From d8857023be06d728cb71220e1f070a592b620c7e Mon Sep 17 00:00:00 2001
From: Scott Williams <166440+tocsoft@users.noreply.github.com>
Date: Sun, 10 Dec 2023 11:30:58 +0000
Subject: [PATCH] Sync 3.1 DrawImage fixes  (#2612)

* Handle dedup of local palette of 256 length

* handle when foreground overhangs bottom of background

* prevent potential overflow

* reduce to a single par of clamping operations

* correctly calculate Rect when negative target set

---------

Co-authored-by: James Jackson-South <james_south@hotmail.com>
---
 .../DrawImageProcessor{TPixelBg,TPixelFg}.cs  |  6 +++
 .../Drawing/DrawImageTests.cs                 | 42 +++++++++++++++++++
 .../Drawing/DrawImageTests/Issue2603.png      |  3 ++
 .../DrawImageTests/Issue2608_NegOffset.png    |  3 ++
 4 files changed, 54 insertions(+)
 create mode 100644 tests/Images/External/ReferenceOutput/Drawing/DrawImageTests/Issue2603.png
 create mode 100644 tests/Images/External/ReferenceOutput/Drawing/DrawImageTests/Issue2608_NegOffset.png

diff --git a/src/ImageSharp/Processing/Processors/Drawing/DrawImageProcessor{TPixelBg,TPixelFg}.cs b/src/ImageSharp/Processing/Processors/Drawing/DrawImageProcessor{TPixelBg,TPixelFg}.cs
index 378ea20fa..0d81270b1 100644
--- a/src/ImageSharp/Processing/Processors/Drawing/DrawImageProcessor{TPixelBg,TPixelFg}.cs
+++ b/src/ImageSharp/Processing/Processors/Drawing/DrawImageProcessor{TPixelBg,TPixelFg}.cs
@@ -87,15 +87,21 @@ internal class DrawImageProcessor<TPixelBg, TPixelFg> : ImageProcessor<TPixelBg>
         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;
         }
 
+        // clamp the height/width to the availible space left to prevent overflowing
+        foregroundRectangle.Width = Math.Min(source.Width - left, foregroundRectangle.Width);
+        foregroundRectangle.Height = Math.Min(source.Height - top, foregroundRectangle.Height);
+
         int width = foregroundRectangle.Width;
         int height = foregroundRectangle.Height;
         if (width <= 0 || height <= 0)
diff --git a/tests/ImageSharp.Tests/Drawing/DrawImageTests.cs b/tests/ImageSharp.Tests/Drawing/DrawImageTests.cs
index 8b0db773a..533f0c6de 100644
--- a/tests/ImageSharp.Tests/Drawing/DrawImageTests.cs
+++ b/tests/ImageSharp.Tests/Drawing/DrawImageTests.cs
@@ -251,4 +251,46 @@ public class DrawImageTests
             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);
+    }
+
+    [Theory]
+    [WithFile(TestImages.Png.Issue2447, PixelTypes.Rgba32)]
+    public void Issue2603<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(80, 80), new Rectangle(32, 32, 32, 32), 1F));
+
+        background.DebugSave(
+            provider,
+            appendPixelTypeToFileName: false,
+            appendSourceFileOrDescription: false);
+
+        background.CompareToReferenceOutput(
+            provider,
+            appendPixelTypeToFileName: false,
+            appendSourceFileOrDescription: false);
+    }
 }
diff --git a/tests/Images/External/ReferenceOutput/Drawing/DrawImageTests/Issue2603.png b/tests/Images/External/ReferenceOutput/Drawing/DrawImageTests/Issue2603.png
new file mode 100644
index 000000000..1940dbba0
--- /dev/null
+++ b/tests/Images/External/ReferenceOutput/Drawing/DrawImageTests/Issue2603.png
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:307ef8cea7999e615420740bb0a403a64b24f1fff5356c2ac45c1952f84c5e4c
+size 508
diff --git a/tests/Images/External/ReferenceOutput/Drawing/DrawImageTests/Issue2608_NegOffset.png b/tests/Images/External/ReferenceOutput/Drawing/DrawImageTests/Issue2608_NegOffset.png
new file mode 100644
index 000000000..747bbca38
--- /dev/null
+++ b/tests/Images/External/ReferenceOutput/Drawing/DrawImageTests/Issue2608_NegOffset.png
@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:edfd0e17aa304f5b16ad42a761c044c3d617aaee9b9e1e74674567bbcd74d532
+size 590