From f298fb8a4cfbc6daee42e871b15cf36bf367d860 Mon Sep 17 00:00:00 2001
From: Jorge Rodriguez <bs.vino@gmail.com>
Date: Tue, 9 Feb 2016 19:40:18 -0800
Subject: [PATCH] Add support for obtaining the entire kerning table from a
 font all at once, for use in rendering packed textures offline.

---
 stb_truetype.h | 54 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 54 insertions(+)

diff --git a/stb_truetype.h b/stb_truetype.h
index fc5b978..bb13b29 100644
--- a/stb_truetype.h
+++ b/stb_truetype.h
@@ -734,6 +734,18 @@ STBTT_DEF int  stbtt_GetGlyphKernAdvance(const stbtt_fontinfo *info, int glyph1,
 STBTT_DEF int  stbtt_GetGlyphBox(const stbtt_fontinfo *info, int glyph_index, int *x0, int *y0, int *x1, int *y1);
 // as above, but takes one or more glyph indices for greater efficiency
 
+typedef struct stbtt_kerningentry
+{
+   int glyph1; // use stbtt_FindGlyphIndex
+   int glyph2;
+   int advance;
+} stbtt_kerningentry;
+
+STBTT_DEF int  stbtt_GetKerningTableLength(const stbtt_fontinfo *info);
+STBTT_DEF int  stbtt_GetKerningTable(const stbtt_fontinfo *info, stbtt_kerningentry* table, int table_length);
+// Retrieves a complete list of all of the kerning pairs provided by the font
+// stbtt_GetKerningTable never writes more than table_length entries and returns how many entries it did write.
+// The table will be sorted by (a.glyph1 == b.glyph1)?(a.glyph2 < b.glyph2):(a.glyph1 < b.glyph1)
 
 //////////////////////////////////////////////////////////////////////////////
 //
@@ -2152,6 +2164,48 @@ STBTT_DEF void stbtt_GetGlyphHMetrics(const stbtt_fontinfo *info, int glyph_inde
    }
 }
 
+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;
+}
+
 STBTT_DEF int  stbtt_GetGlyphKernAdvance(const stbtt_fontinfo *info, int glyph1, int glyph2)
 {
    stbtt_uint8 *data = info->data + info->kern;
-- 
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