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Optimization:

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Avoid calling Math.pow if possible when calculating the transfer
function of the CalRGB color space since calling Math.pow is expensive.

If the value of color is larger than the threshold, 0.99554525,
the final result of the transform is larger that 254.5
since ((1 + 0.055) * 0.99554525 ** (1 / 2.4) - 0.055) * 255 === 254.50000003134699
This commit is contained in:
Takashi Tamura 2020-06-02 22:26:39 +09:00
parent 039307f88c
commit 7acb112ca9
1 changed files with 12 additions and 3 deletions
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15
src/core/colorspace.js
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@ -1057,6 +1057,15 @@ const CalRGBCS = (function CalRGBCSClosure() {
if (color <= 0.0031308) {
return adjustToRange(0, 1, 12.92 * color);
}
// Optimization:
// If color is close enough to 1, skip calling the following transform
// since calling Math.pow is expensive. If color is larger than
// the threshold, the final result is larger than 254.5 since
// ((1 + 0.055) * 0.99554525 ** (1 / 2.4) - 0.055) * 255 ===
// 254.50000003134699
if (color >= 0.99554525) {
return 1;
}
return adjustToRange(0, 1, (1 + 0.055) * color ** (1 / 2.4) - 0.055);
}
@ -1156,9 +1165,9 @@ const CalRGBCS = (function CalRGBCSClosure() {
// A <---> AGR in the spec
// B <---> BGG in the spec
// C <---> CGB in the spec
const AGR = A ** cs.GR;
const BGG = B ** cs.GG;
const CGB = C ** cs.GB;
const AGR = A === 1 ? 1 : A ** cs.GR;
const BGG = B === 1 ? 1 : B ** cs.GG;
const CGB = C === 1 ? 1 : C ** cs.GB;
// Computes intermediate variables L, M, N as per spec.
// To decode X, Y, Z values map L, M, N directly to them.