From 764ce9a481fbda8dc959fb80b41f1319341c7a42 Mon Sep 17 00:00:00 2001
From: Brion Vibber <brion@pobox.com>
Date: Sat, 5 Nov 2022 18:24:01 -0700
Subject: [PATCH] wip

---
 dither4.js | 29 +++++++++++++++++++++--------
 1 file changed, 21 insertions(+), 8 deletions(-)

diff --git a/dither4.js b/dither4.js
index f0f38e5..9d40627 100644
--- a/dither4.js
+++ b/dither4.js
@@ -321,7 +321,7 @@ function decimate(input, palette, n) {
 
     // Apply dithering with given palette
     let dither = (palette) => {
-        let fitness = 0;
+        let fitness = new Float64Array(line.length);
         let error = {
             right: new RGB(0, 0, 0),
             red: new Float64Array(line.length),
@@ -354,6 +354,13 @@ function decimate(input, palette, n) {
             output[x] = pick;
             popularity[pick]++;
 
+            /*
+            // horiz only
+            error.right.r = nextError.r;
+            error.right.g = nextError.g;
+            error.right.b = nextError.b;
+            */
+
             error.right.r = nextError.r / 2;
             error.right.g = nextError.g / 2;
             error.right.b = nextError.b / 2;
@@ -376,9 +383,7 @@ function decimate(input, palette, n) {
             error.green[x + 1] += nextError.g / 8;
             error.blue[x + 1] += nextError.b / 8;
 
-            //fitness += error.r;
-            //fitness += error.g;
-            //fitness += error.b;
+            fitness[x] = 1 / nextError.magnitude();
         }
         return {
             output,
@@ -392,7 +397,7 @@ function decimate(input, palette, n) {
     let start = Date.now();
     let decimated = palette.slice();
     while (decimated.length > n) {
-        let {popularity} = dither(decimated);
+        let {popularity, fitness, output} = dither(decimated);
 
         // Try dropping least used color on each iteration
         let least = Infinity;
@@ -402,11 +407,19 @@ function decimate(input, palette, n) {
                 continue; // keep black always
             }
             if (decimated[i].r == 255 && decimated[i].g == 255 && decimated[i].b == 255) {
-                continue; // keep white always
+                //continue; // keep white always
             }
-            if (popularity[i] < least) {
+            let coolFactor = popularity[i];
+            /*
+            for (let x = 0; x < line.length; x++) {
+                if (output[x] == i) {
+                    coolFactor *= fitness[i];
+                }
+            }
+            */
+            if (coolFactor < least) {
                 pick = i;
-                least = popularity[i];
+                least = coolFactor;
             }
         }
         let old = decimated.length;