Merge pull request #2609 from SixLabors/issue/2608

Correctly calculate foreground Rectangle when negative background location is set (3.1 fix)

Author: JimBobSquarePants

src/ImageSharp/Processing/Processors/Drawing/DrawImageProcessor{TPixelBg,TPixelFg}.cs

@@ -87,12 +87,14 @@ protected override void OnFrameApply(ImageFrame<TPixelBg> source)
         if (this.BackgroundLocation.X < 0)
         {
             foregroundRectangle.Width += this.BackgroundLocation.X;
+            foregroundRectangle.X -= this.BackgroundLocation.X;
             left = 0;
         }
 
         if (this.BackgroundLocation.Y < 0)
         {
             foregroundRectangle.Height += this.BackgroundLocation.Y;
+            foregroundRectangle.Y -= this.BackgroundLocation.Y;
             top = 0;
         }
 

tests/ImageSharp.Tests/Drawing/DrawImageTests.cs

@@ -251,4 +251,25 @@ public void Issue2447_C<TPixel>(TestImageProvider<TPixel> provider)
             appendPixelTypeToFileName: false,
             appendSourceFileOrDescription: false);
     }
+
+    [Theory]
+    [WithFile(TestImages.Png.Issue2447, PixelTypes.Rgba32)]
+    public void Issue2608_NegOffset<TPixel>(TestImageProvider<TPixel> provider)
+    where TPixel : unmanaged, IPixel<TPixel>
+    {
+        using Image<TPixel> foreground = provider.GetImage();
+        using Image<Rgba32> background = new(100, 100, new Rgba32(0, 255, 255));
+
+        background.Mutate(c => c.DrawImage(foreground, new Point(-10, -10), new Rectangle(32, 32, 32, 32), 1F));
+
+        background.DebugSave(
+            provider,
+            appendPixelTypeToFileName: false,
+            appendSourceFileOrDescription: false);
+
+        background.CompareToReferenceOutput(
+            provider,
+            appendPixelTypeToFileName: false,
+            appendSourceFileOrDescription: false);
+    }
 }