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This commit is contained in:
Brooke Vibber 2023-03-19 16:56:18 -07:00
parent 6af5d43943
commit 9a93e7341f
1 changed files with 32 additions and 3 deletions
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35
dither-image.js
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@ -110,6 +110,10 @@ class RGB {
);
}
magnitude() {
return Math.sqrt(this.magnitude2());
}
magnitude2() {
return this.r * this.r +
this.g * this.g +
@ -117,6 +121,8 @@ class RGB {
}
}
const maxDist = (new RGB(255, 255, 255)).magnitude();
// snarfed from https://lospec.com/palette-list/atari-8-bit-family-gtia
// which was calculated with Retrospecs App's Atari 800 emulator
let atariRGB = [
@ -420,7 +426,7 @@ function decimate(input, palette, n, inputError, y) {
// Apply dithering with given palette and collect color usage stats
let dither = (palette) => {
let fitness = new Float64Array(width);
let fitness = new Float64Array(palette.length);
let error = {
cur: [],
next: [],
@ -431,7 +437,7 @@ function decimate(input, palette, n, inputError, y) {
}
let output = new Uint8Array(width);
let popularity = new Int32Array(width);
let popularity = new Int32Array(palette.length);
let distance2 = 0;
let nextError = new RGB(0, 0, 0);
@ -468,9 +474,12 @@ function decimate(input, palette, n, inputError, y) {
error.next[x]?.inc(double);
error.next[x + 1]?.inc(double);
let mag = nextError.magnitude();
fitness[x] = maxDist / mag;
// just store the distance2
let mag2 = nextError.magnitude2();
fitness[x] = mag2;
//fitness[x] = mag2;
distance2 += mag2;
}
return {
@ -521,6 +530,9 @@ function decimate(input, palette, n, inputError, y) {
return arr;
};
// this takes the top hues, and uses the brightest of each hue
// needs tuning
/*
// first, dither to the total atari palette
while (decimated.length > n) {
let {popularity} = dither(decimated);
@ -548,7 +560,24 @@ function decimate(input, palette, n, inputError, y) {
decimated = reserved.concat(a);
}
console.log('end', decimated);
*/
// popularity? not really working right
// first, dither to the total atari palette
while (decimated.length > n) {
let {popularity, fitness} = dither(decimated);
// temporarily strip the reserved items
//console.log(y);
let a = decimated;
a = a.filter((color) => !keepers[color]);
a = a.sort((a, b) => popularity[b] - popularity[a]);
//a = a.slice(0, n - reserved.length);
a = reserved.concat(a);
decimated = a.slice(0, decimated.length - 1);
//console.log(decimated);
}
//console.log('end', decimated);
// Palette fits
return dither(decimated);
}