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Refactor jpg.js and include forceRGBoutput, correct style of image.js

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This refactors getData to be more readable and extracts all the color
conversion algorithms to their own functions. The resulting code was then
cleaned up.
This also introduces a flag `forceRGBoutput` to getData, that allows to always
get the data as a `width * height * 3` bytes long RGB buffer
This commit is contained in:
Thorben Bochenek 2014-03-27 11:11:28 +01:00
parent 26bea20c82
commit e7fe45a5c4
2 changed files with 122 additions and 88 deletions
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195
external/jpgjs/jpg.js vendored
View File

@ -782,9 +782,10 @@ var JpegImage = (function jpegImage() {
blocksPerColumn: component.blocksPerColumn
});
}
this.numComponents = this.components.length;
},
getData: function getData(width, height) {
_getLinearizedBlockData: function getLinearizedBlockData(width, height) {
var scaleX = this.width / width, scaleY = this.height / height;
var component, componentScaleX, componentScaleY;
@ -842,80 +843,124 @@ var JpegImage = (function jpegImage() {
}
}
}
return data;
},
// ... then transform colors, if necessary
switch (numComponents) {
case 1: case 2: break;
// no color conversion for one or two compoenents
_isColorConversionNeeded: function isColorConversionNeeded() {
if (this.adobe && this.adobe.transformCode) {
// The adobe transform marker overrides any previous setting
return true;
} else if (this.numComponents == 3) {
return true;
} else {
return false;
}
},
case 3:
// The default transform for three components is true
colorTransform = true;
// The adobe transform marker overrides any previous setting
if (this.adobe && this.adobe.transformCode)
colorTransform = true;
else if (typeof this.colorTransform !== 'undefined')
colorTransform = !!this.colorTransform;
if (colorTransform) {
for (i = 0; i < dataLength; i += numComponents) {
Y = data[i ];
Cb = data[i + 1];
Cr = data[i + 2];
R = clamp0to255(Y + 1.402 * (Cr - 128));
G = clamp0to255(Y - 0.3441363 * (Cb - 128) - 0.71413636 * (Cr - 128));
B = clamp0to255(Y + 1.772 * (Cb - 128));
data[i ] = R;
data[i + 1] = G;
data[i + 2] = B;
}
}
break;
case 4:
// The default transform for four components is false
colorTransform = false;
// The adobe transform marker overrides any previous setting
if (this.adobe && this.adobe.transformCode)
colorTransform = true;
else if (typeof this.colorTransform !== 'undefined')
colorTransform = !!this.colorTransform;
if (colorTransform) {
for (i = 0; i < dataLength; i += numComponents) {
Y = data[i];
Cb = data[i + 1];
Cr = data[i + 2];
C = 255 - clamp0to255(Y + 1.402 * (Cr - 128));
M = 255 - clamp0to255(Y - 0.3441363 * (Cb - 128) - 0.71413636 * (Cr - 128));
Ye = 255 - clamp0to255(Y + 1.772 * (Cb - 128));
data[i ] = C;
data[i + 1] = M;
data[i + 2] = Ye;
// K is unchanged
}
}
break;
default:
throw 'Unsupported color mode';
_convertYccToRgb: function convertYccToRgb(data) {
var Y, Cb, Cr;
for (var i = 0; i < data.length; i += this.numComponents) {
Y = data[i ];
Cb = data[i + 1];
Cr = data[i + 2];
data[i ] = clamp0to255(Y + 1.402 * (Cr - 128));
data[i + 1] = clamp0to255(Y - 0.3441363 * (Cb - 128) - 0.71413636 * (Cr - 128));
data[i + 2] = clamp0to255(Y + 1.772 * (Cb - 128));
}
return data;
},
_convertYcckToRgb: function convertYcckToRgb(data) {
var Y, Cb, Cr, K, C, M, Ye, oneMinusK255th;
var outputData = new Uint8Array((data.length / 4) * 3);
var offset = 0;
for (var i = 0; i < data.length; i += this.numComponents) {
Y = data[i];
Cb = data[i + 1];
Cr = data[i + 2];
K = data[i + 3];
C = 255 - clamp0to255(Y + 1.402 * (Cr - 128));
M = 255 - clamp0to255(Y - 0.3441363 * (Cb - 128) - 0.71413636 * (Cr - 128));
Ye = 255 - clamp0to255(Y + 1.772 * (Cb - 128));
oneMinusK255th = (1 - K / 255);
outputData[offset++] = 255 - clamp0to255(C * oneMinusK255th + K);
outputData[offset++] = 255 - clamp0to255(M * oneMinusK255th + K);
outputData[offset++] = 255 - clamp0to255(Ye * oneMinusK255th + K);
}
return outputData;
},
_convertYcckToCmyk: function convertYcckToCmyk(data) {
var Y, Cb, Cr;
for (var i = 0; i < data.length; i += this.numComponents) {
Y = data[i];
Cb = data[i + 1];
Cr = data[i + 2];
data[i ] = 255 - clamp0to255(Y + 1.402 * (Cr - 128));
data[i + 1] = 255 - clamp0to255(Y - 0.3441363 * (Cb - 128) - 0.71413636 * (Cr - 128));
data[i + 2] = 255 - clamp0to255(Y + 1.772 * (Cb - 128));
// K in data[i + 3] is unchanged
}
return data;
},
_convertCmykToRgb: function convertCmykToRgb(data) {
var C, M, Y, K, oneMinusK255th;
var outputData = new Uint8Array((data.length / 4) * 3);
var offset = 0;
for (var i = 0; i < data.length; i += this.numComponents) {
C = data[i ];
M = data[i + 1];
Y = data[i + 2];
K = data[i + 3];
oneMinusK255th = (1 - K / 255);
outputData[offset++] = 255 - clamp0to255(C * oneMinusK255th + K);
outputData[offset++] = 255 - clamp0to255(M * oneMinusK255th + K);
outputData[offset++] = 255 - clamp0to255(Y * oneMinusK255th + K);
// K in data[i + 3] is unchanged
}
return outputData;
},
getData: function getData(width, height, forceRGBoutput) {
var i;
var Y, Cb, Cr, K, C, M, Ye, R, G, B;
var colorTransform;
if (this.numComponents > 4) {
throw 'Unsupported color mode';
}
// type of data: Uint8Array(width * height * numComponents)
var data = this._getLinearizedBlockData(width, height);
if (this.numComponents === 3) {
return this._convertYccToRgb(data);
} else if (this.numComponents === 4) {
if (this._isColorConversionNeeded()) {
if (forceRGBoutput) {
return this._convertYcckToRgb(data);
} else {
return this._convertYcckToCmyk(data);
}
} else {
return this._convertCmykToRgb(data);
}
}
return data;
},
copyToImageData: function copyToImageData(imageData) {
var width = imageData.width, height = imageData.height;
var width = imageData.width;
var height = imageData.height;
var imageDataBytes = width * height * 4;
var imageDataArray = imageData.data;
var data = this.getData(width, height);
var data = this.getData(width, height, /* forceRGBoutput = */true);
var i = 0, j = 0;
var Y, K, C, M, R, G, B;
switch (this.components.length) {
case 1:
var Y;
while (j < imageDataBytes) {
Y = data[i++];
imageDataArray[j++] = Y;
imageDataArray[j++] = Y;
imageDataArray[j++] = Y;
@ -923,31 +968,11 @@ var JpegImage = (function jpegImage() {
}
break;
case 3:
while (j < imageDataBytes) {
R = data[i++];
G = data[i++];
B = data[i++];
imageDataArray[j++] = R;
imageDataArray[j++] = G;
imageDataArray[j++] = B;
imageDataArray[j++] = 255;
}
break;
case 4:
while (j < imageDataBytes) {
C = data[i++];
M = data[i++];
Y = data[i++];
K = data[i++];
R = 255 - clamp0to255(C * (1 - K / 255) + K);
G = 255 - clamp0to255(M * (1 - K / 255) + K);
B = 255 - clamp0to255(Y * (1 - K / 255) + K);
imageDataArray[j++] = R;
imageDataArray[j++] = G;
imageDataArray[j++] = B;
imageDataArray[j++] = data[i++];
imageDataArray[j++] = data[i++];
imageDataArray[j++] = data[i++];
imageDataArray[j++] = 255;
}
break;

15
src/core/image.js
View File

@ -44,6 +44,7 @@ var PDFImage = (function PDFImageClosure() {
return Promise.resolve(image);
}
}
/**
* Decode and clamp a value. The formula is different from the spec because we
* don't decode to float range [0,1], we decode it in the [0,max] range.
@ -53,6 +54,7 @@ var PDFImage = (function PDFImageClosure() {
// Clamp the value to the range
return (value < 0 ? 0 : (value > max ? max : value));
}
function PDFImage(xref, res, image, inline, smask, mask, isMask) {
this.image = image;
var dict = image.dict;
@ -279,11 +281,13 @@ var PDFImage = (function PDFImageClosure() {
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;
@ -309,6 +313,7 @@ var PDFImage = (function PDFImageClosure() {
}
}
},
getComponents: function PDFImage_getComponents(buffer) {
var bpc = this.bpc;
@ -385,6 +390,7 @@ var PDFImage = (function PDFImageClosure() {
}
return output;
},
fillOpacity: function PDFImage_fillOpacity(rgbaBuf, width, height,
actualHeight, image) {
var smask = this.smask;
@ -451,6 +457,7 @@ var PDFImage = (function PDFImageClosure() {
}
}
},
undoPreblend: function PDFImage_undoPreblend(buffer, width, height) {
var matte = this.smask && this.smask.matte;
if (!matte) {
@ -467,7 +474,7 @@ var PDFImage = (function PDFImageClosure() {
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
// making it white (tipical paper color) should be okay
buffer[i] = 255;
buffer[i + 1] = 255;
buffer[i + 2] = 255;
@ -479,6 +486,7 @@ var PDFImage = (function PDFImageClosure() {
buffer[i + 2] = clamp((buffer[i + 2] - matteRgb[2]) * k + matteRgb[2]);
}
},
createImageData: function PDFImage_createImageData(forceRGBA) {
var drawWidth = this.drawWidth;
var drawHeight = this.drawHeight;
@ -529,7 +537,6 @@ var PDFImage = (function PDFImageClosure() {
return imgData;
}
}
// imgArray can be incomplete (e.g. after CCITT fax encoding).
var actualHeight = 0 | (imgArray.length / rowBytes *
drawHeight / originalHeight);
@ -567,6 +574,7 @@ var PDFImage = (function PDFImageClosure() {
return imgData;
},
fillGrayBuffer: function PDFImage_fillGrayBuffer(buffer) {
var numComps = this.numComps;
if (numComps != 1) {
@ -589,7 +597,7 @@ var PDFImage = (function PDFImageClosure() {
length = width * height;
if (this.needsDecode) {
// invert and scale to {0, 255}
for (i = 0; i < length; ++i) {
for (var i = 0; i < length; ++i) {
buffer[i] = (comps[i] - 1) & 255;
}
} else {
@ -611,6 +619,7 @@ var PDFImage = (function PDFImageClosure() {
buffer[i] = (scale * comps[i]) | 0;
}
},
getImageBytes: function PDFImage_getImageBytes(length) {
this.image.reset();
return this.image.getBytes(length);