Add rectangle support to images

This massively reduces number of syntax errors

src/ImageSharp/Formats/Jxl/Memory/JxlImage3{T}.cs

@@ -46,6 +46,13 @@ internal class JxlImage3<T> : IDisposable
         return rowSpan;
     }
 
+    public Span<T> PlaneRow(Rectangle rectangle, int c, int y)
+    {
+        DebugGuard.MustBeGreaterThanOrEqualTo(y + rectangle.Top, 0, nameof(y));
+
+        return this.PlaneRow(c, y + rectangle.Top)[rectangle.Left..];
+    }
+
     public JxlPlane<T> Plane(int index) => this.planes[index];
 
     public void Swap(JxlImage3<T> other)

src/ImageSharp/Formats/Jxl/Memory/JxlPlane{T}.cs

@@ -36,6 +36,17 @@ internal class JxlPlane<T> : JxlPlaneBase
 
     public Span<T> GetRow(int y) => this.GetRowBase<T>(y);
 
+    public Span<T> GetRow(Rectangle rectangle, int y)
+    {
+        DebugGuard.MustBeGreaterThanOrEqualTo(y + rectangle.Top, 0, nameof(y));
+
+        return this.GetRow(y + rectangle.Top)[rectangle.Left..];
+    }
+
+    public bool IsRectangleInside(Rectangle rectangle) => rectangle.Contains(this.GetRectangle());
+
+    public Rectangle GetRectangle() => new(0, 0, this.XSize, this.YSize);
+
     /// <summary>
     /// Fills everything in this image with 0.
     /// </summary>