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import cloneDeep from 'clone';
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import Subset from './Subset';
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import Directory from '../tables/directory';
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import Tables from '../tables';
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import TTFGlyphEncoder from '../glyph/TTFGlyphEncoder';
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export default class TTFSubset extends Subset {
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constructor(font) {
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super(font);
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this.glyphEncoder = new TTFGlyphEncoder;
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}
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_addGlyph(gid) {
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let glyph = this.font.getGlyph(gid);
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let glyf = glyph._decode();
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// get the offset to the glyph from the loca table
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let curOffset = this.font.loca.offsets[gid];
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let nextOffset = this.font.loca.offsets[gid + 1];
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let stream = this.font._getTableStream('glyf');
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stream.pos += curOffset;
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let buffer = stream.readBuffer(nextOffset - curOffset);
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// if it is a compound glyph, include its components
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if (glyf && glyf.numberOfContours < 0) {
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buffer = new Buffer(buffer);
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for (let component of glyf.components) {
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gid = this.includeGlyph(component.glyphID);
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buffer.writeUInt16BE(gid, component.pos);
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}
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} else if (glyf && this.font._variationProcessor) {
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// If this is a TrueType variation glyph, re-encode the path
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buffer = this.glyphEncoder.encodeSimple(glyph.path, glyf.instructions);
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}
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this.glyf.push(buffer);
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this.loca.offsets.push(this.offset);
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this.hmtx.metrics.push({
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advance: glyph.advanceWidth,
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bearing: glyph._getMetrics().leftBearing
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});
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this.offset += buffer.length;
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return this.glyf.length - 1;
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}
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encode(stream) {
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// tables required by PDF spec:
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// head, hhea, loca, maxp, cvt , prep, glyf, hmtx, fpgm
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//
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// additional tables required for standalone fonts:
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// name, cmap, OS/2, post
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this.glyf = [];
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this.offset = 0;
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this.loca = {
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offsets: [],
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version: this.font.loca.version
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};
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this.hmtx = {
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metrics: [],
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bearings: []
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};
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// include all the glyphs
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// not using a for loop because we need to support adding more
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// glyphs to the array as we go, and CoffeeScript caches the length.
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let i = 0;
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while (i < this.glyphs.length) {
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this._addGlyph(this.glyphs[i++]);
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}
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let maxp = cloneDeep(this.font.maxp);
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maxp.numGlyphs = this.glyf.length;
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this.loca.offsets.push(this.offset);
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let head = cloneDeep(this.font.head);
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head.indexToLocFormat = this.loca.version;
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let hhea = cloneDeep(this.font.hhea);
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hhea.numberOfMetrics = this.hmtx.metrics.length;
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// map = []
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// for index in [0...256]
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// if index < @numGlyphs
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// map[index] = index
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// else
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// map[index] = 0
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//
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// cmapTable =
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// version: 0
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// length: 262
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// language: 0
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// codeMap: map
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//
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// cmap =
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// version: 0
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// numSubtables: 1
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// tables: [
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// platformID: 1
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// encodingID: 0
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// table: cmapTable
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// ]
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// TODO: subset prep, cvt, fpgm?
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Directory.encode(stream, {
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tables: {
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head,
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hhea,
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loca: this.loca,
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maxp,
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'cvt ': this.font['cvt '],
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prep: this.font.prep,
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glyf: this.glyf,
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hmtx: this.hmtx,
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fpgm: this.font.fpgm
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// name: clone @font.name
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// 'OS/2': clone @font['OS/2']
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// post: clone @font.post
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// cmap: cmap
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}
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});
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}
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}
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