bungeman@google.com | 058670b | 2014-05-01 20:39:14 +0000 | [diff] [blame] | 1 | /* |
| 2 | * Copyright 2014 Google Inc. |
| 3 | * |
| 4 | * Use of this source code is governed by a BSD-style license that can be |
| 5 | * found in the LICENSE file. |
| 6 | */ |
| 7 | |
| 8 | #ifndef SkOTTable_EBLC_DEFINED |
| 9 | #define SkOTTable_EBLC_DEFINED |
| 10 | |
| 11 | #include "SkEndian.h" |
| 12 | #include "SkOTTable_EBDT.h" |
| 13 | #include "SkOTTableTypes.h" |
| 14 | #include "SkTypedEnum.h" |
| 15 | |
| 16 | #pragma pack(push, 1) |
| 17 | |
| 18 | struct SkOTTableEmbeddedBitmapLocation { |
| 19 | static const SK_OT_CHAR TAG0 = 'E'; |
| 20 | static const SK_OT_CHAR TAG1 = 'B'; |
| 21 | static const SK_OT_CHAR TAG2 = 'L'; |
| 22 | static const SK_OT_CHAR TAG3 = 'C'; |
| 23 | static const SK_OT_ULONG TAG = SkOTTableTAG<SkOTTableEmbeddedBitmapLocation>::value; |
| 24 | |
| 25 | SK_OT_Fixed version; |
| 26 | static const SK_OT_Fixed version_initial = SkTEndian_SwapBE32(0x00020000); |
| 27 | |
| 28 | SK_OT_ULONG numSizes; |
| 29 | |
| 30 | struct SbitLineMetrics { |
| 31 | SK_OT_CHAR ascender; |
| 32 | SK_OT_CHAR descender; |
| 33 | SK_OT_BYTE widthMax; |
| 34 | SK_OT_CHAR caretSlopeNumerator; |
| 35 | SK_OT_CHAR caretSlopeDenominator; |
| 36 | SK_OT_CHAR caretOffset; |
| 37 | SK_OT_CHAR minOriginSB; |
| 38 | SK_OT_CHAR minAdvanceSB; |
| 39 | SK_OT_CHAR maxBeforeBL; |
| 40 | SK_OT_CHAR minAfterBL; |
| 41 | SK_OT_CHAR pad1; |
| 42 | SK_OT_CHAR pad2; |
| 43 | }; |
| 44 | |
| 45 | struct BitmapSizeTable { |
| 46 | SK_OT_ULONG indexSubTableArrayOffset; //offset to indexSubtableArray from beginning of EBLC. |
| 47 | SK_OT_ULONG indexTablesSize; //number of bytes in corresponding index subtables and array |
| 48 | SK_OT_ULONG numberOfIndexSubTables; //an index subtable for each range or format change |
| 49 | SK_OT_ULONG colorRef; //not used; set to 0. |
| 50 | SbitLineMetrics hori; //line metrics for text rendered horizontally |
| 51 | SbitLineMetrics vert; //line metrics for text rendered vertically |
| 52 | SK_OT_USHORT startGlyphIndex; //lowest glyph index for this size |
| 53 | SK_OT_USHORT endGlyphIndex; //highest glyph index for this size |
| 54 | SK_OT_BYTE ppemX; //horizontal pixels per Em |
| 55 | SK_OT_BYTE ppemY; //vertical pixels per Em |
| 56 | struct BitDepth { |
| 57 | SK_TYPED_ENUM(Value, SK_OT_BYTE, |
| 58 | ((BW, 1)) |
| 59 | ((Gray4, 2)) |
| 60 | ((Gray16, 4)) |
| 61 | ((Gray256, 8)) |
| 62 | SK_SEQ_END, |
| 63 | SK_SEQ_END) |
| 64 | SK_OT_BYTE value; |
| 65 | } bitDepth; //the Microsoft rasterizer v.1.7 or greater supports |
| 66 | union Flags { |
| 67 | struct Field { |
| 68 | //0-7 |
| 69 | SK_OT_BYTE_BITFIELD( |
| 70 | Horizontal, // Horizontal small glyph metrics |
| 71 | Vertical, // Vertical small glyph metrics |
| 72 | Reserved02, |
| 73 | Reserved03, |
| 74 | Reserved04, |
| 75 | Reserved05, |
| 76 | Reserved06, |
| 77 | Reserved07) |
| 78 | } field; |
| 79 | struct Raw { |
| 80 | static const SK_OT_CHAR Horizontal = 1u << 0; |
| 81 | static const SK_OT_CHAR Vertical = 1u << 1; |
| 82 | SK_OT_CHAR value; |
| 83 | } raw; |
| 84 | } flags; |
| 85 | }; //bitmapSizeTable[numSizes]; |
| 86 | |
| 87 | struct IndexSubTableArray { |
| 88 | SK_OT_USHORT firstGlyphIndex; //first glyph code of this range |
| 89 | SK_OT_USHORT lastGlyphIndex; //last glyph code of this range (inclusive) |
| 90 | SK_OT_ULONG additionalOffsetToIndexSubtable; //add to BitmapSizeTable::indexSubTableArrayOffset to get offset from beginning of 'EBLC' |
| 91 | }; //indexSubTableArray[BitmapSizeTable::numberOfIndexSubTables]; |
| 92 | |
| 93 | struct IndexSubHeader { |
| 94 | SK_OT_USHORT indexFormat; //format of this indexSubTable |
| 95 | SK_OT_USHORT imageFormat; //format of 'EBDT' image data |
| 96 | SK_OT_ULONG imageDataOffset; //offset to image data in 'EBDT' table |
| 97 | }; |
| 98 | |
| 99 | // Variable metrics glyphs with 4 byte offsets |
| 100 | struct IndexSubTable1 { |
| 101 | IndexSubHeader header; |
| 102 | //SK_OT_ULONG offsetArray[lastGlyphIndex - firstGlyphIndex + 1 + 1]; //last element points to one past end of last glyph |
| 103 | //glyphData = offsetArray[glyphIndex - firstGlyphIndex] + imageDataOffset |
| 104 | }; |
| 105 | |
| 106 | // All Glyphs have identical metrics |
| 107 | struct IndexSubTable2 { |
| 108 | IndexSubHeader header; |
| 109 | SK_OT_ULONG imageSize; // all glyphs are of the same size |
| 110 | SkOTTableEmbeddedBitmapData::BigGlyphMetrics bigMetrics; // all glyphs have the same metrics; glyph data may be compressed, byte-aligned, or bit-aligned |
| 111 | }; |
| 112 | |
| 113 | // Variable metrics glyphs with 2 byte offsets |
| 114 | struct IndexSubTable3 { |
| 115 | IndexSubHeader header; |
| 116 | //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 |
| 117 | //glyphData = offsetArray[glyphIndex - firstGlyphIndex] + imageDataOffset |
| 118 | }; |
| 119 | |
| 120 | // Variable metrics glyphs with sparse glyph codes |
| 121 | struct IndexSubTable4 { |
| 122 | IndexSubHeader header; |
| 123 | SK_OT_ULONG numGlyphs; |
| 124 | struct CodeOffsetPair { |
| 125 | SK_OT_USHORT glyphCode; |
| 126 | SK_OT_USHORT offset; //location in EBDT |
| 127 | }; //glyphArray[numGlyphs+1] |
| 128 | }; |
| 129 | |
| 130 | // Constant metrics glyphs with sparse glyph codes |
| 131 | struct IndexSubTable5 { |
| 132 | IndexSubHeader header; |
| 133 | SK_OT_ULONG imageSize; //all glyphs have the same data size |
| 134 | SkOTTableEmbeddedBitmapData::BigGlyphMetrics bigMetrics; //all glyphs have the same metrics |
| 135 | SK_OT_ULONG numGlyphs; |
| 136 | //SK_OT_USHORT glyphCodeArray[numGlyphs] //must have even number of entries (set pad to 0) |
| 137 | }; |
| 138 | |
| 139 | union IndexSubTable { |
| 140 | IndexSubHeader header; |
| 141 | IndexSubTable1 format1; |
| 142 | IndexSubTable2 format2; |
| 143 | IndexSubTable3 format3; |
| 144 | IndexSubTable4 format4; |
| 145 | IndexSubTable5 format5; |
| 146 | }; |
| 147 | |
| 148 | }; |
| 149 | |
| 150 | #pragma pack(pop) |
| 151 | |
| 152 | #endif |