/* -*- Mode: Java; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set shiftwidth=2 tabstop=2 autoindent cindent expandtab: */
/* Copyright 2012 Mozilla Foundation
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/* globals error, info, isArray, isDict, isName, isStream, isString,
PDFFunction, PDFImage, shadow, warn */
'use strict';
var ColorSpace = (function ColorSpaceClosure() {
// Constructor should define this.numComps, this.defaultColor, this.name
function ColorSpace() {
error('should not call ColorSpace constructor');
}
ColorSpace.prototype = {
/**
* Converts the color value to the RGB color. The color components are
* located in the src array starting from the srcOffset. Returns the array
* of the rgb components, each value ranging from [0,255].
*/
getRgb: function ColorSpace_getRgb(src, srcOffset) {
var rgb = new Uint8Array(3);
this.getRgbItem(src, srcOffset, rgb, 0);
return rgb;
},
/**
* Converts the color value to the RGB color, similar to the getRgb method.
* The result placed into the dest array starting from the destOffset.
*/
getRgbItem: function ColorSpace_getRgbItem(src, srcOffset,
dest, destOffset) {
error('Should not call ColorSpace.getRgbItem');
},
/**
* Converts the specified number of the color values to the RGB colors.
* The colors are located in the src array starting from the srcOffset.
* The result is placed into the dest array starting from the destOffset.
* The src array items shall be in [0,2^bits) range, the dest array items
* will be in [0,255] range. alpha01 indicates how many alpha components
* there are in the dest array; it will be either 0 (RGB array) or 1 (RGBA
* array).
*/
getRgbBuffer: function ColorSpace_getRgbBuffer(src, srcOffset, count,
dest, destOffset, bits,
alpha01) {
error('Should not call ColorSpace.getRgbBuffer');
},
/**
* Determines the number of bytes required to store the result of the
* conversion done by the getRgbBuffer method. As in getRgbBuffer,
* |alpha01| is either 0 (RGB output) or 1 (RGBA output).
*/
getOutputLength: function ColorSpace_getOutputLength(inputLength,
alpha01) {
error('Should not call ColorSpace.getOutputLength');
},
/**
* Returns true if source data will be equal the result/output data.
*/
isPassthrough: function ColorSpace_isPassthrough(bits) {
return false;
},
/**
* Fills in the RGB colors in the destination buffer. alpha01 indicates
* how many alpha components there are in the dest array; it will be either
* 0 (RGB array) or 1 (RGBA array).
*/
fillRgb: function ColorSpace_fillRgb(dest, originalWidth,
originalHeight, width, height,
actualHeight, bpc, comps, alpha01) {
var count = originalWidth * originalHeight;
var rgbBuf = null;
var numComponentColors = 1 << bpc;
var needsResizing = originalHeight != height || originalWidth != width;
if (this.isPassthrough(bpc)) {
rgbBuf = comps;
} else if (this.numComps === 1 && count > numComponentColors &&
this.name !== 'DeviceGray' && this.name !== 'DeviceRGB') {
// Optimization: create a color map when there is just one component and
// we are converting more colors than the size of the color map. We
// don't build the map if the colorspace is gray or rgb since those
// methods are faster than building a map. This mainly offers big speed
// ups for indexed and alternate colorspaces.
//
// TODO it may be worth while to cache the color map. While running
// testing I never hit a cache so I will leave that out for now (perhaps
// we are reparsing colorspaces too much?).
var allColors = bpc <= 8 ? new Uint8Array(numComponentColors) :
new Uint16Array(numComponentColors);
for (var i = 0; i < numComponentColors; i++) {
allColors[i] = i;
}
var colorMap = new Uint8Array(numComponentColors * 3);
this.getRgbBuffer(allColors, 0, numComponentColors, colorMap, 0, bpc,
/* alpha01 = */ 0);
if (!needsResizing) {
// Fill in the RGB values directly into |dest|.
var destPos = 0;
for (var i = 0; i < count; ++i) {
var key = comps[i] * 3;
dest[destPos++] = colorMap[key];
dest[destPos++] = colorMap[key + 1];
dest[destPos++] = colorMap[key + 2];
destPos += alpha01;
}
} else {
rgbBuf = new Uint8Array(count * 3);
var rgbPos = 0;
for (var i = 0; i < count; ++i) {
var key = comps[i] * 3;
rgbBuf[rgbPos++] = colorMap[key];
rgbBuf[rgbPos++] = colorMap[key + 1];
rgbBuf[rgbPos++] = colorMap[key + 2];
}
}
} else {
if (!needsResizing) {
// Fill in the RGB values directly into |dest|.
this.getRgbBuffer(comps, 0, width * actualHeight, dest, 0, bpc,
alpha01);
} else {
rgbBuf = new Uint8Array(count * 3);
this.getRgbBuffer(comps, 0, count, rgbBuf, 0, bpc,
/* alpha01 = */ 0);
}
}
if (rgbBuf) {
if (needsResizing) {
rgbBuf = PDFImage.resize(rgbBuf, bpc, 3, originalWidth,
originalHeight, width, height);
}
var rgbPos = 0;
var destPos = 0;
for (var i = 0, ii = width * actualHeight; i < ii; i++) {
dest[destPos++] = rgbBuf[rgbPos++];
dest[destPos++] = rgbBuf[rgbPos++];
dest[destPos++] = rgbBuf[rgbPos++];
destPos += alpha01;
}
}
},
/**
* True if the colorspace has components in the default range of [0, 1].
* This should be true for all colorspaces except for lab color spaces
* which are [0,100], [-128, 127], [-128, 127].
*/
usesZeroToOneRange: true
};
ColorSpace.parse = function ColorSpace_parse(cs, xref, res) {
var IR = ColorSpace.parseToIR(cs, xref, res);
if (IR instanceof AlternateCS)
return IR;
return ColorSpace.fromIR(IR);
};
ColorSpace.fromIR = function ColorSpace_fromIR(IR) {
var name = isArray(IR) ? IR[0] : IR;
switch (name) {
case 'DeviceGrayCS':
return this.singletons.gray;
case 'DeviceRgbCS':
return this.singletons.rgb;
case 'DeviceCmykCS':
return this.singletons.cmyk;
case 'CalGrayCS':
var whitePoint = IR[1].WhitePoint;
var blackPoint = IR[1].BlackPoint;
var gamma = IR[1].Gamma;
return new CalGrayCS(whitePoint, blackPoint, gamma);
case 'PatternCS':
var basePatternCS = IR[1];
if (basePatternCS)
basePatternCS = ColorSpace.fromIR(basePatternCS);
return new PatternCS(basePatternCS);
case 'IndexedCS':
var baseIndexedCS = IR[1];
var hiVal = IR[2];
var lookup = IR[3];
return new IndexedCS(ColorSpace.fromIR(baseIndexedCS), hiVal, lookup);
case 'AlternateCS':
var numComps = IR[1];
var alt = IR[2];
var tintFnIR = IR[3];
return new AlternateCS(numComps, ColorSpace.fromIR(alt),
PDFFunction.fromIR(tintFnIR));
case 'LabCS':
var whitePoint = IR[1].WhitePoint;
var blackPoint = IR[1].BlackPoint;
var range = IR[1].Range;
return new LabCS(whitePoint, blackPoint, range);
default:
error('Unkown name ' + name);
}
return null;
};
ColorSpace.parseToIR = function ColorSpace_parseToIR(cs, xref, res) {
if (isName(cs)) {
var colorSpaces = res.get('ColorSpace');
if (isDict(colorSpaces)) {
var refcs = colorSpaces.get(cs.name);
if (refcs)
cs = refcs;
}
}
cs = xref.fetchIfRef(cs);
var mode;
if (isName(cs)) {
mode = cs.name;
this.mode = mode;
switch (mode) {
case 'DeviceGray':
case 'G':
return 'DeviceGrayCS';
case 'DeviceRGB':
case 'RGB':
return 'DeviceRgbCS';
case 'DeviceCMYK':
case 'CMYK':
return 'DeviceCmykCS';
case 'Pattern':
return ['PatternCS', null];
default:
error('unrecognized colorspace ' + mode);
}
} else if (isArray(cs)) {
mode = cs[0].name;
this.mode = mode;
switch (mode) {
case 'DeviceGray':
case 'G':
return 'DeviceGrayCS';
case 'DeviceRGB':
case 'RGB':
return 'DeviceRgbCS';
case 'DeviceCMYK':
case 'CMYK':
return 'DeviceCmykCS';
case 'CalGray':
var params = cs[1].getAll();
return ['CalGrayCS', params];
case 'CalRGB':
return 'DeviceRgbCS';
case 'ICCBased':
var stream = xref.fetchIfRef(cs[1]);
var dict = stream.dict;
var numComps = dict.get('N');
if (numComps == 1)
return 'DeviceGrayCS';
if (numComps == 3)
return 'DeviceRgbCS';
if (numComps == 4)
return 'DeviceCmykCS';
break;
case 'Pattern':
var basePatternCS = cs[1];
if (basePatternCS)
basePatternCS = ColorSpace.parseToIR(basePatternCS, xref, res);
return ['PatternCS', basePatternCS];
case 'Indexed':
case 'I':
var baseIndexedCS = ColorSpace.parseToIR(cs[1], xref, res);
var hiVal = cs[2] + 1;
var lookup = xref.fetchIfRef(cs[3]);
if (isStream(lookup)) {
lookup = lookup.getBytes();
}
return ['IndexedCS', baseIndexedCS, hiVal, lookup];
case 'Separation':
case 'DeviceN':
var name = cs[1];
var numComps = 1;
if (isName(name))
numComps = 1;
else if (isArray(name))
numComps = name.length;
var alt = ColorSpace.parseToIR(cs[2], xref, res);
var tintFnIR = PDFFunction.getIR(xref, xref.fetchIfRef(cs[3]));
return ['AlternateCS', numComps, alt, tintFnIR];
case 'Lab':
var params = cs[1].getAll();
return ['LabCS', params];
default:
error('unimplemented color space object "' + mode + '"');
}
} else {
error('unrecognized color space object: "' + cs + '"');
}
return null;
};
/**
* Checks if a decode map matches the default decode map for a color space.
* This handles the general decode maps where there are two values per
* component. e.g. [0, 1, 0, 1, 0, 1] for a RGB color.
* This does not handle Lab, Indexed, or Pattern decode maps since they are
* slightly different.
* @param {Array} decode Decode map (usually from an image).
* @param {Number} n Number of components the color space has.
*/
ColorSpace.isDefaultDecode = function ColorSpace_isDefaultDecode(decode, n) {
if (!decode)
return true;
if (n * 2 !== decode.length) {
warn('The decode map is not the correct length');
return true;
}
for (var i = 0, ii = decode.length; i < ii; i += 2) {
if (decode[i] !== 0 || decode[i + 1] != 1)
return false;
}
return true;
};
ColorSpace.singletons = {
get gray() {
return shadow(this, 'gray', new DeviceGrayCS());
},
get rgb() {
return shadow(this, 'rgb', new DeviceRgbCS());
},
get cmyk() {
return shadow(this, 'cmyk', new DeviceCmykCS());
}
};
return ColorSpace;
})();
/**
* Alternate color space handles both Separation and DeviceN color spaces. A
* Separation color space is actually just a DeviceN with one color component.
* Both color spaces use a tinting function to convert colors to a base color
* space.
*/
var AlternateCS = (function AlternateCSClosure() {
function AlternateCS(numComps, base, tintFn) {
this.name = 'Alternate';
this.numComps = numComps;
this.defaultColor = new Float32Array(numComps);
for (var i = 0; i < numComps; ++i) {
this.defaultColor[i] = 1;
}
this.base = base;
this.tintFn = tintFn;
}
AlternateCS.prototype = {
getRgb: ColorSpace.prototype.getRgb,
getRgbItem: function AlternateCS_getRgbItem(src, srcOffset,
dest, destOffset) {
var baseNumComps = this.base.numComps;
var input = 'subarray' in src ?
src.subarray(srcOffset, srcOffset + this.numComps) :
Array.prototype.slice.call(src, srcOffset, srcOffset + this.numComps);
var tinted = this.tintFn(input);
this.base.getRgbItem(tinted, 0, dest, destOffset);
},
getRgbBuffer: function AlternateCS_getRgbBuffer(src, srcOffset, count,
dest, destOffset, bits,
alpha01) {
var tintFn = this.tintFn;
var base = this.base;
var scale = 1 / ((1 << bits) - 1);
var baseNumComps = base.numComps;
var usesZeroToOneRange = base.usesZeroToOneRange;
var isPassthrough = (base.isPassthrough(8) || !usesZeroToOneRange) &&
alpha01 === 0;
var pos = isPassthrough ? destOffset : 0;
var baseBuf = isPassthrough ? dest : new Uint8Array(baseNumComps * count);
var numComps = this.numComps;
var scaled = new Float32Array(numComps);
for (var i = 0; i < count; i++) {
for (var j = 0; j < numComps; j++) {
scaled[j] = src[srcOffset++] * scale;
}
var tinted = tintFn(scaled);
if (usesZeroToOneRange) {
for (var j = 0; j < baseNumComps; j++) {
baseBuf[pos++] = tinted[j] * 255;
}
} else {
base.getRgbItem(tinted, 0, baseBuf, pos);
pos += baseNumComps;
}
}
if (!isPassthrough) {
base.getRgbBuffer(baseBuf, 0, count, dest, destOffset, 8, alpha01);
}
},
getOutputLength: function AlternateCS_getOutputLength(inputLength,
alpha01) {
return this.base.getOutputLength(inputLength *
this.base.numComps / this.numComps,
alpha01);
},
isPassthrough: ColorSpace.prototype.isPassthrough,
fillRgb: ColorSpace.prototype.fillRgb,
isDefaultDecode: function AlternateCS_isDefaultDecode(decodeMap) {
return ColorSpace.isDefaultDecode(decodeMap, this.numComps);
},
usesZeroToOneRange: true
};
return AlternateCS;
})();
var PatternCS = (function PatternCSClosure() {
function PatternCS(baseCS) {
this.name = 'Pattern';
this.base = baseCS;
}
PatternCS.prototype = {};
return PatternCS;
})();
var IndexedCS = (function IndexedCSClosure() {
function IndexedCS(base, highVal, lookup) {
this.name = 'Indexed';
this.numComps = 1;
this.defaultColor = new Uint8Array([0]);
this.base = base;
this.highVal = highVal;
var baseNumComps = base.numComps;
var length = baseNumComps * highVal;
var lookupArray;
if (isStream(lookup)) {
lookupArray = new Uint8Array(length);
var bytes = lookup.getBytes(length);
lookupArray.set(bytes);
} else if (isString(lookup)) {
lookupArray = new Uint8Array(length);
for (var i = 0; i < length; ++i)
lookupArray[i] = lookup.charCodeAt(i);
} else if (lookup instanceof Uint8Array || lookup instanceof Array) {
lookupArray = lookup;
} else {
error('Unrecognized lookup table: ' + lookup);
}
this.lookup = lookupArray;
}
IndexedCS.prototype = {
getRgb: ColorSpace.prototype.getRgb,
getRgbItem: function IndexedCS_getRgbItem(src, srcOffset,
dest, destOffset) {
var numComps = this.base.numComps;
var start = src[srcOffset] * numComps;
this.base.getRgbItem(this.lookup, start, dest, destOffset);
},
getRgbBuffer: function IndexedCS_getRgbBuffer(src, srcOffset, count,
dest, destOffset, bits,
alpha01) {
var base = this.base;
var numComps = base.numComps;
var outputDelta = base.getOutputLength(numComps, alpha01);
var lookup = this.lookup;
for (var i = 0; i < count; ++i) {
var lookupPos = src[srcOffset++] * numComps;
base.getRgbBuffer(lookup, lookupPos, 1, dest, destOffset, 8, alpha01);
destOffset += outputDelta;
}
},
getOutputLength: function IndexedCS_getOutputLength(inputLength, alpha01) {
return this.base.getOutputLength(inputLength * this.base.numComps,
alpha01);
},
isPassthrough: ColorSpace.prototype.isPassthrough,
fillRgb: ColorSpace.prototype.fillRgb,
isDefaultDecode: function IndexedCS_isDefaultDecode(decodeMap) {
// indexed color maps shouldn't be changed
return true;
},
usesZeroToOneRange: true
};
return IndexedCS;
})();
var DeviceGrayCS = (function DeviceGrayCSClosure() {
function DeviceGrayCS() {
this.name = 'DeviceGray';
this.numComps = 1;
this.defaultColor = new Float32Array([0]);
}
DeviceGrayCS.prototype = {
getRgb: ColorSpace.prototype.getRgb,
getRgbItem: function DeviceGrayCS_getRgbItem(src, srcOffset,
dest, destOffset) {
var c = (src[srcOffset] * 255) | 0;
c = c < 0 ? 0 : c > 255 ? 255 : c;
dest[destOffset] = dest[destOffset + 1] = dest[destOffset + 2] = c;
},
getRgbBuffer: function DeviceGrayCS_getRgbBuffer(src, srcOffset, count,
dest, destOffset, bits,
alpha01) {
var scale = 255 / ((1 << bits) - 1);
var j = srcOffset, q = destOffset;
for (var i = 0; i < count; ++i) {
var c = (scale * src[j++]) | 0;
dest[q++] = c;
dest[q++] = c;
dest[q++] = c;
q += alpha01;
}
},
getOutputLength: function DeviceGrayCS_getOutputLength(inputLength,
alpha01) {
return inputLength * (3 + alpha01);
},
isPassthrough: ColorSpace.prototype.isPassthrough,
fillRgb: ColorSpace.prototype.fillRgb,
isDefaultDecode: function DeviceGrayCS_isDefaultDecode(decodeMap) {
return ColorSpace.isDefaultDecode(decodeMap, this.numComps);
},
usesZeroToOneRange: true
};
return DeviceGrayCS;
})();
var DeviceRgbCS = (function DeviceRgbCSClosure() {
function DeviceRgbCS() {
this.name = 'DeviceRGB';
this.numComps = 3;
this.defaultColor = new Float32Array([0, 0, 0]);
}
DeviceRgbCS.prototype = {
getRgb: ColorSpace.prototype.getRgb,
getRgbItem: function DeviceRgbCS_getRgbItem(src, srcOffset,
dest, destOffset) {
var r = (src[srcOffset] * 255) | 0;
var g = (src[srcOffset + 1] * 255) | 0;
var b = (src[srcOffset + 2] * 255) | 0;
dest[destOffset] = r < 0 ? 0 : r > 255 ? 255 : r;
dest[destOffset + 1] = g < 0 ? 0 : g > 255 ? 255 : g;
dest[destOffset + 2] = b < 0 ? 0 : b > 255 ? 255 : b;
},
getRgbBuffer: function DeviceRgbCS_getRgbBuffer(src, srcOffset, count,
dest, destOffset, bits,
alpha01) {
if (bits === 8 && alpha01 === 0) {
dest.set(src.subarray(srcOffset, srcOffset + count * 3), destOffset);
return;
}
var scale = 255 / ((1 << bits) - 1);
var j = srcOffset, q = destOffset;
for (var i = 0; i < count; ++i) {
dest[q++] = (scale * src[j++]) | 0;
dest[q++] = (scale * src[j++]) | 0;
dest[q++] = (scale * src[j++]) | 0;
q += alpha01;
}
},
getOutputLength: function DeviceRgbCS_getOutputLength(inputLength,
alpha01) {
return (inputLength * (3 + alpha01) / 3) | 0;
},
isPassthrough: function DeviceRgbCS_isPassthrough(bits) {
return bits == 8;
},
fillRgb: ColorSpace.prototype.fillRgb,
isDefaultDecode: function DeviceRgbCS_isDefaultDecode(decodeMap) {
return ColorSpace.isDefaultDecode(decodeMap, this.numComps);
},
usesZeroToOneRange: true
};
return DeviceRgbCS;
})();
var DeviceCmykCS = (function DeviceCmykCSClosure() {
// The coefficients below was found using numerical analysis: the method of
// steepest descent for the sum((f_i - color_value_i)^2) for r/g/b colors,
// where color_value is the tabular value from the table of sampled RGB colors
// from CMYK US Web Coated (SWOP) colorspace, and f_i is the corresponding
// CMYK color conversion using the estimation below:
// f(A, B,.. N) = Acc+Bcm+Ccy+Dck+c+Fmm+Gmy+Hmk+Im+Jyy+Kyk+Ly+Mkk+Nk+255
function convertToRgb(src, srcOffset, srcScale, dest, destOffset) {
var c = src[srcOffset + 0] * srcScale;
var m = src[srcOffset + 1] * srcScale;
var y = src[srcOffset + 2] * srcScale;
var k = src[srcOffset + 3] * srcScale;
var r =
c * (-4.387332384609988 * c + 54.48615194189176 * m +
18.82290502165302 * y + 212.25662451639585 * k +
-285.2331026137004) +
m * (1.7149763477362134 * m - 5.6096736904047315 * y +
-17.873870861415444 * k - 5.497006427196366) +
y * (-2.5217340131683033 * y - 21.248923337353073 * k +
17.5119270841813) +
k * (-21.86122147463605 * k - 189.48180835922747) + 255;
var g =
c * (8.841041422036149 * c + 60.118027045597366 * m +
6.871425592049007 * y + 31.159100130055922 * k +
-79.2970844816548) +
m * (-15.310361306967817 * m + 17.575251261109482 * y +
131.35250912493976 * k - 190.9453302588951) +
y * (4.444339102852739 * y + 9.8632861493405 * k - 24.86741582555878) +
k * (-20.737325471181034 * k - 187.80453709719578) + 255;
var b =
c * (0.8842522430003296 * c + 8.078677503112928 * m +
30.89978309703729 * y - 0.23883238689178934 * k +
-14.183576799673286) +
m * (10.49593273432072 * m + 63.02378494754052 * y +
50.606957656360734 * k - 112.23884253719248) +
y * (0.03296041114873217 * y + 115.60384449646641 * k +
-193.58209356861505) +
k * (-22.33816807309886 * k - 180.12613974708367) + 255;
dest[destOffset] = r > 255 ? 255 : r < 0 ? 0 : r;
dest[destOffset + 1] = g > 255 ? 255 : g < 0 ? 0 : g;
dest[destOffset + 2] = b > 255 ? 255 : b < 0 ? 0 : b;
}
function DeviceCmykCS() {
this.name = 'DeviceCMYK';
this.numComps = 4;
this.defaultColor = new Float32Array([0, 0, 0, 1]);
}
DeviceCmykCS.prototype = {
getRgb: ColorSpace.prototype.getRgb,
getRgbItem: function DeviceCmykCS_getRgbItem(src, srcOffset,
dest, destOffset) {
convertToRgb(src, srcOffset, 1, dest, destOffset);
},
getRgbBuffer: function DeviceCmykCS_getRgbBuffer(src, srcOffset, count,
dest, destOffset, bits,
alpha01) {
var scale = 1 / ((1 << bits) - 1);
for (var i = 0; i < count; i++) {
convertToRgb(src, srcOffset, scale, dest, destOffset);
srcOffset += 4;
destOffset += 3 + alpha01;
}
},
getOutputLength: function DeviceCmykCS_getOutputLength(inputLength,
alpha01) {
return (inputLength / 4 * (3 + alpha01)) | 0;
},
isPassthrough: ColorSpace.prototype.isPassthrough,
fillRgb: ColorSpace.prototype.fillRgb,
isDefaultDecode: function DeviceCmykCS_isDefaultDecode(decodeMap) {
return ColorSpace.isDefaultDecode(decodeMap, this.numComps);
},
usesZeroToOneRange: true
};
return DeviceCmykCS;
})();
//
// CalGrayCS: Based on "PDF Reference, Sixth Ed", p.245
//
var CalGrayCS = (function CalGrayCSClosure() {
function CalGrayCS(whitePoint, blackPoint, gamma) {
this.name = 'CalGray';
this.numComps = 1;
this.defaultColor = new Float32Array([0]);
if (!whitePoint) {
error('WhitePoint missing - required for color space CalGray');
}
blackPoint = blackPoint || [0, 0, 0];
gamma = gamma || 1;
// Translate arguments to spec variables.
this.XW = whitePoint[0];
this.YW = whitePoint[1];
this.ZW = whitePoint[2];
this.XB = blackPoint[0];
this.YB = blackPoint[1];
this.ZB = blackPoint[2];
this.G = gamma;
// Validate variables as per spec.
if (this.XW < 0 || this.ZW < 0 || this.YW !== 1) {
error('Invalid WhitePoint components for ' + this.name +
', no fallback available');
}
if (this.XB < 0 || this.YB < 0 || this.ZB < 0) {
info('Invalid BlackPoint for ' + this.name + ', falling back to default');
this.XB = this.YB = this.ZB = 0;
}
if (this.XB !== 0 || this.YB !== 0 || this.ZB !== 0) {
warn(this.name + ', BlackPoint: XB: ' + this.XB + ', YB: ' + this.YB +
', ZB: ' + this.ZB + ', only default values are supported.');
}
if (this.G < 1) {
info('Invalid Gamma: ' + this.G + ' for ' + this.name +
', falling back to default');
this.G = 1;
}
}
function convertToRgb(cs, src, srcOffset, dest, destOffset, scale) {
// A represents a gray component of a calibrated gray space.
// A <---> AG in the spec
var A = src[srcOffset] * scale;
var AG = Math.pow(A, cs.G);
// Computes intermediate variables M, L, N as per spec.
// Except if other than default BlackPoint values are used.
var M = cs.XW * AG;
var L = cs.YW * AG;
var N = cs.ZW * AG;
// Decode XYZ, as per spec.
var X = M;
var Y = L;
var Z = N;
// http://www.poynton.com/notes/colour_and_gamma/ColorFAQ.html, Ch 4.
// This yields values in range [0, 100].
var Lstar = Math.max(116 * Math.pow(Y, 1 / 3) - 16, 0);
// Convert values to rgb range [0, 255].
dest[destOffset] = Lstar * 255 / 100;
dest[destOffset + 1] = Lstar * 255 / 100;
dest[destOffset + 2] = Lstar * 255 / 100;
}
CalGrayCS.prototype = {
getRgb: ColorSpace.prototype.getRgb,
getRgbItem: function CalGrayCS_getRgbItem(src, srcOffset,
dest, destOffset) {
convertToRgb(this, src, srcOffset, dest, destOffset, 1);
},
getRgbBuffer: function CalGrayCS_getRgbBuffer(src, srcOffset, count,
dest, destOffset, bits,
alpha01) {
var scale = 1 / ((1 << bits) - 1);
for (var i = 0; i < count; ++i) {
convertToRgb(this, src, srcOffset, dest, destOffset, scale);
srcOffset += 1;
destOffset += 3 + alpha01;
}
},
getOutputLength: function CalGrayCS_getOutputLength(inputLength, alpha01) {
return inputLength * (3 + alpha01);
},
isPassthrough: ColorSpace.prototype.isPassthrough,
fillRgb: ColorSpace.prototype.fillRgb,
isDefaultDecode: function CalGrayCS_isDefaultDecode(decodeMap) {
return ColorSpace.isDefaultDecode(decodeMap, this.numComps);
},
usesZeroToOneRange: true
};
return CalGrayCS;
})();
//
// LabCS: Based on "PDF Reference, Sixth Ed", p.250
//
var LabCS = (function LabCSClosure() {
function LabCS(whitePoint, blackPoint, range) {
this.name = 'Lab';
this.numComps = 3;
this.defaultColor = new Float32Array([0, 0, 0]);
if (!whitePoint)
error('WhitePoint missing - required for color space Lab');
blackPoint = blackPoint || [0, 0, 0];
range = range || [-100, 100, -100, 100];
// Translate args to spec variables
this.XW = whitePoint[0];
this.YW = whitePoint[1];
this.ZW = whitePoint[2];
this.amin = range[0];
this.amax = range[1];
this.bmin = range[2];
this.bmax = range[3];
// These are here just for completeness - the spec doesn't offer any
// formulas that use BlackPoint in Lab
this.XB = blackPoint[0];
this.YB = blackPoint[1];
this.ZB = blackPoint[2];
// Validate vars as per spec
if (this.XW < 0 || this.ZW < 0 || this.YW !== 1)
error('Invalid WhitePoint components, no fallback available');
if (this.XB < 0 || this.YB < 0 || this.ZB < 0) {
info('Invalid BlackPoint, falling back to default');
this.XB = this.YB = this.ZB = 0;
}
if (this.amin > this.amax || this.bmin > this.bmax) {
info('Invalid Range, falling back to defaults');
this.amin = -100;
this.amax = 100;
this.bmin = -100;
this.bmax = 100;
}
}
// Function g(x) from spec
function fn_g(x) {
if (x >= 6 / 29)
return x * x * x;
else
return (108 / 841) * (x - 4 / 29);
}
function decode(value, high1, low2, high2) {
return low2 + (value) * (high2 - low2) / (high1);
}
// If decoding is needed maxVal should be 2^bits per component - 1.
function convertToRgb(cs, src, srcOffset, maxVal, dest, destOffset) {
// XXX: Lab input is in the range of [0, 100], [amin, amax], [bmin, bmax]
// not the usual [0, 1]. If a command like setFillColor is used the src
// values will already be within the correct range. However, if we are
// converting an image we have to map the values to the correct range given
// above.
// Ls,as,bs <---> L*,a*,b* in the spec
var Ls = src[srcOffset];
var as = src[srcOffset + 1];
var bs = src[srcOffset + 2];
if (maxVal !== false) {
Ls = decode(Ls, maxVal, 0, 100);
as = decode(as, maxVal, cs.amin, cs.amax);
bs = decode(bs, maxVal, cs.bmin, cs.bmax);
}
// Adjust limits of 'as' and 'bs'
as = as > cs.amax ? cs.amax : as < cs.amin ? cs.amin : as;
bs = bs > cs.bmax ? cs.bmax : bs < cs.bmin ? cs.bmin : bs;
// Computes intermediate variables X,Y,Z as per spec
var M = (Ls + 16) / 116;
var L = M + (as / 500);
var N = M - (bs / 200);
var X = cs.XW * fn_g(L);
var Y = cs.YW * fn_g(M);
var Z = cs.ZW * fn_g(N);
var r, g, b;
// Using different conversions for D50 and D65 white points,
// per http://www.color.org/srgb.pdf
if (cs.ZW < 1) {
// Assuming D50 (X=0.9642, Y=1.00, Z=0.8249)
r = X * 3.1339 + Y * -1.6170 + Z * -0.4906;
g = X * -0.9785 + Y * 1.9160 + Z * 0.0333;
b = X * 0.0720 + Y * -0.2290 + Z * 1.4057;
} else {
// Assuming D65 (X=0.9505, Y=1.00, Z=1.0888)
r = X * 3.2406 + Y * -1.5372 + Z * -0.4986;
g = X * -0.9689 + Y * 1.8758 + Z * 0.0415;
b = X * 0.0557 + Y * -0.2040 + Z * 1.0570;
}
// clamp color values to [0,1] range then convert to [0,255] range.
dest[destOffset] = r <= 0 ? 0 : r >= 1 ? 255 : Math.sqrt(r) * 255 | 0;
dest[destOffset + 1] = g <= 0 ? 0 : g >= 1 ? 255 : Math.sqrt(g) * 255 | 0;
dest[destOffset + 2] = b <= 0 ? 0 : b >= 1 ? 255 : Math.sqrt(b) * 255 | 0;
}
LabCS.prototype = {
getRgb: ColorSpace.prototype.getRgb,
getRgbItem: function LabCS_getRgbItem(src, srcOffset, dest, destOffset) {
convertToRgb(this, src, srcOffset, false, dest, destOffset);
},
getRgbBuffer: function LabCS_getRgbBuffer(src, srcOffset, count,
dest, destOffset, bits,
alpha01) {
var maxVal = (1 << bits) - 1;
for (var i = 0; i < count; i++) {
convertToRgb(this, src, srcOffset, maxVal, dest, destOffset);
srcOffset += 3;
destOffset += 3 + alpha01;
}
},
getOutputLength: function LabCS_getOutputLength(inputLength, alpha01) {
return (inputLength * (3 + alpha01) / 3) | 0;
},
isPassthrough: ColorSpace.prototype.isPassthrough,
isDefaultDecode: function LabCS_isDefaultDecode(decodeMap) {
// XXX: Decoding is handled with the lab conversion because of the strange
// ranges that are used.
return true;
},
usesZeroToOneRange: false
};
return LabCS;
})();