Merge pull request #580 from Connum/feature/parse-cff2

implement CFF2 parsing
opentypejs · Mar 4, 2023 · ca3b438 · ca3b438
2 parents c5c2c06 + 97e67bb
commit ca3b438
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Showing 6 changed files with 542 additions and 118 deletions.
diff --git a/src/glyphset.js b/src/glyphset.js
@@ -141,12 +141,12 @@ function ttfGlyphLoader(font, index, parseGlyph, data, position, buildPath) {
  * @param  {string} charstring
  * @return {opentype.Glyph}
  */
-function cffGlyphLoader(font, index, parseCFFCharstring, charstring) {
+function cffGlyphLoader(font, index, parseCFFCharstring, charstring, version) {
     return function() {
         const glyph = new Glyph({index: index, font: font});
 
         glyph.path = function() {
-            const path = parseCFFCharstring(font, glyph, charstring);
+            const path = parseCFFCharstring(font, glyph, charstring, version);
             path.unitsPerEm = font.unitsPerEm;
             return path;
         };

diff --git a/src/opentype.js b/src/opentype.js
@@ -214,6 +214,7 @@ function parseBuffer(buffer, opt={}) {
     }
 
     let cffTableEntry;
+    let cff2TableEntry;
     let fvarTableEntry;
     let statTableEntry;
     let gvarTableEntry;
@@ -319,6 +320,9 @@ function parseBuffer(buffer, opt={}) {
             case 'CFF ':
                 cffTableEntry = tableEntry;
                 break;
+            case 'CFF2':
+                cff2TableEntry = tableEntry;
+                break;
             case 'kern':
                 kernTableEntry = tableEntry;
                 break;
@@ -350,8 +354,11 @@ function parseBuffer(buffer, opt={}) {
     } else if (cffTableEntry) {
         const cffTable = uncompressTable(data, cffTableEntry);
         cff.parse(cffTable.data, cffTable.offset, font, opt);
+    } else if (cff2TableEntry) {
+        const cffTable2 = uncompressTable(data, cff2TableEntry);
+        cff.parse(cffTable2.data, cffTable2.offset, font, opt);
     } else {
-        throw new Error('Font doesn\'t contain TrueType or CFF outlines.');
+        throw new Error('Font doesn\'t contain TrueType, CFF or CFF2 outlines.');
     }
 
     const hmtxTable = uncompressTable(data, hmtxTableEntry);

diff --git a/src/parse.js b/src/parse.js
@@ -86,6 +86,11 @@ const typeOffsets = {
     tag: 4
 };
 
+const masks = {
+    LONG_WORDS: 0x8000,
+    WORD_DELTA_COUNT_MASK: 0x7FFF
+};
+
 // A stateful parser that changes the offset whenever a value is retrieved.
 // The data is a DataView.
 function Parser(data, offset) {
@@ -551,6 +556,7 @@ Parser.uShortList = Parser.prototype.parseUShortList;
 Parser.uLong = Parser.offset32 = Parser.prototype.parseULong;
 Parser.uLongList = Parser.prototype.parseULongList;
 Parser.fixed = Parser.prototype.parseFixed;
+Parser.f2Dot14 = Parser.prototype.parseF2Dot14;
 Parser.struct = Parser.prototype.parseStruct;
 Parser.coverage = Parser.prototype.parseCoverage;
 Parser.classDef = Parser.prototype.parseClassDef;
@@ -615,6 +621,83 @@ Parser.prototype.parseFeatureVariationsList = function() {
     }) || [];
 };
 
+// VariationStore, ItemVariationStore, VariationRegionList, regionAxes, ItemVariationSubtables ...
+// https://learn.microsoft.com/en-us/typography/opentype/spec/otvarcommonformats
+// https://learn.microsoft.com/en-us/typography/opentype/spec/otvarcommonformats#item-variation-store-header-and-item-variation-data-subtables
+
+Parser.prototype.parseVariationStore = function() {
+    const vsOffset = this.relativeOffset;
+    const length = this.parseUShort();
+    const variationStore = {
+        itemVariationStore: this.parseItemVariationStore()
+    };
+    this.relativeOffset = vsOffset + length + 2; // + 2 for length field
+    return variationStore;
+};
+
+Parser.prototype.parseItemVariationStore = function() {
+    const itemStoreOffset = this.relativeOffset;
+    const iVStore = {
+        format: this.parseUShort(),
+        variationRegions: [],
+        itemVariationSubtables: []
+    };
+
+    const variationRegionListOffset = this.parseOffset32();
+    const itemVariationDataCount = this.parseUShort();
+    const itemVariationDataOffsets = this.parseULongList(itemVariationDataCount);    
+
+    this.relativeOffset = itemStoreOffset + variationRegionListOffset;
+    iVStore.variationRegions = this.parseVariationRegionList();
+
+    for( let i = 0; i < itemVariationDataCount; i++ ) {
+        const subtableOffset = itemVariationDataOffsets[i];
+        this.relativeOffset = itemStoreOffset + subtableOffset;
+        iVStore.itemVariationSubtables.push(this.parseItemVariationSubtable());
+    }
+
+    return iVStore;
+};
+
+Parser.prototype.parseVariationRegionList = function() {
+    const axisCount = this.parseUShort();
+    const regionCount = this.parseUShort();
+    return  this.parseRecordList(regionCount, {
+        regionAxes: Parser.recordList(axisCount, {
+            startCoord: Parser.f2Dot14,
+            peakCoord: Parser.f2Dot14,
+            endCoord: Parser.f2Dot14,
+        })
+    });
+};
+
+Parser.prototype.parseItemVariationSubtable = function() {
+    const itemCount = this.parseUShort();
+    const wordDeltaCount = this.parseUShort();
+
+    const subtable = {
+        regionIndexes: this.parseUShortList(),
+        deltaSets: this.parseDeltaSets(itemCount, wordDeltaCount)
+    };
+
+    return subtable;
+};
+
+Parser.prototype.parseDeltaSets = function(itemCount, wordDeltaCount) {
+    const deltas = [];
+    const longFlag = wordDeltaCount & masks.LONG_WORDS;
+    const wordCount = wordDeltaCount & masks.WORD_DELTA_COUNT_MASK;
+
+    const wordParser = (longFlag ? this.parseULong : this.parseUShort).bind(this);
+    const restParser = (longFlag ? this.parseUShort : this.parseByte).bind(this);
+    for( let i = 0; i < itemCount; i++ ) {
+        const deltaParser = i < wordCount ? wordParser : restParser;
+        deltas.push(deltaParser());
+    }
+
+    return deltas;
+};
+
 export default {
     getByte,
     getCard8: getByte,