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Takes SMask's preblending in account

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Yury Delendik 2013-07-02 14:27:06 -05:00
parent 81fa4a0d93
commit 419bee1314
3 changed files with 39 additions and 0 deletions
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31
src/image.js
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@ -70,6 +70,7 @@ var PDFImage = (function PDFImageClosure() {
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) {
@ -386,6 +387,34 @@ var PDFImage = (function PDFImageClosure() {
}
return buf;
},
undoPreblend: function PDFImage_undoPreblend(buffer, width, height) {
var matte = this.smask && this.smask.matte;
if (!matte) {
return;
}
function clamp(value) {
return (value < 0 ? 0 : value > 255 ? 255 : value) | 0;
}
var matteRgb = this.colorSpace.getRgb(matte, 0);
var length = width * height * 4;
for (var i = 0; i < length; i += 4) {
var alpha = buffer[i + 3];
if (alpha === 0) {
// according formula we have to get Infinity in all components
// making it as white (tipical paper color) should be okay
buffer[i] = 255;
buffer[i + 1] = 255;
buffer[i + 2] = 255;
continue;
}
var k = 255 / alpha;
buffer[i] = clamp((buffer[i] - matteRgb[0]) * k + matteRgb[0]);
buffer[i + 1] = clamp((buffer[i + 1] - matteRgb[1]) * k + matteRgb[1]);
buffer[i + 2] = clamp((buffer[i + 2] - matteRgb[2]) * k + matteRgb[2]);
}
},
fillRgbaBuffer: function PDFImage_fillRgbaBuffer(buffer, width, height) {
var numComps = this.numComps;
var originalWidth = this.width;
@ -422,6 +451,8 @@ var PDFImage = (function PDFImageClosure() {
buffer[i + 2] = rgbBuf[compsPos++];
buffer[i + 3] = opacity[opacityPos++];
}
this.undoPreblend(buffer, width, actualHeight);
},
fillGrayBuffer: function PDFImage_fillGrayBuffer(buffer) {
var numComps = this.numComps;