stylus/js/color/color-mimicry.js
tophf b7cfbe6e66
use color palette and enable a simple dark theme (#1405)
* add 'auto' iconset and use it by default
* expose `data-ui-theme` on html

Co-authored-by: narcolepticinsomniac <therealdoctorgonzo@gmail.com>
2022-02-17 03:10:59 +03:00

98 lines
2.7 KiB
JavaScript

/* global $create */// dom.js
/* global debounce */// toolbox.js
'use strict';
/* exported colorMimicry */
/**
* Calculates real color of an element:
* colorMimicry(cm.display.gutters, {bg: 'backgroundColor'})
* colorMimicry('input.foo.bar', null, $('some.parent.to.host.the.dummy'))
*/
function colorMimicry(el, targets, dummyContainer = document.body) {
const styleCache = colorMimicry.styleCache || (colorMimicry.styleCache = new Map());
targets = targets || {};
targets.fore = 'color';
const colors = {};
const done = {};
let numDone = 0;
let numTotal = 0;
const rootStyle = getStyle(document.documentElement);
for (const k in targets) {
const base = {r: 0, g: 0, b: 0, a: 0};
blend(base, rootStyle[targets[k]]);
colors[k] = base;
numTotal++;
}
const isDummy = typeof el === 'string';
if (isDummy) {
el = dummyContainer.appendChild($create(el, {style: 'display: none'}));
}
for (let current = el; current; current = current && current.parentElement) {
const style = getStyle(current);
for (const k in targets) {
if (!done[k]) {
done[k] = blend(colors[k], style[targets[k]]);
numDone += done[k] ? 1 : 0;
if (numDone === numTotal) {
current = null;
break;
}
}
}
colors.style = colors.style || style;
}
if (isDummy) {
el.remove();
}
for (const k in targets) {
const c = colors[k];
if (!isOpaque(c)) {
blend(colors[k] = {r: 255, g: 255, b: 255, a: 1}, c);
}
const {r, g, b, a} = colors[k];
colors[k] = `rgba(${r}, ${g}, ${b}, ${a})`;
// https://www.w3.org/TR/AERT#color-contrast
colors[k + 'Luma'] = (r * .299 + g * .587 + b * .114) / 256;
}
debounce(clearCache);
return colors;
function blend(base, color) {
const [r, g, b, a = 255] = (color.match(/\d+/g) || []).map(Number);
if (a === 255) {
base.r = r;
base.g = g;
base.b = b;
base.a = 1;
} else if (a) {
const mixedA = 1 - (1 - a / 255) * (1 - base.a);
const q1 = a / 255 / mixedA;
const q2 = base.a * (1 - mixedA) / mixedA;
base.r = Math.round(r * q1 + base.r * q2);
base.g = Math.round(g * q1 + base.g * q2);
base.b = Math.round(b * q1 + base.b * q2);
base.a = mixedA;
}
return isOpaque(base);
}
// speed-up for sequential invocations within the same event loop cycle
// (we're assuming the invoker doesn't force CSSOM to refresh between the calls)
function getStyle(el) {
let style = styleCache.get(el);
if (!style) {
style = getComputedStyle(el);
styleCache.set(el, style);
}
return style;
}
function clearCache() {
styleCache.clear();
}
function isOpaque({a}) {
return Math.abs(a - 1) < 1e-3;
}
}