The rest of the loafing.

tommyettinger · May 4, 2024 · 0e90fb6 · 0e90fb6
1 parent 79643dd
commit 0e90fb6
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Showing 3 changed files with 24 additions and 7 deletions.
diff --git a/src/main/java/com/github/tommyettinger/anim8/AnimatedGif.java b/src/main/java/com/github/tommyettinger/anim8/AnimatedGif.java
@@ -647,14 +647,14 @@ protected void analyzeLoaf() {
         final byte[] paletteMapping = palette.paletteMapping;
         boolean hasTransparent = paletteArray[0] == 0;
 
-        final int strength = (int) (11f * ditherStrength / (palette.populationBias * palette.populationBias) + 0.5f);
+        final float strength = ditherStrength * palette.populationBias;
         for (int y = 0, i = 0; y < height && i < nPix; y++) {
             for (int px = 0; px < width & i < nPix; px++) {
                 color = image.getPixel(px, flipped + flipDir * y);
                 if ((color & 0x80) == 0 && hasTransparent)
                     indexedPixels[i++] = 0;
                 else {
-                    int adj = ((px & 1) + (y & 1) - 1) * strength * (2 + (((px ^ y) & 2) - 1));
+                    int adj = (int)((((px + y & 1) << 5) - 16) * strength);
                     int rr = Math.min(Math.max(((color >>> 24)       ) + adj, 0), 255);
                     int gg = Math.min(Math.max(((color >>> 16) & 0xFF) + adj, 0), 255);
                     int bb = Math.min(Math.max(((color >>> 8)  & 0xFF) + adj, 0), 255);

diff --git a/src/main/java/com/github/tommyettinger/anim8/PNG8.java b/src/main/java/com/github/tommyettinger/anim8/PNG8.java
@@ -1177,15 +1177,15 @@ public void writeLoafDithered(OutputStream output, Pixmap pixmap) {
             }
 
             int color;
-            final int strength = (int) (11f * ditherStrength / (palette.populationBias * palette.populationBias) + 0.5f);
+            final float strength = ditherStrength * palette.populationBias;
             for (int y = 0; y < h; y++) {
                 int py = flipY ? (h - y - 1) : y;
                 for (int px = 0; px < w; px++) {
                     color = pixmap.getPixel(px, py);
                     if ((color & 0x80) == 0 && hasTransparent)
                         curLine[px] = 0;
                     else {
-                        int adj = ((px & 1) + (y & 1) - 1) * strength * (2 + (((px ^ y) & 2) - 1));
+                        int adj = (int)((((px + y & 1) << 5) - 16) * strength);
                         int rr = Math.min(Math.max(((color >>> 24)       ) + adj, 0), 255);
                         int gg = Math.min(Math.max(((color >>> 16) & 0xFF) + adj, 0), 255);
                         int bb = Math.min(Math.max(((color >>> 8)  & 0xFF) + adj, 0), 255);
@@ -3331,8 +3331,7 @@ public void writeLoafDithered(OutputStream output, Array<Pixmap> frames, int fps
             byte[] curLine;
             int color;
 
-            final float populationBias = palette.populationBias;
-            final int strength = (int) (11f * ditherStrength / (populationBias * populationBias) + 0.5f);
+            final float strength = ditherStrength * palette.populationBias;
 
             int seq = 0;
             for (int i = 0; i < frames.size; i++) {
@@ -3371,7 +3370,7 @@ public void writeLoafDithered(OutputStream output, Array<Pixmap> frames, int fps
                         if ((color & 0x80) == 0 && hasTransparent)
                             curLine[px] = 0;
                         else {
-                            int adj = ((px & 1) + (y & 1) - 1) * strength * (2 + (((px ^ y) & 2) - 1));
+                            int adj = (int)((((px + y & 1) << 5) - 16) * strength);
                             int rr = Math.min(Math.max(((color >>> 24)       ) + adj, 0), 255);
                             int gg = Math.min(Math.max(((color >>> 16) & 0xFF) + adj, 0), 255);
                             int bb = Math.min(Math.max(((color >>> 8)  & 0xFF) + adj, 0), 255);

diff --git a/src/main/java/com/github/tommyettinger/anim8/PaletteReducer.java b/src/main/java/com/github/tommyettinger/anim8/PaletteReducer.java
@@ -3091,6 +3091,24 @@ public void setDitherStrength(float ditherStrength) {
         this.ditherStrength = Math.max(0f, ditherStrength);
     }
 
+    public float getPopulationBias() {
+        return populationBias;
+    }
+
+    /**
+     * Sets the population bias; rarely needed externally.
+     * Typically, the population bias is between 0.5 and 1, closer to 1 with larger palette sizes, and closer to 0.5
+     * with smaller palettes.
+     * <br>
+     * Within anim8-gdx, this is generally calculated with {@code (float)Math.exp(-1.375 / colorCount)}, where
+     * {@link #colorCount} is already known and between 2 and 256, inclusive.
+     *
+     * @param populationBias a population bias value, which is almost always between 0.5 and 1.0
+     */
+    public void setPopulationBias(float populationBias) {
+        this.populationBias = populationBias;
+    }
+
     /**
      * Modifies the given Pixmap so that it only uses colors present in this PaletteReducer, dithering when it can by
      * using Wren dithering (this merely delegates to {@link #reduceWren(Pixmap)}).