pdfjs-dist/lib/core/glyf.js

/**
 * @licstart The following is the entire license notice for the
 * Javascript code in this page
 *
 * Copyright 2021 Mozilla Foundation
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * @licend The above is the entire license notice for the
 * Javascript code in this page
 */
"use strict";

Object.defineProperty(exports, "__esModule", {
  value: true
});
exports.GlyfTable = void 0;
const ON_CURVE_POINT = 1 << 0;
const X_SHORT_VECTOR = 1 << 1;
const Y_SHORT_VECTOR = 1 << 2;
const REPEAT_FLAG = 1 << 3;
const X_IS_SAME_OR_POSITIVE_X_SHORT_VECTOR = 1 << 4;
const Y_IS_SAME_OR_POSITIVE_Y_SHORT_VECTOR = 1 << 5;
const OVERLAP_SIMPLE = 1 << 6;
const ARG_1_AND_2_ARE_WORDS = 1 << 0;
const ARGS_ARE_XY_VALUES = 1 << 1;
const WE_HAVE_A_SCALE = 1 << 3;
const MORE_COMPONENTS = 1 << 5;
const WE_HAVE_AN_X_AND_Y_SCALE = 1 << 6;
const WE_HAVE_A_TWO_BY_TWO = 1 << 7;
const WE_HAVE_INSTRUCTIONS = 1 << 8;

class GlyfTable {
  constructor({
    glyfTable,
    isGlyphLocationsLong,
    locaTable,
    numGlyphs
  }) {
    this.glyphs = [];
    const loca = new DataView(locaTable.buffer, locaTable.byteOffset, locaTable.byteLength);
    const glyf = new DataView(glyfTable.buffer, glyfTable.byteOffset, glyfTable.byteLength);
    const offsetSize = isGlyphLocationsLong ? 4 : 2;
    let prev = isGlyphLocationsLong ? loca.getUint32(0) : 2 * loca.getUint16(0);
    let pos = 0;

    for (let i = 0; i < numGlyphs; i++) {
      pos += offsetSize;
      const next = isGlyphLocationsLong ? loca.getUint32(pos) : 2 * loca.getUint16(pos);

      if (next === prev) {
        this.glyphs.push(new Glyph({}));
        continue;
      }

      const glyph = Glyph.parse(prev, glyf);
      this.glyphs.push(glyph);
      prev = next;
    }
  }

  getSize() {
    return this.glyphs.reduce((a, g) => {
      const size = g.getSize();
      return a + (size + 3 & ~3);
    }, 0);
  }

  write() {
    const totalSize = this.getSize();
    const glyfTable = new DataView(new ArrayBuffer(totalSize));
    const isLocationLong = totalSize > 0x1fffe;
    const offsetSize = isLocationLong ? 4 : 2;
    const locaTable = new DataView(new ArrayBuffer((this.glyphs.length + 1) * offsetSize));

    if (isLocationLong) {
      locaTable.setUint32(0, 0);
    } else {
      locaTable.setUint16(0, 0);
    }

    let pos = 0;
    let locaIndex = 0;

    for (const glyph of this.glyphs) {
      pos += glyph.write(pos, glyfTable);
      pos = pos + 3 & ~3;
      locaIndex += offsetSize;

      if (isLocationLong) {
        locaTable.setUint32(locaIndex, pos);
      } else {
        locaTable.setUint16(locaIndex, pos >> 1);
      }
    }

    return {
      isLocationLong,
      loca: new Uint8Array(locaTable.buffer),
      glyf: new Uint8Array(glyfTable.buffer)
    };
  }

  scale(factors) {
    for (let i = 0, ii = this.glyphs.length; i < ii; i++) {
      this.glyphs[i].scale(factors[i]);
    }
  }

}

exports.GlyfTable = GlyfTable;

class Glyph {
  constructor({
    header = null,
    simple = null,
    composites = null
  }) {
    this.header = header;
    this.simple = simple;
    this.composites = composites;
  }

  static parse(pos, glyf) {
    const [read, header] = GlyphHeader.parse(pos, glyf);
    pos += read;

    if (header.numberOfContours < 0) {
      const composites = [];

      while (true) {
        const [n, composite] = CompositeGlyph.parse(pos, glyf);
        pos += n;
        composites.push(composite);

        if (!(composite.flags & MORE_COMPONENTS)) {
          break;
        }
      }

      return new Glyph({
        header,
        composites
      });
    }

    const simple = SimpleGlyph.parse(pos, glyf, header.numberOfContours);
    return new Glyph({
      header,
      simple
    });
  }

  getSize() {
    if (!this.header) {
      return 0;
    }

    const size = this.simple ? this.simple.getSize() : this.composites.reduce((a, c) => a + c.getSize(), 0);
    return this.header.getSize() + size;
  }

  write(pos, buf) {
    if (!this.header) {
      return 0;
    }

    const spos = pos;
    pos += this.header.write(pos, buf);

    if (this.simple) {
      pos += this.simple.write(pos, buf);
    } else {
      for (const composite of this.composites) {
        pos += composite.write(pos, buf);
      }
    }

    return pos - spos;
  }

  scale(factor) {
    if (!this.header) {
      return;
    }

    const xMiddle = (this.header.xMin + this.header.xMax) / 2;
    this.header.scale(xMiddle, factor);

    if (this.simple) {
      this.simple.scale(xMiddle, factor);
    } else {
      for (const composite of this.composites) {
        composite.scale(xMiddle, factor);
      }
    }
  }

}

class GlyphHeader {
  constructor({
    numberOfContours,
    xMin,
    yMin,
    xMax,
    yMax
  }) {
    this.numberOfContours = numberOfContours;
    this.xMin = xMin;
    this.yMin = yMin;
    this.xMax = xMax;
    this.yMax = yMax;
  }

  static parse(pos, glyf) {
    return [10, new GlyphHeader({
      numberOfContours: glyf.getInt16(pos),
      xMin: glyf.getInt16(pos + 2),
      yMin: glyf.getInt16(pos + 4),
      xMax: glyf.getInt16(pos + 6),
      yMax: glyf.getInt16(pos + 8)
    })];
  }

  getSize() {
    return 10;
  }

  write(pos, buf) {
    buf.setInt16(pos, this.numberOfContours);
    buf.setInt16(pos + 2, this.xMin);
    buf.setInt16(pos + 4, this.yMin);
    buf.setInt16(pos + 6, this.xMax);
    buf.setInt16(pos + 8, this.yMax);
    return 10;
  }

  scale(x, factor) {
    this.xMin = Math.round(x + (this.xMin - x) * factor);
    this.xMax = Math.round(x + (this.xMax - x) * factor);
  }

}

class Contour {
  constructor({
    flags,
    xCoordinates,
    yCoordinates
  }) {
    this.xCoordinates = xCoordinates;
    this.yCoordinates = yCoordinates;
    this.flags = flags;
  }

}

class SimpleGlyph {
  constructor({
    contours,
    instructions
  }) {
    this.contours = contours;
    this.instructions = instructions;
  }

  static parse(pos, glyf, numberOfContours) {
    const endPtsOfContours = [];

    for (let i = 0; i < numberOfContours; i++) {
      const endPt = glyf.getUint16(pos);
      pos += 2;
      endPtsOfContours.push(endPt);
    }

    const numberOfPt = endPtsOfContours[numberOfContours - 1] + 1;
    const instructionLength = glyf.getUint16(pos);
    pos += 2;
    const instructions = new Uint8Array(glyf).slice(pos, pos + instructionLength);
    pos += instructionLength;
    const flags = [];

    for (let i = 0; i < numberOfPt; pos++, i++) {
      let flag = glyf.getUint8(pos);
      flags.push(flag);

      if (flag & REPEAT_FLAG) {
        const count = glyf.getUint8(++pos);
        flag ^= REPEAT_FLAG;

        for (let m = 0; m < count; m++) {
          flags.push(flag);
        }

        i += count;
      }
    }

    const allXCoordinates = [];
    let xCoordinates = [];
    let yCoordinates = [];
    let pointFlags = [];
    const contours = [];
    let endPtsOfContoursIndex = 0;
    let lastCoordinate = 0;

    for (let i = 0; i < numberOfPt; i++) {
      const flag = flags[i];

      if (flag & X_SHORT_VECTOR) {
        const x = glyf.getUint8(pos++);
        lastCoordinate += flag & X_IS_SAME_OR_POSITIVE_X_SHORT_VECTOR ? x : -x;
        xCoordinates.push(lastCoordinate);
      } else if (flag & X_IS_SAME_OR_POSITIVE_X_SHORT_VECTOR) {
        xCoordinates.push(lastCoordinate);
      } else {
        lastCoordinate += glyf.getInt16(pos);
        pos += 2;
        xCoordinates.push(lastCoordinate);
      }

      if (endPtsOfContours[endPtsOfContoursIndex] === i) {
        endPtsOfContoursIndex++;
        allXCoordinates.push(xCoordinates);
        xCoordinates = [];
      }
    }

    lastCoordinate = 0;
    endPtsOfContoursIndex = 0;

    for (let i = 0; i < numberOfPt; i++) {
      const flag = flags[i];

      if (flag & Y_SHORT_VECTOR) {
        const y = glyf.getUint8(pos++);
        lastCoordinate += flag & Y_IS_SAME_OR_POSITIVE_Y_SHORT_VECTOR ? y : -y;
        yCoordinates.push(lastCoordinate);
      } else if (flag & Y_IS_SAME_OR_POSITIVE_Y_SHORT_VECTOR) {
        yCoordinates.push(lastCoordinate);
      } else {
        lastCoordinate += glyf.getInt16(pos);
        pos += 2;
        yCoordinates.push(lastCoordinate);
      }

      pointFlags.push(flag & ON_CURVE_POINT | flag & OVERLAP_SIMPLE);

      if (endPtsOfContours[endPtsOfContoursIndex] === i) {
        xCoordinates = allXCoordinates[endPtsOfContoursIndex];
        endPtsOfContoursIndex++;
        contours.push(new Contour({
          flags: pointFlags,
          xCoordinates,
          yCoordinates
        }));
        yCoordinates = [];
        pointFlags = [];
      }
    }

    return new SimpleGlyph({
      contours,
      instructions
    });
  }

  getSize() {
    let size = this.contours.length * 2 + 2 + this.instructions.length;
    let lastX = 0;
    let lastY = 0;

    for (const contour of this.contours) {
      size += contour.flags.length;

      for (let i = 0, ii = contour.xCoordinates.length; i < ii; i++) {
        const x = contour.xCoordinates[i];
        const y = contour.yCoordinates[i];
        let abs = Math.abs(x - lastX);

        if (abs > 255) {
          size += 2;
        } else if (abs > 0) {
          size += 1;
        }

        lastX = x;
        abs = Math.abs(y - lastY);

        if (abs > 255) {
          size += 2;
        } else if (abs > 0) {
          size += 1;
        }

        lastY = y;
      }
    }

    return size;
  }

  write(pos, buf) {
    const spos = pos;
    const xCoordinates = [];
    const yCoordinates = [];
    const flags = [];
    let lastX = 0;
    let lastY = 0;

    for (const contour of this.contours) {
      for (let i = 0, ii = contour.xCoordinates.length; i < ii; i++) {
        let flag = contour.flags[i];
        const x = contour.xCoordinates[i];
        let delta = x - lastX;

        if (delta === 0) {
          flag |= X_IS_SAME_OR_POSITIVE_X_SHORT_VECTOR;
          xCoordinates.push(0);
        } else {
          const abs = Math.abs(delta);

          if (abs <= 255) {
            flag |= delta >= 0 ? X_SHORT_VECTOR | X_IS_SAME_OR_POSITIVE_X_SHORT_VECTOR : X_SHORT_VECTOR;
            xCoordinates.push(abs);
          } else {
            xCoordinates.push(delta);
          }
        }

        lastX = x;
        const y = contour.yCoordinates[i];
        delta = y - lastY;

        if (delta === 0) {
          flag |= Y_IS_SAME_OR_POSITIVE_Y_SHORT_VECTOR;
          yCoordinates.push(0);
        } else {
          const abs = Math.abs(delta);

          if (abs <= 255) {
            flag |= delta >= 0 ? Y_SHORT_VECTOR | Y_IS_SAME_OR_POSITIVE_Y_SHORT_VECTOR : Y_SHORT_VECTOR;
            yCoordinates.push(abs);
          } else {
            yCoordinates.push(delta);
          }
        }

        lastY = y;
        flags.push(flag);
      }

      buf.setUint16(pos, xCoordinates.length - 1);
      pos += 2;
    }

    buf.setUint16(pos, this.instructions.length);
    pos += 2;

    if (this.instructions.length) {
      new Uint8Array(buf.buffer, 0, buf.buffer.byteLength).set(this.instructions, pos);
      pos += this.instructions.length;
    }

    for (const flag of flags) {
      buf.setUint8(pos++, flag);
    }

    for (let i = 0, ii = xCoordinates.length; i < ii; i++) {
      const x = xCoordinates[i];
      const flag = flags[i];

      if (flag & X_SHORT_VECTOR) {
        buf.setUint8(pos++, x);
      } else if (!(flag & X_IS_SAME_OR_POSITIVE_X_SHORT_VECTOR)) {
        buf.setInt16(pos, x);
        pos += 2;
      }
    }

    for (let i = 0, ii = yCoordinates.length; i < ii; i++) {
      const y = yCoordinates[i];
      const flag = flags[i];

      if (flag & Y_SHORT_VECTOR) {
        buf.setUint8(pos++, y);
      } else if (!(flag & Y_IS_SAME_OR_POSITIVE_Y_SHORT_VECTOR)) {
        buf.setInt16(pos, y);
        pos += 2;
      }
    }

    return pos - spos;
  }

  scale(x, factor) {
    for (const contour of this.contours) {
      if (contour.xCoordinates.length === 0) {
        continue;
      }

      for (let i = 0, ii = contour.xCoordinates.length; i < ii; i++) {
        contour.xCoordinates[i] = Math.round(x + (contour.xCoordinates[i] - x) * factor);
      }
    }
  }

}

class CompositeGlyph {
  constructor({
    flags,
    glyphIndex,
    argument1,
    argument2,
    transf,
    instructions
  }) {
    this.flags = flags;
    this.glyphIndex = glyphIndex;
    this.argument1 = argument1;
    this.argument2 = argument2;
    this.transf = transf;
    this.instructions = instructions;
  }

  static parse(pos, glyf) {
    const spos = pos;
    const transf = [];
    let flags = glyf.getUint16(pos);
    const glyphIndex = glyf.getUint16(pos + 2);
    pos += 4;
    let argument1, argument2;

    if (flags & ARG_1_AND_2_ARE_WORDS) {
      if (flags & ARGS_ARE_XY_VALUES) {
        argument1 = glyf.getInt16(pos);
        argument2 = glyf.getInt16(pos + 2);
      } else {
        argument1 = glyf.getUint16(pos);
        argument2 = glyf.getUint16(pos + 2);
      }

      pos += 4;
      flags ^= ARG_1_AND_2_ARE_WORDS;
    } else {
      argument1 = glyf.getUint8(pos);
      argument2 = glyf.getUint8(pos + 1);

      if (flags & ARGS_ARE_XY_VALUES) {
        const abs1 = argument1 & 0x7f;
        argument1 = argument1 & 0x80 ? -abs1 : abs1;
        const abs2 = argument2 & 0x7f;
        argument2 = argument2 & 0x80 ? -abs2 : abs2;
      }

      pos += 2;
    }

    if (flags & WE_HAVE_A_SCALE) {
      transf.push(glyf.getUint16(pos));
      pos += 2;
    } else if (flags & WE_HAVE_AN_X_AND_Y_SCALE) {
      transf.push(glyf.getUint16(pos), glyf.getUint16(pos + 2));
      pos += 4;
    } else if (flags & WE_HAVE_A_TWO_BY_TWO) {
      transf.push(glyf.getUint16(pos), glyf.getUint16(pos + 2), glyf.getUint16(pos + 4), glyf.getUint16(pos + 6));
      pos += 8;
    }

    let instructions = null;

    if (flags & WE_HAVE_INSTRUCTIONS) {
      const instructionLength = glyf.getUint16(pos);
      pos += 2;
      instructions = new Uint8Array(glyf).slice(pos, pos + instructionLength);
      pos += instructionLength;
    }

    return [pos - spos, new CompositeGlyph({
      flags,
      glyphIndex,
      argument1,
      argument2,
      transf,
      instructions
    })];
  }

  getSize() {
    let size = 2 + 2 + this.transf.length * 2;

    if (this.flags & WE_HAVE_INSTRUCTIONS) {
      size += 2 + this.instructions.length;
    }

    size += 2;

    if (this.flags & 2) {
      if (!(this.argument1 >= -128 && this.argument1 <= 127 && this.argument2 >= -128 && this.argument2 <= 127)) {
        size += 2;
      }
    } else {
      if (!(this.argument1 >= 0 && this.argument1 <= 255 && this.argument2 >= 0 && this.argument2 <= 255)) {
        size += 2;
      }
    }

    return size;
  }

  write(pos, buf) {
    const spos = pos;

    if (this.flags & ARGS_ARE_XY_VALUES) {
      if (!(this.argument1 >= -128 && this.argument1 <= 127 && this.argument2 >= -128 && this.argument2 <= 127)) {
        this.flags |= ARG_1_AND_2_ARE_WORDS;
      }
    } else {
      if (!(this.argument1 >= 0 && this.argument1 <= 255 && this.argument2 >= 0 && this.argument2 <= 255)) {
        this.flags |= ARG_1_AND_2_ARE_WORDS;
      }
    }

    buf.setUint16(pos, this.flags);
    buf.setUint16(pos + 2, this.glyphIndex);
    pos += 4;

    if (this.flags & ARG_1_AND_2_ARE_WORDS) {
      if (this.flags & ARGS_ARE_XY_VALUES) {
        buf.setInt16(pos, this.argument1);
        buf.setInt16(pos + 2, this.argument2);
      } else {
        buf.setUint16(pos, this.argument1);
        buf.setUint16(pos + 2, this.argument2);
      }

      pos += 4;
    } else {
      buf.setUint8(pos, this.argument1);
      buf.setUint8(pos + 1, this.argument2);
      pos += 2;
    }

    if (this.flags & WE_HAVE_INSTRUCTIONS) {
      buf.setUint16(pos, this.instructions.length);
      pos += 2;

      if (this.instructions.length) {
        new Uint8Array(buf.buffer, 0, buf.buffer.byteLength).set(this.instructions, pos);
        pos += this.instructions.length;
      }
    }

    return pos - spos;
  }

  scale(x, factor) {}

}