ref: ec9b6c314dc018bbf0af4ff657fa5ff56a5bf9f7
dir: /src/sfnt/ttcolr.c/
/****************************************************************************
*
* ttcolr.c
*
* TrueType and OpenType colored glyph layer support (body).
*
* Copyright (C) 2018-2020 by
* David Turner, Robert Wilhelm, 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>
#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 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 Colr_
{
FT_UShort version;
FT_UShort num_base_glyphs;
FT_UShort num_layers;
FT_Byte* base_glyphs;
FT_Byte* layers;
/* The memory which 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;
Colr* colr = NULL;
FT_ULong base_glyph_offset, layer_offset;
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 )
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;
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;
}
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 */