Moved alignment into child Control.

Perspex.UnitTests/StyleTests.cs

@@ -119,7 +119,7 @@ namespace Perspex.UnitTests
                 set { this.SetValue(FooProperty, value); }
             }
 
-            protected override Size MeasureContent(Size availableSize)
+            protected override Size MeasureOverride(Size availableSize)
             {
                 throw new NotImplementedException();
             }

Perspex/Controls/Border.cs

@@ -42,16 +42,20 @@ namespace Perspex.Controls
             }
         }
 
-        protected override Size ArrangeContent(Size finalSize)
+        protected override Size ArrangeOverride(Size finalSize)
         {
-            return LayoutHelper.ArrangeDecorator(
-                this,
-                this.Content,
-                finalSize,
-                this.Padding + new Thickness(this.BorderThickness));
+            Control content = this.Content;
+
+            if (content != null)
+            {
+                Thickness padding = this.Padding + new Thickness(this.BorderThickness);
+                content.Arrange(new Rect(finalSize).Deflate(padding));
+            }
+
+            return finalSize;
         }
 
-        protected override Size MeasureContent(Size availableSize)
+        protected override Size MeasureOverride(Size availableSize)
         {
             return LayoutHelper.MeasureDecorator(
                 this, 

Perspex/Controls/ContentControl.cs

@@ -48,7 +48,7 @@ namespace Perspex.Controls
             }
         }
 
-        protected override Size ArrangeContent(Size finalSize)
+        protected override Size ArrangeOverride(Size finalSize)
         {
             Control child = ((IVisual)this).VisualChildren.SingleOrDefault() as Control;
 
@@ -63,7 +63,7 @@ namespace Perspex.Controls
             }
         }
 
-        protected override Size MeasureContent(Size availableSize)
+        protected override Size MeasureOverride(Size availableSize)
         {
             if (this.Visibility != Visibility.Collapsed)
             {

Perspex/Controls/ContentPresenter.cs

@@ -86,7 +86,7 @@ namespace Perspex.Controls
             }
         }
 
-        protected override Size ArrangeContent(Size finalSize)
+        protected override Size ArrangeOverride(Size finalSize)
         {
             Control child = ((IVisual)this).VisualChildren.SingleOrDefault() as Control;
 
@@ -143,7 +143,7 @@ namespace Perspex.Controls
             return finalSize;
         }
 
-        protected override Size MeasureContent(Size availableSize)
+        protected override Size MeasureOverride(Size availableSize)
         {
             if (this.Visibility != Visibility.Collapsed)
             {

Perspex/Controls/Control.cs

@@ -332,17 +332,13 @@ namespace Perspex.Controls
 
         public void Arrange(Rect rect)
         {
-            Thickness margin = this.Margin;
-
-            ((IVisual)this).Bounds = new Rect(
-                new Point(rect.Position.X + margin.Left, rect.Position.Y + margin.Top),
-                this.ArrangeContent(rect.Size.Deflate(margin).Constrain(rect.Size)));
+            this.ArrangeCore(rect);
         }
 
         public void Measure(Size availableSize)
         {
             availableSize = availableSize.Deflate(this.Margin);
-            this.DesiredSize = this.MeasureContent(availableSize).Constrain(availableSize);
+            this.DesiredSize = this.MeasureCore(availableSize).Constrain(availableSize);
         }
 
         public void InvalidateArrange()
@@ -365,12 +361,63 @@ namespace Perspex.Controls
             }
         }
 
-        protected virtual Size ArrangeContent(Size finalSize)
+        protected virtual void ArrangeCore(Rect finalRect)
+        {
+            double originX = finalRect.X + this.Margin.Left;
+            double originY = finalRect.Y + this.Margin.Top;
+            double sizeX = Math.Max(0, finalRect.Width - this.Margin.Left - this.Margin.Right);
+            double sizeY = Math.Max(0, finalRect.Height - this.Margin.Top - this.Margin.Bottom);
+
+            if (this.HorizontalAlignment != HorizontalAlignment.Stretch)
+            {
+                sizeX = Math.Min(sizeX, this.DesiredSize.Value.Width);
+            }
+
+            if (this.VerticalAlignment != VerticalAlignment.Stretch)
+            {
+                sizeY = Math.Min(sizeY, this.DesiredSize.Value.Height);
+            }
+
+            Size taken = this.ArrangeOverride(new Size(sizeX, sizeY));
+
+            sizeX = Math.Min(taken.Width, sizeX);
+            sizeY = Math.Min(taken.Height, sizeY);
+
+            switch (this.HorizontalAlignment)
+            {
+                case HorizontalAlignment.Center:
+                    originX += (finalRect.Width - sizeX) / 2;
+                    break;
+                case HorizontalAlignment.Right:
+                    originX += finalRect.Width - sizeX;
+                    break;
+            }
+
+            switch (this.VerticalAlignment)
+            {
+                case VerticalAlignment.Center:
+                    originY += (finalRect.Height - sizeY) / 2;
+                    break;
+                case VerticalAlignment.Bottom:
+                    originY += finalRect.Height - sizeY;
+                    break;
+            }
+
+            ((IVisual)this).Bounds = new Rect(originX, originY, sizeX, sizeY);
+        }
+
+        protected virtual Size ArrangeOverride(Size finalSize)
         {
             return finalSize;
         }
 
-        protected virtual Size MeasureContent(Size availableSize)
+        protected virtual Size MeasureCore(Size availableSize)
+        {
+            availableSize = availableSize.Deflate(this.Margin);
+            return this.MeasureOverride(availableSize);
+        }
+
+        protected virtual Size MeasureOverride(Size availableSize)
         {
             return new Size();
         }

Perspex/Controls/Decorator.cs

@@ -64,12 +64,19 @@ namespace Perspex.Controls
             }
         }
 
-        protected override Size ArrangeContent(Size finalSize)
+        protected override Size ArrangeOverride(Size finalSize)
         {
-            return LayoutHelper.ArrangeDecorator(this, this.Content, finalSize, this.Padding);
+            Control content = this.Content;
+
+            if (content != null)
+            {
+                content.Arrange(new Rect(finalSize).Deflate(this.Padding));
+            }
+
+            return finalSize;
         }
 
-        protected override Size MeasureContent(Size availableSize)
+        protected override Size MeasureOverride(Size availableSize)
         {
             return LayoutHelper.MeasureDecorator(this, this.Content, availableSize, this.Padding);
         }

Perspex/Controls/Grid.cs

@@ -88,7 +88,7 @@ namespace Perspex.Controls
             element.SetValue(RowSpanProperty, value);
         }
 
-        protected override Size MeasureContent(Size constraint)
+        protected override Size MeasureOverride(Size constraint)
         {
             Size totalSize = constraint;
             int colCount = this.ColumnDefinitions.Count;
@@ -379,7 +379,7 @@ namespace Perspex.Controls
             return new Size(gridSizeX, gridSizeY);
         }
 
-        protected override Size ArrangeContent(Size finalSize)
+        protected override Size ArrangeOverride(Size finalSize)
         {
             int colCount = this.ColumnDefinitions.Count;
             int rowCount = this.RowDefinitions.Count;

Perspex/Controls/StackPanel.cs

@@ -38,7 +38,7 @@ namespace Perspex.Controls
             set { this.SetValue(OrientationProperty, value); }
         }
 
-        protected override Size MeasureContent(Size availableSize)
+        protected override Size MeasureOverride(Size availableSize)
         {
             if (this.Visibility != Visibility.Collapsed)
             {
@@ -97,7 +97,7 @@ namespace Perspex.Controls
             return new Size();
         }
 
-        protected override Size ArrangeContent(Size finalSize)
+        protected override Size ArrangeOverride(Size finalSize)
         {
             double arrangedWidth = finalSize.Width;
             double arrangedHeight = finalSize.Height;

Perspex/Controls/TextBlock.cs

@@ -67,7 +67,7 @@ namespace Perspex.Controls
             }
         }
 
-        protected override Size MeasureContent(Size availableSize)
+        protected override Size MeasureOverride(Size availableSize)
         {
             if (this.Visibility != Visibility.Collapsed)
             {

Perspex/Layout/LayoutHelper.cs

@@ -47,91 +47,5 @@ namespace Perspex.Layout
 
             return new Size(width, height);
         }
-
-        public static Size ArrangeDecorator(
-            Control decorator,
-            Control content,
-            Size finalSize,
-            Thickness padding)
-        {
-            if (content != null)
-            {
-                Rect childRect = AlignChild(
-                    new Rect(finalSize).Deflate(padding),
-                    content.DesiredSize.Value,
-                    content.HorizontalAlignment,
-                    content.VerticalAlignment);
-
-                content.Arrange(childRect);
-            }
-
-            return finalSize;
-        }
-
-        public static Rect AlignChild(
-            Rect parentRect,
-            Size desiredSize,
-            HorizontalAlignment horizontalAlignment,
-            VerticalAlignment verticalAlignment)
-        {
-            double x;
-            double y;
-            double width;
-            double height;
-
-            switch (horizontalAlignment)
-            {
-                case HorizontalAlignment.Stretch:
-                    width = parentRect.Width;
-                    x = parentRect.X;
-                    break;
-
-                case HorizontalAlignment.Left:
-                    width = desiredSize.Width;
-                    x = parentRect.X;
-                    break;
-
-                case HorizontalAlignment.Center:
-                    width = desiredSize.Width;
-                    x = (parentRect.Width - width) / 2;
-                    break;
-
-                case HorizontalAlignment.Right:
-                    width = desiredSize.Width;
-                    x = parentRect.Right - width;
-                    break;
-
-                default:
-                    throw new InvalidOperationException("Invalid HorizontalAlignment.");
-            }
-
-            switch (verticalAlignment)
-            {
-                case VerticalAlignment.Stretch:
-                    height = parentRect.Height;
-                    y = parentRect.Y;
-                    break;
-
-                case VerticalAlignment.Top:
-                    height = desiredSize.Height;
-                    y = parentRect.Y;
-                    break;
-
-                case VerticalAlignment.Center:
-                    height = desiredSize.Height;
-                    y = (parentRect.Height - height) / 2;
-                    break;
-
-                case VerticalAlignment.Bottom:
-                    height = desiredSize.Height;
-                    y = parentRect.Bottom - height;
-                    break;
-
-                default:
-                    throw new InvalidOperationException("Invalid VerticalAlignment.");
-            }
-
-            return new Rect(x, y, width, height);
-        }
     }
 }

Perspex/Shapes/Rectangle.cs

@@ -19,15 +19,15 @@ namespace Perspex.Shapes
             get { return new RectangleGeometry(new Rect(size)); }
         }
 
-        protected override Size MeasureContent(Size availableSize)
+        protected override Size MeasureOverride(Size availableSize)
         {
             return new Size(this.Width, this.Height);
         }
 
-        protected override Size ArrangeContent(Size finalSize)
+        protected override Size ArrangeOverride(Size finalSize)
         {
             this.size = finalSize;
-            return base.ArrangeContent(finalSize);
+            return base.ArrangeOverride(finalSize);
         }
     }
 }

Perspex/Shapes/Shape.cs

@@ -58,7 +58,7 @@ namespace Perspex.Shapes
             set { this.SetValue(StrokeThicknessProperty, value); }
         }
 
-        protected override Size MeasureContent(Size availableSize)
+        protected override Size MeasureOverride(Size availableSize)
         {
             Rect shapeBounds = this.RenderedGeometry.Bounds;
             double width = this.Width;