https://libregraphicsmeeting.org/2026/js/culori-4.0.1/src/util/normalizePositions.js

1/*
2	Normalize an array of color stop positions for a gradient
3	based on the rules defined in the CSS Images Module 4 spec:
4
5	1. make the first position 0 and the last position 1 if missing
6	2. sequences of unpositioned color stops should be spread out evenly
7	3. no position can be smaller than any of the ones preceding it
8	
9	Reference: https://drafts.csswg.org/css-images-4/#color-stop-fixup
10
11	Note: this method does not make a defensive copy of the array
12	it receives as argument. Instead, it adjusts the values in-place.
13 */
14const normalizePositions = arr => {
15	// 1. fix up first/last position if missing
16	if (arr[0] === undefined) {
17		arr[0] = 0;
18	}
19	if (arr[arr.length - 1] === undefined) {
20		arr[arr.length - 1] = 1;
21	}
22
23	let i = 1;
24	let j;
25	let from_idx;
26	let from_pos;
27	let inc;
28	while (i < arr.length) {
29		// 2. fill up undefined positions
30		if (arr[i] === undefined) {
31			from_idx = i;
32			from_pos = arr[i - 1];
33			j = i;
34
35			// find end of `undefined` sequence...
36			while (arr[j] === undefined) j++;
37
38			// ...and add evenly-spread positions
39			inc = (arr[j] - from_pos) / (j - i + 1);
40			while (i < j) {
41				arr[i] = from_pos + (i + 1 - from_idx) * inc;
42				i++;
43			}
44		} else if (arr[i] < arr[i - 1]) {
45			// 3. make positions increase
46			arr[i] = arr[i - 1];
47		}
48		i++;
49	}
50	return arr;
51};
52
53export default normalizePositions;