pdfjs-dist/lib/display/pattern_helper.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.getShadingPattern = getShadingPattern;
exports.TilingPattern = void 0;

var _util = require("../shared/util.js");

function applyBoundingBox(ctx, bbox) {
  if (!bbox || typeof Path2D === "undefined") {
    return;
  }

  const width = bbox[2] - bbox[0];
  const height = bbox[3] - bbox[1];
  const region = new Path2D();
  region.rect(bbox[0], bbox[1], width, height);
  ctx.clip(region);
}

class BaseShadingPattern {
  constructor() {
    if (this.constructor === BaseShadingPattern) {
      (0, _util.unreachable)("Cannot initialize BaseShadingPattern.");
    }
  }

  getPattern() {
    (0, _util.unreachable)("Abstract method `getPattern` called.");
  }

}

class RadialAxialShadingPattern extends BaseShadingPattern {
  constructor(IR) {
    super();
    this._type = IR[1];
    this._bbox = IR[2];
    this._colorStops = IR[3];
    this._p0 = IR[4];
    this._p1 = IR[5];
    this._r0 = IR[6];
    this._r1 = IR[7];
    this._matrix = IR[8];
    this._patternCache = null;
  }

  _createGradient(ctx) {
    let grad;

    if (this._type === "axial") {
      grad = ctx.createLinearGradient(this._p0[0], this._p0[1], this._p1[0], this._p1[1]);
    } else if (this._type === "radial") {
      grad = ctx.createRadialGradient(this._p0[0], this._p0[1], this._r0, this._p1[0], this._p1[1], this._r1);
    }

    for (const colorStop of this._colorStops) {
      grad.addColorStop(colorStop[0], colorStop[1]);
    }

    return grad;
  }

  getPattern(ctx, owner, inverse, shadingFill = false) {
    let pattern;

    if (this._patternCache) {
      pattern = this._patternCache;
    } else {
      if (!shadingFill) {
        const tmpCanvas = owner.cachedCanvases.getCanvas("pattern", owner.ctx.canvas.width, owner.ctx.canvas.height, true);
        const tmpCtx = tmpCanvas.context;
        tmpCtx.clearRect(0, 0, tmpCtx.canvas.width, tmpCtx.canvas.height);
        tmpCtx.beginPath();
        tmpCtx.rect(0, 0, tmpCtx.canvas.width, tmpCtx.canvas.height);
        tmpCtx.setTransform.apply(tmpCtx, owner.baseTransform);

        if (this._matrix) {
          tmpCtx.transform.apply(tmpCtx, this._matrix);
        }

        applyBoundingBox(tmpCtx, this._bbox);
        tmpCtx.fillStyle = this._createGradient(tmpCtx);
        tmpCtx.fill();
        pattern = ctx.createPattern(tmpCanvas.canvas, "repeat");
      } else {
        applyBoundingBox(ctx, this._bbox);
        pattern = this._createGradient(ctx);
      }

      this._patternCache = pattern;
    }

    if (!shadingFill) {
      const domMatrix = new DOMMatrix(inverse);

      try {
        pattern.setTransform(domMatrix);
      } catch (ex) {
        (0, _util.warn)(`RadialAxialShadingPattern.getPattern: "${ex?.message}".`);
      }
    }

    return pattern;
  }

}

function drawTriangle(data, context, p1, p2, p3, c1, c2, c3) {
  const coords = context.coords,
        colors = context.colors;
  const bytes = data.data,
        rowSize = data.width * 4;
  let tmp;

  if (coords[p1 + 1] > coords[p2 + 1]) {
    tmp = p1;
    p1 = p2;
    p2 = tmp;
    tmp = c1;
    c1 = c2;
    c2 = tmp;
  }

  if (coords[p2 + 1] > coords[p3 + 1]) {
    tmp = p2;
    p2 = p3;
    p3 = tmp;
    tmp = c2;
    c2 = c3;
    c3 = tmp;
  }

  if (coords[p1 + 1] > coords[p2 + 1]) {
    tmp = p1;
    p1 = p2;
    p2 = tmp;
    tmp = c1;
    c1 = c2;
    c2 = tmp;
  }

  const x1 = (coords[p1] + context.offsetX) * context.scaleX;
  const y1 = (coords[p1 + 1] + context.offsetY) * context.scaleY;
  const x2 = (coords[p2] + context.offsetX) * context.scaleX;
  const y2 = (coords[p2 + 1] + context.offsetY) * context.scaleY;
  const x3 = (coords[p3] + context.offsetX) * context.scaleX;
  const y3 = (coords[p3 + 1] + context.offsetY) * context.scaleY;

  if (y1 >= y3) {
    return;
  }

  const c1r = colors[c1],
        c1g = colors[c1 + 1],
        c1b = colors[c1 + 2];
  const c2r = colors[c2],
        c2g = colors[c2 + 1],
        c2b = colors[c2 + 2];
  const c3r = colors[c3],
        c3g = colors[c3 + 1],
        c3b = colors[c3 + 2];
  const minY = Math.round(y1),
        maxY = Math.round(y3);
  let xa, car, cag, cab;
  let xb, cbr, cbg, cbb;

  for (let y = minY; y <= maxY; y++) {
    if (y < y2) {
      let k;

      if (y < y1) {
        k = 0;
      } else {
        k = (y1 - y) / (y1 - y2);
      }

      xa = x1 - (x1 - x2) * k;
      car = c1r - (c1r - c2r) * k;
      cag = c1g - (c1g - c2g) * k;
      cab = c1b - (c1b - c2b) * k;
    } else {
      let k;

      if (y > y3) {
        k = 1;
      } else if (y2 === y3) {
        k = 0;
      } else {
        k = (y2 - y) / (y2 - y3);
      }

      xa = x2 - (x2 - x3) * k;
      car = c2r - (c2r - c3r) * k;
      cag = c2g - (c2g - c3g) * k;
      cab = c2b - (c2b - c3b) * k;
    }

    let k;

    if (y < y1) {
      k = 0;
    } else if (y > y3) {
      k = 1;
    } else {
      k = (y1 - y) / (y1 - y3);
    }

    xb = x1 - (x1 - x3) * k;
    cbr = c1r - (c1r - c3r) * k;
    cbg = c1g - (c1g - c3g) * k;
    cbb = c1b - (c1b - c3b) * k;
    const x1_ = Math.round(Math.min(xa, xb));
    const x2_ = Math.round(Math.max(xa, xb));
    let j = rowSize * y + x1_ * 4;

    for (let x = x1_; x <= x2_; x++) {
      k = (xa - x) / (xa - xb);

      if (k < 0) {
        k = 0;
      } else if (k > 1) {
        k = 1;
      }

      bytes[j++] = car - (car - cbr) * k | 0;
      bytes[j++] = cag - (cag - cbg) * k | 0;
      bytes[j++] = cab - (cab - cbb) * k | 0;
      bytes[j++] = 255;
    }
  }
}

function drawFigure(data, figure, context) {
  const ps = figure.coords;
  const cs = figure.colors;
  let i, ii;

  switch (figure.type) {
    case "lattice":
      const verticesPerRow = figure.verticesPerRow;
      const rows = Math.floor(ps.length / verticesPerRow) - 1;
      const cols = verticesPerRow - 1;

      for (i = 0; i < rows; i++) {
        let q = i * verticesPerRow;

        for (let j = 0; j < cols; j++, q++) {
          drawTriangle(data, context, ps[q], ps[q + 1], ps[q + verticesPerRow], cs[q], cs[q + 1], cs[q + verticesPerRow]);
          drawTriangle(data, context, ps[q + verticesPerRow + 1], ps[q + 1], ps[q + verticesPerRow], cs[q + verticesPerRow + 1], cs[q + 1], cs[q + verticesPerRow]);
        }
      }

      break;

    case "triangles":
      for (i = 0, ii = ps.length; i < ii; i += 3) {
        drawTriangle(data, context, ps[i], ps[i + 1], ps[i + 2], cs[i], cs[i + 1], cs[i + 2]);
      }

      break;

    default:
      throw new Error("illegal figure");
  }
}

class MeshShadingPattern extends BaseShadingPattern {
  constructor(IR) {
    super();
    this._coords = IR[2];
    this._colors = IR[3];
    this._figures = IR[4];
    this._bounds = IR[5];
    this._matrix = IR[6];
    this._bbox = IR[7];
    this._background = IR[8];
  }

  _createMeshCanvas(combinedScale, backgroundColor, cachedCanvases) {
    const EXPECTED_SCALE = 1.1;
    const MAX_PATTERN_SIZE = 3000;
    const BORDER_SIZE = 2;
    const offsetX = Math.floor(this._bounds[0]);
    const offsetY = Math.floor(this._bounds[1]);
    const boundsWidth = Math.ceil(this._bounds[2]) - offsetX;
    const boundsHeight = Math.ceil(this._bounds[3]) - offsetY;
    const width = Math.min(Math.ceil(Math.abs(boundsWidth * combinedScale[0] * EXPECTED_SCALE)), MAX_PATTERN_SIZE);
    const height = Math.min(Math.ceil(Math.abs(boundsHeight * combinedScale[1] * EXPECTED_SCALE)), MAX_PATTERN_SIZE);
    const scaleX = boundsWidth / width;
    const scaleY = boundsHeight / height;
    const context = {
      coords: this._coords,
      colors: this._colors,
      offsetX: -offsetX,
      offsetY: -offsetY,
      scaleX: 1 / scaleX,
      scaleY: 1 / scaleY
    };
    const paddedWidth = width + BORDER_SIZE * 2;
    const paddedHeight = height + BORDER_SIZE * 2;
    const tmpCanvas = cachedCanvases.getCanvas("mesh", paddedWidth, paddedHeight, false);
    const tmpCtx = tmpCanvas.context;
    const data = tmpCtx.createImageData(width, height);

    if (backgroundColor) {
      const bytes = data.data;

      for (let i = 0, ii = bytes.length; i < ii; i += 4) {
        bytes[i] = backgroundColor[0];
        bytes[i + 1] = backgroundColor[1];
        bytes[i + 2] = backgroundColor[2];
        bytes[i + 3] = 255;
      }
    }

    for (const figure of this._figures) {
      drawFigure(data, figure, context);
    }

    tmpCtx.putImageData(data, BORDER_SIZE, BORDER_SIZE);
    const canvas = tmpCanvas.canvas;
    return {
      canvas,
      offsetX: offsetX - BORDER_SIZE * scaleX,
      offsetY: offsetY - BORDER_SIZE * scaleY,
      scaleX,
      scaleY
    };
  }

  getPattern(ctx, owner, inverse, shadingFill = false) {
    applyBoundingBox(ctx, this._bbox);
    let scale;

    if (shadingFill) {
      scale = _util.Util.singularValueDecompose2dScale(ctx.mozCurrentTransform);
    } else {
      scale = _util.Util.singularValueDecompose2dScale(owner.baseTransform);

      if (this._matrix) {
        const matrixScale = _util.Util.singularValueDecompose2dScale(this._matrix);

        scale = [scale[0] * matrixScale[0], scale[1] * matrixScale[1]];
      }
    }

    const temporaryPatternCanvas = this._createMeshCanvas(scale, shadingFill ? null : this._background, owner.cachedCanvases);

    if (!shadingFill) {
      ctx.setTransform.apply(ctx, owner.baseTransform);

      if (this._matrix) {
        ctx.transform.apply(ctx, this._matrix);
      }
    }

    ctx.translate(temporaryPatternCanvas.offsetX, temporaryPatternCanvas.offsetY);
    ctx.scale(temporaryPatternCanvas.scaleX, temporaryPatternCanvas.scaleY);
    return ctx.createPattern(temporaryPatternCanvas.canvas, "no-repeat");
  }

}

class DummyShadingPattern extends BaseShadingPattern {
  getPattern() {
    return "hotpink";
  }

}

function getShadingPattern(IR) {
  switch (IR[0]) {
    case "RadialAxial":
      return new RadialAxialShadingPattern(IR);

    case "Mesh":
      return new MeshShadingPattern(IR);

    case "Dummy":
      return new DummyShadingPattern();
  }

  throw new Error(`Unknown IR type: ${IR[0]}`);
}

const PaintType = {
  COLORED: 1,
  UNCOLORED: 2
};

class TilingPattern {
  static get MAX_PATTERN_SIZE() {
    return (0, _util.shadow)(this, "MAX_PATTERN_SIZE", 3000);
  }

  constructor(IR, color, ctx, canvasGraphicsFactory, baseTransform) {
    this.operatorList = IR[2];
    this.matrix = IR[3] || [1, 0, 0, 1, 0, 0];
    this.bbox = IR[4];
    this.xstep = IR[5];
    this.ystep = IR[6];
    this.paintType = IR[7];
    this.tilingType = IR[8];
    this.color = color;
    this.ctx = ctx;
    this.canvasGraphicsFactory = canvasGraphicsFactory;
    this.baseTransform = baseTransform;
  }

  createPatternCanvas(owner) {
    const operatorList = this.operatorList;
    const bbox = this.bbox;
    const xstep = this.xstep;
    const ystep = this.ystep;
    const paintType = this.paintType;
    const tilingType = this.tilingType;
    const color = this.color;
    const canvasGraphicsFactory = this.canvasGraphicsFactory;
    (0, _util.info)("TilingType: " + tilingType);
    const x0 = bbox[0],
          y0 = bbox[1],
          x1 = bbox[2],
          y1 = bbox[3];

    const matrixScale = _util.Util.singularValueDecompose2dScale(this.matrix);

    const curMatrixScale = _util.Util.singularValueDecompose2dScale(this.baseTransform);

    const combinedScale = [matrixScale[0] * curMatrixScale[0], matrixScale[1] * curMatrixScale[1]];
    const dimx = this.getSizeAndScale(xstep, this.ctx.canvas.width, combinedScale[0]);
    const dimy = this.getSizeAndScale(ystep, this.ctx.canvas.height, combinedScale[1]);
    const tmpCanvas = owner.cachedCanvases.getCanvas("pattern", dimx.size, dimy.size, true);
    const tmpCtx = tmpCanvas.context;
    const graphics = canvasGraphicsFactory.createCanvasGraphics(tmpCtx);
    graphics.groupLevel = owner.groupLevel;
    this.setFillAndStrokeStyleToContext(graphics, paintType, color);
    let adjustedX0 = x0;
    let adjustedY0 = y0;
    let adjustedX1 = x1;
    let adjustedY1 = y1;

    if (x0 < 0) {
      adjustedX0 = 0;
      adjustedX1 += Math.abs(x0);
    }

    if (y0 < 0) {
      adjustedY0 = 0;
      adjustedY1 += Math.abs(y0);
    }

    tmpCtx.translate(-(dimx.scale * adjustedX0), -(dimy.scale * adjustedY0));
    graphics.transform(dimx.scale, 0, 0, dimy.scale, 0, 0);
    this.clipBbox(graphics, adjustedX0, adjustedY0, adjustedX1, adjustedY1);
    graphics.baseTransform = graphics.ctx.mozCurrentTransform.slice();
    graphics.executeOperatorList(operatorList);
    graphics.endDrawing();
    return {
      canvas: tmpCanvas.canvas,
      scaleX: dimx.scale,
      scaleY: dimy.scale,
      offsetX: adjustedX0,
      offsetY: adjustedY0
    };
  }

  getSizeAndScale(step, realOutputSize, scale) {
    step = Math.abs(step);
    const maxSize = Math.max(TilingPattern.MAX_PATTERN_SIZE, realOutputSize);
    let size = Math.ceil(step * scale);

    if (size >= maxSize) {
      size = maxSize;
    } else {
      scale = size / step;
    }

    return {
      scale,
      size
    };
  }

  clipBbox(graphics, x0, y0, x1, y1) {
    const bboxWidth = x1 - x0;
    const bboxHeight = y1 - y0;
    graphics.ctx.rect(x0, y0, bboxWidth, bboxHeight);
    graphics.clip();
    graphics.endPath();
  }

  setFillAndStrokeStyleToContext(graphics, paintType, color) {
    const context = graphics.ctx,
          current = graphics.current;

    switch (paintType) {
      case PaintType.COLORED:
        const ctx = this.ctx;
        context.fillStyle = ctx.fillStyle;
        context.strokeStyle = ctx.strokeStyle;
        current.fillColor = ctx.fillStyle;
        current.strokeColor = ctx.strokeStyle;
        break;

      case PaintType.UNCOLORED:
        const cssColor = _util.Util.makeHexColor(color[0], color[1], color[2]);

        context.fillStyle = cssColor;
        context.strokeStyle = cssColor;
        current.fillColor = cssColor;
        current.strokeColor = cssColor;
        break;

      default:
        throw new _util.FormatError(`Unsupported paint type: ${paintType}`);
    }
  }

  getPattern(ctx, owner, inverse, shadingFill = false) {
    let matrix = inverse;

    if (!shadingFill) {
      matrix = _util.Util.transform(matrix, owner.baseTransform);

      if (this.matrix) {
        matrix = _util.Util.transform(matrix, this.matrix);
      }
    }

    const temporaryPatternCanvas = this.createPatternCanvas(owner);
    let domMatrix = new DOMMatrix(matrix);
    domMatrix = domMatrix.translate(temporaryPatternCanvas.offsetX, temporaryPatternCanvas.offsetY);
    domMatrix = domMatrix.scale(1 / temporaryPatternCanvas.scaleX, 1 / temporaryPatternCanvas.scaleY);
    const pattern = ctx.createPattern(temporaryPatternCanvas.canvas, "repeat");

    try {
      pattern.setTransform(domMatrix);
    } catch (ex) {
      (0, _util.warn)(`TilingPattern.getPattern: "${ex?.message}".`);
    }

    return pattern;
  }

}

exports.TilingPattern = TilingPattern;