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css-color-parser : fix interpolation of longer hue #1138

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4 changes: 4 additions & 0 deletions packages/css-color-parser/CHANGELOG.md
Original file line number Diff line number Diff line change
@@ -1,5 +1,9 @@
# Changes to CSS Color Parser

### Unreleased (patch)

- Fix interpolation of `hue` when either or both components are `none` and `longer` is the interpolation method.

### 1.3.2

_September 24, 2023_
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2 changes: 1 addition & 1 deletion packages/css-color-parser/dist/index.cjs

Large diffs are not rendered by default.

2 changes: 1 addition & 1 deletion packages/css-color-parser/dist/index.mjs

Large diffs are not rendered by default.

93 changes: 58 additions & 35 deletions packages/css-color-parser/src/functions/color-mix.ts
Original file line number Diff line number Diff line change
Expand Up @@ -320,6 +320,15 @@ function colorMixRectangular(colorSpace: string, colors: ColorMixColors | false)
a_channels = colorDataTo(a_color, outputColorNotation).channels;
b_channels = colorDataTo(b_color, outputColorNotation).channels;

a_channels[0] = fillInMissingComponent(a_channels[0], b_channels[0]);
b_channels[0] = fillInMissingComponent(b_channels[0], a_channels[0]);

a_channels[1] = fillInMissingComponent(a_channels[1], b_channels[1]);
b_channels[1] = fillInMissingComponent(b_channels[1], a_channels[1]);

a_channels[2] = fillInMissingComponent(a_channels[2], b_channels[2]);
b_channels[2] = fillInMissingComponent(b_channels[2], a_channels[2]);

a_channels[0] = premultiply(a_channels[0], a_alpha);
a_channels[1] = premultiply(a_channels[1], a_alpha);
a_channels[2] = premultiply(a_channels[2], a_alpha);
Expand Down Expand Up @@ -431,43 +440,57 @@ function colorMixPolar(colorSpace: string, hueInterpolationMethod: string, color
break;
}

if (!Number.isNaN(a_hue) && !Number.isNaN(b_hue)) {
const angleDiff = b_hue - a_hue;
a_hue = fillInMissingComponent(a_hue, b_hue);
if (Number.isNaN(a_hue)) {
a_hue = 0;
}

switch (hueInterpolationMethod) {
case 'shorter':
if (angleDiff > 180) {
a_hue += 360;
} else if (angleDiff < -180) {
b_hue += 360;
}
b_hue = fillInMissingComponent(b_hue, a_hue);
if (Number.isNaN(b_hue)) {
b_hue = 0;
}

break;
case 'longer':
if (-180 < angleDiff && angleDiff < 180) {
if (angleDiff > 0) {
a_hue += 360;
} else {
b_hue += 360;
}
}
a_first = fillInMissingComponent(a_first, b_first);
b_first = fillInMissingComponent(b_first, a_first);

break;
case 'increasing':
if (angleDiff < 0) {
b_hue += 360;
}
a_second = fillInMissingComponent(a_second, b_second);
b_second = fillInMissingComponent(b_second, a_second);

const angleDiff = b_hue - a_hue;

break;
case 'decreasing':
switch (hueInterpolationMethod) {
case 'shorter':
if (angleDiff > 180) {
a_hue += 360;
} else if (angleDiff < -180) {
b_hue += 360;
}

break;
case 'longer':
if (-180 < angleDiff && angleDiff < 180) {
if (angleDiff > 0) {
a_hue += 360;
} else {
b_hue += 360;
}
}

break;
default:
throw new Error('Unknown hue interpolation method');
}
break;
case 'increasing':
if (angleDiff < 0) {
b_hue += 360;
}

break;
case 'decreasing':
if (angleDiff > 0) {
a_hue += 360;
}

break;
default:
throw new Error('Unknown hue interpolation method');
}

a_first = premultiply(a_first, a_alpha);
Expand Down Expand Up @@ -511,15 +534,15 @@ function colorMixPolar(colorSpace: string, hueInterpolationMethod: string, color
return colorData;
}

function interpolate(start: number, end: number, p: number): number {
if (Number.isNaN(start)) {
return end;
function fillInMissingComponent(a: number, b: number): number {
if (Number.isNaN(a)) {
return b;
}

if (Number.isNaN(end)) {
return start;
}
return a;
}

function interpolate(start: number, end: number, p: number): number {
return (start * p) + end * (1 - p);
}

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8 changes: 6 additions & 2 deletions packages/css-color-parser/test/basic/color-mix-function.mjs
Original file line number Diff line number Diff line change
Expand Up @@ -70,14 +70,18 @@ const tests = [
['color-mix(in oklab, #09232c, white 50%)', 'rgb(123, 137, 142)'],

['color-mix(in hsl longer hue, hsl(90deg 50% 50%), hsl(0deg 50% 50%)', canonicalize('hsl(225deg 50% 50%)')],
['color-mix(in hsl longer hue, hsl(90deg 50% 50%), hsl(none 50% 50%)', canonicalize('hsl(90deg 50% 50%)')],
['color-mix(in hsl longer hue, hsl(90deg 50% 50%), hsl(none 50% 50%)', canonicalize('hsl(270deg 50% 50%)')],
['color-mix(in hsl shorter hue, hsl(90deg 50% 50%), hsl(none 50% 50%)', canonicalize('hsl(90deg 50% 50%)')],
['color-mix(in hsl increasing hue, hsl(90deg 50% 50%), hsl(none 50% 50%)', canonicalize('hsl(90deg 50% 50%)')],
['color-mix(in hsl decreasing hue, hsl(90deg 50% 50%), hsl(none 50% 50%)', canonicalize('hsl(90deg 50% 50%)')],
['color-mix(in hsl longer hue, hsl(none 50% 50%), hsl(90deg 50% 50%)', canonicalize('hsl(90deg 50% 50%)')],
['color-mix(in hsl longer hue, hsl(none 50% 50%), hsl(90deg 50% 50%)', canonicalize('hsl(270deg 50% 50%)')],
['color-mix(in hsl shorter hue, hsl(none 50% 50%), hsl(90deg 50% 50%)', canonicalize('hsl(90deg 50% 50%)')],
['color-mix(in hsl increasing hue, hsl(none 50% 50%), hsl(90deg 50% 50%)', canonicalize('hsl(90deg 50% 50%)')],
['color-mix(in hsl decreasing hue, hsl(none 50% 50%), hsl(90deg 50% 50%)', canonicalize('hsl(90deg 50% 50%)')],
['color-mix(in hsl longer hue, hsl(none 50% 50%), hsl(none 50% 50%)', canonicalize('hsl(180deg 50% 50%)')],
['color-mix(in hsl shorter hue, hsl(none 50% 50%), hsl(none 50% 50%)', canonicalize('hsl(0deg 50% 50%)')],
['color-mix(in hsl increasing hue, hsl(none 50% 50%), hsl(none 50% 50%)', canonicalize('hsl(0deg 50% 50%)')],
['color-mix(in hsl decreasing hue, hsl(none 50% 50%), hsl(none 50% 50%)', canonicalize('hsl(0deg 50% 50%)')],
];

for (const test of tests) {
Expand Down
Original file line number Diff line number Diff line change
Expand Up @@ -350,9 +350,9 @@

.patterns-2 {
background:
conic-gradient(at 20px calc(100% - 20px), rgba(0, 0, 0, 0) 270deg, rgba(192, 41, 66, 0.1), rgba(192, 41, 66, 0.2), rgba(192, 41, 66, 0.3), rgba(192, 41, 66, 0.4), rgba(192, 41, 66, 0.5), rgba(192, 41, 66, 0.6), rgba(192, 41, 66, 0.7), rgba(192, 41, 66, 0.8), rgba(192, 41, 66, 0.9), rgb(192, 41, 66) 0) calc(20px + 15px) 0,
conic-gradient(at 20px calc(100% - 20px), rgba(0, 0, 0, 0) 270deg, rgba(192, 107, 41, 0.1), rgba(187, 192, 41, 0.2), rgba(96, 192, 41, 0.3), rgba(41, 192, 76, 0.4), rgba(41, 192, 167, 0.5), rgba(41, 126, 192, 0.6), rgba(46, 41, 192, 0.7), rgba(137, 41, 192, 0.8), rgba(192, 41, 157, 0.9), rgb(192, 41, 66) 0) calc(20px + 15px) 0,
linear-gradient(#53777A 20px, #0000 0) 0 15px,
conic-gradient(at 20px calc(100% - 20px), rgba(0, 0, 0, 0) 90deg, rgba(83, 119, 122, 0.1), rgba(83, 119, 122, 0.2), rgba(83, 119, 122, 0.3), rgba(83, 119, 122, 0.4), rgba(83, 119, 122, 0.5), rgba(83, 119, 122, 0.6), rgba(83, 119, 122, 0.7), rgba(83, 119, 122, 0.8), rgba(83, 119, 122, 0.9), rgb(83, 119, 122) 0, rgb(83, 96, 122), rgb(94, 83, 122), rgb(117, 83, 122), rgb(122, 83, 103), rgb(122, 86, 83), rgb(122, 109, 83), rgb(111, 122, 83), rgb(88, 122, 83), rgb(83, 122, 102), rgb(83, 119, 122) 180deg, rgb(79, 128, 116), rgb(76, 135, 101), rgb(72, 142, 79), rgb(86, 148, 68), rgb(114, 155, 64), rgb(149, 162, 59), rgb(170, 148, 55), rgb(177, 112, 50), rgb(184, 68, 46), rgb(192, 41, 66) 0),
conic-gradient(at 20px calc(100% - 20px), rgba(0, 0, 0, 0) 90deg, rgba(83, 96, 122, 0.1), rgba(94, 83, 122, 0.2), rgba(117, 83, 122, 0.3), rgba(122, 83, 103, 0.4), rgba(122, 86, 83, 0.5), rgba(122, 109, 83, 0.6), rgba(111, 122, 83, 0.7), rgba(88, 122, 83, 0.8), rgba(83, 122, 102, 0.9), rgb(83, 119, 122) 0, rgb(83, 96, 122), rgb(94, 83, 122), rgb(117, 83, 122), rgb(122, 83, 103), rgb(122, 86, 83), rgb(122, 109, 83), rgb(111, 122, 83), rgb(88, 122, 83), rgb(83, 122, 102), rgb(83, 119, 122) 180deg, rgb(79, 128, 116), rgb(76, 135, 101), rgb(72, 142, 79), rgb(86, 148, 68), rgb(114, 155, 64), rgb(149, 162, 59), rgb(170, 148, 55), rgb(177, 112, 50), rgb(184, 68, 46), rgb(192, 41, 66) 0),
#ECD078;
background:
conic-gradient(in hsl longer hue at 20px calc(100% - 20px), #0000 270deg, #C02942 0) calc(20px + 15px) 0,
Expand Down
Original file line number Diff line number Diff line change
Expand Up @@ -283,9 +283,9 @@

.patterns-2 {
background:
conic-gradient(at 20px calc(100% - 20px), rgba(0, 0, 0, 0) 270deg, rgba(192, 41, 66, 0.1), rgba(192, 41, 66, 0.2), rgba(192, 41, 66, 0.3), rgba(192, 41, 66, 0.4), rgba(192, 41, 66, 0.5), rgba(192, 41, 66, 0.6), rgba(192, 41, 66, 0.7), rgba(192, 41, 66, 0.8), rgba(192, 41, 66, 0.9), rgb(192, 41, 66) 0) calc(20px + 15px) 0,
conic-gradient(at 20px calc(100% - 20px), rgba(0, 0, 0, 0) 270deg, rgba(192, 107, 41, 0.1), rgba(187, 192, 41, 0.2), rgba(96, 192, 41, 0.3), rgba(41, 192, 76, 0.4), rgba(41, 192, 167, 0.5), rgba(41, 126, 192, 0.6), rgba(46, 41, 192, 0.7), rgba(137, 41, 192, 0.8), rgba(192, 41, 157, 0.9), rgb(192, 41, 66) 0) calc(20px + 15px) 0,
linear-gradient(#53777A 20px, #0000 0) 0 15px,
conic-gradient(at 20px calc(100% - 20px), rgba(0, 0, 0, 0) 90deg, rgba(83, 119, 122, 0.1), rgba(83, 119, 122, 0.2), rgba(83, 119, 122, 0.3), rgba(83, 119, 122, 0.4), rgba(83, 119, 122, 0.5), rgba(83, 119, 122, 0.6), rgba(83, 119, 122, 0.7), rgba(83, 119, 122, 0.8), rgba(83, 119, 122, 0.9), rgb(83, 119, 122) 0, rgb(83, 96, 122), rgb(94, 83, 122), rgb(117, 83, 122), rgb(122, 83, 103), rgb(122, 86, 83), rgb(122, 109, 83), rgb(111, 122, 83), rgb(88, 122, 83), rgb(83, 122, 102), rgb(83, 119, 122) 180deg, rgb(79, 128, 116), rgb(76, 135, 101), rgb(72, 142, 79), rgb(86, 148, 68), rgb(114, 155, 64), rgb(149, 162, 59), rgb(170, 148, 55), rgb(177, 112, 50), rgb(184, 68, 46), rgb(192, 41, 66) 0),
conic-gradient(at 20px calc(100% - 20px), rgba(0, 0, 0, 0) 90deg, rgba(83, 96, 122, 0.1), rgba(94, 83, 122, 0.2), rgba(117, 83, 122, 0.3), rgba(122, 83, 103, 0.4), rgba(122, 86, 83, 0.5), rgba(122, 109, 83, 0.6), rgba(111, 122, 83, 0.7), rgba(88, 122, 83, 0.8), rgba(83, 122, 102, 0.9), rgb(83, 119, 122) 0, rgb(83, 96, 122), rgb(94, 83, 122), rgb(117, 83, 122), rgb(122, 83, 103), rgb(122, 86, 83), rgb(122, 109, 83), rgb(111, 122, 83), rgb(88, 122, 83), rgb(83, 122, 102), rgb(83, 119, 122) 180deg, rgb(79, 128, 116), rgb(76, 135, 101), rgb(72, 142, 79), rgb(86, 148, 68), rgb(114, 155, 64), rgb(149, 162, 59), rgb(170, 148, 55), rgb(177, 112, 50), rgb(184, 68, 46), rgb(192, 41, 66) 0),
#ECD078;
}

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Original file line number Diff line number Diff line change
Expand Up @@ -350,9 +350,9 @@

.patterns-2 {
background:
conic-gradient(at 20px calc(100% - 20px), rgba(0, 0, 0, 0) 270deg, rgba(192, 41, 66, 0.1), rgba(192, 41, 66, 0.2), rgba(192, 41, 66, 0.3), rgba(192, 41, 66, 0.4), rgba(192, 41, 66, 0.5), rgba(192, 41, 66, 0.6), rgba(192, 41, 66, 0.7), rgba(192, 41, 66, 0.8), rgba(192, 41, 66, 0.9), rgb(192, 41, 66) 0) calc(20px + 15px) 0,
conic-gradient(at 20px calc(100% - 20px), rgba(0, 0, 0, 0) 270deg, rgba(192, 107, 41, 0.1), rgba(187, 192, 41, 0.2), rgba(96, 192, 41, 0.3), rgba(41, 192, 76, 0.4), rgba(41, 192, 167, 0.5), rgba(41, 126, 192, 0.6), rgba(46, 41, 192, 0.7), rgba(137, 41, 192, 0.8), rgba(192, 41, 157, 0.9), rgb(192, 41, 66) 0) calc(20px + 15px) 0,
linear-gradient(#53777A 20px, #0000 0) 0 15px,
conic-gradient(at 20px calc(100% - 20px), rgba(0, 0, 0, 0) 90deg, rgba(83, 119, 122, 0.1), rgba(83, 119, 122, 0.2), rgba(83, 119, 122, 0.3), rgba(83, 119, 122, 0.4), rgba(83, 119, 122, 0.5), rgba(83, 119, 122, 0.6), rgba(83, 119, 122, 0.7), rgba(83, 119, 122, 0.8), rgba(83, 119, 122, 0.9), rgb(83, 119, 122) 0, rgb(83, 96, 122), rgb(94, 83, 122), rgb(117, 83, 122), rgb(122, 83, 103), rgb(122, 86, 83), rgb(122, 109, 83), rgb(111, 122, 83), rgb(88, 122, 83), rgb(83, 122, 102), rgb(83, 119, 122) 180deg, rgb(79, 128, 116), rgb(76, 135, 101), rgb(72, 142, 79), rgb(86, 148, 68), rgb(114, 155, 64), rgb(149, 162, 59), rgb(170, 148, 55), rgb(177, 112, 50), rgb(184, 68, 46), rgb(192, 41, 66) 0),
conic-gradient(at 20px calc(100% - 20px), rgba(0, 0, 0, 0) 90deg, rgba(83, 96, 122, 0.1), rgba(94, 83, 122, 0.2), rgba(117, 83, 122, 0.3), rgba(122, 83, 103, 0.4), rgba(122, 86, 83, 0.5), rgba(122, 109, 83, 0.6), rgba(111, 122, 83, 0.7), rgba(88, 122, 83, 0.8), rgba(83, 122, 102, 0.9), rgb(83, 119, 122) 0, rgb(83, 96, 122), rgb(94, 83, 122), rgb(117, 83, 122), rgb(122, 83, 103), rgb(122, 86, 83), rgb(122, 109, 83), rgb(111, 122, 83), rgb(88, 122, 83), rgb(83, 122, 102), rgb(83, 119, 122) 180deg, rgb(79, 128, 116), rgb(76, 135, 101), rgb(72, 142, 79), rgb(86, 148, 68), rgb(114, 155, 64), rgb(149, 162, 59), rgb(170, 148, 55), rgb(177, 112, 50), rgb(184, 68, 46), rgb(192, 41, 66) 0),
#ECD078;
background:
conic-gradient(in hsl longer hue at 20px calc(100% - 20px), #0000 270deg, #C02942 0) calc(20px + 15px) 0,
Expand Down