Skip filling rectangles when effective fill area is zero width or height

Author: tocsoft

src/ImageSharp.Drawing/Processing/Processors/Drawing/FillProcessor{TPixel}.cs

@@ -29,10 +29,15 @@ public FillProcessor(Configuration configuration, FillProcessor definition, Imag
         /// <inheritdoc/>
         protected override void OnFrameApply(ImageFrame<TPixel> source)
         {
+            var interest = Rectangle.Intersect(this.SourceRectangle, source.Bounds());
+            if (interest.Width == 0 || interest.Height == 0)
+            {
+                return;
+            }
+
             Configuration configuration = this.Configuration;
             IBrush brush = this.definition.Brush;
             GraphicsOptions options = this.definition.Options;
-            var interest = Rectangle.Intersect(this.SourceRectangle, source.Bounds());
 
             // If there's no reason for blending, then avoid it.
             if (this.IsSolidBrushWithoutBlending(out SolidBrush solidBrush))

tests/ImageSharp.Drawing.Tests/Issues/Issue_65.cs

@@ -0,0 +1,50 @@
+using System;
+using System.Collections.Generic;
+using System.Runtime.InteropServices;
+using System.Text;
+using SixLabors.ImageSharp.Drawing.Processing;
+using SixLabors.ImageSharp.PixelFormats;
+using SixLabors.ImageSharp.Processing;
+using Xunit;
+
+namespace SixLabors.ImageSharp.Drawing.Tests.Issues
+{
+    public class Issue_65
+    {
+        [Theory]
+        [InlineData(-100)] //Crash
+        [InlineData(-99)]  //Fine
+        [InlineData(99)]   //Fine
+        [InlineData(100)]  //Crash
+        public void DrawRectactangleOutsideBoundsDrawingArea(int xpos)
+        {
+            int width = 100;
+            int height = 100;
+
+            using (var image = new Image<Rgba32>(width, height, Color.Red))
+            {
+                var rectangle = new Rectangle(xpos, 0, width, height);
+
+                image.Mutate(x => x.Fill(Color.Black, rectangle));
+            }
+        }
+
+        [Theory]
+        [InlineData(-110)] //Crash
+        [InlineData(-99)]  //Fine
+        [InlineData(99)]   //Fine
+        [InlineData(110)]  //Crash
+        public void DrawCircleOutsideBoundsDrawingArea(int xpos)
+        {
+            int width = 100;
+            int height = 100;
+
+            using (var image = new Image<Rgba32>(width, height, Color.Red))
+            {
+                var circle = new EllipsePolygon(xpos, 0, width, height);
+
+                image.Mutate(x => x.Fill(Color.Black, circle));
+            }
+        }
+    }
+}