chore: bump version to 1.8.1 (#297)

* feat(dithering): improve blue noise quality with decorrelated RGB channels

- Replace blue noise texture with high-quality 64x64 from Christoph Peters
- Add getBlueNoiseThresholdRGB() for per-channel decorrelation
- Use spatial offsets (17,31 for G, 41,23 for B) to prevent pixel clustering
- Update map-and-dither.ts and quantize-mode-r.ts for new RGB thresholds
- Fix preprocessImageForRaster dithering condition logic

* chore: bump version to 1.8.1

---------

Co-authored-by: Ivan Duchauffour <iduchauffour@welcomr.com>

Author: IIIvan37

package.json

@@ -1,7 +1,7 @@
 {
   "name": "pixsaur",
   "private": true,
-  "version": "1.8.0",
+  "version": "1.8.1",
   "type": "module",
   "engines": {
     "node": ">=24.11.0",

src-tauri/tauri.conf.json

@@ -1,7 +1,7 @@
 {
   "$schema": "../node_modules/@tauri-apps/cli/config.schema.json",
   "productName": "Pixsaur",
-  "version": "1.8.0",
+  "version": "1.8.1",
   "identifier": "com.iiiivan37.pixsaur",
   "build": {
     "removeUnusedCommands": true,

src/app/store/raster/use-auto-regenerate-rasters.ts

@@ -76,19 +76,25 @@ export function useAutoRegenerateRasters() {
     previousRasterDitheringRef.current = rasterDitheringIntensity
     previousMaxChangesRef.current = maxChangesPerLine
 
-    // Skip if nothing changed, raster not enabled, or no auto-generated rasters
-    if (
-      !rasterEnabled ||
-      !hasGeneratedRasters ||
-      (!selectionChanged && !rasterDitheringChanged && !maxChangesChanged)
-    ) {
-      logger.debug('[RASTER-REGEN] Skipping regeneration:', {
-        reason: !rasterEnabled
-          ? 'raster not enabled'
-          : !hasGeneratedRasters
-            ? 'no generated rasters'
-            : 'no changes detected'
-      })
+    // Skip if nothing changed or raster not enabled
+    // Note: We don't check hasGeneratedRasters for dithering/maxChanges changes
+    // because user expects immediate feedback when adjusting these sliders
+    if (!rasterEnabled) {
+      logger.debug('[RASTER-REGEN] Skipping: raster not enabled')
+      return
+    }
+
+    // For selection changes, only regenerate if rasters were already generated
+    if (selectionChanged && !hasGeneratedRasters) {
+      logger.debug(
+        '[RASTER-REGEN] Skipping selection change: no generated rasters'
+      )
+      return
+    }
+
+    // Skip if nothing actually changed
+    if (!selectionChanged && !rasterDitheringChanged && !maxChangesChanged) {
+      logger.debug('[RASTER-REGEN] Skipping: no changes detected')
       return
     }
 

src/libs/pixsaur-color/src/map/blue-noise-texture.ts

@@ -1,4 +1,4 @@
-import { getBlueNoiseThresholdCentered } from './blue-noise-texture'
+import { getBlueNoiseThresholdRGB } from './blue-noise-texture'
 
 const BAYER_MATRICES: Record<
   'bayer2x2' | 'bayer4x4' | 'bayer8x8' | 'atkinson' | 'halftone4x4',
@@ -406,20 +406,22 @@ export function applyBlueNoiseDither(
 ): Uint8ClampedArray {
   const out = new Uint8ClampedArray(width * height * 4)
   const pixelCS = new Float32Array(3)
+  const scale = intensity * 255
 
   for (let y = 0; y < height; y++) {
     for (let x = 0; x < width; x++) {
       const i = y * width + x
       const i3 = i * 3
       const i4 = i * 4
 
-      // Get blue noise threshold (-0.5 to 0.5, centered)
-      const threshold = getBlueNoiseThresholdCentered(x, y) * intensity * 255
+      // Get decorrelated blue noise thresholds for each RGB channel
+      // This prevents pixels from clustering together
+      const [tR, tG, tB] = getBlueNoiseThresholdRGB(x, y)
 
-      // Clamp to valid range to avoid dark artifacts
-      pixelCS[0] = Math.max(0, Math.min(255, bufCS[i3] + threshold))
-      pixelCS[1] = Math.max(0, Math.min(255, bufCS[i3 + 1] + threshold))
-      pixelCS[2] = Math.max(0, Math.min(255, bufCS[i3 + 2] + threshold))
+      // Apply per-channel dithering
+      pixelCS[0] = Math.max(0, Math.min(255, bufCS[i3] + tR * scale))
+      pixelCS[1] = Math.max(0, Math.min(255, bufCS[i3 + 1] + tG * scale))
+      pixelCS[2] = Math.max(0, Math.min(255, bufCS[i3 + 2] + tB * scale))
 
       const bestIndex = findClosestColorIndex(pixelCS, paletteCS, distFn)
 
@@ -922,6 +924,7 @@ function applyBlueNoiseDitherWithDynamicPalette(
 ): Uint8ClampedArray {
   const out = new Uint8ClampedArray(width * height * 4)
   const pixel = new Float32Array(3)
+  const scale = intensity * 255
 
   for (let y = 0; y < height; y++) {
     const palette = getPaletteForLine(y)
@@ -934,13 +937,13 @@ function applyBlueNoiseDitherWithDynamicPalette(
       const i3 = idx * 3
       const i4 = idx * 4
 
-      // Get blue noise threshold (-0.5 to 0.5, centered)
-      const noise = getBlueNoiseThresholdCentered(x, y) * intensity * 255
+      // Get decorrelated blue noise thresholds for each RGB channel
+      const [tR, tG, tB] = getBlueNoiseThresholdRGB(x, y)
 
-      // Get pixel with blue noise, clamped to valid range
-      pixel[0] = Math.max(0, Math.min(255, bufCS[i3] + noise))
-      pixel[1] = Math.max(0, Math.min(255, bufCS[i3 + 1] + noise))
-      pixel[2] = Math.max(0, Math.min(255, bufCS[i3 + 2] + noise))
+      // Apply per-channel dithering
+      pixel[0] = Math.max(0, Math.min(255, bufCS[i3] + tR * scale))
+      pixel[1] = Math.max(0, Math.min(255, bufCS[i3 + 1] + tG * scale))
+      pixel[2] = Math.max(0, Math.min(255, bufCS[i3 + 2] + tB * scale))
 
       // Find nearest palette color for this line
       const bestIndex = findClosestColorIndex(pixel, paletteCS, distFn)

src/libs/pixsaur-color/src/map/map-and-dither.ts

@@ -28,7 +28,7 @@
 
 import { logger } from '@/core/logger'
 import type { DitheringMode } from '@/libs/pixsaur-color/src'
-import { getBlueNoiseThresholdCentered } from '@/libs/pixsaur-color/src/map/blue-noise-texture'
+import { getBlueNoiseThresholdRGB } from '@/libs/pixsaur-color/src/map/blue-noise-texture'
 import { getOstromoukhovCoefficients } from '@/libs/pixsaur-color/src/map/ostromoukhov-coefficients'
 import type { Vector } from '@/libs/pixsaur-color/src/type'
 import { colorDistance } from './blend'
@@ -122,16 +122,17 @@ function isBlueNoiseMode(mode: DitheringMode | 'none'): boolean {
 }
 
 /**
- * Get Blue Noise threshold for a pixel position
- * Uses the same formula as applyBlueNoiseDither in pixsaur-color:
- * threshold = getBlueNoiseThresholdCentered(x, y) * intensity * 255
+ * Get Blue Noise thresholds for a pixel position (decorrelated per RGB channel)
+ * Uses the same formula as applyBlueNoiseDither in pixsaur-color
  */
-function getBlueNoiseThreshold(
+function getBlueNoiseThresholds(
   x: number,
   y: number,
   intensity: number
-): number {
-  return getBlueNoiseThresholdCentered(x, y) * intensity * 255
+): [number, number, number] {
+  const [tR, tG, tB] = getBlueNoiseThresholdRGB(x, y)
+  const scale = intensity * 255
+  return [tR * scale, tG * scale, tB * scale]
 }
 
 /**
@@ -354,23 +355,23 @@ export function quantizeModeR(
           threshold
         )
       } else if (useBlueNoise) {
-        // Blue Noise dithering: apply threshold-based color adjustment
+        // Blue Noise dithering: apply per-channel threshold-based color adjustment
         // Use OUTPUT coordinates (x, y) for the dithering pattern
-        const threshold = getBlueNoiseThreshold(x, y, ditherIntensity)
+        const thresholds = getBlueNoiseThresholds(x, y, ditherIntensity)
 
-        colorA = getSourceColorWithThreshold(
+        colorA = getSourceColorWithRGBThresholds(
           imageData,
           width,
           srcXA,
           y,
-          threshold
+          thresholds
         )
-        colorB = getSourceColorWithThreshold(
+        colorB = getSourceColorWithRGBThresholds(
           imageData,
           width,
           srcXB,
           y,
-          threshold
+          thresholds
         )
       } else {
         // Error diffusion or no dithering: use error buffer
@@ -517,6 +518,29 @@ function getSourceColorWithThreshold(
   ]
 }
 
+/**
+ * Get source pixel color with per-channel RGB thresholds applied
+ * Used for decorrelated blue noise dithering
+ */
+function getSourceColorWithRGBThresholds(
+  imageData: Uint8ClampedArray,
+  width: number,
+  x: number,
+  y: number,
+  thresholds: [number, number, number]
+): Vector<'RGB'> {
+  const pixelIdx = (y * width + x) * 4
+  const r = imageData[pixelIdx]
+  const g = imageData[pixelIdx + 1]
+  const b = imageData[pixelIdx + 2]
+
+  return [
+    Math.max(0, Math.min(255, r + thresholds[0])),
+    Math.max(0, Math.min(255, g + thresholds[1])),
+    Math.max(0, Math.min(255, b + thresholds[2]))
+  ]
+}
+
 /**
  * Check if two colors are very similar (used to detect margin areas)
  * Margin areas should use uniform pairs to avoid flicker

src/libs/pixsaur-mode-r/quantize-mode-r.ts

@@ -1431,8 +1431,8 @@ export function preprocessImageForRaster(
       .fill(null)
       .map(() => [0, 0, 0])
 
-    if (shouldApplyDithering) {
-      // Line already has ≤nColors colors: direct mapping without dithering
+    if (!shouldApplyDithering) {
+      // Line already has ≤nColors colors AND no dithering requested: direct mapping
       for (let x = 0; x < width; x++) {
         const pixelIdx = lineStart + x * 4
         const sourceColor: Vector<'RGB'> = [
@@ -1460,7 +1460,7 @@ export function preprocessImageForRaster(
       // Reset vertical error for next line (no error to propagate)
       // Keep it at zero
     } else {
-      // Line has >4 colors: apply dithering
+      // Apply dithering (either line has >nColors or user wants dithering)
       // Horizontal error buffer for this line (floating-point)
       const horizError: [number, number, number][] = new Array(width)
         .fill(null)