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node_modules/fontkit/src/subset/CFFSubset.js

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+import Subset from './Subset';
+import CFFTop from '../cff/CFFTop';
+import CFFPrivateDict from '../cff/CFFPrivateDict';
+import standardStrings from '../cff/CFFStandardStrings';
+
+export default class CFFSubset extends Subset {
+  constructor(font) {
+    super(font);
+
+    this.cff = this.font['CFF '];
+    if (!this.cff) {
+      throw new Error('Not a CFF Font');
+    }
+  }
+
+  subsetCharstrings() {
+    this.charstrings = [];
+    let gsubrs = {};
+
+    for (let gid of this.glyphs) {
+      this.charstrings.push(this.cff.getCharString(gid));
+
+      let glyph = this.font.getGlyph(gid);
+      let path = glyph.path; // this causes the glyph to be parsed
+
+      for (let subr in glyph._usedGsubrs) {
+        gsubrs[subr] = true;
+      }
+    }
+
+    this.gsubrs = this.subsetSubrs(this.cff.globalSubrIndex, gsubrs);
+  }
+
+  subsetSubrs(subrs, used) {
+    let res = [];
+    for (let i = 0; i < subrs.length; i++) {
+      let subr = subrs[i];
+      if (used[i]) {
+        this.cff.stream.pos = subr.offset;
+        res.push(this.cff.stream.readBuffer(subr.length));
+      } else {
+        res.push(new Uint8Array([11])); // return
+      }
+    }
+
+    return res;
+  }
+
+  subsetFontdict(topDict) {
+    topDict.FDArray = [];
+    topDict.FDSelect = {
+      version: 0,
+      fds: []
+    };
+
+    let used_fds = {};
+    let used_subrs = [];
+    let fd_select = {};
+    for (let gid of this.glyphs) {
+      let fd = this.cff.fdForGlyph(gid);
+      if (fd == null) {
+        continue;
+      }
+
+      if (!used_fds[fd]) {
+        topDict.FDArray.push(Object.assign({}, this.cff.topDict.FDArray[fd]));
+        used_subrs.push({});
+        fd_select[fd] = topDict.FDArray.length - 1;
+      }
+
+      used_fds[fd] = true;
+      topDict.FDSelect.fds.push(fd_select[fd]);
+
+      let glyph = this.font.getGlyph(gid);
+      let path = glyph.path; // this causes the glyph to be parsed
+      for (let subr in glyph._usedSubrs) {
+        used_subrs[fd_select[fd]][subr] = true;
+      }
+    }
+
+    for (let i = 0; i < topDict.FDArray.length; i++) {
+      let dict = topDict.FDArray[i];
+      delete dict.FontName;
+      if (dict.Private && dict.Private.Subrs) {
+        dict.Private = Object.assign({}, dict.Private);
+        dict.Private.Subrs = this.subsetSubrs(dict.Private.Subrs, used_subrs[i]);
+      }
+    }
+
+    return;
+  }
+
+  createCIDFontdict(topDict) {
+    let used_subrs = {};
+    for (let gid of this.glyphs) {
+      let glyph = this.font.getGlyph(gid);
+      let path = glyph.path; // this causes the glyph to be parsed
+
+      for (let subr in glyph._usedSubrs) {
+        used_subrs[subr] = true;
+      }
+    }
+
+    let privateDict = Object.assign({}, this.cff.topDict.Private);
+    if (this.cff.topDict.Private && this.cff.topDict.Private.Subrs) {
+      privateDict.Subrs = this.subsetSubrs(this.cff.topDict.Private.Subrs, used_subrs);
+    }
+
+    topDict.FDArray = [{ Private: privateDict }];
+    return topDict.FDSelect = {
+      version: 3,
+      nRanges: 1,
+      ranges: [{ first: 0, fd: 0 }],
+      sentinel: this.charstrings.length
+    };
+  }
+
+  addString(string) {
+    if (!string) {
+      return null;
+    }
+
+    if (!this.strings) {
+      this.strings = [];
+    }
+
+    this.strings.push(string);
+    return standardStrings.length + this.strings.length - 1;
+  }
+
+  encode() {
+    this.subsetCharstrings();
+
+    let charset = {
+      version: this.charstrings.length > 255 ? 2 : 1,
+      ranges: [{ first: 1, nLeft: this.charstrings.length - 2 }]
+    };
+
+    let topDict = Object.assign({}, this.cff.topDict);
+    topDict.Private = null;
+    topDict.charset = charset;
+    topDict.Encoding = null;
+    topDict.CharStrings = this.charstrings;
+
+    for (let key of ['version', 'Notice', 'Copyright', 'FullName', 'FamilyName', 'Weight', 'PostScript', 'BaseFontName', 'FontName']) {
+      topDict[key] = this.addString(this.cff.string(topDict[key]));
+    }
+
+    topDict.ROS = [this.addString('Adobe'), this.addString('Identity'), 0];
+    topDict.CIDCount = this.charstrings.length;
+
+    if (this.cff.isCIDFont) {
+      this.subsetFontdict(topDict);
+    } else {
+      this.createCIDFontdict(topDict);
+    }
+
+    let top = {
+      version: 1,
+      hdrSize: this.cff.hdrSize,
+      offSize: 4,
+      header: this.cff.header,
+      nameIndex: [this.cff.postscriptName],
+      topDictIndex: [topDict],
+      stringIndex: this.strings,
+      globalSubrIndex: this.gsubrs
+    };
+
+    return CFFTop.toBuffer(top);
+  }
+}