ref: 93715ab2c4f382f6bfebf9cfe70a1ed4cf11f2b5
dir: /src/sfnt/ttcolr.c/
/****************************************************************************
*
* ttcolr.c
*
* TrueType and OpenType colored glyph layer support (body).
*
* Copyright (C) 2018-2021 by
* David Turner, Robert Wilhelm, Dominik Röttsches, and Werner Lemberg.
*
* Originally written by Shao Yu Zhang <shaozhang@fb.com>.
*
* This file is part of the FreeType project, and may only be used,
* modified, and distributed under the terms of the FreeType project
* license, LICENSE.TXT. By continuing to use, modify, or distribute
* this file you indicate that you have read the license and
* understand and accept it fully.
*
*/
/**************************************************************************
*
* `COLR' table specification:
*
* https://www.microsoft.com/typography/otspec/colr.htm
*
*/
#include <freetype/internal/ftdebug.h>
#include <freetype/internal/ftstream.h>
#include <freetype/tttags.h>
#include <freetype/ftcolor.h>
#include <freetype/config/integer-types.h>
#ifdef TT_CONFIG_OPTION_COLOR_LAYERS
#include "ttcolr.h"
/* NOTE: These are the table sizes calculated through the specs. */
#define BASE_GLYPH_SIZE 6U
#define BASE_GLYPH_V1_RECORD_SIZE 6U
#define LAYER_V1_LIST_PAINT_OFFSET_SIZE 4U
#define LAYER_V1_LIST_NUM_LAYERS_SIZE 4U
#define COLOR_STOP_SIZE 6U
#define LAYER_SIZE 4U
#define COLR_HEADER_SIZE 14U
typedef struct BaseGlyphRecord_
{
FT_UShort gid;
FT_UShort first_layer_index;
FT_UShort num_layers;
} BaseGlyphRecord;
typedef struct BaseGlyphV1Record_
{
FT_UShort gid;
/* Offset from start of BaseGlyphV1List, i.e., from base_glyphs_v1. */
FT_ULong paint_offset;
} BaseGlyphV1Record;
typedef struct Colr_
{
FT_UShort version;
FT_UShort num_base_glyphs;
FT_UShort num_layers;
FT_Byte* base_glyphs;
FT_Byte* layers;
FT_ULong num_base_glyphs_v1;
/* Points at beginning of BaseGlyphV1List. */
FT_Byte* base_glyphs_v1;
FT_ULong num_layers_v1;
FT_Byte* layers_v1;
/* The memory that backs up the `COLR' table. */
void* table;
FT_ULong table_size;
} Colr;
/**************************************************************************
*
* The macro FT_COMPONENT is used in trace mode. It is an implicit
* parameter of the FT_TRACE() and FT_ERROR() macros, used to print/log
* messages during execution.
*/
#undef FT_COMPONENT
#define FT_COMPONENT ttcolr
FT_LOCAL_DEF( FT_Error )
tt_face_load_colr( TT_Face face,
FT_Stream stream )
{
FT_Error error;
FT_Memory memory = face->root.memory;
FT_Byte* table = NULL;
FT_Byte* p = NULL;
/* Needed for reading array lengths in referenced tables. */
FT_Byte* p1 = NULL;
Colr* colr = NULL;
FT_ULong base_glyph_offset, layer_offset;
FT_ULong base_glyphs_offset_v1, num_base_glyphs_v1;
FT_ULong layer_offset_v1, num_layers_v1;
FT_ULong table_size;
/* `COLR' always needs `CPAL' */
if ( !face->cpal )
return FT_THROW( Invalid_File_Format );
error = face->goto_table( face, TTAG_COLR, stream, &table_size );
if ( error )
goto NoColr;
if ( table_size < COLR_HEADER_SIZE )
goto InvalidTable;
if ( FT_FRAME_EXTRACT( table_size, table ) )
goto NoColr;
p = table;
if ( FT_NEW( colr ) )
goto NoColr;
colr->version = FT_NEXT_USHORT( p );
if ( colr->version != 0 && colr->version != 1 )
goto InvalidTable;
colr->num_base_glyphs = FT_NEXT_USHORT( p );
base_glyph_offset = FT_NEXT_ULONG( p );
if ( base_glyph_offset >= table_size )
goto InvalidTable;
if ( colr->num_base_glyphs * BASE_GLYPH_SIZE >
table_size - base_glyph_offset )
goto InvalidTable;
layer_offset = FT_NEXT_ULONG( p );
colr->num_layers = FT_NEXT_USHORT( p );
if ( layer_offset >= table_size )
goto InvalidTable;
if ( colr->num_layers * LAYER_SIZE > table_size - layer_offset )
goto InvalidTable;
if ( colr->version == 1 )
{
base_glyphs_offset_v1 = FT_NEXT_ULONG( p );
if ( base_glyphs_offset_v1 >= table_size )
goto InvalidTable;
p1 = (FT_Byte*)( table + base_glyphs_offset_v1 );
num_base_glyphs_v1 = FT_PEEK_ULONG( p1 );
if ( num_base_glyphs_v1 * BASE_GLYPH_V1_RECORD_SIZE >
table_size - base_glyphs_offset_v1 )
goto InvalidTable;
colr->num_base_glyphs_v1 = num_base_glyphs_v1;
colr->base_glyphs_v1 = p1;
layer_offset_v1 = FT_NEXT_ULONG( p );
if ( !layer_offset_v1 || layer_offset_v1 >= table_size )
goto InvalidTable;
p1 = (FT_Byte*)( table + layer_offset_v1 );
num_layers_v1 = FT_PEEK_ULONG( p1 );
colr->num_layers_v1 = num_layers_v1;
colr->layers_v1 = p1;
}
colr->base_glyphs = (FT_Byte*)( table + base_glyph_offset );
colr->layers = (FT_Byte*)( table + layer_offset );
colr->table = table;
colr->table_size = table_size;
face->colr = colr;
return FT_Err_Ok;
InvalidTable:
error = FT_THROW( Invalid_Table );
NoColr:
FT_FRAME_RELEASE( table );
FT_FREE( colr );
return error;
}
FT_LOCAL_DEF( void )
tt_face_free_colr( TT_Face face )
{
FT_Stream stream = face->root.stream;
FT_Memory memory = face->root.memory;
Colr* colr = (Colr*)face->colr;
if ( colr )
{
FT_FRAME_RELEASE( colr->table );
FT_FREE( colr );
}
}
static FT_Bool
find_base_glyph_record( FT_Byte* base_glyph_begin,
FT_Int num_base_glyph,
FT_UInt glyph_id,
BaseGlyphRecord* record )
{
FT_Int min = 0;
FT_Int max = num_base_glyph - 1;
while ( min <= max )
{
FT_Int mid = min + ( max - min ) / 2;
FT_Byte* p = base_glyph_begin + mid * BASE_GLYPH_SIZE;
FT_UShort gid = FT_NEXT_USHORT( p );
if ( gid < glyph_id )
min = mid + 1;
else if (gid > glyph_id )
max = mid - 1;
else
{
record->gid = gid;
record->first_layer_index = FT_NEXT_USHORT( p );
record->num_layers = FT_NEXT_USHORT( p );
return 1;
}
}
return 0;
}
FT_LOCAL_DEF( FT_Bool )
tt_face_get_colr_layer( TT_Face face,
FT_UInt base_glyph,
FT_UInt *aglyph_index,
FT_UInt *acolor_index,
FT_LayerIterator* iterator )
{
Colr* colr = (Colr*)face->colr;
BaseGlyphRecord glyph_record;
if ( !colr )
return 0;
if ( !iterator->p )
{
FT_ULong offset;
/* first call to function */
iterator->layer = 0;
if ( !find_base_glyph_record( colr->base_glyphs,
colr->num_base_glyphs,
base_glyph,
&glyph_record ) )
return 0;
if ( glyph_record.num_layers )
iterator->num_layers = glyph_record.num_layers;
else
return 0;
offset = LAYER_SIZE * glyph_record.first_layer_index;
if ( offset + LAYER_SIZE * glyph_record.num_layers > colr->table_size )
return 0;
iterator->p = colr->layers + offset;
}
if ( iterator->layer >= iterator->num_layers )
return 0;
*aglyph_index = FT_NEXT_USHORT( iterator->p );
*acolor_index = FT_NEXT_USHORT( iterator->p );
if ( *aglyph_index >= (FT_UInt)( FT_FACE( face )->num_glyphs ) ||
( *acolor_index != 0xFFFF &&
*acolor_index >= face->palette_data.num_palette_entries ) )
return 0;
iterator->layer++;
return 1;
}
static FT_Bool
read_color_line( FT_Byte* color_line_p,
FT_ColorLine *colorline )
{
FT_Byte* p = color_line_p;
FT_PaintExtend paint_extend;
paint_extend = FT_NEXT_BYTE( p );
if ( paint_extend > FT_COLR_PAINT_EXTEND_REFLECT )
return 0;
colorline->extend = paint_extend;
colorline->color_stop_iterator.num_color_stops = FT_NEXT_USHORT( p );
colorline->color_stop_iterator.p = p;
colorline->color_stop_iterator.current_color_stop = 0;
return 1;
}
/*
* Read a paint offset for `FT_Paint*` objects that have them and check
* whether it is within reasonable limits within the font and the COLR
* table.
*
* Return 1 on success, 0 on failure.
*/
static FT_Bool
get_child_table_pointer ( Colr* colr,
FT_Byte* paint_base,
FT_Byte** p,
FT_Byte** child_table_pointer )
{
FT_UInt32 paint_offset;
FT_Byte* child_table_p;
if ( !child_table_pointer )
return 0;
paint_offset = FT_NEXT_UOFF3( *p );
if ( !paint_offset )
return 0;
child_table_p = (FT_Byte*)( paint_base + paint_offset );
if ( child_table_p < colr->base_glyphs_v1 ||
child_table_p >= ( (FT_Byte*)colr->table + colr->table_size ) )
return 0;
*child_table_pointer = child_table_p;
return 1;
}
static FT_Bool
read_paint( Colr* colr,
FT_Byte* p,
FT_COLR_Paint* apaint )
{
FT_Byte* paint_base = p;
FT_Byte* child_table_p = NULL;
if ( !p || !colr || !colr->table )
return 0;
if ( p < colr->base_glyphs_v1 ||
p >= ( (FT_Byte*)colr->table + colr->table_size ) )
return 0;
apaint->format = FT_NEXT_BYTE( p );
if ( apaint->format >= FT_COLR_PAINT_FORMAT_MAX )
return 0;
if ( apaint->format == FT_COLR_PAINTFORMAT_COLR_LAYERS )
{
/* Initialize layer iterator/ */
FT_Byte num_layers;
FT_UInt32 first_layer_index;
num_layers = FT_NEXT_BYTE( p );
if ( num_layers > colr->num_layers_v1 )
return 0;
first_layer_index = FT_NEXT_ULONG( p );
if ( first_layer_index + num_layers > colr->num_layers_v1 )
return 0;
apaint->u.colr_layers.layer_iterator.num_layers = num_layers;
apaint->u.colr_layers.layer_iterator.layer = 0;
/* TODO: Check whether pointer is outside colr? */
apaint->u.colr_layers.layer_iterator.p =
colr->layers_v1 +
LAYER_V1_LIST_NUM_LAYERS_SIZE +
LAYER_V1_LIST_PAINT_OFFSET_SIZE * first_layer_index;
return 1;
}
else if ( apaint->format == FT_COLR_PAINTFORMAT_SOLID )
{
apaint->u.solid.color.palette_index = FT_NEXT_USHORT ( p );
apaint->u.solid.color.alpha = FT_NEXT_USHORT ( p );
return 1;
}
else if ( apaint->format == FT_COLR_PAINTFORMAT_COLR_GLYPH )
{
apaint->u.colr_glyph.glyphID = FT_NEXT_USHORT( p );
return 1;
}
/*
* Grouped below here are all paint formats that have an offset to a
* child paint table as the first entry (for example, a color line or a
* child paint table). Retrieve that and determine whether that paint
* offset is valid first.
*/
if ( !get_child_table_pointer( colr, paint_base, &p, &child_table_p ) )
return 0;
if ( apaint->format == FT_COLR_PAINTFORMAT_LINEAR_GRADIENT )
{
if ( !read_color_line( child_table_p,
&apaint->u.linear_gradient.colorline ) )
return 0;
apaint->u.linear_gradient.p0.x = FT_NEXT_SHORT ( p );
apaint->u.linear_gradient.p0.y = FT_NEXT_SHORT ( p );
apaint->u.linear_gradient.p1.x = FT_NEXT_SHORT ( p );
apaint->u.linear_gradient.p1.y = FT_NEXT_SHORT ( p );
apaint->u.linear_gradient.p2.x = FT_NEXT_SHORT ( p );
apaint->u.linear_gradient.p2.y = FT_NEXT_SHORT ( p );
return 1;
}
else if ( apaint->format == FT_COLR_PAINTFORMAT_RADIAL_GRADIENT )
{
if ( !read_color_line( child_table_p,
&apaint->u.radial_gradient.colorline ) )
return 0;
apaint->u.radial_gradient.c0.x = FT_NEXT_SHORT ( p );
apaint->u.radial_gradient.c0.y = FT_NEXT_SHORT ( p );
apaint->u.radial_gradient.r0 = FT_NEXT_USHORT ( p );
apaint->u.radial_gradient.c1.x = FT_NEXT_SHORT ( p );
apaint->u.radial_gradient.c1.y = FT_NEXT_SHORT ( p );
apaint->u.radial_gradient.r1 = FT_NEXT_USHORT ( p );
return 1;
}
else if ( apaint->format == FT_COLR_PAINTFORMAT_SWEEP_GRADIENT )
{
if ( !read_color_line( child_table_p,
&apaint->u.sweep_gradient.colorline ) )
return 0;
apaint->u.sweep_gradient.center.x = FT_NEXT_SHORT ( p );
apaint->u.sweep_gradient.center.y = FT_NEXT_SHORT ( p );
apaint->u.sweep_gradient.start_angle = FT_NEXT_LONG( p );
apaint->u.sweep_gradient.end_angle = FT_NEXT_LONG( p );
return 1;
}
if ( apaint->format == FT_COLR_PAINTFORMAT_GLYPH )
{
apaint->u.glyph.paint.p = child_table_p;
apaint->u.glyph.paint.insert_root_transform = 0;
apaint->u.glyph.glyphID = FT_NEXT_USHORT( p );
return 1;
}
else if ( apaint->format == FT_COLR_PAINTFORMAT_TRANSFORMED )
{
apaint->u.transformed.paint.p = child_table_p;
apaint->u.transformed.paint.insert_root_transform = 0;
apaint->u.transformed.affine.xx = FT_NEXT_LONG( p );
apaint->u.transformed.affine.yx = FT_NEXT_LONG( p );
apaint->u.transformed.affine.xy = FT_NEXT_LONG( p );
apaint->u.transformed.affine.yy = FT_NEXT_LONG( p );
apaint->u.transformed.affine.dx = FT_NEXT_LONG( p );
apaint->u.transformed.affine.dy = FT_NEXT_LONG( p );
return 1;
}
else if ( apaint->format == FT_COLR_PAINTFORMAT_TRANSLATE )
{
apaint->u.translate.paint.p = child_table_p;
apaint->u.translate.paint.insert_root_transform = 0;
apaint->u.translate.dx = FT_NEXT_LONG( p );
apaint->u.translate.dy = FT_NEXT_LONG( p );
return 1;
}
else if ( apaint->format == FT_COLR_PAINTFORMAT_ROTATE )
{
apaint->u.rotate.paint.p = child_table_p;
apaint->u.rotate.paint.insert_root_transform = 0;
apaint->u.rotate.angle = FT_NEXT_LONG( p );
apaint->u.rotate.center_x = FT_NEXT_LONG( p );
apaint->u.rotate.center_y = FT_NEXT_LONG( p );
return 1;
}
else if ( apaint->format == FT_COLR_PAINTFORMAT_SKEW )
{
apaint->u.skew.paint.p = child_table_p;
apaint->u.skew.paint.insert_root_transform = 0;
apaint->u.skew.x_skew_angle = FT_NEXT_LONG( p );
apaint->u.skew.y_skew_angle = FT_NEXT_LONG( p );
apaint->u.skew.center_x = FT_NEXT_LONG( p );
apaint->u.skew.center_y = FT_NEXT_LONG( p );
return 1;
}
else if ( apaint->format == FT_COLR_PAINTFORMAT_COMPOSITE )
{
FT_UInt composite_mode;
apaint->u.composite.source_paint.p = child_table_p;
apaint->u.composite.source_paint.insert_root_transform = 0;
composite_mode = FT_NEXT_BYTE( p );
if ( composite_mode >= FT_COLR_COMPOSITE_MAX )
return 0;
apaint->u.composite.composite_mode = composite_mode;
if ( !get_child_table_pointer( colr, paint_base, &p, &child_table_p ) )
return 0;
apaint->u.composite.backdrop_paint.p =
child_table_p;
apaint->u.composite.backdrop_paint.insert_root_transform =
0;
return 1;
}
return 0;
}
static FT_Bool
find_base_glyph_v1_record ( FT_Byte * base_glyph_begin,
FT_Int num_base_glyph,
FT_UInt glyph_id,
BaseGlyphV1Record *record )
{
FT_Int min = 0;
FT_Int max = num_base_glyph - 1;
while ( min <= max )
{
FT_Int mid = min + ( max - min ) / 2;
/*
* `base_glyph_begin` is the beginning of `BaseGlyphV1List`;
* skip `numBaseGlyphV1Records` by adding 4 to start binary search
* in the array of `BaseGlyphV1Record`.
*/
FT_Byte *p = base_glyph_begin + 4 + mid * BASE_GLYPH_V1_RECORD_SIZE;
FT_UShort gid = FT_NEXT_USHORT( p );
if ( gid < glyph_id )
min = mid + 1;
else if (gid > glyph_id )
max = mid - 1;
else
{
record->gid = gid;
record->paint_offset = FT_NEXT_ULONG ( p );
return 1;
}
}
return 0;
}
FT_LOCAL_DEF ( FT_Bool )
tt_face_get_colr_glyph_paint( TT_Face face,
FT_UInt base_glyph,
FT_Color_Root_Transform root_transform,
FT_OpaquePaint* opaque_paint )
{
Colr* colr = (Colr*)face->colr;
BaseGlyphV1Record base_glyph_v1_record;
FT_Byte* p;
if ( !colr || !colr->table )
return 0;
if ( colr->version < 1 || !colr->num_base_glyphs_v1 ||
!colr->base_glyphs_v1 )
return 0;
if ( opaque_paint->p )
return 0;
if ( !find_base_glyph_v1_record( colr->base_glyphs_v1,
colr->num_base_glyphs_v1,
base_glyph,
&base_glyph_v1_record ) )
return 0;
if ( !base_glyph_v1_record.paint_offset ||
base_glyph_v1_record.paint_offset > colr->table_size )
return 0;
p = (FT_Byte*)( colr->base_glyphs_v1 +
base_glyph_v1_record.paint_offset );
if ( p >= ( (FT_Byte*)colr->table + colr->table_size ) )
return 0;
opaque_paint->p = p;
if ( root_transform == FT_COLOR_INCLUDE_ROOT_TRANSFORM )
opaque_paint->insert_root_transform = 1;
else
opaque_paint->insert_root_transform = 0;
return 1;
}
FT_LOCAL_DEF( FT_Bool )
tt_face_get_paint_layers( TT_Face face,
FT_LayerIterator* iterator,
FT_OpaquePaint* opaque_paint )
{
FT_Byte* p = NULL;
FT_Byte* p_first_layer = NULL;
FT_Byte* p_paint = NULL;
FT_UInt32 paint_offset;
Colr* colr;
if ( iterator->layer == iterator->num_layers )
return 0;
colr = (Colr*)face->colr;
if ( !colr )
return 0;
/*
* We have an iterator pointing at a paint offset as part of the
* `paintOffset` array in `LayerV1List`.
*/
p = iterator->p;
/*
* Do a cursor sanity check of the iterator. Counting backwards from
* where it stands, we need to end up at a position after the beginning
* of the `LayerV1List` table and not after the end of the
* `LayerV1List`.
*/
p_first_layer = p -
iterator->layer * LAYER_V1_LIST_PAINT_OFFSET_SIZE -
LAYER_V1_LIST_NUM_LAYERS_SIZE;
if ( p_first_layer < (FT_Byte*)colr->layers_v1 )
return 0;
if ( p_first_layer >= (FT_Byte*)(
colr->layers_v1 + LAYER_V1_LIST_NUM_LAYERS_SIZE +
colr->num_layers_v1 * LAYER_V1_LIST_PAINT_OFFSET_SIZE ) )
return 0;
paint_offset =
FT_NEXT_ULONG( p );
opaque_paint->insert_root_transform =
0;
p_paint = (FT_Byte*)( colr->layers_v1 + paint_offset );
if ( p_paint < colr->base_glyphs_v1 ||
p_paint >= ( (FT_Byte*)colr->table + colr->table_size ) )
return 0;
opaque_paint->p = p_paint;
iterator->p = p;
iterator->layer++;
return 1;
}
FT_LOCAL_DEF ( FT_Bool )
tt_face_get_colorline_stops( TT_Face face,
FT_ColorStop* color_stop,
FT_ColorStopIterator *iterator )
{
Colr* colr = (Colr*)face->colr;
FT_Byte* p;
if ( !colr || !colr->table )
return 0;
if ( iterator->current_color_stop >= iterator->num_color_stops )
return 0;
if ( iterator->p +
( ( iterator->num_color_stops - iterator->current_color_stop ) *
COLOR_STOP_SIZE ) >
( (FT_Byte *)colr->table + colr->table_size ) )
return 0;
/* Iterator points at first `ColorStop` of `ColorLine`. */
p = iterator->p;
color_stop->stop_offset = FT_NEXT_USHORT ( p );
color_stop->color.palette_index = FT_NEXT_USHORT ( p );
color_stop->color.alpha = FT_NEXT_USHORT ( p );
iterator->p = p;
iterator->current_color_stop++;
return 1;
}
FT_LOCAL_DEF( FT_Bool )
tt_face_get_paint( TT_Face face,
FT_OpaquePaint opaque_paint,
FT_COLR_Paint* paint )
{
Colr* colr = (Colr*)face->colr;
FT_OpaquePaint next_paint;
FT_Matrix ft_root_scale;
if ( !colr || !colr->base_glyphs_v1 || !colr->table )
return 0;
if ( opaque_paint.insert_root_transform )
{
/* 'COLR' v1 glyph information is returned in unscaled coordinates,
* i.e., `FT_Size` is not applied or multiplied into the values. When
* client applications draw color glyphs, they can request to include
* a top-level transform, which includes the active `x_scale` and
* `y_scale` information for scaling the glyph, as well the additional
* transform and translate configured through `FT_Set_Transform`.
* This allows client applications to apply this top-level transform
* to the graphics context first and only once, then have gradient and
* contour scaling applied correctly when performing the additional
* drawing operations for subsequenct paints. Prepare this initial
* transform here.
*/
paint->format = FT_COLR_PAINTFORMAT_TRANSFORMED;
next_paint.p = opaque_paint.p;
next_paint.insert_root_transform = 0;
paint->u.transformed.paint = next_paint;
/* `x_scale` and `y_scale` are in 26.6 format, representing the scale
* factor to get from font units to requested size. However, expected
* return values are in 16.16, so we shift accordingly with rounding.
*/
ft_root_scale.xx = ( face->root.size->metrics.x_scale + 32 ) >> 6;
ft_root_scale.xy = 0;
ft_root_scale.yx = 0;
ft_root_scale.yy = ( face->root.size->metrics.y_scale + 32 ) >> 6;
if ( face->root.internal->transform_flags & 1 )
FT_Matrix_Multiply( &face->root.internal->transform_matrix,
&ft_root_scale );
paint->u.transformed.affine.xx = ft_root_scale.xx;
paint->u.transformed.affine.xy = ft_root_scale.xy;
paint->u.transformed.affine.yx = ft_root_scale.yx;
paint->u.transformed.affine.yy = ft_root_scale.yy;
/* The translation is specified in 26.6 format and, according to the
* documentation of `FT_Set_Translate`, is performed on the character
* size given in the last call to `FT_Set_Char_Size`. The
* 'PaintTransformed' paint table's `FT_Affine23` format expects
* values in 16.16 format, thus we need to shift by 10 bits.
*/
if ( face->root.internal->transform_flags & 2 )
{
paint->u.transformed.affine.dx =
face->root.internal->transform_delta.x << 10;
paint->u.transformed.affine.dy =
face->root.internal->transform_delta.y << 10;
}
else
{
paint->u.transformed.affine.dx = 0;
paint->u.transformed.affine.dy = 0;
}
return 1;
}
return read_paint( colr, opaque_paint.p, paint );
}
FT_LOCAL_DEF( FT_Error )
tt_face_colr_blend_layer( TT_Face face,
FT_UInt color_index,
FT_GlyphSlot dstSlot,
FT_GlyphSlot srcSlot )
{
FT_Error error;
FT_UInt x, y;
FT_Byte b, g, r, alpha;
FT_ULong size;
FT_Byte* src;
FT_Byte* dst;
if ( !dstSlot->bitmap.buffer )
{
/* Initialize destination of color bitmap */
/* with the size of first component. */
dstSlot->bitmap_left = srcSlot->bitmap_left;
dstSlot->bitmap_top = srcSlot->bitmap_top;
dstSlot->bitmap.width = srcSlot->bitmap.width;
dstSlot->bitmap.rows = srcSlot->bitmap.rows;
dstSlot->bitmap.pixel_mode = FT_PIXEL_MODE_BGRA;
dstSlot->bitmap.pitch = (int)dstSlot->bitmap.width * 4;
dstSlot->bitmap.num_grays = 256;
size = dstSlot->bitmap.rows * (unsigned int)dstSlot->bitmap.pitch;
error = ft_glyphslot_alloc_bitmap( dstSlot, size );
if ( error )
return error;
FT_MEM_ZERO( dstSlot->bitmap.buffer, size );
}
else
{
/* Resize destination if needed such that new component fits. */
FT_Int x_min, x_max, y_min, y_max;
x_min = FT_MIN( dstSlot->bitmap_left, srcSlot->bitmap_left );
x_max = FT_MAX( dstSlot->bitmap_left + (FT_Int)dstSlot->bitmap.width,
srcSlot->bitmap_left + (FT_Int)srcSlot->bitmap.width );
y_min = FT_MIN( dstSlot->bitmap_top - (FT_Int)dstSlot->bitmap.rows,
srcSlot->bitmap_top - (FT_Int)srcSlot->bitmap.rows );
y_max = FT_MAX( dstSlot->bitmap_top, srcSlot->bitmap_top );
if ( x_min != dstSlot->bitmap_left ||
x_max != dstSlot->bitmap_left + (FT_Int)dstSlot->bitmap.width ||
y_min != dstSlot->bitmap_top - (FT_Int)dstSlot->bitmap.rows ||
y_max != dstSlot->bitmap_top )
{
FT_Memory memory = face->root.memory;
FT_UInt width = (FT_UInt)( x_max - x_min );
FT_UInt rows = (FT_UInt)( y_max - y_min );
FT_UInt pitch = width * 4;
FT_Byte* buf = NULL;
FT_Byte* p;
FT_Byte* q;
size = rows * pitch;
if ( FT_ALLOC( buf, size ) )
return error;
p = dstSlot->bitmap.buffer;
q = buf +
(int)pitch * ( y_max - dstSlot->bitmap_top ) +
4 * ( dstSlot->bitmap_left - x_min );
for ( y = 0; y < dstSlot->bitmap.rows; y++ )
{
FT_MEM_COPY( q, p, dstSlot->bitmap.width * 4 );
p += dstSlot->bitmap.pitch;
q += pitch;
}
ft_glyphslot_set_bitmap( dstSlot, buf );
dstSlot->bitmap_top = y_max;
dstSlot->bitmap_left = x_min;
dstSlot->bitmap.width = width;
dstSlot->bitmap.rows = rows;
dstSlot->bitmap.pitch = (int)pitch;
dstSlot->internal->flags |= FT_GLYPH_OWN_BITMAP;
dstSlot->format = FT_GLYPH_FORMAT_BITMAP;
}
}
if ( color_index == 0xFFFF )
{
if ( face->have_foreground_color )
{
b = face->foreground_color.blue;
g = face->foreground_color.green;
r = face->foreground_color.red;
alpha = face->foreground_color.alpha;
}
else
{
if ( face->palette_data.palette_flags &&
( face->palette_data.palette_flags[face->palette_index] &
FT_PALETTE_FOR_DARK_BACKGROUND ) )
{
/* white opaque */
b = 0xFF;
g = 0xFF;
r = 0xFF;
alpha = 0xFF;
}
else
{
/* black opaque */
b = 0x00;
g = 0x00;
r = 0x00;
alpha = 0xFF;
}
}
}
else
{
b = face->palette[color_index].blue;
g = face->palette[color_index].green;
r = face->palette[color_index].red;
alpha = face->palette[color_index].alpha;
}
/* XXX Convert if srcSlot.bitmap is not grey? */
src = srcSlot->bitmap.buffer;
dst = dstSlot->bitmap.buffer +
dstSlot->bitmap.pitch * ( dstSlot->bitmap_top - srcSlot->bitmap_top ) +
4 * ( srcSlot->bitmap_left - dstSlot->bitmap_left );
for ( y = 0; y < srcSlot->bitmap.rows; y++ )
{
for ( x = 0; x < srcSlot->bitmap.width; x++ )
{
int aa = src[x];
int fa = alpha * aa / 255;
int fb = b * fa / 255;
int fg = g * fa / 255;
int fr = r * fa / 255;
int ba2 = 255 - fa;
int bb = dst[4 * x + 0];
int bg = dst[4 * x + 1];
int br = dst[4 * x + 2];
int ba = dst[4 * x + 3];
dst[4 * x + 0] = (FT_Byte)( bb * ba2 / 255 + fb );
dst[4 * x + 1] = (FT_Byte)( bg * ba2 / 255 + fg );
dst[4 * x + 2] = (FT_Byte)( br * ba2 / 255 + fr );
dst[4 * x + 3] = (FT_Byte)( ba * ba2 / 255 + fa );
}
src += srcSlot->bitmap.pitch;
dst += dstSlot->bitmap.pitch;
}
return FT_Err_Ok;
}
#else /* !TT_CONFIG_OPTION_COLOR_LAYERS */
/* ANSI C doesn't like empty source files */
typedef int _tt_colr_dummy;
#endif /* !TT_CONFIG_OPTION_COLOR_LAYERS */
/* EOF */