Fixed brightness tool symmetry

src/ChunkyImageLib/ChunkyImage.cs

@@ -606,6 +606,17 @@ public class ChunkyImage : IReadOnlyChunkyImage, IDisposable
         }
     }
 
+    /// <exception cref="ObjectDisposedException">This image is disposed</exception>
+    public void EnqueueDrawPixel(VecI pos, PixelProcessor pixelProcessor, BlendMode blendMode)
+    {
+        lock (lockObject)
+        {
+            ThrowIfDisposed();
+            PixelOperation operation = new(pos, pixelProcessor, blendMode);
+            EnqueueOperation(operation);
+        }
+    }
+
     /// <exception cref="ObjectDisposedException">This image is disposed</exception>
     public void EnqueueDrawChunkyImage(VecI pos, ChunkyImage image, bool flipHor = false, bool flipVer = false)
     {

src/ChunkyImageLib/Operations/PixelOperation.cs

@@ -6,6 +6,7 @@ using PixiEditor.DrawingApi.Core.Surface.PaintImpl;
 
 namespace ChunkyImageLib.Operations;
 
+public delegate Color PixelProcessor(Color input);
 internal class PixelOperation : IMirroredDrawOperation
 {
     public bool IgnoreEmptyChunks => false;
@@ -14,6 +15,8 @@ internal class PixelOperation : IMirroredDrawOperation
     private readonly BlendMode blendMode;
     private readonly Paint paint;
 
+    private readonly PixelProcessor? _colorProcessor = null;
+
     public PixelOperation(VecI pixel, Color color, BlendMode blendMode)
     {
         this.pixel = pixel;
@@ -22,10 +25,18 @@ internal class PixelOperation : IMirroredDrawOperation
         paint = new Paint() { BlendMode = blendMode };
     }
 
+    public PixelOperation(VecI pixel, PixelProcessor colorProcessor, BlendMode blendMode)
+    {
+        this.pixel = pixel;
+        this._colorProcessor = colorProcessor;
+        this.blendMode = blendMode;
+        paint = new Paint() { BlendMode = blendMode };
+    }
+
     public void DrawOnChunk(Chunk chunk, VecI chunkPos)
     {
         // a hacky way to make the lines look slightly better on non full res chunks
-        paint.Color = new Color(color.R, color.G, color.B, (byte)(color.A * chunk.Resolution.Multiplier()));
+        paint.Color = GetColor(chunk, chunkPos);
 
         DrawingSurface surf = chunk.Surface.DrawingSurface;
         surf.Canvas.Save();
@@ -35,6 +46,17 @@ internal class PixelOperation : IMirroredDrawOperation
         surf.Canvas.Restore();
     }
 
+    private Color GetColor(Chunk chunk, VecI chunkPos)
+    {
+        Color pixelColor = color;
+        if (_colorProcessor != null)
+        {
+            pixelColor = _colorProcessor(chunk.Surface.GetSRGBPixel(pixel - chunkPos * ChunkyImage.FullChunkSize));
+        }
+
+        return new Color(pixelColor.R, pixelColor.G, pixelColor.B, (byte)(pixelColor.A * chunk.Resolution.Multiplier()));
+    }
+
     public AffectedArea FindAffectedArea(VecI imageSize)
     {
         return new AffectedArea(new HashSet<VecI>() { OperationHelper.GetChunkPos(pixel, ChunkyImage.FullChunkSize) }, new RectI(pixel, VecI.One));
@@ -47,6 +69,11 @@ internal class PixelOperation : IMirroredDrawOperation
             pixelRect = pixelRect.ReflectX((int)verAxisX);
         if (horAxisY is not null)
             pixelRect = pixelRect.ReflectY((int)horAxisY);
+        if (_colorProcessor != null)
+        {
+            return new PixelOperation(pixelRect.Pos, _colorProcessor, blendMode);
+        }
+
         return new PixelOperation(pixelRect.Pos, color, blendMode);
     }
 

src/PixiEditor.ChangeableDocument/Changes/Drawing/ChangeBrightness_UpdateableChange.cs

@@ -88,9 +88,14 @@ internal class ChangeBrightness_UpdateableChange : UpdateableChange
             
             for (VecI pos = new VecI(left.X, y); pos.X <= right.X; pos.X++)
             {
-                Color pixel = tempSurface.GetSRGBPixel(pos);
-                Color newColor = ColorHelper.ChangeColorBrightness(pixel, correctionFactor);
-                layerImage.EnqueueDrawPixel(pos + offset, newColor, BlendMode.Src);
+                layerImage.EnqueueDrawPixel(
+                    pos + offset,
+                    (pixel) =>
+                    {
+                        Color newColor = ColorHelper.ChangeColorBrightness(pixel, correctionFactor);
+                        return ColorHelper.ChangeColorBrightness(newColor, correctionFactor);
+                    },
+                    BlendMode.Src);
             }
         }
     }