Sakurai/pdf.js
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Optimized PDFImage_undoPreblend

Browse Source
This commit is contained in:
p01 2014-04-28 17:21:56 +02:00
parent 83cd530f45
commit 27d532efeb
1 changed files with 11 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

20
src/core/image.js
View File

@ -463,27 +463,29 @@ var PDFImage = (function PDFImageClosure() {
if (!matte) {
return;
}
function clamp(value) {
return (value < 0 ? 0 : (value > 255 ? 255 : value)) | 0;
}
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) {
// according formula we have to get Infinity in all components
// making it white (tipical paper color) should be okay
// making it white (typical 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]);
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;
}
},