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Special-case 24-bit RGB image-handling.

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This commit is contained in:
Nicholas Nethercote 2014-02-24 19:37:19 -08:00
parent f11a6ae238
commit f62c1c469f
3 changed files with 51 additions and 23 deletions
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6
src/core/evaluator.js
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@ -166,7 +166,9 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
(w + h) < SMALL_IMAGE_DIMENSIONS) {
var imageObj = new PDFImage(this.xref, resources, image,
inline, null, null);
var imgData = imageObj.createImageData();
// We force the use of 'rgba_32bpp' images here, because we can't
// handle any other kind.
var imgData = imageObj.createImageData(/* forceRGBA = */ true);
operatorList.addOp(OPS.paintInlineImageXObject, [imgData]);
return;
}
@ -189,7 +191,7 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
PDFImage.buildImage(function(imageObj) {
var imgData = imageObj.createImageData();
var imgData = imageObj.createImageData(/* forceRGBA = */ false);
self.handler.send('obj', [objId, self.pageIndex, 'Image', imgData],
null, [imgData.data.buffer]);
}, self.handler, self.xref, resources, image, inline);

52
src/core/image.js
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@ -417,7 +417,7 @@ var PDFImage = (function PDFImageClosure() {
buffer[i + 2] = clamp((buffer[i + 2] - matteRgb[2]) * k + matteRgb[2]);
}
},
createImageData: function PDFImage_createImageData() {
createImageData: function PDFImage_createImageData(forceRGBA) {
var drawWidth = this.drawWidth;
var drawHeight = this.drawHeight;
var imgData = { // other fields are filled in below
@ -430,32 +430,42 @@ var PDFImage = (function PDFImageClosure() {
var originalHeight = this.height;
var bpc = this.bpc;
// rows start at byte boundary;
// Rows start at byte boundary.
var rowBytes = (originalWidth * numComps * bpc + 7) >> 3;
var imgArray = this.getImageBytes(originalHeight * rowBytes);
// imgArray can be incomplete (e.g. after CCITT fax encoding)
if (!forceRGBA) {
// If it is a 1-bit-per-pixel grayscale (i.e. black-and-white) image
// without any complications, we pass a same-sized copy to the main
// thread rather than expanding by 32x to RGBA form. This saves *lots*
// of memory for many scanned documents. It's also much faster.
//
// Similarly, if it is a 24-bit-per pixel RGB image without any
// complications, we avoid expanding by 1.333x to RGBA form.
var kind;
if (this.colorSpace.name === 'DeviceGray' && bpc === 1) {
kind = 'grayscale_1bpp';
} else if (this.colorSpace.name === 'DeviceRGB' && bpc === 8) {
kind = 'rgb_24bpp';
}
if (kind && !this.smask && !this.mask && !this.needsDecode &&
drawWidth === originalWidth && drawHeight === originalHeight) {
imgData.kind = kind;
// We must make a copy of imgArray, otherwise it'll be neutered upon
// transfer which will break any code that subsequently reuses it.
var newArray = new Uint8Array(imgArray.length);
newArray.set(imgArray);
imgData.data = newArray;
imgData.origLength = imgArray.length;
return imgData;
}
}
// imgArray can be incomplete (e.g. after CCITT fax encoding).
var actualHeight = 0 | (imgArray.length / rowBytes *
drawHeight / originalHeight);
// If it is a 1-bit-per-pixel grayscale (i.e. black-and-white) image
// without any complications, we pass a same-sized copy to the main
// thread rather than expanding by 32x to RGBA form. This saves *lots* of
// memory for many scanned documents. It's also much faster.
if (this.colorSpace.name === 'DeviceGray' && bpc === 1 &&
!this.smask && !this.mask && !this.needsDecode &&
drawWidth === originalWidth && drawHeight === originalHeight) {
imgData.kind = 'grayscale_1bpp';
// We must make a copy of imgArray, otherwise it'll be neutered upon
// transfer which will break any code that subsequently reuses it.
var newArray = new Uint8Array(imgArray.length);
newArray.set(imgArray);
imgData.data = newArray;
imgData.origLength = imgArray.length;
return imgData;
}
var comps = this.getComponents(imgArray);
var rgbaBuf = new Uint8Array(drawWidth * drawHeight * 4);

16
src/display/canvas.js
View File

@ -526,6 +526,22 @@ var CanvasGraphics = (function CanvasGraphicsClosure() {
ctx.putImageData(chunkImgData, 0, i * fullChunkHeight);
}
} else if (imgData.kind === 'rgb_24bpp') {
// RGB, 24-bits per pixel.
for (var i = 0; i < totalChunks; i++) {
var thisChunkHeight =
(i < fullChunks) ? fullChunkHeight : partialChunkHeight;
var elemsInThisChunk = imgData.width * thisChunkHeight * 3;
var destPos = 0;
for (var j = 0; j < elemsInThisChunk; j += 3) {
chunkImgData.data[destPos++] = imgData.data[srcPos++];
chunkImgData.data[destPos++] = imgData.data[srcPos++];
chunkImgData.data[destPos++] = imgData.data[srcPos++];
chunkImgData.data[destPos++] = 255;
}
ctx.putImageData(chunkImgData, 0, i * fullChunkHeight);
}
} else {
error('bad image kind: ' + imgData.kind);
}