[sfnt] Add API to retrieve 'COLR' v1 root paint (#59703).
* src/sfnt/ttcolr.c (BaseGlyphV1Record): New structure. (tt_face_load_colr): Handle version 1 table header. (find_base_glyph_v1_record): New auxiliary function. (tt_face_get_colr_glyph_paint): New function to find the root `FT_OpaquePaint` object for a given glyph ID. * src/sfnt/ttcolr.h: Updated.
This commit is contained in:
Dominik Röttsches
Werner Lemberg
parent
08dba4dc35
commit
9e422b67c8
12
ChangeLog
12
ChangeLog
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@ -1,3 +1,15 @@
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2020-12-16 Dominik Röttsches <drott@chromium.org>
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[sfnt] Add API to retrieve 'COLR' v1 root paint (#59703).
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* src/sfnt/ttcolr.c (BaseGlyphV1Record): New structure.
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(tt_face_load_colr): Handle version 1 table header.
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(find_base_glyph_v1_record): New auxiliary function.
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(tt_face_get_colr_glyph_paint): New function to find the root
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`FT_OpaquePaint` object for a given glyph ID.
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* src/sfnt/ttcolr.h: Updated.
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2020-12-16 Dominik Röttsches <drott@chromium.org>
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Add new methods required for 'COLR' v1 to public API (#59703).
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@ -5,7 +5,7 @@
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* TrueType and OpenType colored glyph layer support (body).
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*
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* Copyright (C) 2018-2020 by
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* David Turner, Robert Wilhelm, and Werner Lemberg.
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* David Turner, Robert Wilhelm, Dominik Röttsches, and Werner Lemberg.
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*
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* Originally written by Shao Yu Zhang <shaozhang@fb.com>.
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*
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@ -31,6 +31,7 @@
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#include <freetype/internal/ftstream.h>
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#include <freetype/tttags.h>
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#include <freetype/ftcolor.h>
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#include <freetype/config/integer-types.h>
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#ifdef TT_CONFIG_OPTION_COLOR_LAYERS
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@ -39,12 +40,16 @@
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/* NOTE: These are the table sizes calculated through the specs. */
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#define BASE_GLYPH_SIZE 6U
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#define LAYER_SIZE 4U
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#define COLR_HEADER_SIZE 14U
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#define BASE_GLYPH_SIZE 6U
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#define BASE_GLYPH_V1_RECORD_SIZE 6U
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#define LAYER_V1_LIST_PAINT_OFFSET_SIZE 4U
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#define LAYER_V1_LIST_NUM_LAYERS_SIZE 4U
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#define COLOR_STOP_SIZE 6U
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#define LAYER_SIZE 4U
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#define COLR_HEADER_SIZE 14U
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typedef struct BaseGlyphRecord_
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typedef struct BaseGlyphRecord_
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{
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FT_UShort gid;
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FT_UShort first_layer_index;
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@ -53,7 +58,16 @@
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} BaseGlyphRecord;
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typedef struct Colr_
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typedef struct BaseGlyphV1Record_
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{
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FT_UShort gid;
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/* Offset from start of BaseGlyphV1List, i.e., from base_glyphs_v1. */
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FT_ULong paint_offset;
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} BaseGlyphV1Record;
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typedef struct Colr_
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{
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FT_UShort version;
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FT_UShort num_base_glyphs;
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@ -62,7 +76,14 @@
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FT_Byte* base_glyphs;
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FT_Byte* layers;
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/* The memory which backs up the `COLR' table. */
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FT_ULong num_base_glyphs_v1;
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/* Points at beginning of BaseGlyphV1List. */
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FT_Byte* base_glyphs_v1;
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FT_ULong num_layers_v1;
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FT_Byte* layers_v1;
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/* The memory that backs up the `COLR' table. */
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void* table;
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FT_ULong table_size;
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@ -88,10 +109,14 @@
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FT_Byte* table = NULL;
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FT_Byte* p = NULL;
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/* Needed for reading array lengths in referenced tables. */
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FT_Byte* p1 = NULL;
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Colr* colr = NULL;
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FT_ULong base_glyph_offset, layer_offset;
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FT_ULong base_glyphs_offset_v1, num_base_glyphs_v1;
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FT_ULong layer_offset_v1, num_layers_v1;
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FT_ULong table_size;
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@ -115,7 +140,7 @@
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goto NoColr;
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colr->version = FT_NEXT_USHORT( p );
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if ( colr->version != 0 )
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if ( colr->version != 0 && colr->version != 1 )
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goto InvalidTable;
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colr->num_base_glyphs = FT_NEXT_USHORT( p );
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@ -135,6 +160,35 @@
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if ( colr->num_layers * LAYER_SIZE > table_size - layer_offset )
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goto InvalidTable;
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if ( colr->version == 1 )
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{
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base_glyphs_offset_v1 = FT_NEXT_ULONG( p );
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if ( base_glyphs_offset_v1 >= table_size )
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goto InvalidTable;
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p1 = (FT_Byte*)( table + base_glyphs_offset_v1 );
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num_base_glyphs_v1 = FT_PEEK_ULONG( p1 );
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if ( num_base_glyphs_v1 * BASE_GLYPH_V1_RECORD_SIZE >
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table_size - base_glyphs_offset_v1 )
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goto InvalidTable;
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colr->num_base_glyphs_v1 = num_base_glyphs_v1;
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colr->base_glyphs_v1 = p1;
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layer_offset_v1 = FT_NEXT_ULONG( p );
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if ( !layer_offset_v1 || layer_offset_v1 >= table_size )
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goto InvalidTable;
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p1 = (FT_Byte*)( table + layer_offset_v1 );
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num_layers_v1 = FT_PEEK_ULONG( p1 );
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colr->num_layers_v1 = num_layers_v1;
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colr->layers_v1 = p1;
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}
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colr->base_glyphs = (FT_Byte*)( table + base_glyph_offset );
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colr->layers = (FT_Byte*)( table + layer_offset );
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colr->table = table;
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@ -265,6 +319,85 @@
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}
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static FT_Bool
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find_base_glyph_v1_record ( FT_Byte * base_glyph_begin,
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FT_Int num_base_glyph,
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FT_UInt glyph_id,
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BaseGlyphV1Record *record )
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{
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FT_Int min = 0;
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FT_Int max = num_base_glyph - 1;
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while ( min <= max )
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{
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FT_Int mid = min + ( max - min ) / 2;
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/*
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* `base_glyph_begin` is the beginning of `BaseGlyphV1List`;
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* skip `numBaseGlyphV1Records` by adding 4 to start binary search
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* in the array of `BaseGlyphV1Record`.
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*/
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FT_Byte *p = base_glyph_begin + 4 + mid * BASE_GLYPH_V1_RECORD_SIZE;
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FT_UShort gid = FT_NEXT_USHORT( p );
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if ( gid < glyph_id )
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min = mid + 1;
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else if (gid > glyph_id )
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max = mid - 1;
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else
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{
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record->gid = gid;
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record->paint_offset = FT_NEXT_ULONG ( p );
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return 1;
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}
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}
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return 0;
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}
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FT_LOCAL_DEF ( FT_Bool )
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tt_face_get_colr_glyph_paint( TT_Face face,
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FT_UInt base_glyph,
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FT_OpaquePaint* opaque_paint )
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{
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Colr* colr = (Colr*)face->colr;
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BaseGlyphV1Record base_glyph_v1_record;
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FT_Byte* p;
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if ( colr->version < 1 || !colr->num_base_glyphs_v1 ||
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!colr->base_glyphs_v1 )
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return 0;
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if ( opaque_paint->p )
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return 0;
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if ( !find_base_glyph_v1_record( colr->base_glyphs_v1,
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colr->num_base_glyphs_v1,
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base_glyph,
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&base_glyph_v1_record ) )
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return 0;
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if ( !base_glyph_v1_record.paint_offset ||
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base_glyph_v1_record.paint_offset > colr->table_size )
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return 0;
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p = (FT_Byte*)( colr->base_glyphs_v1 +
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base_glyph_v1_record.paint_offset );
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if ( p >= ( (FT_Byte*)colr->table + colr->table_size ) )
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return 0;
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opaque_paint->p = p;
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return 1;
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}
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FT_LOCAL_DEF( FT_Error )
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tt_face_colr_blend_layer( TT_Face face,
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FT_UInt color_index,
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@ -42,6 +42,11 @@ FT_BEGIN_HEADER
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FT_UInt *acolor_index,
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FT_LayerIterator* iterator );
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FT_LOCAL( FT_Bool )
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tt_face_get_colr_glyph_paint( TT_Face face,
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FT_UInt base_glyph,
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FT_OpaquePaint* paint );
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FT_LOCAL( FT_Error )
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tt_face_colr_blend_layer( TT_Face face,
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FT_UInt color_index,
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