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* Copyright 2014 Google Inc.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
#ifndef SkOTTable_EBLC_DEFINED
#define SkOTTable_EBLC_DEFINED
#include "src/core/SkEndian.h"
#include "src/sfnt/SkOTTableTypes.h"
#include "src/sfnt/SkOTTable_EBDT.h"
#pragma pack(push, 1)
struct SkOTTableEmbeddedBitmapLocation {
static const SK_OT_CHAR TAG0 = 'E';
static const SK_OT_CHAR TAG1 = 'B';
static const SK_OT_CHAR TAG2 = 'L';
static const SK_OT_CHAR TAG3 = 'C';
static const SK_OT_ULONG TAG = SkOTTableTAG<SkOTTableEmbeddedBitmapLocation>::value;
SK_OT_Fixed version;
static const SK_OT_Fixed version_initial = SkTEndian_SwapBE32(0x00020000);
SK_OT_ULONG numSizes;
struct SbitLineMetrics {
SK_OT_CHAR ascender;
SK_OT_CHAR descender;
SK_OT_BYTE widthMax;
SK_OT_CHAR caretSlopeNumerator;
SK_OT_CHAR caretSlopeDenominator;
SK_OT_CHAR caretOffset;
SK_OT_CHAR minOriginSB;
SK_OT_CHAR minAdvanceSB;
SK_OT_CHAR maxBeforeBL;
SK_OT_CHAR minAfterBL;
SK_OT_CHAR pad1;
SK_OT_CHAR pad2;
struct BitmapSizeTable {
SK_OT_ULONG indexSubTableArrayOffset; //offset to indexSubtableArray from beginning of EBLC.
SK_OT_ULONG indexTablesSize; //number of bytes in corresponding index subtables and array
SK_OT_ULONG numberOfIndexSubTables; //an index subtable for each range or format change
SK_OT_ULONG colorRef; //not used; set to 0.
SbitLineMetrics hori; //line metrics for text rendered horizontally
SbitLineMetrics vert; //line metrics for text rendered vertically
SK_OT_USHORT startGlyphIndex; //lowest glyph index for this size
SK_OT_USHORT endGlyphIndex; //highest glyph index for this size
SK_OT_BYTE ppemX; //horizontal pixels per Em
SK_OT_BYTE ppemY; //vertical pixels per Em
struct BitDepth {
enum Value : SK_OT_BYTE {
BW = 1,
Gray4 = 2,
Gray16 = 4,
Gray256 = 8,
SK_OT_BYTE value;
} bitDepth; //the Microsoft rasterizer v.1.7 or greater supports
union Flags {
struct Field {
Horizontal, // Horizontal small glyph metrics
Vertical, // Vertical small glyph metrics
} field;
struct Raw {
static const SK_OT_CHAR Horizontal = 1u << 0;
static const SK_OT_CHAR Vertical = 1u << 1;
SK_OT_CHAR value;
} raw;
} flags;
}; //bitmapSizeTable[numSizes];
struct IndexSubTableArray {
SK_OT_USHORT firstGlyphIndex; //first glyph code of this range
SK_OT_USHORT lastGlyphIndex; //last glyph code of this range (inclusive)
SK_OT_ULONG additionalOffsetToIndexSubtable; //add to BitmapSizeTable::indexSubTableArrayOffset to get offset from beginning of 'EBLC'
}; //indexSubTableArray[BitmapSizeTable::numberOfIndexSubTables];
struct IndexSubHeader {
SK_OT_USHORT indexFormat; //format of this indexSubTable
SK_OT_USHORT imageFormat; //format of 'EBDT' image data
SK_OT_ULONG imageDataOffset; //offset to image data in 'EBDT' table
// Variable metrics glyphs with 4 byte offsets
struct IndexSubTable1 {
IndexSubHeader header;
//SK_OT_ULONG offsetArray[lastGlyphIndex - firstGlyphIndex + 1 + 1]; //last element points to one past end of last glyph
//glyphData = offsetArray[glyphIndex - firstGlyphIndex] + imageDataOffset
// All Glyphs have identical metrics
struct IndexSubTable2 {
IndexSubHeader header;
SK_OT_ULONG imageSize; // all glyphs are of the same size
SkOTTableEmbeddedBitmapData::BigGlyphMetrics bigMetrics; // all glyphs have the same metrics; glyph data may be compressed, byte-aligned, or bit-aligned
// Variable metrics glyphs with 2 byte offsets
struct IndexSubTable3 {
IndexSubHeader header;
//SK_OT_USHORT offsetArray[lastGlyphIndex - firstGlyphIndex + 1 + 1]; //last element points to one past end of last glyph, may have extra element to force even number of elements
//glyphData = offsetArray[glyphIndex - firstGlyphIndex] + imageDataOffset
// Variable metrics glyphs with sparse glyph codes
struct IndexSubTable4 {
IndexSubHeader header;
SK_OT_ULONG numGlyphs;
struct CodeOffsetPair {
SK_OT_USHORT glyphCode;
SK_OT_USHORT offset; //location in EBDT
}; //glyphArray[numGlyphs+1]
// Constant metrics glyphs with sparse glyph codes
struct IndexSubTable5 {
IndexSubHeader header;
SK_OT_ULONG imageSize; //all glyphs have the same data size
SkOTTableEmbeddedBitmapData::BigGlyphMetrics bigMetrics; //all glyphs have the same metrics
SK_OT_ULONG numGlyphs;
//SK_OT_USHORT glyphCodeArray[numGlyphs] //must have even number of entries (set pad to 0)
union IndexSubTable {
IndexSubHeader header;
IndexSubTable1 format1;
IndexSubTable2 format2;
IndexSubTable3 format3;
IndexSubTable4 format4;
IndexSubTable5 format5;
#pragma pack(pop)