The avatar for @smitop
Smitty
Published
Edited
Nov 6, 2021
9 stars
4
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filter((orig, a, b, c) => mod256(orig - a))
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mod256 = x => x & 0xFF
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filter((orig, a, b, c) => mod256(orig - b))
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filter((orig, a, b, c) => mod256(orig - mod256(Math.floor((a + b) / 2))))
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function paeth(a, b, c) {
const p = a + b - c; // extend the gradient
// return whatever input is closest to p
const pa = Math.abs(p - a);
const pb = Math.abs(p - b);
const pc = Math.abs(p - c);
if (pa <= pb && pa <= pc) {
return a;
} else if (pb <= pc) {
return b;
} else {
return c;
}
}
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filter((orig, a, b, c) => mod256(orig - paeth(a, b, c)))
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