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CalRGB: optimize CalRGB calculations

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Also fix one silly mistake.
This commit is contained in:
Kalervo Kujala 2014-08-16 11:37:52 +03:00
parent 3ad972ad45
commit 0c5525dc8a
3 changed files with 40 additions and 20 deletions
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46
src/core/colorspace.js
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@ -829,6 +829,8 @@ var CalRGBCS = (function CalRGBCSClosure() {
var tempConvertMatrix1 = new Float32Array(3);
var tempConvertMatrix2 = new Float32Array(3);
var DECODE_L_CONSTANT = Math.pow(((8 + 16) / 116), 3) / 8.0;
function CalRGBCS(whitePoint, blackPoint, gamma, matrix) {
this.name = 'CalRGB';
this.numComps = 3;
@ -937,18 +939,30 @@ var CalRGBCS = (function CalRGBCSClosure() {
return -decodeL(-L);
}
if (L > 80) {
if (L > 8.0) {
return Math.pow(((L + 16) / 116), 3);
}
return L * Math.pow(((8 + 16) / 116), 3) / 8.0;
return L * DECODE_L_CONSTANT;
}
function compensateBlackPoint(sourceBlackPoint, XYZ_Flat, result) {
// For the BlackPoint calculation details, please see
// In case the blackPoint is already the default blackPoint then there is
// no need to do compensation.
if (sourceBlackPoint[0] === 0 &&
sourceBlackPoint[1] === 0 &&
sourceBlackPoint[2] === 0) {
result[0] = XYZ_Flat[0];
result[1] = XYZ_Flat[1];
result[2] = XYZ_Flat[2];
return;
}
// For the blackPoint calculation details, please see
// http://www.adobe.com/content/dam/Adobe/en/devnet/photoshop/sdk/
// AdobeBPC.pdf.
// The destination BlackPoint is the default BlackPoint [0, 0, 0].
// The destination blackPoint is the default blackPoint [0, 0, 0].
var zeroDecodeL = decodeL(0);
var X_DST = zeroDecodeL;
@ -976,6 +990,15 @@ var CalRGBCS = (function CalRGBCSClosure() {
function normalizeWhitePointToFlat(sourceWhitePoint, XYZ_In, result) {
// In case the whitePoint is already flat then there is no need to do
// normalization.
if (sourceWhitePoint[0] === 1 && sourceWhitePoint[2] === 1) {
result[0] = XYZ_In[0];
result[1] = XYZ_In[1];
result[2] = XYZ_In[2];
return;
}
var LMS = result;
matrixProduct(BRADFORD_SCALE_MATRIX, XYZ_In, LMS);
@ -1010,15 +1033,11 @@ var CalRGBCS = (function CalRGBCSClosure() {
var BGG = Math.pow(B, cs.GG);
var CGB = Math.pow(C, cs.GB);
// Computes intermediate variables M, L, N as per spec.
var M = cs.MXA * AGR + cs.MXB * BGG + cs.MXC * CGB;
var L = cs.MYA * AGR + cs.MYB * BGG + cs.MYC * CGB;
var N = cs.MZA * AGR + cs.MZB * BGG + cs.MZC * CGB;
// Decode XYZ, as per spec.
var X = M;
var Y = L;
var Z = N;
// Computes intermediate variables L, M, N as per spec.
// To decode X, Y, Z values map L, M, N directly to them.
var X = cs.MXA * AGR + cs.MXB * BGG + cs.MXC * CGB;
var Y = cs.MYA * AGR + cs.MYB * BGG + cs.MYC * CGB;
var Z = cs.MZA * AGR + cs.MZB * BGG + cs.MZC * CGB;
// The following calculations are based on this document:
// http://www.adobe.com/content/dam/Adobe/en/devnet/photoshop/sdk/
@ -1028,6 +1047,7 @@ var CalRGBCS = (function CalRGBCSClosure() {
XYZ[1] = Y;
XYZ[2] = Z;
var XYZ_Flat = tempConvertMatrix2;
normalizeWhitePointToFlat(cs.whitePoint, XYZ, XYZ_Flat);
var XYZ_Black = tempConvertMatrix1;