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Merge pull request #10482 from janpe2/indexed-decode

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Implement Decode entry in Indexed images
This commit is contained in:
Tim van der Meij 2019-01-24 23:46:55 +01:00 • committed by GitHub
commit e2701d5422
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GPG key ID: 4AEE18F83AFDEB23
7 changed files with 37 additions and 14 deletions
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29
src/core/colorspace.js
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@ -492,7 +492,7 @@ class AlternateCS extends ColorSpace {
alpha01);
}
isDefaultDecode(decodeMap) {
isDefaultDecode(decodeMap, bpc) {
return ColorSpace.isDefaultDecode(decodeMap, this.numComps);
}
}
@ -565,8 +565,19 @@ class IndexedCS extends ColorSpace {
return this.base.getOutputLength(inputLength * this.base.numComps, alpha01);
}
isDefaultDecode(decodeMap) {
return true; // Indexed color maps shouldn't be changed.
isDefaultDecode(decodeMap, bpc) {
if (!Array.isArray(decodeMap)) {
return true;
}
if (decodeMap.length !== 2) {
warn('Decode map length is not correct');
return true;
}
if (!Number.isInteger(bpc) || bpc < 1) {
warn('Bits per component is not correct');
return true;
}
return decodeMap[0] === 0 && decodeMap[1] === (1 << bpc) - 1;
}
}
@ -609,7 +620,7 @@ class DeviceGrayCS extends ColorSpace {
return inputLength * (3 + alpha01);
}
isDefaultDecode(decodeMap) {
isDefaultDecode(decodeMap, bpc) {
return ColorSpace.isDefaultDecode(decodeMap, this.numComps);
}
}
@ -661,7 +672,7 @@ class DeviceRgbCS extends ColorSpace {
return bits === 8;
}
isDefaultDecode(decodeMap) {
isDefaultDecode(decodeMap, bpc) {
return ColorSpace.isDefaultDecode(decodeMap, this.numComps);
}
}
@ -744,7 +755,7 @@ const DeviceCmykCS = (function DeviceCmykCSClosure() {
return (inputLength / 4 * (3 + alpha01)) | 0;
}
isDefaultDecode(decodeMap) {
isDefaultDecode(decodeMap, bpc) {
return ColorSpace.isDefaultDecode(decodeMap, this.numComps);
}
}
@ -847,7 +858,7 @@ const CalGrayCS = (function CalGrayCSClosure() {
return inputLength * (3 + alpha01);
}
isDefaultDecode(decodeMap) {
isDefaultDecode(decodeMap, bpc) {
return ColorSpace.isDefaultDecode(decodeMap, this.numComps);
}
}
@ -1129,7 +1140,7 @@ const CalRGBCS = (function CalRGBCSClosure() {
return (inputLength * (3 + alpha01) / 3) | 0;
}
isDefaultDecode(decodeMap) {
isDefaultDecode(decodeMap, bpc) {
return ColorSpace.isDefaultDecode(decodeMap, this.numComps);
}
}
@ -1280,7 +1291,7 @@ const LabCS = (function LabCSClosure() {
return (inputLength * (3 + alpha01) / 3) | 0;
}
isDefaultDecode(decodeMap) {
isDefaultDecode(decodeMap, bpc) {
// XXX: Decoding is handled with the lab conversion because of the strange
// ranges that are used.
return true;

4
src/core/evaluator.js
View file

@ -100,6 +100,7 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
}
var cs = ColorSpace.parse(dict.get('ColorSpace', 'CS'), xref, res,
pdfFunctionFactory);
// isDefaultDecode() of DeviceGray and DeviceRGB needs no `bpc` argument.
return (cs.name === 'DeviceGray' || cs.name === 'DeviceRGB') &&
cs.isDefaultDecode(dict.getArray('Decode', 'D'));
};
@ -114,8 +115,9 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
}
var cs = ColorSpace.parse(dict.get('ColorSpace', 'CS'), xref, res,
pdfFunctionFactory);
const bpc = dict.get('BitsPerComponent', 'BPC') || 1;
return (cs.numComps === 1 || cs.numComps === 3) &&
cs.isDefaultDecode(dict.getArray('Decode', 'D'));
cs.isDefaultDecode(dict.getArray('Decode', 'D'), bpc);
};
function PartialEvaluator({ pdfManager, xref, handler, pageIndex, idFactory,

9
src/core/image.js
View file

@ -169,18 +169,21 @@ var PDFImage = (function PDFImageClosure() {
this.decode = dict.getArray('Decode', 'D');
this.needsDecode = false;
if (this.decode &&
((this.colorSpace && !this.colorSpace.isDefaultDecode(this.decode)) ||
((this.colorSpace &&
!this.colorSpace.isDefaultDecode(this.decode, bitsPerComponent)) ||
(isMask && !ColorSpace.isDefaultDecode(this.decode, 1)))) {
this.needsDecode = true;
// Do some preprocessing to avoid more math.
var max = (1 << bitsPerComponent) - 1;
this.decodeCoefficients = [];
this.decodeAddends = [];
const isIndexed = this.colorSpace && this.colorSpace.name === 'Indexed';
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;
this.decodeCoefficients[j] = isIndexed ? ((dmax - dmin) / max) :
(dmax - dmin);
this.decodeAddends[j] = isIndexed ? dmin : (max * dmin);
}
}