK) * max_weight) >> STBTT_FIXSHIFT);
                   else
                      j = len; // clip
 
                   for (++i; i < j; ++i) // fill pixels between x0 and x1
                      scanline[i] = scanline[i] + (stbtt_uint8) max_weight;
                }
             }
          }
       }
 
       e = e->next;
    }
 }
 
 static void stbtt__rasterize_sorted_edges(stbtt__bitmap *result, stbtt__edge *e, int n, int vsubsample, int off_x, int off_y, void *userdata)
 {
    stbtt__hheap hh = { 0, 0, 0 };
    stbtt__active_edge *active = NULL;
    int y,j=0;
    int max_weight = (255 / vsubsample);  // weight per vertical scanline
    int s; // vertical subsample index
    unsigned char scanline_data[512], *scanline;
 
    if (result->w > 512)
       scanline = (unsigned char *) STBTT_malloc(result->w, userdata);
    else
       scanline = scanline_data;
 
    y = off_y * vsubsample;
    e[n].y0 = (off_y + result->h) * (float) vsubsample + 1;
 
    while (j < result->h) {
       STBTT_memset(scanline, 0, result->w);
       for (s=0; s < vsubsample; ++s) {
          // find center of pixel for this scanline
          float scan_y = y + 0.5f;
          stbtt__active_edge **step = &active;
 
          // update all active edges;
          // remove all active edges that terminate before the center of this scanline
          while (*step) {
             stbtt__active_edge * z = *step;
             if (z->ey <= scan_y) {
                *step = z->next; // delete from list
                STBTT_assert(z->direction);
                z->direction = 0;
                stbtt__hheap_free(&hh, z);
             } else {
                z->x += z->dx; // advance to position for current scanline
                step = &((*step)->next); // advance through list
             }
          }
 
          // resort the list if needed
          for(;;) {
             int changed=0;
             step = &active;
             while (*step && (*step)->next) {
                if ((*step)->x > (*step)->next->x) {
                   stbtt__active_edge *t = *step;
                   stbtt__active_edge *q = t->next;
 
                   t->next = q->next;
                   q->next = t;
                   *step = q;
                   changed = 1;
                }
                step = &(*step)->next;
             }
             if (!changed) break;
          }
 
          // insert all edges that start before the center of this scanline -- omit ones that also end on this scanline
          while (e->y0 <= scan_y) {
             if (e->y1 > scan_y) {
                stbtt__active_edge *z = stbtt__new_active(&hh, e, off_x, scan_y, userdata);
                if (z != NULL) {
                   // find insertion point
                   if (active == NULL)
                      active = z;
                   else if (z->x < active->x) {
                      // insert at front
                      z->next = active;
                      active = z;
                   } else {
                      // find thing to insert AFTER
                      stbtt__active_edge *p = active;
                      while (p->next && p->next->x < z->x)
                         p = p->next;
                      // at this point, p->next->x is NOT < z->x
                      z->next = p->next;
                      p->next = z;
                   }
                }
             }
             ++e;
          }
 
          // now process all active edges in XOR fashion
          if (active)
             stbtt__fill_active_edges(scanline, result->w, active, max_weight);
 
          ++y;
       }
       STBTT_memcpy(result->pixels + j * result->stride, scanline, result->w);
       ++j;
    }
 
    stbtt__hheap_cleanup(&hh, userdata);
 
    if (scanline != scanline_data)
       STBTT_free(scanline, userdata);
 }
 
 #elif STBTT_RASTERIZER_VERSION == 2
 
 // the edge passed in here does not cross the vertical line at x or the vertical line at x+1
 // (i.e. it has already been clipped to those)
 static void stbtt__handle_clipped_edge(float *scanline, int x, stbtt__active_edge *e, float x0, float y0, float x1, float y1)
 {
    if (y0 == y1) return;
    STBTT_assert(y0 < y1);
    STBTT_assert(e->sy <= e->ey);
    if (y0 > e->ey) return;
    if (y1 < e->sy) return;
    if (y0 < e->sy) {
       x0 += (x1-x0) * (e->sy - y0) / (y1-y0);
       y0 = e->sy;
    }
    if (y1 > e->ey) {
       x1 += (x1-x0) * (e->ey - y1) / (y1-y0);
       y1 = e->ey;
    }
 
    if (x0 == x)
       STBTT_assert(x1 <= x+1);
    else if (x0 == x+1)
       STBTT_assert(x1 >= x);
    else if (x0 <= x)
       STBTT_assert(x1 <= x);
    else if (x0 >= x+1)
       STBTT_assert(x1 >= x+1);
    else
       STBTT_assert(x1 >= x && x1 <= x+1);
 
    if (x0 <= x && x1 <= x)
       scanline[x] += e->direction * (y1-y0);
    else if (x0 >= x+1 && x1 >= x+1)
       ;
    else {
       STBTT_assert(x0 >= x && x0 <= x+1 && x1 >= x && x1 <= x+1);
       scanline[x] += e->direction * (y1-y0) * (1-((x0-x)+(x1-x))/2); // coverage = 1 - average x position
    }
 }
 
 static float stbtt__sized_trapezoid_area(float height, float top_width, float bottom_width)
 {
    STBTT_assert(top_width >= 0);
    STBTT_assert(bottom_width >= 0);
    return (top_width + bottom_width) / 2.0f * height;
 }
 
 static float stbtt__position_trapezoid_area(float height, float tx0, float tx1, float bx0, float bx1)
 {
    return stbtt__sized_trapezoid_area(height, tx1 - tx0, bx1 - bx0);
 }
 
 static float stbtt__sized_triangle_area(float height, float width)
 {
    return height * width / 2;
 }
 
 static void stbtt__fill_active_edges_new(float *scanline, float *scanline_fill, int len, stbtt__active_edge *e, float y_top)
 {
    float y_bottom = y_top+1;
 
    while (e) {
       // brute force every pixel
 
       // compute intersection points with top & bottom
       STBTT_assert(e->ey >= y_top);
 
       if (e->fdx == 0) {
          float x0 = e->fx;
          if (x0 < len) {
             if (x0 >= 0) {
                stbtt__handle_clipped_edge(scanline,(int) x0,e, x0,y_top, x0,y_bottom);
                stbtt__handle_clipped_edge(scanline_fill-1,(int) x0+1,e, x0,y_top, x0,y_bottom);
             } else {
                stbtt__handle_clipped_edge(scanline_fill-1,0,e, x0,y_top, x0,y_bottom);
             }
          }
       } else {
          float x0 = e->fx;
          float dx = e->fdx;
          float xb = x0 + dx;
          float x_top, x_bottom;
          float sy0,sy1;
          float dy = e->fdy;
          STBTT_assert(e->sy <= y_bottom && e->ey >= y_top);
 
          // compute endpoints of line segment clipped to this scanline (if the
          // line segment starts on this scanline. x0 is the intersection of the
          // line with y_top, but that may be off the line segment.
          if (e->sy > y_top) {
             x_top = x0 + dx * (e->sy - y_top);
             sy0 = e->sy;
          } else {
             x_top = x0;
             sy0 = y_top;
          }
          if (e->ey < y_bottom) {
             x_bottom = x0 + dx * (e->ey - y_top);
             sy1 = e->ey;
          } else {
             x_bottom = xb;
             sy1 = y_bottom;
          }
 
          if (x_top >= 0 && x_bottom >= 0 && x_top < len && x_bottom < len) {
             // from here on, we don't have to range check x values
 
             if ((int) x_top == (int) x_bottom) {
                float height;
                // simple case, only spans one pixel
                int x = (int) x_top;
                height = (sy1 - sy0) * e->direction;
                STBTT_assert(x >= 0 && x < len);
                scanline[x]      += stbtt__position_trapezoid_area(height, x_top, x+1.0f, x_bottom, x+1.0f);
                scanline_fill[x] += height; // everything right of this pixel is filled
             } else {
                int x,x1,x2;
                float y_crossing, y_final, step, sign, area;
                // covers 2+ pixels
                if (x_top > x_bottom) {
                   // flip scanline vertically; signed area is the same
                   float t;
                   sy0 = y_bottom - (sy0 - y_top);
                   sy1 = y_bottom - (sy1 - y_top);
                   t = sy0, sy0 = sy1, sy1 = t;
                   t = x_bottom, x_bottom = x_top, x_top = t;
                   dx = -dx;
                   dy = -dy;
                   t = x0, x0 = xb, xb = t;
                }
                STBTT_assert(dy >= 0);
                STBTT_assert(dx >= 0);
 
                x1 = (int) x_top;
                x2 = (int) x_bottom;
                // compute intersection with y axis at x1+1
                y_crossing = y_top + dy * (x1+1 - x0);
 
                // compute intersection with y axis at x2
                y_final = y_top + dy * (x2 - x0);
 
                //           x1    x_top                            x2    x_bottom
                //     y_top  +------|-----+------------+------------+--------|---+------------+
                //            |            |            |            |            |            |
                //            |            |            |            |            |            |
                //       sy0  |      Txxxxx|............|............|............|............|
                // y_crossing |            *xxxxx.......|............|............|............|
                //            |            |     xxxxx..|............|............|............|
                //            |            |     /-   xx*xxxx........|............|............|
                //            |            | dy <       |    xxxxxx..|............|............|
                //   y_final  |            |     \-     |          xx*xxx.........|............|
                //       sy1  |            |            |            |   xxxxxB...|............|
                //            |            |            |            |            |            |
                //            |            |            |            |            |            |
                //  y_bottom  +------------+------------+------------+------------+------------+
                //
                // goal is to measure the area covered by '.' in each pixel
 
                // if x2 is right at the right edge of x1, y_crossing can blow up, github #1057
                // @TODO: maybe test against sy1 rather than y_bottom?
                if (y_crossing > y_bottom)
                   y_crossing = y_bottom;
 
                sign = e->direction;
 
                // area of the rectangle covered from sy0..y_crossing
                area = sign * (y_crossing-sy0);
 
                // area of the triangle (x_top,sy0), (x1+1,sy0), (x1+1,y_crossing)
                scanline[x1] += stbtt__sized_triangle_area(area, x1+1 - x_top);
 
                // check if final y_crossing is blown up; no test case for this
                if (y_final > y_bottom) {
                   y_final = y_bottom;
                   dy = (y_final - y_crossing ) / (x2 - (x1+1)); // if denom=0, y_final = y_crossing, so y_final <= y_bottom
                }
 
                // in second pixel, area covered by line segment found in first pixel
                // is always a rectangle 1 wide * the height of that line segment; this
                // is exactly what the variable 'area' stores. it also gets a contribution
                // from the line segment within it. the THIRD pixel will get the first
                // pixel's rectangle contribution, the second pixel's rectangle contribution,
                // and its own contribution. the 'own contribution' is the same in every pixel except
                // the leftmost and rightmost, a trapezoid that slides down in each pixel.
                // the second pixel's contribution to the third pixel will be the
                // rectangle 1 wide times the height change in the second pixel, which is dy.
 
                step = sign * dy * 1; // dy is dy/dx, change in y for every 1 change in x,
                // which multiplied by 1-pixel-width is how much pixel area changes for each step in x
                // so the area advances by 'step' every time
 
                for (x = x1+1; x < x2; ++x) {
                   scanline[x] += area + step/2; // area of trapezoid is 1*step/2
                   area += step;
                }
                STBTT_assert(STBTT_fabs(area) <= 1.01f); // accumulated error from area += step unless we round step down
                STBTT_assert(sy1 > y_final-0.01f);
 
                // area covered in the last pixel is the rectangle from all the pixels to the left,
                // plus the trapezoid filled by the line segment in this pixel all the way to the right edge
                scanline[x2] += area + sign * stbtt__position_trapezoid_area(sy1-y_final, (float) x2, x2+1.0f, x_bottom, x2+1.0f);
 
                // the rest of the line is filled based on the total height of the line segment in this pixel
                scanline_fill[x2] += sign * (sy1-sy0);
             }
          } else {
             // if edge goes outside of box we're drawing, we require
             // clipping logic. since this does not match the intended use
             // of this library, we use a different, very slow brute
             // force implementation
             // note though that this does happen some of the time because
             // x_top and x_bottom can be extrapolated at the top & bottom of
             // the shape and actually lie outside the bounding box
             int x;
             for (x=0; x < len; ++x) {
                // cases:
                //
                // there can be up to two intersections with the pixel. any intersection
                // with left or right edges can be handled by splitting into two (or three)
                // regions. intersections with top & bottom do not necessitate case-wise logic.
                //
                // the old way of doing this found the intersections with the left & right edges,
                // then used some simple logic to produce up to three segments in sorted order
                // from top-to-bottom. however, this had a problem: if an x edge was epsilon
                // across the x border, then the corresponding y position might not be distinct
                // from the other y segment, and it might ignored as an empty segment. to avoid
                // that, we need to explicitly produce segments based on x positions.
 
                // rename variables to clearly-defined pairs
                float y0 = y_top;
                float x1 = (float) (x);
                float x2 = (float) (x+1);
                float x3 = xb;
                float y3 = y_bottom;
 
                // x = e->x + e->dx * (y-y_top)
                // (y-y_top) = (x - e->x) / e->dx
                // y = (x - e->x) / e->dx + y_top
                float y1 = (x - x0) / dx + y_top;
                float y2 = (x+1 - x0) / dx + y_top;
 
                if (x0 < x1 && x3 > x2) {         // three segments descending down-right
                   stbtt__handle_clipped_edge(scanline,x,e, x0,y0, x1,y1);
                   stbtt__handle_clipped_edge(scanline,x,e, x1,y1, x2,y2);
                   stbtt__handle_clipped_edge(scanline,x,e, x2,y2, x3,y3);
                } else if (x3 < x1 && x0 > x2) {  // three segments descending down-left
                   stbtt__handle_clipped_edge(scanline,x,e, x0,y0, x2,y2);
                   stbtt__handle_clipped_edge(scanline,x,e, x2,y2, x1,y1);
                   stbtt__handle_clipped_edge(scanline,x,e, x1,y1, x3,y3);
                } else if (x0 < x1 && x3 > x1) {  // two segments across x, down-right
                   stbtt__handle_clipped_edge(scanline,x,e, x0,y0, x1,y1);
                   stbtt__handle_clipped_edge(scanline,x,e, x1,y1, x3,y3);
                } else if (x3 < x1 && x0 > x1) {  // two segments across x, down-left
                   stbtt__handle_clipped_edge(scanline,x,e, x0,y0, x1,y1);
                   stbtt__handle_clipped_edge(scanline,x,e, x1,y1, x3,y3);
                } else if (x0 < x2 && x3 > x2) {  // two segments across x+1, down-right
                   stbtt__handle_clipped_edge(scanline,x,e, x0,y0, x2,y2);
                   stbtt__handle_clipped_edge(scanline,x,e, x2,y2, x3,y3);
                } else if (x3 < x2 && x0 > x2) {  // two segments across x+1, down-left
                   stbtt__handle_clipped_edge(scanline,x,e, x0,y0, x2,y2);
                   stbtt__handle_clipped_edge(scanline,x,e, x2,y2, x3,y3);
                } else {  // one segment
                   stbtt__handle_clipped_edge(scanline,x,e, x0,y0, x3,y3);
                }
             }
          }
       }
       e = e->next;
    }
 }
 
 // directly AA rasterize edges w/o supersampling
 static void stbtt__rasterize_sorted_edges(stbtt__bitmap *result, stbtt__edge *e, int n, int vsubsample, int off_x, int off_y, void *userdata)
 {
    stbtt__hheap hh = { 0, 0, 0 };
    stbtt__active_edge *active = NULL;
    int y,j=0, i;
    float scanline_data[129], *scanline, *scanline2;
 
    STBTT__NOTUSED(vsubsample);
 
    if (result->w > 64)
       scanline = (float *) STBTT_malloc((result->w*2+1) * sizeof(float), userdata);
    else
       scanline = scanline_data;
 
    scanline2 = scanline + result->w;
 
    y = off_y;
    e[n].y0 = (float) (off_y + result->h) + 1;
 
    while (j < result->h) {
       // find center of pixel for this scanline
       float scan_y_top    = y + 0.0f;
       float scan_y_bottom = y + 1.0f;
       stbtt__active_edge **step = &active;
 
       STBTT_memset(scanline , 0, result->w*sizeof(scanline[0]));
       STBTT_memset(scanline2, 0, (result->w+1)*sizeof(scanline[0]));
 
       // update all active edges;
       // remove all active edges that terminate before the top of this scanline
       while (*step) {
          stbtt__active_edge * z = *step;
          if (z->ey <= scan_y_top) {
             *step = z->next; // delete from list
             STBTT_assert(z->direction);
             z->direction = 0;
             stbtt__hheap_free(&hh, z);
          } else {
             step = &((*step)->next); // advance through list
          }
       }
 
       // insert all edges that start before the bottom of this scanline
       while (e->y0 <= scan_y_bottom) {
          if (e->y0 != e->y1) {
             stbtt__active_edge *z = stbtt__new_active(&hh, e, off_x, scan_y_top, userdata);
             if (z != NULL) {
                if (j == 0 && off_y != 0) {
                   if (z->ey < scan_y_top) {
                      // this can happen due to subpixel positioning and some kind of fp rounding error i think
                      z->ey = scan_y_top;
                   }
                }
                STBTT_assert(z->ey >= scan_y_top); // if we get really unlucky a tiny bit of an edge can be out of bounds
                // insert at front
                z->next = active;
                active = z;
             }
          }
          ++e;
       }
 
       // now process all active edges
       if (active)
          stbtt__fill_active_edges_new(scanline, scanline2+1, result->w, active, scan_y_top);
 
       {
          float sum = 0;
          for (i=0; i < result->w; ++i) {
             float k;
             int m;
             sum += scanline2[i];
             k = scanline[i] + sum;
             k = (float) STBTT_fabs(k)*255 + 0.5f;
             m = (int) k;
             if (m > 255) m = 255;
             result->pixels[j*result->stride + i] = (unsigned char) m;
          }
       }
       // advance all the edges
       step = &active;
       while (*step) {
          stbtt__active_edge *z = *step;
          z->fx += z->fdx; // advance to position for current scanline
          step = &((*step)->next); // advance through list
       }
 
       ++y;
       ++j;
    }
 
    stbtt__hheap_cleanup(&hh, userdata);
 
    if (scanline != scanline_data)
       STBTT_free(scanline, userdata);
 }
 #else
 #error "Unrecognized value of STBTT_RASTERIZER_VERSION"
 #endif
 
 #define STBTT__COMPARE(a,b)  ((a)->y0 < (b)->y0)
 
 static void stbtt__sort_edges_ins_sort(stbtt__edge *p, int n)
 {
    int i,j;
    for (i=1; i < n; ++i) {
       stbtt__edge t = p[i], *a = &t;
       j = i;
       while (j > 0) {
          stbtt__edge *b = &p[j-1];
          int c = STBTT__COMPARE(a,b);
          if (!c) break;
          p[j] = p[j-1];
          --j;
       }
       if (i != j)
          p[j] = t;
    }
 }
 
 static void stbtt__sort_edges_quicksort(stbtt__edge *p, int n)
 {
    /* threshold for transitioning to insertion sort */
    while (n > 12) {
       stbtt__edge t;
       int c01,c12,c,m,i,j;
 
       /* compute median of three */
       m = n >> 1;
       c01 = STBTT__COMPARE(&p[0],&p[m]);
       c12 = STBTT__COMPARE(&p[m],&p[n-1]);
       /* if 0 >= mid >= end, or 0 < mid < end, then use mid */
       if (c01 != c12) {
          /* otherwise, we'll need to swap something else to middle */
          int z;
          c = STBTT__COMPARE(&p[0],&p[n-1]);
          /* 0>mid && mid<n:  0>n => n; 0<n => 0 */
          /* 0<mid && mid>n:  0>n => 0; 0<n => n */
          z = (c == c12) ? 0 : n-1;
          t = p[z];
          p[z] = p[m];
          p[m] = t;
       }
       /* now p[m] is the median-of-three */
       /* swap it to the beginning so it won't move around */
       t = p[0];
       p[0] = p[m];
       p[m] = t;
 
       /* partition loop */
       i=1;
       j=n-1;
       for(;;) {
          /* handling of equality is crucial here */
          /* for sentinels & efficiency with duplicates */
          for (;;++i) {
             if (!STBTT__COMPARE(&p[i], &p[0])) break;
          }
          for (;;--j) {
             if (!STBTT__COMPARE(&p[0], &p[j])) break;
          }
          /* make sure we haven't crossed */
          if (i >= j) break;
          t = p[i];
          p[i] = p[j];
          p[j] = t;
 
          ++i;
          --j;
       }
       /* recurse on smaller side, iterate on larger */
       if (j < (n-i)) {
          stbtt__sort_edges_quicksort(p,j);
          p = p+i;
          n = n-i;
       } else {
          stbtt__sort_edges_quicksort(p+i, n-i);
          n = j;
       }
    }
 }
 
 static void stbtt__sort_edges(stbtt__edge *p, int n)
 {
    stbtt__sort_edges_quicksort(p, n);
    stbtt__sort_edges_ins_sort(p, n);
 }
 
 typedef struct
 {
    float x,y;
 } stbtt__point;
 
 static void stbtt__rasterize(stbtt__bitmap *result, stbtt__point *pts, int *wcount, int windings, float scale_x, float scale_y, float shift_x, float shift_y, int off_x, int off_y, int invert, void *userdata)
 {
    float y_scale_inv = invert ? -scale_y : scale_y;
    stbtt__edge *e;
    int n,i,j,k,m;
 #if STBTT_RASTERIZER_VERSION == 1
    int vsubsample = result->h < 8 ? 15 : 5;
 #elif STBTT_RASTERIZER_VERSION == 2
    int vsubsample = 1;
 #else
    #error "Unrecognized value of STBTT_RASTERIZER_VERSION"
 #endif
    // vsubsample should divide 255 evenly; otherwise we won't reach full opacity
 
    // now we have to blow out the windings into explicit edge lists
    n = 0;
    for (i=0; i < windings; ++i)
       n += wcount[i];
 
    e = (stbtt__edge *) STBTT_malloc(sizeof(*e) * (n+1), userdata); // add an extra one as a sentinel
    if (e == 0) return;
    n = 0;
 
    m=0;
    for (i=0; i < windings; ++i) {
       stbtt__point *p = pts + m;
       m += wcount[i];
       j = wcount[i]-1;
       for (k=0; k < wcount[i]; j=k++) {
          int a=k,b=j;
          // skip the edge if horizontal
          if (p[j].y == p[k].y)
             continue;
          // add edge from j to k to the list
          e[n].invert = 0;
          if (invert ? p[j].y > p[k].y : p[j].y < p[k].y) {
             e[n].invert = 1;
             a=j,b=k;
          }
          e[n].x0 = p[a].x * scale_x + shift_x;
          e[n].y0 = (p[a].y * y_scale_inv + shift_y) * vsubsample;
          e[n].x1 = p[b].x * scale_x + shift_x;
          e[n].y1 = (p[b].y * y_scale_inv + shift_y) * vsubsample;
          ++n;
       }
    }
 
    // now sort the edges by their highest point (should snap to integer, and then by x)
    //STBTT_sort(e, n, sizeof(e[0]), stbtt__edge_compare);
    stbtt__sort_edges(e, n);
 
    // now, traverse the scanlines and find the intersections on each scanline, use xor winding rule
    stbtt__rasterize_sorted_edges(result, e, n, vsubsample, off_x, off_y, userdata);
 
    STBTT_free(e, userdata);
 }
 
 static void stbtt__add_point(stbtt__point *points, int n, float x, float y)
 {
    if (!points) return; // during first pass, it's unallocated
    points[n].x = x;
    points[n].y = y;
 }
 
 // tessellate until threshold p is happy... @TODO warped to compensate for non-linear stretching
 static int stbtt__tesselate_curve(stbtt__point *points, int *num_points, float x0, float y0, float x1, float y1, float x2, float y2, float objspace_flatness_squared, int n)
 {
    // midpoint
    float mx = (x0 + 2*x1 + x2)/4;
    float my = (y0 + 2*y1 + y2)/4;
    // versus directly drawn line
    float dx = (x0+x2)/2 - mx;
    float dy = (y0+y2)/2 - my;
    if (n > 16) // 65536 segments on one curve better be enough!
       return 1;
    if (dx*dx+dy*dy > objspace_flatness_squared) { // half-pixel error allowed... need to be smaller if AA
       stbtt__tesselate_curve(points, num_points, x0,y0, (x0+x1)/2.0f,(y0+y1)/2.0f, mx,my, objspace_flatness_squared,n+1);
       stbtt__tesselate_curve(points, num_points, mx,my, (x1+x2)/2.0f,(y1+y2)/2.0f, x2,y2, objspace_flatness_squared,n+1);
    } else {
       stbtt__add_point(points, *num_points,x2,y2);
       *num_points = *num_points+1;
    }
    return 1;
 }
 
 static void stbtt__tesselate_cubic(stbtt__point *points, int *num_points, float x0, float y0, float x1, float y1, float x2, float y2, float x3, float y3, float objspace_flatness_squared, int n)
 {
    // @TODO this "flatness" calculation is just made-up nonsense that seems to work well enough
    float dx0 = x1-x0;
    float dy0 = y1-y0;
    float dx1 = x2-x1;
    float dy1 = y2-y1;
    float dx2 = x3-x2;
    float dy2 = y3-y2;
    float dx = x3-x0;
    float dy = y3-y0;
    float longlen = (float) (STBTT_sqrt(dx0*dx0+dy0*dy0)+STBTT_sqrt(dx1*dx1+dy1*dy1)+STBTT_sqrt(dx2*dx2+dy2*dy2));
    float shortlen = (float) STBTT_sqrt(dx*dx+dy*dy);
    float flatness_squared = longlen*longlen-shortlen*shortlen;
 
    if (n > 16) // 65536 segments on one curve better be enough!
       return;
 
    if (flatness_squared > objspace_flatness_squared) {
       float x01 = (x0+x1)/2;
       float y01 = (y0+y1)/2;
       float x12 = (x1+x2)/2;
       float y12 = (y1+y2)/2;
       float x23 = (x2+x3)/2;
       float y23 = (y2+y3)/2;
 
       float xa = (x01+x12)/2;
       float ya = (y01+y12)/2;
       float xb = (x12+x23)/2;
       float yb = (y12+y23)/2;
 
       float mx = (xa+xb)/2;
       float my = (ya+yb)/2;
 
       stbtt__tesselate_cubic(points, num_points, x0,y0, x01,y01, xa,ya, mx,my, objspace_flatness_squared,n+1);
       stbtt__tesselate_cubic(points, num_points, mx,my, xb,yb, x23,y23, x3,y3, objspace_flatness_squared,n+1);
    } else {
       stbtt__add_point(points, *num_points,x3,y3);
       *num_points = *num_points+1;
    }
 }
 
 // returns number of contours
 static stbtt__point *stbtt_FlattenCurves(stbtt_vertex *vertices, int num_verts, float objspace_flatness, int **contour_lengths, int *num_contours, void *userdata)
 {
    stbtt__point *points=0;
    int num_points=0;
 
    float objspace_flatness_squared = objspace_flatness * objspace_flatness;
    int i,n=0,start=0, pass;
 
    // count how many "moves" there are to get the contour count
    for (i=0; i < num_verts; ++i)
       if (vertices[i].type == STBTT_vmove)
          ++n;
 
    *num_contours = n;
    if (n == 0) return 0;
 
    *contour_lengths = (int *) STBTT_malloc(sizeof(**contour_lengths) * n, userdata);
 
    if (*contour_lengths == 0) {
       *num_contours = 0;
       return 0;
    }
 
    // make two passes through the points so we don't need to realloc
    for (pass=0; pass < 2; ++pass) {
       float x=0,y=0;
       if (pass == 1) {
          points = (stbtt__point *) STBTT_malloc(num_points * sizeof(points[0]), userdata);
          if (points == NULL) goto error;
       }
       num_points = 0;
       n= -1;
       for (i=0; i < num_verts; ++i) {
          switch (vertices[i].type) {
             case STBTT_vmove:
                // start the next contour
                if (n >= 0)
                   (*contour_lengths)[n] = num_points - start;
                ++n;
                start = num_points;
 
                x = vertices[i].x, y = vertices[i].y;
                stbtt__add_point(points, num_points++, x,y);
                break;
             case STBTT_vline:
                x = vertices[i].x, y = vertices[i].y;
                stbtt__add_point(points, num_points++, x, y);
                break;
             case STBTT_vcurve:
                stbtt__tesselate_curve(points, &num_points, x,y,
                                         vertices[i].cx, vertices[i].cy,
                                         vertices[i].x,  vertices[i].y,
                                         objspace_flatness_squared, 0);
                x = vertices[i].x, y = vertices[i].y;
                break;
             case STBTT_vcubic:
                stbtt__tesselate_cubic(points, &num_points, x,y,
                                         vertices[i].cx, vertices[i].cy,
                                         vertices[i].cx1, vertices[i].cy1,
                                         vertices[i].x,  vertices[i].y,
                                         objspace_flatness_squared, 0);
                x = vertices[i].x, y = vertices[i].y;
                break;
          }
       }
       (*contour_lengths)[n] = num_points - start;
    }
 
    return points;
 error:
    STBTT_free(points, userdata);
    STBTT_free(*contour_lengths, userdata);
    *contour_lengths = 0;
    *num_contours = 0;
    return NULL;
 }
 
 STBTT_DEF void stbtt_Rasterize(stbtt__bitmap *result, float flatness_in_pixels, stbtt_vertex *vertices, int num_verts, float scale_x, float scale_y, float shift_x, float shift_y, int x_off, int y_off, int invert, void *userdata)
 {
    float scale            = scale_x > scale_y ? scale_y : scale_x;
    int winding_count      = 0;
    int *winding_lengths   = NULL;
    stbtt__point *windings = stbtt_FlattenCurves(vertices, num_verts, flatness_in_pixels / scale, &winding_lengths, &winding_count, userdata);
    if (windings) {
       stbtt__rasterize(result, windings, winding_lengths, winding_count, scale_x, scale_y, shift_x, shift_y, x_off, y_off, invert, userdata);
       STBTT_free(winding_lengths, userdata);
       STBTT_free(windings, userdata);
    }
 }
 
 STBTT_DEF void stbtt_FreeBitmap(unsigned char *bitmap, void *userdata)
 {
    STBTT_free(bitmap, userdata);
 }
 
 STBTT_DEF unsigned char *stbtt_GetGlyphBitmapSubpixel(const stbtt_fontinfo *info, float scale_x, float scale_y, float shift_x, float shift_y, int glyph, int *width, int *height, int *xoff, int *yoff)
 {
    int ix0,iy0,ix1,iy1;
    stbtt__bitmap gbm;
    stbtt_vertex *vertices;
    int num_verts = stbtt_GetGlyphShape(info, glyph, &vertices);
 
    if (scale_x == 0) scale_x = scale_y;
    if (scale_y == 0) {
       if (scale_x == 0) {
          STBTT_free(vertices, info->userdata);
          return NULL;
       }
       scale_y = scale_x;
    }
 
    stbtt_GetGlyphBitmapBoxSubpixel(info, glyph, scale_x, scale_y, shift_x, shift_y, &ix0,&iy0,&ix1,&iy1);
 
    // now we get the size
    gbm.w = (ix1 - ix0);
    gbm.h = (iy1 - iy0);
    gbm.pixels = NULL; // in case we error
 
    if (width ) *width  = gbm.w;
    if (height) *height = gbm.h;
    if (xoff  ) *xoff   = ix0;
    if (yoff  ) *yoff   = iy0;
 
    if (gbm.w && gbm.h) {
       gbm.pixels = (unsigned char *) STBTT_malloc(gbm.w * gbm.h, info->userdata);
       if (gbm.pixels) {
          gbm.stride = gbm.w;
 
          stbtt_Rasterize(&gbm, 0.35f, vertices, num_verts, scale_x, scale_y, shift_x, shift_y, ix0, iy0, 1, info->userdata);
       }
    }
    STBTT_free(vertices, info->userdata);
    return gbm.pixels;
 }
 
 STBTT_DEF unsigned char *stbtt_GetGlyphBitmap(const stbtt_fontinfo *info, float scale_x, float scale_y, int glyph, int *width, int *height, int *xoff, int *yoff)
 {
    return stbtt_GetGlyphBitmapSubpixel(info, scale_x, scale_y, 0.0f, 0.0f, glyph, width, height, xoff, yoff);
 }
 
 STBTT_DEF void stbtt_MakeGlyphBitmapSubpixel(const stbtt_fontinfo *info, unsigned char *output, int out_w, int out_h, int out_stride, float scale_x, float scale_y, float shift_x, float shift_y, int glyph)
 {
    int ix0,iy0;
    stbtt_vertex *vertices;
    int num_verts = stbtt_GetGlyphShape(info, glyph, &vertices);
    stbtt__bitmap gbm;
 
    stbtt_GetGlyphBitmapBoxSubpixel(info, glyph, scale_x, scale_y, shift_x, shift_y, &ix0,&iy0,0,0);
    gbm.pixels = output;
    gbm.w = out_w;
    gbm.h = out_h;
    gbm.stride = out_stride;
 
    if (gbm.w && gbm.h)
       stbtt_Rasterize(&gbm, 0.35f, vertices, num_verts, scale_x, scale_y, shift_x, shift_y, ix0,iy0, 1, info->userdata);
 
    STBTT_free(vertices, info->userdata);
 }
 
 STBTT_DEF void stbtt_MakeGlyphBitmap(const stbtt_fontinfo *info, unsigned char *output, int out_w, int out_h, int out_stride, float scale_x, float scale_y, int glyph)
 {
    stbtt_MakeGlyphBitmapSubpixel(info, output, out_w, out_h, out_stride, scale_x, scale_y, 0.0f,0.0f, glyph);
 }
 
 STBTT_DEF unsigned char *stbtt_GetCodepointBitmapSubpixel(const stbtt_fontinfo *info, float scale_x, float scale_y, float shift_x, float shift_y, int codepoint, int *width, int *height, int *xoff, int *yoff)
 {
    return stbtt_GetGlyphBitmapSubpixel(info, scale_x, scale_y,shift_x,shift_y, stbtt_FindGlyphIndex(info,codepoint), width,height,xoff,yoff);
 }
 
 STBTT_DEF void stbtt_MakeCodepointBitmapSubpixelPrefilter(const stbtt_fontinfo *info, unsigned char *output, int out_w, int out_h, int out_stride, float scale_x, float scale_y, float shift_x, float shift_y, int oversample_x, int oversample_y, float *sub_x, float *sub_y, int codepoint)
 {
    stbtt_MakeGlyphBitmapSubpixelPrefilter(info, output, out_w, out_h, out_stride, scale_x, scale_y, shift_x, shift_y, oversample_x, oversample_y, sub_x, sub_y, stbtt_FindGlyphIndex(info,codepoint));
 }
 
 STBTT_DEF void stbtt_MakeCodepointBitmapSubpixel(const stbtt_fontinfo *info, unsigned char *output, int out_w, int out_h, int out_stride, float scale_x, float scale_y, float shift_x, float shift_y, int codepoint)
 {
    stbtt_MakeGlyphBitmapSubpixel(info, output, out_w, out_h, out_stride, scale_x, scale_y, shift_x, shift_y, stbtt_FindGlyphIndex(info,codepoint));
 }
 
 STBTT_DEF unsigned char *stbtt_GetCodepointBitmap(const stbtt_fontinfo *info, float scale_x, float scale_y, int codepoint, int *width, int *height, int *xoff, int *yoff)
 {
    return stbtt_GetCodepointBitmapSubpixel(info, scale_x, scale_y, 0.0f,0.0f, codepoint, width,height,xoff,yoff);
 }
 
 STBTT_DEF void stbtt_MakeCodepointBitmap(const stbtt_fontinfo *info, unsigned char *output, int out_w, int out_h, int out_stride, float scale_x, float scale_y, int codepoint)
 {
    stbtt_MakeCodepointBitmapSubpixel(info, output, out_w, out_h, out_stride, scale_x, scale_y, 0.0f,0.0f, codepoint);
 }
 
 //////////////////////////////////////////////////////////////////////////////
 //
 // bitmap baking
 //
 // This is SUPER-CRAPPY packing to keep source code small
 
 static int stbtt_BakeFontBitmap_internal(unsigned char *data, int offset,  // font location (use offset=0 for plain .ttf)
                                 float pixel_height,                     // height of font in pixels
                                 unsigned char *pixels, int pw, int ph,  // bitmap to be filled in
                                 int first_char, int num_chars,          // characters to bake
                                 stbtt_bakedchar *chardata)
 {
    float scale;
    int x,y,bottom_y, i;
    stbtt_fontinfo f;
    f.userdata = NULL;
    if (!stbtt_InitFont(&f, data, offset))
       return -1;
    STBTT_memset(pixels, 0, pw*ph); // background of 0 around pixels
    x=y=1;
    bottom_y = 1;
 
    scale = stbtt_ScaleForPixelHeight(&f, pixel_height);
 
    for (i=0; i < num_chars; ++i) {
       int advance, lsb, x0,y0,x1,y1,gw,gh;
       int g = stbtt_FindGlyphIndex(&f, first_char + i);
       stbtt_GetGlyphHMetrics(&f, g, &advance, &lsb);
       stbtt_GetGlyphBitmapBox(&f, g, scale,scale, &x0,&y0,&x1,&y1);
       gw = x1-x0;
       gh = y1-y0;
       if (x + gw + 1 >= pw)
          y = bottom_y, x = 1; // advance to next row
       if (y + gh + 1 >= ph) // check if it fits vertically AFTER potentially moving to next row
          return -i;
       STBTT_assert(x+gw < pw);
       STBTT_assert(y+gh < ph);
       stbtt_MakeGlyphBitmap(&f, pixels+x+y*pw, gw,gh,pw, scale,scale, g);
       chardata[i].x0 = (stbtt_int16) x;
       chardata[i].y0 = (stbtt_int16) y;
       chardata[i].x1 = (stbtt_int16) (x + gw);
       chardata[i].y1 = (stbtt_int16) (y + gh);
       chardata[i].xadvance = scale * advance;
       chardata[i].xoff     = (float) x0;
       chardata[i].yoff     = (float) y0;
       x = x + gw + 1;
       if (y+gh+1 > bottom_y)
          bottom_y = y+gh+1;
    }
    return bottom_y;
 }
 
 STBTT_DEF void stbtt_GetBakedQuad(const stbtt_bakedchar *chardata, int pw, int ph, int char_index, float *xpos, float *ypos, stbtt_aligned_quad *q, int opengl_fillrule)
 {
    float d3d_bias = opengl_fillrule ? 0 : -0.5f;
    float ipw = 1.0f / pw, iph = 1.0f / ph;
    const stbtt_bakedchar *b = chardata + char_index;
    int round_x = STBTT_ifloor((*xpos + b->xoff) + 0.5f);
    int round_y = STBTT_ifloor((*ypos + b->yoff) + 0.5f);
 
    q->x0 = round_x + d3d_bias;
    q->y0 = round_y + d3d_bias;
    q->x1 = round_x + b->x1 - b->x0 + d3d_bias;
    q->y1 = round_y + b->y1 - b->y0 + d3d_bias;
 
    q->s0 = b->x0 * ipw;
    q->t0 = b->y0 * iph;
    q->s1 = b->x1 * ipw;
    q->t1 = b->y1 * iph;
 
    *xpos += b->xadvance;
 }
 
 //////////////////////////////////////////////////////////////////////////////
 //
 // rectangle packing replacement routines if you don't have stb_rect_pack.h
 //
 
 #ifndef STB_RECT_PACK_VERSION
 
 typedef int stbrp_coord;
 
 ////////////////////////////////////////////////////////////////////////////////////
 //                                                                                //
 //                                                                                //
 // COMPILER WARNING ?!?!?                                                         //
 //                                                                                //
 //                                                                                //
 // if you get a compile warning due to these symbols being defined more than      //
 // once, move #include "stb_rect_pack.h" before #include "stb_truetype.h"         //
 //                                                                                //
 ////////////////////////////////////////////////////////////////////////////////////
 
 typedef struct
 {
    int width,height;
    int x,y,bottom_y;
 } stbrp_context;
 
 typedef struct
 {
    unsigned char x;
 } stbrp_node;
 
 struct stbrp_rect
 {
    stbrp_coord x,y;
    int id,w,h,was_packed;
 };
 
 static void stbrp_init_target(stbrp_context *con, int pw, int ph, stbrp_node *nodes, int num_nodes)
 {
    con->width  = pw;
    con->height = ph;
    con->x = 0;
    con->y = 0;
    con->bottom_y = 0;
    STBTT__NOTUSED(nodes);
    STBTT__NOTUSED(num_nodes);
 }
 
 static void stbrp_pack_rects(stbrp_context *con, stbrp_rect *rects, int num_rects)
 {
    int i;
    for (i=0; i < num_rects; ++i) {
       if (con->x + rects[i].w > con->width) {
          con->x = 0;
          con->y = con->bottom_y;
       }
       if (con->y + rects[i].h > con->height)
          break;
       rects[i].x = con->x;
       rects[i].y = con->y;
       rects[i].was_packed = 1;
       con->x += rects[i].w;
       if (con->y + rects[i].h > con->bottom_y)
          con->bottom_y = con->y + rects[i].h;
    }
    for (   ; i < num_rects; ++i)
       rects[i].was_packed = 0;
 }
 #endif
 
 //////////////////////////////////////////////////////////////////////////////
 //
 // bitmap baking
 //
 // This is SUPER-AWESOME (tm Ryan Gordon) packing using stb_rect_pack.h. If
 // stb_rect_pack.h isn't available, it uses the BakeFontBitmap strategy.
 
 STBTT_DEF int stbtt_PackBegin(stbtt_pack_context *spc, unsigned char *pixels, int pw, int ph, int stride_in_bytes, int padding, void *alloc_context)
 {
    stbrp_context *context = (stbrp_context *) STBTT_malloc(sizeof(*context)            ,alloc_context);
    int            num_nodes = pw - padding;
    stbrp_node    *nodes   = (stbrp_node    *) STBTT_malloc(sizeof(*nodes  ) * num_nodes,alloc_context);
 
    if (context == NULL || nodes == NULL) {
       if (context != NULL) STBTT_free(context, alloc_context);
       if (nodes   != NULL) STBTT_free(nodes  , alloc_context);
       return 0;
    }
 
    spc->user_allocator_context = alloc_context;
    spc->width = pw;
    spc->height = ph;
    spc->pixels = pixels;
    spc->pack_info = context;
    spc->nodes = nodes;
    spc->padding = padding;
    spc->stride_in_bytes = stride_in_bytes != 0 ? stride_in_bytes : pw;
    spc->h_oversample = 1;
    spc->v_oversample = 1;
    spc->skip_missing = 0;
 
    stbrp_init_target(context, pw-padding, ph-padding, nodes, num_nodes);
 
    if (pixels)
       STBTT_memset(pixels, 0, pw*ph); // background of 0 around pixels
 
    return 1;
 }
 
 STBTT_DEF void stbtt_PackEnd  (stbtt_pack_context *spc)
 {
    STBTT_free(spc->nodes    , spc->user_allocator_context);
    STBTT_free(spc->pack_info, spc->user_allocator_context);
 }
 
 STBTT_DEF void stbtt_PackSetOversampling(stbtt_pack_context *spc, unsigned int h_oversample, unsigned int v_oversample)
 {
    STBTT_assert(h_oversample <= STBTT_MAX_OVERSAMPLE);
    STBTT_assert(v_oversample <= STBTT_MAX_OVERSAMPLE);
    if (h_oversample <= STBTT_MAX_OVERSAMPLE)
       spc->h_oversample = h_oversample;
    if (v_oversample <= STBTT_MAX_OVERSAMPLE)
       spc->v_oversample = v_oversample;
 }
 
 STBTT_DEF void stbtt_PackSetSkipMissingCodepoints(stbtt_pack_context *spc, int skip)
 {
    spc->skip_missing = skip;
 }
 
 #define STBTT__OVER_MASK  (STBTT_MAX_OVERSAMPLE-1)
 
 static void stbtt__h_prefilter(unsigned char *pixels, int w, int h, int stride_in_bytes, unsigned int kernel_width)
 {
    unsigned char buffer[STBTT_MAX_OVERSAMPLE];
    int safe_w = w - kernel_width;
    int j;
    STBTT_memset(buffer, 0, STBTT_MAX_OVERSAMPLE); // suppress bogus warning from VS2013 -analyze
    for (j=0; j < h; ++j) {
       int i;
       unsigned int total;
       STBTT_memset(buffer, 0, kernel_width);
 
       total = 0;
 
       // make kernel_width a constant in common cases so compiler can optimize out the divide
       switch (kernel_width) {
          case 2:
             for (i=0; i <= safe_w; ++i) {
                total += pixels[i] - buffer[i & STBTT__OVER_MASK];
                buffer[(i+kernel_width) & STBTT__OVER_MASK] = pixels[i];
                pixels[i] = (unsigned char) (total / 2);
             }
             break;
          case 3:
             for (i=0; i <= safe_w; ++i) {
                total += pixels[i] - buffer[i & STBTT__OVER_MASK];
                buffer[(i+kernel_width) & STBTT__OVER_MASK] = pixels[i];
                pixels[i] = (unsigned char) (total / 3);
             }
             break;
          case 4:
             for (i=0; i <= safe_w; ++i) {
                total += pixels[i] - buffer[i & STBTT__OVER_MASK];
                buffer[(i+kernel_width) & STBTT__OVER_MASK] = pixels[i];
                pixels[i] = (unsigned char) (total / 4);
             }
             break;
          case 5:
             for (i=0; i <= safe_w; ++i) {
                total += pixels[i] - buffer[i & STBTT__OVER_MASK];
                buffer[(i+kernel_width) & STBTT__OVER_MASK] = pixels[i];
                pixels[i] = (unsigned char) (total / 5);
             }
             break;
          default:
             for (i=0; i <= safe_w; ++i) {
                total += pixels[i] - buffer[i & STBTT__OVER_MASK];
                buffer[(i+kernel_width) & STBTT__OVER_MASK] = pixels[i];
                pixels[i] = (unsigned char) (total / kernel_width);
             }
             break;
       }
 
       for (; i < w; ++i) {
          STBTT_assert(pixels[i] == 0);
          total -= buffer[i & STBTT__OVER_MASK];
          pixels[i] = (unsigned char) (total / kernel_width);
       }
 
       pixels += stride_in_bytes;
    }
 }
 
 static void stbtt__v_prefilter(unsigned char *pixels, int w, int h, int stride_in_bytes, unsigned int kernel_width)
 {
    unsigned char buffer[STBTT_MAX_OVERSAMPLE];
    int safe_h = h - kernel_width;
    int j;
    STBTT_memset(buffer, 0, STBTT_MAX_OVERSAMPLE); // suppress bogus warning from VS2013 -analyze
    for (j=0; j < w; ++j) {
       int i;
       unsigned int total;
       STBTT_memset(buffer, 0, kernel_width);
 
       total = 0;
 
       // make kernel_width a constant in common cases so compiler can optimize out the divide
       switch (kernel_width) {
          case 2:
             for (i=0; i <= safe_h; ++i) {
                total += pixels[i*stride_in_bytes] - buffer[i & STBTT__OVER_MASK];
                buffer[(i+kernel_width) & STBTT__OVER_MASK] = pixels[i*stride_in_bytes];
                pixels[i*stride_in_bytes] = (unsigned char) (total / 2);
             }
             break;
          case 3:
             for (i=0; i <= safe_h; ++i) {
                total += pixels[i*stride_in_bytes] - buffer[i & STBTT__OVER_MASK];
                buffer[(i+kernel_width) & STBTT__OVER_MASK] = pixels[i*stride_in_bytes];
                pixels[i*stride_in_bytes] = (unsigned char) (total / 3);
             }
             break;
          case 4:
             for (i=0; i <= safe_h; ++i) {
                total += pixels[i*stride_in_bytes] - buffer[i & STBTT__OVER_MASK];
                buffer[(i+kernel_width) & STBTT__OVER_MASK] = pixels[i*stride_in_bytes];
                pixels[i*stride_in_bytes] = (unsigned char) (total / 4);
             }
             break;
          case 5:
             for (i=0; i <= safe_h; ++i) {
                total += pixels[i*stride_in_bytes] - buffer[i & STBTT__OVER_MASK];
                buffer[(i+kernel_width) & STBTT__OVER_MASK] = pixels[i*stride_in_bytes];
                pixels[i*stride_in_bytes] = (unsigned char) (total / 5);
             }
             break;
          default:
             for (i=0; i <= safe_h; ++i) {
                total += pixels[i*stride_in_bytes] - buffer[i & STBTT__OVER_MASK];
                buffer[(i+kernel_width) & STBTT__OVER_MASK] = pixels[i*stride_in_bytes];
                pixels[i*stride_in_bytes] = (unsigned char) (total / kernel_width);
             }
             break;
       }
 
       for (; i < h; ++i) {
          STBTT_assert(pixels[i*stride_in_bytes] == 0);
          total -= buffer[i & STBTT__OVER_MASK];
          pixels[i*stride_in_bytes] = (unsigned char) (total / kernel_width);
       }
 
       pixels += 1;
    }
 }
 
 static float stbtt__oversample_shift(int oversample)
 {
    if (!oversample)
       return 0.0f;
 
    // The prefilter is a box filter of width "oversample",
    // which shifts phase by (oversample - 1)/2 pixels in
    // oversampled space. We want to shift in the opposite
    // direction to counter this.
    return (float)-(oversample - 1) / (2.0f * (float)oversample);
 }
 
 // rects array must be big enough to accommodate all characters in the given ranges
 STBTT_DEF int stbtt_PackFontRangesGatherRects(stbtt_pack_context *spc, const stbtt_fontinfo *info, stbtt_pack_range *ranges, int num_ranges, stbrp_rect *rects)
 {
    int i,j,k;
    int missing_glyph_added = 0;
 
    k=0;
    for (i=0; i < num_ranges; ++i) {
       float fh = ranges[i].font_size;
       float scale = fh > 0 ? stbtt_ScaleForPixelHeight(info, fh) : stbtt_ScaleForMappingEmToPixels(info, -fh);
       ranges[i].h_oversample = (unsigned char) spc->h_oversample;
       ranges[i].v_oversample = (unsigned char) spc->v_oversample;
       for (j=0; j < ranges[i].num_chars; ++j) {
          int x0,y0,x1,y1;
          int codepoint = ranges[i].array_of_unicode_codepoints == NULL ? ranges[i].first_unicode_codepoint_in_range + j : ranges[i].array_of_unicode_codepoints[j];
          int glyph = stbtt_FindGlyphIndex(info, codepoint);
          if (glyph == 0 && (spc->skip_missing || missing_glyph_added)) {
             rects[k].w = rects[k].h = 0;
          } else {
             stbtt_GetGlyphBitmapBoxSubpixel(info,glyph,
                                             scale * spc->h_oversample,
                                             scale * spc->v_oversample,
                                             0,0,
                                             &x0,&y0,&x1,&y1);
             rects[k].w = (stbrp_coord) (x1-x0 + spc->padding + spc->h_oversample-1);
             rects[k].h = (stbrp_coord) (y1-y0 + spc->padding + spc->v_oversample-1);
             if (glyph == 0)
                missing_glyph_added = 1;
          }
          ++k;
       }
    }
 
    return k;
 }
 
 STBTT_DEF void stbtt_MakeGlyphBitmapSubpixelPrefilter(const stbtt_fontinfo *info, unsigned char *output, int out_w, int out_h, int out_stride, float scale_x, float scale_y, float shift_x, float shift_y, int prefilter_x, int prefilter_y, float *sub_x, float *sub_y, int glyph)
 {
    stbtt_MakeGlyphBitmapSubpixel(info,
                                  output,
                                  out_w - (prefilter_x - 1),
                                  out_h - (prefilter_y - 1),
                                  out_stride,
                                  scale_x,
                                  scale_y,
                                  shift_x,
                                  shift_y,
                                  glyph);
 
    if (prefilter_x > 1)
       stbtt__h_prefilter(output, out_w, out_h, out_stride, prefilter_x);
 
    if (prefilter_y > 1)
       stbtt__v_prefilter(output, out_w, out_h, out_stride, prefilter_y);
 
    *sub_x = stbtt__oversample_shift(prefilter_x);
    *sub_y = stbtt__oversample_shift(prefilter_y);
 }
 
 // rects array must be big enough to accommodate all characters in the given ranges
 STBTT_DEF int stbtt_PackFontRangesRenderIntoRects(stbtt_pack_context *spc, const stbtt_fontinfo *info, stbtt_pack_range *ranges, int num_ranges, stbrp_rect *rects)
 {
    int i,j,k, missing_glyph = -1, return_value = 1;
 
    // save current values
    int old_h_over = spc->h_oversample;
    int old_v_over = spc->v_oversample;
 
    k = 0;
    for (i=0; i < num_ranges; ++i) {
       float fh = ranges[i].font_size;
       float scale = fh > 0 ? stbtt_ScaleForPixelHeight(info, fh) : stbtt_ScaleForMappingEmToPixels(info, -fh);
       float recip_h,recip_v,sub_x,sub_y;
       spc->h_oversample = ranges[i].h_oversample;
       spc->v_oversample = ranges[i].v_oversample;
       recip_h = 1.0f / spc->h_oversample;
       recip_v = 1.0f / spc->v_oversample;
       sub_x = stbtt__oversample_shift(spc->h_oversample);
       sub_y = stbtt__oversample_shift(spc->v_oversample);
       for (j=0; j < ranges[i].num_chars; ++j) {
          stbrp_rect *r = &rects[k];
          if (r->was_packed && r->w != 0 && r->h != 0) {
             stbtt_packedchar *bc = &ranges[i].chardata_for_range[j];
             int advance, lsb, x0,y0,x1,y1;
             int codepoint = ranges[i].array_of_unicode_codepoints == NULL ? ranges[i].first_unicode_codepoint_in_range + j : ranges[i].array_of_unicode_codepoints[j];
             int glyph = stbtt_FindGlyphIndex(info, codepoint);
             stbrp_coord pad = (stbrp_coord) spc->padding;
 
             // pad on left and top
             r->x += pad;
             r->y += pad;
             r->w -= pad;
             r->h -= pad;
             stbtt_GetGlyphHMetrics(info, glyph, &advance, &lsb);
             stbtt_GetGlyphBitmapBox(info, glyph,
                                     scale * spc->h_oversample,
                                     scale * spc->v_oversample,
                                     &x0,&y0,&x1,&y1);
             stbtt_MakeGlyphBitmapSubpixel(info,
                                           spc->pixels + r->x + r->y*spc->stride_in_bytes,
                                           r->w - spc->h_oversample+1,
                                           r->h - spc->v_oversample+1,
                                           spc->stride_in_bytes,
                                           scale * spc->h_oversample,
                                           scale * spc->v_oversample,
                                           0,0,
                                           glyph);
 
             if (spc->h_oversample > 1)
                stbtt__h_prefilter(spc->pixels + r->x + r->y*spc->stride_in_bytes,
                                   r->w, r->h, spc->stride_in_bytes,
                                   spc->h_oversample);
 
             if (spc->v_oversample > 1)
                stbtt__v_prefilter(spc->pixels + r->x + r->y*spc->stride_in_bytes,
                                   r->w, r->h, spc->stride_in_bytes,
                                   spc->v_oversample);
 
             bc->x0       = (stbtt_int16)  r->x;
             bc->y0       = (stbtt_int16)  r->y;
             bc->x1       = (stbtt_int16) (r->x + r->w);
             bc->y1       = (stbtt_int16) (r->y + r->h);
             bc->xadvance =                scale * advance;
             bc->xoff     =       (float)  x0 * recip_h + sub_x;
             bc->yoff     =       (float)  y0 * recip_v + sub_y;
             bc->xoff2    =                (x0 + r->w) * recip_h + sub_x;
             bc->yoff2    =                (y0 + r->h) * recip_v + sub_y;
 
             if (glyph == 0)
                missing_glyph = j;
          } else if (spc->skip_missing) {
             return_value = 0;
          } else if (r->was_packed && r->w == 0 && r->h == 0 && missing_glyph >= 0) {
             ranges[i].chardata_for_range[j] = ranges[i].chardata_for_range[missing_glyph];
          } else {
             return_value = 0; // if any fail, report failure
          }
 
          ++k;
       }
    }
 
    // restore original values
    spc->h_oversample = old_h_over;
    spc->v_oversample = old_v_over;
 
    return return_value;
 }
 
 STBTT_DEF void stbtt_PackFontRangesPackRects(stbtt_pack_context *spc, stbrp_rect *rects, int num_rects)
 {
    stbrp_pack_rects((stbrp_context *) spc->pack_info, rects, num_rects);
 }
 
 STBTT_DEF int stbtt_PackFontRanges(stbtt_pack_context *spc, const unsigned char *fontdata, int font_index, stbtt_pack_range *ranges, int num_ranges)
 {
    stbtt_fontinfo info;
    int i,j,n, return_value = 1;
    //stbrp_context *context = (stbrp_context *) spc->pack_info;
    stbrp_rect    *rects;
 
    // flag all characters as NOT packed
    for (i=0; i < num_ranges; ++i)
       for (j=0; j < ranges[i].num_chars; ++j)
          ranges[i].chardata_for_range[j].x0 =
          ranges[i].chardata_for_range[j].y0 =
          ranges[i].chardata_for_range[j].x1 =
          ranges[i].chardata_for_range[j].y1 = 0;
 
    n = 0;
    for (i=0; i < num_ranges; ++i)
       n += ranges[i].num_chars;
 
    rects = (stbrp_rect *) STBTT_malloc(sizeof(*rects) * n, spc->user_allocator_context);
    if (rects == NULL)
       return 0;
 
    info.userdata = spc->user_allocator_context;
    stbtt_InitFont(&info, fontdata, stbtt_GetFontOffsetForIndex(fontdata,font_index));
 
    n = stbtt_PackFontRangesGatherRects(spc, &info, ranges, num_ranges, rects);
 
    stbtt_PackFontRangesPackRects(spc, rects, n);
 
    return_value = stbtt_PackFontRangesRenderIntoRects(spc, &info, ranges, num_ranges, rects);
 
    STBTT_free(rects, spc->user_allocator_context);
    return return_value;
 }
 
 STBTT_DEF int stbtt_PackFontRange(stbtt_pack_context *spc, const unsigned char *fontdata, int font_index, float font_size,
             int first_unicode_codepoint_in_range, int num_chars_in_range, stbtt_packedchar *chardata_for_range)
 {
    stbtt_pack_range range;
    range.first_unicode_codepoint_in_range = first_unicode_codepoint_in_range;
    range.array_of_unicode_codepoints = NULL;
    range.num_chars                   = num_chars_in_range;
    range.chardata_for_range          = chardata_for_range;
    range.font_size                   = font_size;
    return stbtt_PackFontRanges(spc, fontdata, font_index, &range, 1);
 }
 
 STBTT_DEF void stbtt_GetScaledFontVMetrics(const unsigned char *fontdata, int index, float size, float *ascent, float *descent, float *lineGap)
 {
    int i_ascent, i_descent, i_lineGap;
    float scale;
    stbtt_fontinfo info;
    stbtt_InitFont(&info, fontdata, stbtt_GetFontOffsetForIndex(fontdata, index));
    scale = size > 0 ? stbtt_ScaleForPixelHeight(&info, size) : stbtt_ScaleForMappingEmToPixels(&info, -size);
    stbtt_GetFontVMetrics(&info, &i_ascent, &i_descent, &i_lineGap);
    *ascent  = (float) i_ascent  * scale;
    *descent = (float) i_descent * scale;
    *lineGap = (float) i_lineGap * scale;
 }
 
 STBTT_DEF void stbtt_GetPackedQuad(const stbtt_packedchar *chardata, int pw, int ph, int char_index, float *xpos, float *ypos, stbtt_aligned_quad *q, int align_to_integer)
 {
    float ipw = 1.0f / pw, iph = 1.0f / ph;
    const stbtt_packedchar *b = chardata + char_index;
 
    if (align_to_integer) {
       float x = (float) STBTT_ifloor((*xpos + b->xoff) + 0.5f);
       float y = (float) STBTT_ifloor((*ypos + b->yoff) + 0.5f);
       q->x0 = x;
       q->y0 = y;
       q->x1 = x + b->xoff2 - b->xoff;
       q->y1 = y + b->yoff2 - b->yoff;
    } else {
       q->x0 = *xpos + b->xoff;
       q->y0 = *ypos + b->yoff;
       q->x1 = *xpos + b->xoff2;
       q->y1 = *ypos + b->yoff2;
    }
 
    q->s0 = b->x0 * ipw;
    q->t0 = b->y0 * iph;
    q->s1 = b->x1 * ipw;
    q->t1 = b->y1 * iph;
 
    *xpos += b->xadvance;
 }
 
 //////////////////////////////////////////////////////////////////////////////
 //
 // sdf computation
 //
 
 #define STBTT_min(a,b)  ((a) < (b) ? (a) : (b))
 #define STBTT_max(a,b)  ((a) < (b) ? (b) : (a))
 
 static int stbtt__ray_intersect_bezier(float orig[2], float ray[2], float q0[2], float q1[2], float q2[2], float hits[2][2])
 {
    float q0perp = q0[1]*ray[0] - q0[0]*ray[1];
    float q1perp = q1[1]*ray[0] - q1[0]*ray[1];
    float q2perp = q2[1]*ray[0] - q2[0]*ray[1];
    float roperp = orig[1]*ray[0] - orig[0]*ray[1];
 
    float a = q0perp - 2*q1perp + q2perp;
    float b = q1perp - q0perp;
    float c = q0perp - roperp;
 
    float s0 = 0., s1 = 0.;
    int num_s = 0;
 
    if (a != 0.0) {
       float discr = b*b - a*c;
       if (discr > 0.0) {
          float rcpna = -1 / a;
          float d = (float) STBTT_sqrt(discr);
          s0 = (b+d) * rcpna;
          s1 = (b-d) * rcpna;
          if (s0 >= 0.0 && s0 <= 1.0)
             num_s = 1;
          if (d > 0.0 && s1 >= 0.0 && s1 <= 1.0) {
             if (num_s == 0) s0 = s1;
             ++num_s;
          }
       }
    } else {
       // 2*b*s + c = 0
       // s = -c / (2*b)
       s0 = c / (-2 * b);
       if (s0 >= 0.0 && s0 <= 1.0)
          num_s = 1;
    }
 
    if (num_s == 0)
       return 0;
    else {
       float rcp_len2 = 1 / (ray[0]*ray[0] + ray[1]*ray[1]);
       float rayn_x = ray[0] * rcp_len2, rayn_y = ray[1] * rcp_len2;
 
       float q0d =   q0[0]*rayn_x +   q0[1]*rayn_y;
       float q1d =   q1[0]*rayn_x +   q1[1]*rayn_y;
       float q2d =   q2[0]*rayn_x +   q2[1]*rayn_y;
       float rod = orig[0]*rayn_x + orig[1]*rayn_y;
 
       float q10d = q1d - q0d;
       float q20d = q2d - q0d;
       float q0rd = q0d - rod;
 
       hits[0][0] = q0rd + s0*(2.0f - 2.0f*s0)*q10d + s0*s0*q20d;
       hits[0][1] = a*s0+b;
 
       if (num_s > 1) {
          hits[1][0] = q0rd + s1*(2.0f - 2.0f*s1)*q10d + s1*s1*q20d;
          hits[1][1] = a*s1+b;
          return 2;
       } else {
          return 1;
       }
    }
 }
 
 static int equal(float *a, float *b)
 {
    return (a[0] == b[0] && a[1] == b[1]);
 }
 
 static int stbtt__compute_crossings_x(float x, float y, int nverts, stbtt_vertex *verts)
 {
    int i;
    float orig[2], ray[2] = { 1, 0 };
    float y_frac;
    int winding = 0;
 
    // make sure y never passes through a vertex of the shape
    y_frac = (float) STBTT_fmod(y, 1.0f);
    if (y_frac < 0.01f)
       y += 0.01f;
    else if (y_frac > 0.99f)
       y -= 0.01f;
 
    orig[0] = x;
    orig[1] = y;
 
    // test a ray from (-infinity,y) to (x,y)
    for (i=0; i < nverts; ++i) {
       if (verts[i].type == STBTT_vline) {
          int x0 = (int) verts[i-1].x, y0 = (int) verts[i-1].y;
          int x1 = (int) verts[i  ].x, y1 = (int) verts[i  ].y;
          if (y > STBTT_min(y0,y1) && y < STBTT_max(y0,y1) && x > STBTT_min(x0,x1)) {
             float x_inter = (y - y0) / (y1 - y0) * (x1-x0) + x0;
             if (x_inter < x)
                winding += (y0 < y1) ? 1 : -1;
          }
       }
       if (verts[i].type == STBTT_vcurve) {
          int x0 = (int) verts[i-1].x , y0 = (int) verts[i-1].y ;
          int x1 = (int) verts[i  ].cx, y1 = (int) verts[i  ].cy;
          int x2 = (int) verts[i  ].x , y2 = (int) verts[i  ].y ;
          int ax = STBTT_min(x0,STBTT_min(x1,x2)), ay = STBTT_min(y0,STBTT_min(y1,y2));
          int by = STBTT_max(y0,STBTT_max(y1,y2));
          if (y > ay && y < by && x > ax) {
             float q0[2],q1[2],q2[2];
             float hits[2][2];
             q0[0] = (float)x0;
             q0[1] = (float)y0;
             q1[0] = (float)x1;
             q1[1] = (float)y1;
             q2[0] = (float)x2;
             q2[1] = (float)y2;
             if (equal(q0,q1) || equal(q1,q2)) {
                x0 = (int)verts[i-1].x;
                y0 = (int)verts[i-1].y;
                x1 = (int)verts[i  ].x;
                y1 = (int)verts[i  ].y;
                if (y > STBTT_min(y0,y1) && y < STBTT_max(y0,y1) && x > STBTT_min(x0,x1)) {
                   float x_inter = (y - y0) / (y1 - y0) * (x1-x0) + x0;
                   if (x_inter < x)
                      winding += (y0 < y1) ? 1 : -1;
                }
             } else {
                int num_hits = stbtt__ray_intersect_bezier(orig, ray, q0, q1, q2, hits);
                if (num_hits >= 1)
                   if (hits[0][0] < 0)
                      winding += (hits[0][1] < 0 ? -1 : 1);
                if (num_hits >= 2)
                   if (hits[1][0] < 0)
                      winding += (hits[1][1] < 0 ? -1 : 1);
             }
          }
       }
    }
    return winding;
 }
 
 static float stbtt__cuberoot( float x )
 {
    if (x<0)
       return -(float) STBTT_pow(-x,1.0f/3.0f);
    else
       return  (float) STBTT_pow( x,1.0f/3.0f);
 }
 
 // x^3 + a*x^2 + b*x + c = 0
 static int stbtt__solve_cubic(float a, float b, float c, float* r)
 {
    float s = -a / 3;
    float p = b - a*a / 3;
    float q = a * (2*a*a - 9*b) / 27 + c;
    float p3 = p*p*p;
    float d = q*q + 4*p3 / 27;
    if (d >= 0) {
       float z = (float) STBTT_sqrt(d);
       float u = (-q + z) / 2;
       float v = (-q - z) / 2;
       u = stbtt__cuberoot(u);
       v = stbtt__cuberoot(v);
       r[0] = s + u + v;
       return 1;
    } else {
       float u = (float) STBTT_sqrt(-p/3);
       float v = (float) STBTT_acos(-STBTT_sqrt(-27/p3) * q / 2) / 3; // p3 must be negative, since d is negative
       float m = (float) STBTT_cos(v);
       float n = (float) STBTT_cos(v-3.141592/2)*1.732050808f;
       r[0] = s + u * 2 * m;
       r[1] = s - u * (m + n);
       r[2] = s - u * (m - n);
 
       //STBTT_assert( STBTT_fabs(((r[0]+a)*r[0]+b)*r[0]+c) < 0.05f);  // these asserts may not be safe at all scales, though they're in bezier t parameter units so maybe?
       //STBTT_assert( STBTT_fabs(((r[1]+a)*r[1]+b)*r[1]+c) < 0.05f);
       //STBTT_assert( STBTT_fabs(((r[2]+a)*r[2]+b)*r[2]+c) < 0.05f);
       return 3;
    }
 }
 
 STBTT_DEF unsigned char * stbtt_GetGlyphSDF(const stbtt_fontinfo *info, float scale, int glyph, int padding, unsigned char onedge_value, float pixel_dist_scale, int *width, int *height, int *xoff, int *yoff)
 {
    float scale_x = scale, scale_y = scale;
    int ix0,iy0,ix1,iy1;
    int w,h;
    unsigned char *data;
 
    if (scale == 0) return NULL;
 
    stbtt_GetGlyphBitmapBoxSubpixel(info, glyph, scale, scale, 0.0f,0.0f, &ix0,&iy0,&ix1,&iy1);
 
    // if empty, return NULL
    if (ix0 == ix1 || iy0 == iy1)
       return NULL;
 
    ix0 -= padding;
    iy0 -= padding;
    ix1 += padding;
    iy1 += padding;
 
    w = (ix1 - ix0);
    h = (iy1 - iy0);
 
    if (width ) *width  = w;
    if (height) *height = h;
    if (xoff  ) *xoff   = ix0;
    if (yoff  ) *yoff   = iy0;
 
    // invert for y-downwards bitmaps
    scale_y = -scale_y;
 
    {
       int x,y,i,j;
       float *precompute;
       stbtt_vertex *verts;
       int num_verts = stbtt_GetGlyphShape(info, glyph, &verts);
       data = (unsigned char *) STBTT_malloc(w * h, info->userdata);
       precompute = (float *) STBTT_malloc(num_verts * sizeof(float), info->userdata);
 
       for (i=0,j=num_verts-1; i < num_verts; j=i++) {
          if (verts[i].type == STBTT_vline) {
             float x0 = verts[i].x*scale_x, y0 = verts[i].y*scale_y;
             float x1 = verts[j].x*scale_x, y1 = verts[j].y*scale_y;
             float dist = (float) STBTT_sqrt((x1-x0)*(x1-x0) + (y1-y0)*(y1-y0));
             precompute[i] = (dist == 0) ? 0.0f : 1.0f / dist;
          } else if (verts[i].type == STBTT_vcurve) {
             float x2 = verts[j].x *scale_x, y2 = verts[j].y *scale_y;
             float x1 = verts[i].cx*scale_x, y1 = verts[i].cy*scale_y;
             float x0 = verts[i].x *scale_x, y0 = verts[i].y *scale_y;
             float bx = x0 - 2*x1 + x2, by = y0 - 2*y1 + y2;
             float len2 = bx*bx + by*by;
             if (len2 != 0.0f)
                precompute[i] = 1.0f / (bx*bx + by*by);
             else
                precompute[i] = 0.0f;
          } else
             precompute[i] = 0.0f;
       }
 
       for (y=iy0; y < iy1; ++y) {
          for (x=ix0; x < ix1; ++x) {
             float val;
             float min_dist = 999999.0f;
             float sx = (float) x + 0.5f;
             float sy = (float) y + 0.5f;
             float x_gspace = (sx / scale_x);
             float y_gspace = (sy / scale_y);
 
             int winding = stbtt__compute_crossings_x(x_gspace, y_gspace, num_verts, verts); // @OPTIMIZE: this could just be a rasterization, but needs to be line vs. non-tesselated curves so a new path
 
             for (i=0; i < num_verts; ++i) {
                float x0 = verts[i].x*scale_x, y0 = verts[i].y*scale_y;
 
                if (verts[i].type == STBTT_vline && precompute[i] != 0.0f) {
                   float x1 = verts[i-1].x*scale_x, y1 = verts[i-1].y*scale_y;
 
                   float dist,dist2 = (x0-sx)*(x0-sx) + (y0-sy)*(y0-sy);
                   if (dist2 < min_dist*min_dist)
                      min_dist = (float) STBTT_sqrt(dist2);
 
                   // coarse culling against bbox
                   //if (sx > STBTT_min(x0,x1)-min_dist && sx < STBTT_max(x0,x1)+min_dist &&
                   //    sy > STBTT_min(y0,y1)-min_dist && sy < STBTT_max(y0,y1)+min_dist)
                   dist = (float) STBTT_fabs((x1-x0)*(y0-sy) - (y1-y0)*(x0-sx)) * precompute[i];
                   STBTT_assert(i != 0);
                   if (dist < min_dist) {
                      // check position along line
                      // x' = x0 + t*(x1-x0), y' = y0 + t*(y1-y0)
                      // minimize (x'-sx)*(x'-sx)+(y'-sy)*(y'-sy)
                      float dx = x1-x0, dy = y1-y0;
                      float px = x0-sx, py = y0-sy;
                      // minimize (px+t*dx)^2 + (py+t*dy)^2 = px*px + 2*px*dx*t + t^2*dx*dx + py*py + 2*py*dy*t + t^2*dy*dy
                      // derivative: 2*px*dx + 2*py*dy + (2*dx*dx+2*dy*dy)*t, set to 0 and solve
                      float t = -(px*dx + py*dy) / (dx*dx + dy*dy);
                      if (t >= 0.0f && t <= 1.0f)
                         min_dist = dist;
                   }
                } else if (verts[i].type == STBTT_vcurve) {
                   float x2 = verts[i-1].x *scale_x, y2 = verts[i-1].y *scale_y;
                   float x1 = verts[i  ].cx*scale_x, y1 = verts[i  ].cy*scale_y;
                   float box_x0 = STBTT_min(STBTT_min(x0,x1),x2);
                   float box_y0 = STBTT_min(STBTT_min(y0,y1),y2);
                   float box_x1 = STBTT_max(STBTT_max(x0,x1),x2);
                   float box_y1 = STBTT_max(STBTT_max(y0,y1),y2);
                   // coarse culling against bbox to avoid computing cubic unnecessarily
                   if (sx > box_x0-min_dist && sx < box_x1+min_dist && sy > box_y0-min_dist && sy < box_y1+min_dist) {
                      int num=0;
                      float ax = x1-x0, ay = y1-y0;
                      float bx = x0 - 2*x1 + x2, by = y0 - 2*y1 + y2;
                      float mx = x0 - sx, my = y0 - sy;
                      float res[3] = {0.f,0.f,0.f};
                      float px,py,t,it,dist2;
                      float a_inv = precompute[i];
                      if (a_inv == 0.0) { // if a_inv is 0, it's 2nd degree so use quadratic formula
                         float a = 3*(ax*bx + ay*by);
                         float b = 2*(ax*ax + ay*ay) + (mx*bx+my*by);
                         float c = mx*ax+my*ay;
                         if (a == 0.0) { // if a is 0, it's linear
                            if (b != 0.0) {
                               res[num++] = -c/b;
                            }
                         } else {
                            float discriminant = b*b - 4*a*c;
                            if (discriminant < 0)
                               num = 0;
                            else {
                               float root = (float) STBTT_sqrt(discriminant);
                               res[0] = (-b - root)/(2*a);
                               res[1] = (-b + root)/(2*a);
                               num = 2; // don't bother distinguishing 1-solution case, as code below will still work
                            }
                         }
                      } else {
                         float b = 3*(ax*bx + ay*by) * a_inv; // could precompute this as it doesn't depend on sample point
                         float c = (2*(ax*ax + ay*ay) + (mx*bx+my*by)) * a_inv;
                         float d = (mx*ax+my*ay) * a_inv;
                         num = stbtt__solve_cubic(b, c, d, res);
                      }
                      dist2 = (x0-sx)*(x0-sx) + (y0-sy)*(y0-sy);
                      if (dist2 < min_dist*min_dist)
                         min_dist = (float) STBTT_sqrt(dist2);
 
                      if (num >= 1 && res[0] >= 0.0f && res[0] <= 1.0f) {
                         t = res[0], it = 1.0f - t;
                         px = it*it*x0 + 2*t*it*x1 + t*t*x2;
                         py = it*it*y0 + 2*t*it*y1 + t*t*y2;
                         dist2 = (px-sx)*(px-sx) + (py-sy)*(py-sy);
                         if (dist2 < min_dist * min_dist)
                            min_dist = (float) STBTT_sqrt(dist2);
                      }
                      if (num >= 2 && res[1] >= 0.0f && res[1] <= 1.0f) {
                         t = res[1], it = 1.0f - t;
                         px = it*it*x0 + 2*t*it*x1 + t*t*x2;
                         py = it*it*y0 + 2*t*it*y1 + t*t*y2;
                         dist2 = (px-sx)*(px-sx) + (py-sy)*(py-sy);
                         if (dist2 < min_dist * min_dist)
                            min_dist = (float) STBTT_sqrt(dist2);
                      }
                      if (num >= 3 && res[2] >= 0.0f && res[2] <= 1.0f) {
                         t = res[2], it = 1.0f - t;
                         px = it*it*x0 + 2*t*it*x1 + t*t*x2;
                         py = it*it*y0 + 2*t*it*y1 + t*t*y2;
                         dist2 = (px-sx)*(px-sx) + (py-sy)*(py-sy);
                         if (dist2 < min_dist * min_dist)
                            min_dist = (float) STBTT_sqrt(dist2);
                      }
                   }
                }
             }
             if (winding == 0)
                min_dist = -min_dist;  // if outside the shape, value is negative
             val = onedge_value + pixel_dist_scale * min_dist;
             if (val < 0)
                val = 0;
             else if (val > 255)
                val = 255;
             data[(y-iy0)*w+(x-ix0)] = (unsigned char) val;
          }
       }
       STBTT_free(precompute, info->userdata);
       STBTT_free(verts, info->userdata);
    }
    return data;
 }
 
 STBTT_DEF unsigned char * stbtt_GetCodepointSDF(const stbtt_fontinfo *info, float scale, int codepoint, int padding, unsigned char onedge_value, float pixel_dist_scale, int *width, int *height, int *xoff, int *yoff)
 {
    return stbtt_GetGlyphSDF(info, scale, stbtt_FindGlyphIndex(info, codepoint), padding, onedge_value, pixel_dist_scale, width, height, xoff, yoff);
 }
 
 STBTT_DEF void stbtt_FreeSDF(unsigned char *bitmap, void *userdata)
 {
    STBTT_free(bitmap, userdata);
 }
 
 //////////////////////////////////////////////////////////////////////////////
 //
 // font name matching -- recommended not to use this
 //
 
 // check if a utf8 string contains a prefix which is the utf16 string; if so return length of matching utf8 string
 static stbtt_int32 stbtt__CompareUTF8toUTF16_bigendian_prefix(stbtt_uint8 *s1, stbtt_int32 len1, stbtt_uint8 *s2, stbtt_int32 len2)
 {
    stbtt_int32 i=0;
 
    // convert utf16 to utf8 and compare the results while converting
    while (len2) {
       stbtt_uint16 ch = s2[0]*256 + s2[1];
       if (ch < 0x80) {
          if (i >= len1) return -1;
          if (s1[i++] != ch) return -1;
       } else if (ch < 0x800) {
          if (i+1 >= len1) return -1;
          if (s1[i++] != 0xc0 + (ch >> 6)) return -1;
          if (s1[i++] != 0x80 + (ch & 0x3f)) return -1;
       } else if (ch >= 0xd800 && ch < 0xdc00) {
          stbtt_uint32 c;
          stbtt_uint16 ch2 = s2[2]*256 + s2[3];
          if (i+3 >= len1) return -1;
          c = ((ch - 0xd800) << 10) + (ch2 - 0xdc00) + 0x10000;
          if (s1[i++] != 0xf0 + (c >> 18)) return -1;
          if (s1[i++] != 0x80 + ((c >> 12) & 0x3f)) return -1;
          if (s1[i++] != 0x80 + ((c >>  6) & 0x3f)) return -1;
          if (s1[i++] != 0x80 + ((c      ) & 0x3f)) return -1;
          s2 += 2; // plus another 2 below
          len2 -= 2;
       } else if (ch >= 0xdc00 && ch < 0xe000) {
          return -1;
       } else {
          if (i+2 >= len1) return -1;
          if (s1[i++] != 0xe0 + (ch >> 12)) return -1;
          if (s1[i++] != 0x80 + ((ch >> 6) & 0x3f)) return -1;
          if (s1[i++] != 0x80 + ((ch     ) & 0x3f)) return -1;
       }
       s2 += 2;
       len2 -= 2;
    }
    return i;
 }
 
 static int stbtt_CompareUTF8toUTF16_bigendian_internal(char *s1, int len1, char *s2, int len2)
 {
    return len1 == stbtt__CompareUTF8toUTF16_bigendian_prefix((stbtt_uint8*) s1, len1, (stbtt_uint8*) s2, len2);
 }
 
 // returns results in whatever encoding you request... but note that 2-byte encodings
 // will be BIG-ENDIAN... use stbtt_CompareUTF8toUTF16_bigendian() to compare
 STBTT_DEF const char *stbtt_GetFontNameString(const stbtt_fontinfo *font, int *length, int platformID, int encodingID, int languageID, int nameID)
 {
    stbtt_int32 i,count,stringOffset;
    stbtt_uint8 *fc = font->data;
    stbtt_uint32 offset = font->fontstart;
    stbtt_uint32 nm = stbtt__find_table(fc, offset, "name");
    if (!nm) return NULL;
 
    count = ttUSHORT(fc+nm+2);
    stringOffset = nm + ttUSHORT(fc+nm+4);
    for (i=0; i < count; ++i) {
       stbtt_uint32 loc = nm + 6 + 12 * i;
       if (platformID == ttUSHORT(fc+loc+0) && encodingID == ttUSHORT(fc+loc+2)
           && languageID == ttUSHORT(fc+loc+4) && nameID == ttUSHORT(fc+loc+6)) {
          *length = ttUSHORT(fc+loc+8);
          return (const char *) (fc+stringOffset+ttUSHORT(fc+loc+10));
       }
    }
    return NULL;
 }
 
 static int stbtt__matchpair(stbtt_uint8 *fc, stbtt_uint32 nm, stbtt_uint8 *name, stbtt_int32 nlen, stbtt_int32 target_id, stbtt_int32 next_id)
 {
    stbtt_int32 i;
    stbtt_int32 count = ttUSHORT(fc+nm+2);
    stbtt_int32 stringOffset = nm + ttUSHORT(fc+nm+4);
 
    for (i=0; i < count; ++i) {
       stbtt_uint32 loc = nm + 6 + 12 * i;
       stbtt_int32 id = ttUSHORT(fc+loc+6);
       if (id == target_id) {
          // find the encoding
          stbtt_int32 platform = ttUSHORT(fc+loc+0), encoding = ttUSHORT(fc+loc+2), language = ttUSHORT(fc+loc+4);
 
          // is this a Unicode encoding?
          if (platform == 0 || (platform == 3 && encoding == 1) || (platform == 3 && encoding == 10)) {
             stbtt_int32 slen = ttUSHORT(fc+loc+8);
             stbtt_int32 off = ttUSHORT(fc+loc+10);
 
             // check if there's a prefix match
             stbtt_int32 matchlen = stbtt__CompareUTF8toUTF16_bigendian_prefix(name, nlen, fc+stringOffset+off,slen);
             if (matchlen >= 0) {
                // check for target_id+1 immediately following, with same encoding & language
                if (i+1 < count && ttUSHORT(fc+loc+12+6) == next_id && ttUSHORT(fc+loc+12) == platform && ttUSHORT(fc+loc+12+2) == encoding && ttUSHORT(fc+loc+12+4) == language) {
                   slen = ttUSHORT(fc+loc+12+8);
                   off = ttUSHORT(fc+loc+12+10);
                   if (slen == 0) {
                      if (matchlen == nlen)
                         return 1;
                   } else if (matchlen < nlen && name[matchlen] == ' ') {
                      ++matchlen;
                      if (stbtt_CompareUTF8toUTF16_bigendian_internal((char*) (name+matchlen), nlen-matchlen, (char*)(fc+stringOffset+off),slen))
                         return 1;
                   }
                } else {
                   // if nothing immediately following
                   if (matchlen == nlen)
                      return 1;
                }
             }
          }
 
          // @TODO handle other encodings
       }
    }
    return 0;
 }
 
 static int stbtt__matches(stbtt_uint8 *fc, stbtt_uint32 offset, stbtt_uint8 *name, stbtt_int32 flags)
 {
    stbtt_int32 nlen = (stbtt_int32) STBTT_strlen((char *) name);
    stbtt_uint32 nm,hd;
    if (!stbtt__isfont(fc+offset)) return 0;
 
    // check italics/bold/underline flags in macStyle...
    if (flags) {
       hd = stbtt__find_table(fc, offset, "head");
       if ((ttUSHORT(fc+hd+44) & 7) != (flags & 7)) return 0;
    }
 
    nm = stbtt__find_table(fc, offset, "name");
    if (!nm) return 0;
 
    if (flags) {
       // if we checked the macStyle flags, then just check the family and ignore the subfamily
       if (stbtt__matchpair(fc, nm, name, nlen, 16, -1))  return 1;
       if (stbtt__matchpair(fc, nm, name, nlen,  1, -1))  return 1;
       if (stbtt__matchpair(fc, nm, name, nlen,  3, -1))  return 1;
    } else {
       if (stbtt__matchpair(fc, nm, name, nlen, 16, 17))  return 1;
       if (stbtt__matchpair(fc, nm, name, nlen,  1,  2))  return 1;
       if (stbtt__matchpair(fc, nm, name, nlen,  3, -1))  return 1;
    }
 
    return 0;
 }
 
 static int stbtt_FindMatchingFont_internal(unsigned char *font_collection, char *name_utf8, stbtt_int32 flags)
 {
    stbtt_int32 i;
    for (i=0;;++i) {
       stbtt_int32 off = stbtt_GetFontOffsetForIndex(font_collection, i);
       if (off < 0) return off;
       if (stbtt__matches((stbtt_uint8 *) font_collection, off, (stbtt_uint8*) name_utf8, flags))
          return off;
    }
 }
 
 #if defined(__GNUC__) || defined(__clang__)
 #pragma GCC diagnostic push
 #pragma GCC diagnostic ignored "-Wcast-qual"
 #endif
 
 STBTT_DEF int stbtt_BakeFontBitmap(const unsigned char *data, int offset,
                                 float pixel_height, unsigned char *pixels, int pw, int ph,
                                 int first_char, int num_chars, stbtt_bakedchar *chardata)
 {
    return stbtt_BakeFontBitmap_internal((unsigned char *) data, offset, pixel_height, pixels, pw, ph, first_char, num_chars, chardata);
 }
 
 STBTT_DEF int stbtt_GetFontOffsetForIndex(const unsigned char *data, int index)
 {
    return stbtt_GetFontOffsetForIndex_internal((unsigned char *) data, index);
 }
 
 STBTT_DEF int stbtt_GetNumberOfFonts(const unsigned char *data)
 {
    return stbtt_GetNumberOfFonts_internal((unsigned char *) data);
 }
 
 STBTT_DEF int stbtt_InitFont(stbtt_fontinfo *info, const unsigned char *data, int offset)
 {
    return stbtt_InitFont_internal(info, (unsigned char *) data, offset);
 }
 
 STBTT_DEF int stbtt_FindMatchingFont(const unsigned char *fontdata, const char *name, int flags)
 {
    return stbtt_FindMatchingFont_internal((unsigned char *) fontdata, (char *) name, flags);
 }
 
 STBTT_DEF int stbtt_CompareUTF8toUTF16_bigendian(const char *s1, int len1, const char *s2, int len2)
 {
    return stbtt_CompareUTF8toUTF16_bigendian_internal((char *) s1, len1, (char *) s2, len2);
 }
 
 #if defined(__GNUC__) || defined(__clang__)
 #pragma GCC diagnostic pop
 #endif
 
 // FULL VERSION HISTORY
 //
 //   1.25 (2021-07-11) many fixes
 //   1.24 (2020-02-05) fix warning
 //   1.23 (2020-02-02) query SVG data for glyphs; query whole kerning table (but only kern not GPOS)
 //   1.22 (2019-08-11) minimize missing-glyph duplication; fix kerning if both 'GPOS' and 'kern' are defined
 //   1.21 (2019-02-25) fix warning
 //   1.20 (2019-02-07) PackFontRange skips missing codepoints; GetScaleFontVMetrics()
 //   1.19 (2018-02-11) OpenType GPOS kerning (horizontal only), STBTT_fmod
 //   1.18 (2018-01-29) add missing function
 //   1.17 (2017-07-23) make more arguments const; doc fix
 //   1.16 (2017-07-12) SDF support
 //   1.15 (2017-03-03) make more arguments const
 //   1.14 (2017-01-16) num-fonts-in-TTC function
 //   1.13 (2017-01-02) support OpenType fonts, certain Apple fonts
 //   1.12 (2016-10-25) suppress warnings about casting away const with -Wcast-qual
 //   1.11 (2016-04-02) fix unused-variable warning
 //   1.10 (2016-04-02) allow user-defined fabs() replacement
 //                     fix memory leak if fontsize=0.0
 //                     fix warning from duplicate typedef
 //   1.09 (2016-01-16) warning fix; avoid crash on outofmem; use alloc userdata for PackFontRanges
 //   1.08 (2015-09-13) document stbtt_Rasterize(); fixes for vertical & horizontal edges
 //   1.07 (2015-08-01) allow PackFontRanges to accept arrays of sparse codepoints;
 //                     allow PackFontRanges to pack and render in separate phases;
 //                     fix stbtt_GetFontOFfsetForIndex (never worked for non-0 input?);
 //                     fixed an assert() bug in the new rasterizer
 //                     replace assert() with STBTT_assert() in new rasterizer
 //   1.06 (2015-07-14) performance improvements (~35% faster on x86 and x64 on test machine)
 //                     also more precise AA rasterizer, except if shapes overlap
 //                     remove need for STBTT_sort
 //   1.05 (2015-04-15) fix misplaced definitions for STBTT_STATIC
 //   1.04 (2015-04-15) typo in example
 //   1.03 (2015-04-12) STBTT_STATIC, fix memory leak in new packing, various fixes
 //   1.02 (2014-12-10) fix various warnings & compile issues w/ stb_rect_pack, C++
 //   1.01 (2014-12-08) fix subpixel position when oversampling to exactly match
 //                        non-oversampled; STBTT_POINT_SIZE for packed case only
 //   1.00 (2014-12-06) add new PackBegin etc. API, w/ support for oversampling
 //   0.99 (2014-09-18) fix multiple bugs with subpixel rendering (ryg)
 //   0.9  (2014-08-07) support certain mac/iOS fonts without an MS platformID
 //   0.8b (2014-07-07) fix a warning
 //   0.8  (2014-05-25) fix a few more warnings
 //   0.7  (2013-09-25) bugfix: subpixel glyph bug fixed in 0.5 had come back
 //   0.6c (2012-07-24) improve documentation
 //   0.6b (2012-07-20) fix a few more warnings
 //   0.6  (2012-07-17) fix warnings; added stbtt_ScaleForMappingEmToPixels,
 //                        stbtt_GetFontBoundingBox, stbtt_IsGlyphEmpty
 //   0.5  (2011-12-09) bugfixes:
 //                        subpixel glyph renderer computed wrong bounding box
 //                        first vertex of shape can be off-curve (FreeSans)
 //   0.4b (2011-12-03) fixed an error in the font baking example
 //   0.4  (2011-12-01) kerning, subpixel rendering (tor)
 //                    bugfixes for:
 //                        codepoint-to-glyph conversion using table fmt=12
 //                        codepoint-to-glyph conversion using table fmt=4
 //                        stbtt_GetBakedQuad with non-square texture (Zer)
 //                    updated Hello World! sample to use kerning and subpixel
 //                    fixed some warnings
 //   0.3  (2009-06-24) cmap fmt=12, compound shapes (MM)
 //                    userdata, malloc-from-userdata, non-zero fill (stb)
 //   0.2  (2009-03-11) Fix unsigned/signed char warnings
 //   0.1  (2009-03-09) First public release
 //
 
 /*
 ------------------------------------------------------------------------------
 This software is available under 2 licenses -- choose whichever you prefer.
 ------------------------------------------------------------------------------
 ALTERNATIVE A - MIT License
 Copyright (c) 2017 Sean Barrett
 Permission is hereby granted, free of charge, to any person obtaining a copy of
 this software and associated documentation files (the "Software"), to deal in
 the Software without restriction, including without limitation the rights to
 use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
 of the Software, and to permit persons to whom the Software is furnished to do
 so, subject to the following conditions:
 The above copyright notice and this permission notice shall be included in all
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 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 SOFTWARE.
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 ALTERNATIVE B - Public Domain (www.unlicense.org)
 This is free and unencumbered software released into the public domain.
 Anyone is free to copy, modify, publish, use, compile, sell, or distribute this
 software, either in source code form or as a compiled binary, for any purpose,
 commercial or non-commercial, and by any means.
 In jurisdictions that recognize copyright laws, the author or authors of this
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 the detriment of our heirs and successors. We intend this dedication to be an
 overt act of relinquishment in perpetuity of all present and future rights to
 this software under copyright law.
 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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 */