pdfjs-dist/lib/core/image.js

/* Copyright 2017 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.
 */
'use strict';
var sharedUtil = require('../shared/util.js');
var corePrimitives = require('./primitives.js');
var coreColorSpace = require('./colorspace.js');
var coreStream = require('./stream.js');
var coreJpx = require('./jpx.js');
var ImageKind = sharedUtil.ImageKind;
var assert = sharedUtil.assert;
var error = sharedUtil.error;
var info = sharedUtil.info;
var isArray = sharedUtil.isArray;
var warn = sharedUtil.warn;
var Name = corePrimitives.Name;
var isStream = corePrimitives.isStream;
var ColorSpace = coreColorSpace.ColorSpace;
var DecodeStream = coreStream.DecodeStream;
var JpegStream = coreStream.JpegStream;
var JpxImage = coreJpx.JpxImage;
var PDFImage = function PDFImageClosure() {
 function handleImageData(image, nativeDecoder) {
  if (nativeDecoder && nativeDecoder.canDecode(image)) {
   return nativeDecoder.decode(image);
  }
  return Promise.resolve(image);
 }
 function decodeAndClamp(value, addend, coefficient, max) {
  value = addend + value * coefficient;
  return value < 0 ? 0 : value > max ? max : value;
 }
 function resizeImageMask(src, bpc, w1, h1, w2, h2) {
  var length = w2 * h2;
  var dest = bpc <= 8 ? new Uint8Array(length) : bpc <= 16 ? new Uint16Array(length) : new Uint32Array(length);
  var xRatio = w1 / w2;
  var yRatio = h1 / h2;
  var i, j, py, newIndex = 0, oldIndex;
  var xScaled = new Uint16Array(w2);
  var w1Scanline = w1;
  for (i = 0; i < w2; i++) {
   xScaled[i] = Math.floor(i * xRatio);
  }
  for (i = 0; i < h2; i++) {
   py = Math.floor(i * yRatio) * w1Scanline;
   for (j = 0; j < w2; j++) {
    oldIndex = py + xScaled[j];
    dest[newIndex++] = src[oldIndex];
   }
  }
  return dest;
 }
 function PDFImage(xref, res, image, inline, smask, mask, isMask) {
  this.image = image;
  var dict = image.dict;
  if (dict.has('Filter')) {
   var filter = dict.get('Filter').name;
   if (filter === 'JPXDecode') {
    var jpxImage = new JpxImage();
    jpxImage.parseImageProperties(image.stream);
    image.stream.reset();
    image.bitsPerComponent = jpxImage.bitsPerComponent;
    image.numComps = jpxImage.componentsCount;
   } else if (filter === 'JBIG2Decode') {
    image.bitsPerComponent = 1;
    image.numComps = 1;
   }
  }
  this.width = dict.get('Width', 'W');
  this.height = dict.get('Height', 'H');
  if (this.width < 1 || this.height < 1) {
   error('Invalid image width: ' + this.width + ' or height: ' + this.height);
  }
  this.interpolate = dict.get('Interpolate', 'I') || false;
  this.imageMask = dict.get('ImageMask', 'IM') || false;
  this.matte = dict.get('Matte') || false;
  var bitsPerComponent = image.bitsPerComponent;
  if (!bitsPerComponent) {
   bitsPerComponent = dict.get('BitsPerComponent', 'BPC');
   if (!bitsPerComponent) {
    if (this.imageMask) {
     bitsPerComponent = 1;
    } else {
     error('Bits per component missing in image: ' + this.imageMask);
    }
   }
  }
  this.bpc = bitsPerComponent;
  if (!this.imageMask) {
   var colorSpace = dict.get('ColorSpace', 'CS');
   if (!colorSpace) {
    info('JPX images (which do not require color spaces)');
    switch (image.numComps) {
    case 1:
     colorSpace = Name.get('DeviceGray');
     break;
    case 3:
     colorSpace = Name.get('DeviceRGB');
     break;
    case 4:
     colorSpace = Name.get('DeviceCMYK');
     break;
    default:
     error('JPX images with ' + this.numComps + ' color components not supported.');
    }
   }
   this.colorSpace = ColorSpace.parse(colorSpace, xref, res);
   this.numComps = this.colorSpace.numComps;
  }
  this.decode = dict.getArray('Decode', 'D');
  this.needsDecode = false;
  if (this.decode && (this.colorSpace && !this.colorSpace.isDefaultDecode(this.decode) || isMask && !ColorSpace.isDefaultDecode(this.decode, 1))) {
   this.needsDecode = true;
   var max = (1 << bitsPerComponent) - 1;
   this.decodeCoefficients = [];
   this.decodeAddends = [];
   for (var i = 0, j = 0; i < this.decode.length; i += 2, ++j) {
    var dmin = this.decode[i];
    var dmax = this.decode[i + 1];
    this.decodeCoefficients[j] = dmax - dmin;
    this.decodeAddends[j] = max * dmin;
   }
  }
  if (smask) {
   this.smask = new PDFImage(xref, res, smask, false);
  } else if (mask) {
   if (isStream(mask)) {
    var maskDict = mask.dict, imageMask = maskDict.get('ImageMask', 'IM');
    if (!imageMask) {
     warn('Ignoring /Mask in image without /ImageMask.');
    } else {
     this.mask = new PDFImage(xref, res, mask, false, null, null, true);
    }
   } else {
    this.mask = mask;
   }
  }
 }
 PDFImage.buildImage = function PDFImage_buildImage(handler, xref, res, image, inline, nativeDecoder) {
  var imagePromise = handleImageData(image, nativeDecoder);
  var smaskPromise;
  var maskPromise;
  var smask = image.dict.get('SMask');
  var mask = image.dict.get('Mask');
  if (smask) {
   smaskPromise = handleImageData(smask, nativeDecoder);
   maskPromise = Promise.resolve(null);
  } else {
   smaskPromise = Promise.resolve(null);
   if (mask) {
    if (isStream(mask)) {
     maskPromise = handleImageData(mask, nativeDecoder);
    } else if (isArray(mask)) {
     maskPromise = Promise.resolve(mask);
    } else {
     warn('Unsupported mask format.');
     maskPromise = Promise.resolve(null);
    }
   } else {
    maskPromise = Promise.resolve(null);
   }
  }
  return Promise.all([
   imagePromise,
   smaskPromise,
   maskPromise
  ]).then(function (results) {
   var imageData = results[0];
   var smaskData = results[1];
   var maskData = results[2];
   return new PDFImage(xref, res, imageData, inline, smaskData, maskData);
  });
 };
 PDFImage.createMask = function PDFImage_createMask(imgArray, width, height, imageIsFromDecodeStream, inverseDecode) {
  var computedLength = (width + 7 >> 3) * height;
  var actualLength = imgArray.byteLength;
  var haveFullData = computedLength === actualLength;
  var data, i;
  if (imageIsFromDecodeStream && (!inverseDecode || haveFullData)) {
   data = imgArray;
  } else if (!inverseDecode) {
   data = new Uint8Array(actualLength);
   data.set(imgArray);
  } else {
   data = new Uint8Array(computedLength);
   data.set(imgArray);
   for (i = actualLength; i < computedLength; i++) {
    data[i] = 0xff;
   }
  }
  if (inverseDecode) {
   for (i = 0; i < actualLength; i++) {
    data[i] = ~data[i];
   }
  }
  return {
   data: data,
   width: width,
   height: height
  };
 };
 PDFImage.prototype = {
  get drawWidth() {
   return Math.max(this.width, this.smask && this.smask.width || 0, this.mask && this.mask.width || 0);
  },
  get drawHeight() {
   return Math.max(this.height, this.smask && this.smask.height || 0, this.mask && this.mask.height || 0);
  },
  decodeBuffer: function PDFImage_decodeBuffer(buffer) {
   var bpc = this.bpc;
   var numComps = this.numComps;
   var decodeAddends = this.decodeAddends;
   var decodeCoefficients = this.decodeCoefficients;
   var max = (1 << bpc) - 1;
   var i, ii;
   if (bpc === 1) {
    for (i = 0, ii = buffer.length; i < ii; i++) {
     buffer[i] = +!buffer[i];
    }
    return;
   }
   var index = 0;
   for (i = 0, ii = this.width * this.height; i < ii; i++) {
    for (var j = 0; j < numComps; j++) {
     buffer[index] = decodeAndClamp(buffer[index], decodeAddends[j], decodeCoefficients[j], max);
     index++;
    }
   }
  },
  getComponents: function PDFImage_getComponents(buffer) {
   var bpc = this.bpc;
   if (bpc === 8) {
    return buffer;
   }
   var width = this.width;
   var height = this.height;
   var numComps = this.numComps;
   var length = width * height * numComps;
   var bufferPos = 0;
   var output = bpc <= 8 ? new Uint8Array(length) : bpc <= 16 ? new Uint16Array(length) : new Uint32Array(length);
   var rowComps = width * numComps;
   var max = (1 << bpc) - 1;
   var i = 0, ii, buf;
   if (bpc === 1) {
    var mask, loop1End, loop2End;
    for (var j = 0; j < height; j++) {
     loop1End = i + (rowComps & ~7);
     loop2End = i + rowComps;
     while (i < loop1End) {
      buf = buffer[bufferPos++];
      output[i] = buf >> 7 & 1;
      output[i + 1] = buf >> 6 & 1;
      output[i + 2] = buf >> 5 & 1;
      output[i + 3] = buf >> 4 & 1;
      output[i + 4] = buf >> 3 & 1;
      output[i + 5] = buf >> 2 & 1;
      output[i + 6] = buf >> 1 & 1;
      output[i + 7] = buf & 1;
      i += 8;
     }
     if (i < loop2End) {
      buf = buffer[bufferPos++];
      mask = 128;
      while (i < loop2End) {
       output[i++] = +!!(buf & mask);
       mask >>= 1;
      }
     }
    }
   } else {
    var bits = 0;
    buf = 0;
    for (i = 0, ii = length; i < ii; ++i) {
     if (i % rowComps === 0) {
      buf = 0;
      bits = 0;
     }
     while (bits < bpc) {
      buf = buf << 8 | buffer[bufferPos++];
      bits += 8;
     }
     var remainingBits = bits - bpc;
     var value = buf >> remainingBits;
     output[i] = value < 0 ? 0 : value > max ? max : value;
     buf = buf & (1 << remainingBits) - 1;
     bits = remainingBits;
    }
   }
   return output;
  },
  fillOpacity: function PDFImage_fillOpacity(rgbaBuf, width, height, actualHeight, image) {
   var smask = this.smask;
   var mask = this.mask;
   var alphaBuf, sw, sh, i, ii, j;
   if (smask) {
    sw = smask.width;
    sh = smask.height;
    alphaBuf = new Uint8Array(sw * sh);
    smask.fillGrayBuffer(alphaBuf);
    if (sw !== width || sh !== height) {
     alphaBuf = resizeImageMask(alphaBuf, smask.bpc, sw, sh, width, height);
    }
   } else if (mask) {
    if (mask instanceof PDFImage) {
     sw = mask.width;
     sh = mask.height;
     alphaBuf = new Uint8Array(sw * sh);
     mask.numComps = 1;
     mask.fillGrayBuffer(alphaBuf);
     for (i = 0, ii = sw * sh; i < ii; ++i) {
      alphaBuf[i] = 255 - alphaBuf[i];
     }
     if (sw !== width || sh !== height) {
      alphaBuf = resizeImageMask(alphaBuf, mask.bpc, sw, sh, width, height);
     }
    } else if (isArray(mask)) {
     alphaBuf = new Uint8Array(width * height);
     var numComps = this.numComps;
     for (i = 0, ii = width * height; i < ii; ++i) {
      var opacity = 0;
      var imageOffset = i * numComps;
      for (j = 0; j < numComps; ++j) {
       var color = image[imageOffset + j];
       var maskOffset = j * 2;
       if (color < mask[maskOffset] || color > mask[maskOffset + 1]) {
        opacity = 255;
        break;
       }
      }
      alphaBuf[i] = opacity;
     }
    } else {
     error('Unknown mask format.');
    }
   }
   if (alphaBuf) {
    for (i = 0, j = 3, ii = width * actualHeight; i < ii; ++i, j += 4) {
     rgbaBuf[j] = alphaBuf[i];
    }
   } else {
    for (i = 0, j = 3, ii = width * actualHeight; i < ii; ++i, j += 4) {
     rgbaBuf[j] = 255;
    }
   }
  },
  undoPreblend: function PDFImage_undoPreblend(buffer, width, height) {
   var matte = this.smask && this.smask.matte;
   if (!matte) {
    return;
   }
   var matteRgb = this.colorSpace.getRgb(matte, 0);
   var matteR = matteRgb[0];
   var matteG = matteRgb[1];
   var matteB = matteRgb[2];
   var length = width * height * 4;
   var r, g, b;
   for (var i = 0; i < length; i += 4) {
    var alpha = buffer[i + 3];
    if (alpha === 0) {
     buffer[i] = 255;
     buffer[i + 1] = 255;
     buffer[i + 2] = 255;
     continue;
    }
    var k = 255 / alpha;
    r = (buffer[i] - matteR) * k + matteR;
    g = (buffer[i + 1] - matteG) * k + matteG;
    b = (buffer[i + 2] - matteB) * k + matteB;
    buffer[i] = r <= 0 ? 0 : r >= 255 ? 255 : r | 0;
    buffer[i + 1] = g <= 0 ? 0 : g >= 255 ? 255 : g | 0;
    buffer[i + 2] = b <= 0 ? 0 : b >= 255 ? 255 : b | 0;
   }
  },
  createImageData: function PDFImage_createImageData(forceRGBA) {
   var drawWidth = this.drawWidth;
   var drawHeight = this.drawHeight;
   var imgData = {
    width: drawWidth,
    height: drawHeight
   };
   var numComps = this.numComps;
   var originalWidth = this.width;
   var originalHeight = this.height;
   var bpc = this.bpc;
   var rowBytes = originalWidth * numComps * bpc + 7 >> 3;
   var imgArray;
   if (!forceRGBA) {
    var kind;
    if (this.colorSpace.name === 'DeviceGray' && bpc === 1) {
     kind = ImageKind.GRAYSCALE_1BPP;
    } else if (this.colorSpace.name === 'DeviceRGB' && bpc === 8 && !this.needsDecode) {
     kind = ImageKind.RGB_24BPP;
    }
    if (kind && !this.smask && !this.mask && drawWidth === originalWidth && drawHeight === originalHeight) {
     imgData.kind = kind;
     imgArray = this.getImageBytes(originalHeight * rowBytes);
     if (this.image instanceof DecodeStream) {
      imgData.data = imgArray;
     } else {
      var newArray = new Uint8Array(imgArray.length);
      newArray.set(imgArray);
      imgData.data = newArray;
     }
     if (this.needsDecode) {
      assert(kind === ImageKind.GRAYSCALE_1BPP);
      var buffer = imgData.data;
      for (var i = 0, ii = buffer.length; i < ii; i++) {
       buffer[i] ^= 0xff;
      }
     }
     return imgData;
    }
    if (this.image instanceof JpegStream && !this.smask && !this.mask && (this.colorSpace.name === 'DeviceGray' || this.colorSpace.name === 'DeviceRGB' || this.colorSpace.name === 'DeviceCMYK')) {
     imgData.kind = ImageKind.RGB_24BPP;
     imgData.data = this.getImageBytes(originalHeight * rowBytes, drawWidth, drawHeight, true);
     return imgData;
    }
   }
   imgArray = this.getImageBytes(originalHeight * rowBytes);
   var actualHeight = 0 | imgArray.length / rowBytes * drawHeight / originalHeight;
   var comps = this.getComponents(imgArray);
   var alpha01, maybeUndoPreblend;
   if (!forceRGBA && !this.smask && !this.mask) {
    imgData.kind = ImageKind.RGB_24BPP;
    imgData.data = new Uint8Array(drawWidth * drawHeight * 3);
    alpha01 = 0;
    maybeUndoPreblend = false;
   } else {
    imgData.kind = ImageKind.RGBA_32BPP;
    imgData.data = new Uint8Array(drawWidth * drawHeight * 4);
    alpha01 = 1;
    maybeUndoPreblend = true;
    this.fillOpacity(imgData.data, drawWidth, drawHeight, actualHeight, comps);
   }
   if (this.needsDecode) {
    this.decodeBuffer(comps);
   }
   this.colorSpace.fillRgb(imgData.data, originalWidth, originalHeight, drawWidth, drawHeight, actualHeight, bpc, comps, alpha01);
   if (maybeUndoPreblend) {
    this.undoPreblend(imgData.data, drawWidth, actualHeight);
   }
   return imgData;
  },
  fillGrayBuffer: function PDFImage_fillGrayBuffer(buffer) {
   var numComps = this.numComps;
   if (numComps !== 1) {
    error('Reading gray scale from a color image: ' + numComps);
   }
   var width = this.width;
   var height = this.height;
   var bpc = this.bpc;
   var rowBytes = width * numComps * bpc + 7 >> 3;
   var imgArray = this.getImageBytes(height * rowBytes);
   var comps = this.getComponents(imgArray);
   var i, length;
   if (bpc === 1) {
    length = width * height;
    if (this.needsDecode) {
     for (i = 0; i < length; ++i) {
      buffer[i] = comps[i] - 1 & 255;
     }
    } else {
     for (i = 0; i < length; ++i) {
      buffer[i] = -comps[i] & 255;
     }
    }
    return;
   }
   if (this.needsDecode) {
    this.decodeBuffer(comps);
   }
   length = width * height;
   var scale = 255 / ((1 << bpc) - 1);
   for (i = 0; i < length; ++i) {
    buffer[i] = scale * comps[i] | 0;
   }
  },
  getImageBytes: function PDFImage_getImageBytes(length, drawWidth, drawHeight, forceRGB) {
   this.image.reset();
   this.image.drawWidth = drawWidth || this.width;
   this.image.drawHeight = drawHeight || this.height;
   this.image.forceRGB = !!forceRGB;
   return this.image.getBytes(length);
  }
 };
 return PDFImage;
}();
exports.PDFImage = PDFImage;