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Merge pull request #4062 from kkujala/calgray

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calgray: fix getRgbBuffer problem
This commit is contained in:
Yury Delendik 2014-01-07 10:54:09 -08:00
commit 4d01ff4079
3 changed files with 45 additions and 33 deletions
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68
src/shared/colorspace.js
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@ -639,8 +639,8 @@ var DeviceCmykCS = (function DeviceCmykCSClosure() {
var CalGrayCS = (function CalGrayCSClosure() {
function CalGrayCS(whitePoint, blackPoint, gamma) {
this.name = 'CalGray';
this.numComps = 3;
this.defaultColor = new Float32Array([0, 0, 0]);
this.numComps = 1;
this.defaultColor = new Float32Array([0]);
if (!whitePoint) {
error('WhitePoint missing - required for color space CalGray');
@ -682,6 +682,33 @@ var CalGrayCS = (function CalGrayCSClosure() {
}
}
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: function CalGrayCS_getRgb(src, srcOffset) {
var rgb = new Uint8Array(3);
@ -690,41 +717,16 @@ var CalGrayCS = (function CalGrayCSClosure() {
},
getRgbItem: function CalGrayCS_getRgbItem(src, srcOffset,
dest, destOffset) {
// A represents a gray component of a calibrated gray space.
// A <---> AG in the spec
var A = src[srcOffset];
var AG = Math.pow(A, this.G);
// Computes intermediate variables M, L, N as per spec.
// Except if other than default BlackPoint values are used.
var M = this.XW * AG;
var L = this.YW * AG;
var N = this.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;
convertToRgb(this, src, srcOffset, dest, destOffset, 1);
},
getRgbBuffer: function CalGrayCS_getRgbBuffer(src, srcOffset, count,
dest, destOffset, bits) {
// TODO: This part is copied from DeviceGray. Make this utility function.
var scale = 255 / ((1 << bits) - 1);
var j = srcOffset, q = destOffset;
var scale = 1 / ((1 << bits) - 1);
for (var i = 0; i < count; ++i) {
var c = (scale * src[j++]) | 0;
dest[q++] = c;
dest[q++] = c;
dest[q++] = c;
convertToRgb(this, src, srcOffset, dest, destOffset, scale);
srcOffset += 1;
destOffset += 3;
}
},
getOutputLength: function CalGrayCS_getOutputLength(inputLength) {