From de1cc1d9b78864e5023d958b2d6f9e9aafe444b2 Mon Sep 17 00:00:00 2001
From: Eric Maupin <ermaup@microsoft.com>
Date: Fri, 13 Sep 2019 10:22:37 -0400
Subject: [Win] AutoResizing mask editor

---
 .../AutoResizingMaskEditorControl.cs               | 116 ++++++++++++++++++++
 .../Themes/Resources.xaml                          | 122 ++++++++++++++++++++-
 .../Themes/VS.Dark.xaml                            |   5 +
 .../Xamarin.PropertyEditing.Windows.csproj         |   1 +
 .../Common/AutoResizingFlags.cs                    |  19 ++++
 .../Properties/Resources.Designer.cs               |  66 +++++++++++
 Xamarin.PropertyEditing/Properties/Resources.resx  |  99 +++++++++++------
 .../ViewModels/AutoResizingPropertyViewModel.cs    |  60 +++++++++-
 8 files changed, 455 insertions(+), 33 deletions(-)
 create mode 100644 Xamarin.PropertyEditing.Windows/AutoResizingMaskEditorControl.cs
 create mode 100644 Xamarin.PropertyEditing/Common/AutoResizingFlags.cs

diff --git a/Xamarin.PropertyEditing.Windows/AutoResizingMaskEditorControl.cs b/Xamarin.PropertyEditing.Windows/AutoResizingMaskEditorControl.cs
new file mode 100644
index 0000000..23ba339
--- /dev/null
+++ b/Xamarin.PropertyEditing.Windows/AutoResizingMaskEditorControl.cs
@@ -0,0 +1,116 @@
+using System;
+using System.ComponentModel;
+using System.Windows;
+using System.Windows.Automation;
+using System.Windows.Controls;
+using System.Windows.Controls.Primitives;
+using Xamarin.PropertyEditing.Drawing;
+using Xamarin.PropertyEditing.ViewModels;
+
+namespace Xamarin.PropertyEditing.Windows
+{
+	[TemplatePart (Name = "sizingButton", Type = typeof(ButtonBase))]
+	[TemplatePart (Name = "windowRect", Type = typeof (FrameworkElement))]
+	[TemplatePart (Name = "elementRect", Type = typeof (FrameworkElement))]
+	internal class AutoResizingMaskEditorControl
+		: PropertyEditorControl
+	{
+		public AutoResizingMaskEditorControl ()
+		{
+			DataContextChanged += OnDataContextChanged;
+		}
+
+		public override void OnApplyTemplate ()
+		{
+			base.OnApplyTemplate ();
+
+			this.sizingButton = GetTemplateChild ("sizingButton") as ButtonBase;
+			if (this.sizingButton == null)
+				throw new InvalidOperationException ($"Template for {nameof(AutoResizingMaskEditorControl)} must have a sizingButton");
+
+			this.window = GetTemplateChild ("windowRect") as FrameworkElement;
+			if (this.window == null)
+				throw new InvalidOperationException ($"Template for {nameof(AutoResizingMaskEditorControl)} must have a windowRect");
+
+			this.elementVisual = GetTemplateChild ("elementRect") as FrameworkElement;
+			if (this.elementVisual == null)
+				throw new InvalidOperationException ($"Template for {nameof(AutoResizingMaskEditorControl)} must have a elementRect");
+
+			this.window.SizeChanged += OnPreviewWindowSizeChanged;
+
+			UpdateSizeName();
+			UpdateVisual();
+		}
+
+		private AutoResizingPropertyViewModel vm;
+		private ButtonBase sizingButton;
+		private FrameworkElement elementVisual, window;
+
+		private void OnDataContextChanged (object sender, DependencyPropertyChangedEventArgs e)
+		{
+			if (this.vm != null) {
+				this.vm.PropertyChanged -= OnViewModelPropertyChanged;
+			}
+
+			this.vm = e.NewValue as AutoResizingPropertyViewModel;
+			if (this.vm != null) {
+				this.vm.PropertyChanged += OnViewModelPropertyChanged;
+			}
+
+			UpdateSizeName();
+		}
+
+		private void OnViewModelPropertyChanged (object sender, PropertyChangedEventArgs e)
+		{
+			if (e.PropertyName == nameof(AutoResizingPropertyViewModel.WidthSizable) || e.PropertyName == nameof(AutoResizingPropertyViewModel.HeightSizable)) {
+				UpdateSizeName ();
+				UpdateVisual();
+			} else if (e.PropertyName == nameof(AutoResizingPropertyViewModel.LeftMarginFixed)
+			           || e.PropertyName == nameof(AutoResizingPropertyViewModel.RightMarginFixed)
+			           || e.PropertyName == nameof(AutoResizingPropertyViewModel.TopMarginFixed)
+			           || e.PropertyName == nameof(AutoResizingPropertyViewModel.BottomMarginFixed)) {
+				UpdateVisual();
+			}
+		}
+
+		private void OnPreviewWindowSizeChanged (object sender, SizeChangedEventArgs e)
+		{
+			UpdateVisual ();
+		}
+
+		private void UpdateVisual ()
+		{
+			if (this.vm == null)
+				return;
+
+			var elementRect = this.vm.GetPreviewElementRectangle (new CommonSize (this.window.ActualWidth, this.window.ActualHeight), this.vm.Value);
+			Canvas.SetLeft (this.elementVisual, elementRect.X);
+			Canvas.SetTop (this.elementVisual, elementRect.Y);
+			this.elementVisual.Width = elementRect.Width;
+			this.elementVisual.Height = elementRect.Height;
+		}
+
+		private void UpdateSizeName ()
+		{
+			if (this.sizingButton == null)
+				return;
+
+			string name = null;
+			if (this.vm != null) {
+				string current;
+				if (!this.vm.HeightSizable && !this.vm.WidthSizable)
+					current = Properties.Resources.AutoresizingFixedSized;
+				else if (this.vm.HeightSizable && !this.vm.WidthSizable)
+					current = Properties.Resources.AutoresizingHeightSizable;
+				else if (!this.vm.HeightSizable && this.vm.WidthSizable)
+					current = Properties.Resources.AutoresizingWidthSizable;
+				else
+					current = Properties.Resources.AutoresizingWidthHeightSizable;
+
+				name = String.Format (Properties.Resources.AutoresizingSizingName, current);
+			}
+
+			AutomationProperties.SetName (this.sizingButton, name);
+		}
+	}
+}
diff --git a/Xamarin.PropertyEditing.Windows/Themes/Resources.xaml b/Xamarin.PropertyEditing.Windows/Themes/Resources.xaml
index 4a883d6..1996520 100644
--- a/Xamarin.PropertyEditing.Windows/Themes/Resources.xaml
+++ b/Xamarin.PropertyEditing.Windows/Themes/Resources.xaml
@@ -6,7 +6,8 @@
 					xmlns:prop="clr-namespace:Xamarin.PropertyEditing.Properties;assembly=Xamarin.PropertyEditing"
 					xmlns:system="clr-namespace:System;assembly=mscorlib"
 					xmlns:vm="clr-namespace:Xamarin.PropertyEditing.ViewModels;assembly=Xamarin.PropertyEditing"
-					xmlns:pe="clr-namespace:Xamarin.PropertyEditing;assembly=Xamarin.PropertyEditing">
+					xmlns:pe="clr-namespace:Xamarin.PropertyEditing;assembly=Xamarin.PropertyEditing"
+					xmlns:common="clr-namespace:Xamarin.PropertyEditing.Common;assembly=Xamarin.PropertyEditing">
 
     <ResourceDictionary.MergedDictionaries>
         <ResourceDictionary Source="MenuButtonStyle.xaml" />
@@ -414,6 +415,125 @@
 		</Setter>
 	</Style>
 
+	<Style TargetType="local:AutoResizingMaskEditorControl">
+		<Setter Property="UseLayoutRounding" Value="True" />
+		<Setter Property="Template">
+			<Setter.Value>
+				<ControlTemplate TargetType="local:AutoResizingMaskEditorControl">
+					<ControlTemplate.Resources>
+						<Style x:Key="MarginButton" TargetType="ToggleButton">
+							<Setter Property="BorderThickness" Value="0" />
+							<Setter Property="Foreground" Value="{DynamicResource GuidelineEnabledForegroundBrush}" />
+							<Setter Property="Background" Value="Transparent" />
+							<Setter Property="RenderTransformOrigin" Value="0.5,0.5" />
+							<Setter Property="Padding" Value="0" />
+							<Setter Property="VerticalAlignment" Value="Center" />
+							<Setter Property="HorizontalAlignment" Value="Center" />
+							<Setter Property="Template">
+								<Setter.Value>
+									<ControlTemplate TargetType="ToggleButton">
+										<Border BorderThickness="{TemplateBinding BorderThickness}" BorderBrush="{TemplateBinding BorderBrush}" Background="{TemplateBinding Background}" Margin="{TemplateBinding Margin}" Padding="{TemplateBinding Padding}" UseLayoutRounding="{TemplateBinding UseLayoutRounding}">
+											<Polyline Stroke="{TemplateBinding Foreground}" Points="4,15 4,12 4,15 4,18 4,15 26,15 26,15 26,12 26,15 26,18 26,15" Height="30" Width="30" />
+										</Border>
+									</ControlTemplate>
+								</Setter.Value>
+							</Setter>
+							<Style.Triggers>
+								<Trigger Property="IsChecked" Value="False">
+									<Setter Property="Foreground" Value="{DynamicResource GuidelineDisabledForegroundBrush}" />
+								</Trigger>
+							</Style.Triggers>
+						</Style>
+					</ControlTemplate.Resources>
+
+					<Grid VerticalAlignment="Top" Height="100" UseLayoutRounding="{TemplateBinding UseLayoutRounding}">
+						<Grid.ColumnDefinitions>
+							<ColumnDefinition Width="Auto"/>
+							<ColumnDefinition />
+						</Grid.ColumnDefinitions>
+
+						<Border Grid.Row="0" Grid.Column="0" BorderBrush="{DynamicResource InputBorderBrush}" BorderThickness="1" Background="{DynamicResource InputBackgroundBrush}">
+							<Grid>
+								<Grid.RowDefinitions>
+									<RowDefinition />
+									<RowDefinition Height="40" />
+									<RowDefinition />
+								</Grid.RowDefinitions>
+								<Grid.ColumnDefinitions>
+									<ColumnDefinition />
+									<ColumnDefinition Width="40" />
+									<ColumnDefinition />
+								</Grid.ColumnDefinitions>
+								<ToggleButton Style="{StaticResource MarginButton}" AutomationProperties.Name="{x:Static prop:Resources.AutoresizingLeftMarginName}" IsChecked="{Binding LeftMarginFixed,Mode=TwoWay}" Grid.Row="1" Grid.Column="0" />
+								<ToggleButton Style="{StaticResource MarginButton}" AutomationProperties.Name="{x:Static prop:Resources.AutoresizingTopMarginName}" IsChecked="{Binding TopMarginFixed,Mode=TwoWay}" Grid.Row="0" Grid.Column="1">
+									<ToggleButton.RenderTransform>
+										<RotateTransform Angle="90" />
+									</ToggleButton.RenderTransform>
+								</ToggleButton>
+								<ToggleButton Style="{StaticResource MarginButton}" AutomationProperties.Name="{x:Static prop:Resources.AutoresizingRightMarginName}" IsChecked="{Binding RightMarginFixed,Mode=TwoWay}" Grid.Row="1" Grid.Column="2" />
+								<ToggleButton Style="{StaticResource MarginButton}" AutomationProperties.Name="{x:Static prop:Resources.AutoresizingBottomMarginName}" IsChecked="{Binding BottomMarginFixed,Mode=TwoWay}" Grid.Row="2" Grid.Column="1">
+									<ToggleButton.RenderTransform>
+										<RotateTransform Angle="90" />
+									</ToggleButton.RenderTransform>
+								</ToggleButton>
+
+								<Button Name="sizingButton" Grid.Row="1" Grid.Column="1" Command="{Binding CycleSizingCommand,Mode=OneTime}" BorderThickness="1" BorderBrush="{DynamicResource GuidelineDisabledForegroundBrush}" Background="Transparent" Content="{Binding}" AutomationProperties.HelpText="{x:Static prop:Resources.AutoresizingSizingHelpText}">
+									<Button.ContentTemplate>
+										<DataTemplate DataType="vm:AutoResizingPropertyViewModel">
+											<Grid>
+												<Polyline Name="widthSizable" Stroke="{DynamicResource GuidelineEnabledForegroundBrush}" Points="0,15 0.2,14.8 0,15 0.2,15.2 0,15 30,15 30,15 29.8,14.8 30,15 29.8,15.2 30,15" Width="30" Height="30" SnapsToDevicePixels="True" />
+												<Polyline Name="heightSizable" Stroke="{DynamicResource GuidelineEnabledForegroundBrush}" Points="15,0 14.8,0.2 15,0 15.2,0.2 15,0 15,30 15,30 14.8,29.8 15,30 15.2,29.8 15,30" Width="30" Height="30" SnapsToDevicePixels="True" />
+											</Grid>
+											<DataTemplate.Triggers>
+												<DataTrigger Binding="{Binding HeightSizable}" Value="False">
+													<Setter TargetName="heightSizable" Property="Stroke" Value="{DynamicResource GuidelineDisabledForegroundBrush}" />
+												</DataTrigger>
+												<DataTrigger Binding="{Binding WidthSizable}" Value="False">
+													<Setter TargetName="widthSizable" Property="Stroke" Value="{DynamicResource GuidelineDisabledForegroundBrush}" />
+												</DataTrigger>
+											</DataTemplate.Triggers>
+										</DataTemplate>
+									</Button.ContentTemplate>
+								</Button>
+							</Grid>
+						</Border>
+
+						<Border Grid.Row="0" Grid.Column="1" BorderBrush="{DynamicResource InputBorderBrush}" BorderThickness="1" Background="{DynamicResource InputBackgroundBrush}" Margin="2,0,0,0">
+							<Border Name="osBorder" Margin="2" Background="{DynamicResource ExampleWindowBackgroundBrush}" BorderThickness="0">
+								<Grid>
+									<Grid.RowDefinitions>
+										<RowDefinition Height="Auto" />
+										<RowDefinition />
+									</Grid.RowDefinitions>
+
+									<Border Grid.Row="0" BorderThickness="0" Background="{DynamicResource ExampleWindowTitleBackgroundBrush}" Height="4" />
+									<Canvas Grid.Row="1" Margin="6,6,0,0">
+										<Canvas.Resources>
+											<Storyboard FillBehavior="Stop" RepeatBehavior="Forever" AutoReverse="True" Duration="0:0:0.5" x:Key="GrowStoryboard" Storyboard.TargetName="windowRect">
+												<DoubleAnimation Storyboard.TargetProperty="Width" To="{Binding ElementName=osBorder,Path=ActualWidth}" />
+												<DoubleAnimation Storyboard.TargetProperty="Height" To="{Binding ElementName=osBorder,Path=ActualHeight}" />
+											</Storyboard>
+										</Canvas.Resources>
+										<Canvas.Triggers>
+											<EventTrigger RoutedEvent="MouseEnter">
+												<BeginStoryboard Storyboard="{StaticResource GrowStoryboard}" Name="BeginGrowStoryboard" />
+											</EventTrigger>
+											<EventTrigger RoutedEvent="MouseLeave">
+												<RemoveStoryboard BeginStoryboardName="BeginGrowStoryboard" />
+											</EventTrigger>
+										</Canvas.Triggers>
+										<Rectangle Name="windowRect" Fill="White" Width="30" Height="30" Margin="0" HorizontalAlignment="Left" VerticalAlignment="Top" SnapsToDevicePixels="False" />
+										<Rectangle Name="elementRect" Fill="Red" Margin="0" HorizontalAlignment="Left" VerticalAlignment="Top" SnapsToDevicePixels="False" />
+									</Canvas>
+								</Grid>
+							</Border>
+						</Border>
+					</Grid>
+				</ControlTemplate>
+			</Setter.Value>
+		</Setter>
+	</Style>
+
 	<Style TargetType="local:ObjectEditorControl">
 		<Setter Property="Template">
 			<Setter.Value>
diff --git a/Xamarin.PropertyEditing.Windows/Themes/VS.Dark.xaml b/Xamarin.PropertyEditing.Windows/Themes/VS.Dark.xaml
index cb76cf1..113401b 100644
--- a/Xamarin.PropertyEditing.Windows/Themes/VS.Dark.xaml
+++ b/Xamarin.PropertyEditing.Windows/Themes/VS.Dark.xaml
@@ -20,6 +20,11 @@
 	<SolidColorBrush x:Key="VariantBackgroundBrush">#ABABAB</SolidColorBrush>
 	<SolidColorBrush x:Key="VariantLineBrush">#5E5E5E</SolidColorBrush>
 
+	<SolidColorBrush x:Key="GuidelineDisabledForegroundBrush">#777777</SolidColorBrush>
+	<SolidColorBrush x:Key="GuidelineEnabledForegroundBrush">#F56D4F</SolidColorBrush>
+	<SolidColorBrush x:Key="ExampleWindowTitleBackgroundBrush">#575757</SolidColorBrush>
+	<SolidColorBrush x:Key="ExampleWindowBackgroundBrush">#7D7D7F</SolidColorBrush>
+
 	<SolidColorBrush x:Key="AdvancedExpanderCollapsedForegroundBrush">#F1F1F1</SolidColorBrush>
 	<SolidColorBrush x:Key="AdvancedExpanderMouseOverForegroundBrush">#007ACC</SolidColorBrush>
 	<SolidColorBrush x:Key="AdvancedExpanderMouseOverBorderBrush">#3E3E40</SolidColorBrush>
diff --git a/Xamarin.PropertyEditing.Windows/Xamarin.PropertyEditing.Windows.csproj b/Xamarin.PropertyEditing.Windows/Xamarin.PropertyEditing.Windows.csproj
index b21e249..fd84130 100644
--- a/Xamarin.PropertyEditing.Windows/Xamarin.PropertyEditing.Windows.csproj
+++ b/Xamarin.PropertyEditing.Windows/Xamarin.PropertyEditing.Windows.csproj
@@ -53,6 +53,7 @@
       <Link>Properties\GlobalAssemblyInfo.cs</Link>
     </Compile>
     <Compile Include="ArrangeModeLocalizedConverter.cs" />
+    <Compile Include="AutoResizingMaskEditorControl.cs" />
     <Compile Include="BoolEditorControl.cs" />
     <Compile Include="BoolsToVisibilityConverter.cs" />
     <Compile Include="BrushBoxControl.cs" />
diff --git a/Xamarin.PropertyEditing/Common/AutoResizingFlags.cs b/Xamarin.PropertyEditing/Common/AutoResizingFlags.cs
new file mode 100644
index 0000000..8c21b55
--- /dev/null
+++ b/Xamarin.PropertyEditing/Common/AutoResizingFlags.cs
@@ -0,0 +1,19 @@
+using System;
+
+namespace Xamarin.PropertyEditing.Common
+{
+	[Flags]
+	public enum AutoResizingFlags
+	{
+		None                 = 0,
+		FlexibleLeftMargin   = 1 << 0,
+		FlexibleWidth        = 1 << 1,
+		FlexibleRightMargin  = 1 << 2,
+		FlexibleTopMargin    = 1 << 3,
+		FlexibleHeight       = 1 << 4,
+		FlexibleBottomMargin = 1 << 5,
+		FlexibleMargins      = FlexibleBottomMargin | FlexibleTopMargin | FlexibleLeftMargin | FlexibleRightMargin,
+		FlexibleDimensions   = FlexibleHeight | FlexibleWidth,
+		All = FlexibleMargins | FlexibleDimensions
+	}
+}
diff --git a/Xamarin.PropertyEditing/Properties/Resources.Designer.cs b/Xamarin.PropertyEditing/Properties/Resources.Designer.cs
index c8cc438..1d9813f 100644
--- a/Xamarin.PropertyEditing/Properties/Resources.Designer.cs
+++ b/Xamarin.PropertyEditing/Properties/Resources.Designer.cs
@@ -1270,5 +1270,71 @@ namespace Xamarin.PropertyEditing.Properties {
 		        return ResourceManager.GetString("PropertyButtonName", resourceCulture);
 	        }
         }
+
+        public static string AutoresizingBottomMarginName {
+            get {
+                return ResourceManager.GetString("AutoresizingBottomMarginName", resourceCulture);
+            }
+        }
+
+        public static string AutoresizingFixedSized {
+            get {
+                return ResourceManager.GetString("AutoresizingFixedSized", resourceCulture);
+            }
+        }
+
+        public static string AutoresizingHeightSizable {
+            get {
+                return ResourceManager.GetString("AutoresizingHeightSizable", resourceCulture);
+            }
+        }
+
+        public static string AutoresizingLeftMarginName {
+            get {
+                return ResourceManager.GetString("AutoresizingLeftMarginName", resourceCulture);
+            }
+        }
+
+        public static string AutoresizingRightMarginName {
+            get {
+                return ResourceManager.GetString("AutoresizingRightMarginName", resourceCulture);
+            }
+        }
+
+        public static string AutoresizingSizingHelpText {
+            get {
+                return ResourceManager.GetString("AutoresizingSizingHelpText", resourceCulture);
+            }
+        }
+
+        public static string AutoresizingSizingName {
+            get {
+                return ResourceManager.GetString("AutoresizingSizingName", resourceCulture);
+            }
+        }
+
+        public static string AutoresizingTopMarginName {
+            get {
+                return ResourceManager.GetString("AutoresizingTopMarginName", resourceCulture);
+            }
+        }
+
+        public static string AutoresizingWidthHeightSizable {
+            get {
+                return ResourceManager.GetString("AutoresizingWidthHeightSizable", resourceCulture);
+            }
+        }
+
+        public static string AutoresizingWidthSizable {
+            get {
+                return ResourceManager.GetString("AutoresizingWidthSizable", resourceCulture);
+            }
+        }
+
+        public static string Autosizing {
+            get {
+                return ResourceManager.GetString("Autosizing", resourceCulture);
+            }
+        }
     }
 }
diff --git a/Xamarin.PropertyEditing/Properties/Resources.resx b/Xamarin.PropertyEditing/Properties/Resources.resx
index e778724..6713737 100644
--- a/Xamarin.PropertyEditing/Properties/Resources.resx
+++ b/Xamarin.PropertyEditing/Properties/Resources.resx
@@ -1,17 +1,17 @@
 <?xml version="1.0" encoding="utf-8"?>
 <root>
-  <!-- 
-    Microsoft ResX Schema 
-    
+  <!--
+    Microsoft ResX Schema
+
     Version 2.0
-    
-    The primary goals of this format is to allow a simple XML format 
-    that is mostly human readable. The generation and parsing of the 
-    various data types are done through the TypeConverter classes 
+
+    The primary goals of this format is to allow a simple XML format
+    that is mostly human readable. The generation and parsing of the
+    various data types are done through the TypeConverter classes
     associated with the data types.
-    
+
     Example:
-    
+
     ... ado.net/XML headers & schema ...
     <resheader name="resmimetype">text/microsoft-resx</resheader>
     <resheader name="version">2.0</resheader>
@@ -26,36 +26,36 @@
         <value>[base64 mime encoded string representing a byte array form of the .NET Framework object]</value>
         <comment>This is a comment</comment>
     </data>
-                
-    There are any number of "resheader" rows that contain simple 
+
+    There are any number of "resheader" rows that contain simple
     name/value pairs.
-    
-    Each data row contains a name, and value. The row also contains a 
-    type or mimetype. Type corresponds to a .NET class that support 
-    text/value conversion through the TypeConverter architecture. 
-    Classes that don't support this are serialized and stored with the 
+
+    Each data row contains a name, and value. The row also contains a
+    type or mimetype. Type corresponds to a .NET class that support
+    text/value conversion through the TypeConverter architecture.
+    Classes that don't support this are serialized and stored with the
     mimetype set.
-    
-    The mimetype is used for serialized objects, and tells the 
-    ResXResourceReader how to depersist the object. This is currently not 
+
+    The mimetype is used for serialized objects, and tells the
+    ResXResourceReader how to depersist the object. This is currently not
     extensible. For a given mimetype the value must be set accordingly:
-    
-    Note - application/x-microsoft.net.object.binary.base64 is the format 
-    that the ResXResourceWriter will generate, however the reader can 
+
+    Note - application/x-microsoft.net.object.binary.base64 is the format
+    that the ResXResourceWriter will generate, however the reader can
     read any of the formats listed below.
-    
+
     mimetype: application/x-microsoft.net.object.binary.base64
-    value   : The object must be serialized with 
+    value   : The object must be serialized with
             : System.Runtime.Serialization.Formatters.Binary.BinaryFormatter
             : and then encoded with base64 encoding.
-    
+
     mimetype: application/x-microsoft.net.object.soap.base64
-    value   : The object must be serialized with 
+    value   : The object must be serialized with
             : System.Runtime.Serialization.Formatters.Soap.SoapFormatter
             : and then encoded with base64 encoding.
 
     mimetype: application/x-microsoft.net.object.bytearray.base64
-    value   : The object must be serialized into a byte array 
+    value   : The object must be serialized into a byte array
             : using a System.ComponentModel.TypeConverter
             : and then encoded with base64 encoding.
     -->
@@ -633,7 +633,7 @@
   <data name="AccessibilityDateTime" xml:space="preserve">
     <value>{0} DateTime Editor</value>
     <comment>Editor for DateTime Value</comment>
-  </data>  
+  </data>
   <data name="AccessibilityXEditor" xml:space="preserve">
     <value>{0} X Editor</value>
     <comment>Editor for X Value</comment>
@@ -649,7 +649,7 @@
   <data name="AccessibilityHeightEditor" xml:space="preserve">
     <value>{0} Height Editor</value>
     <comment>Editor for Height Value</comment>
-  </data> 
+  </data>
   <data name="ArrangeByLabel" xml:space="preserve">
     <value>Arrange By:</value>
   </data>
@@ -725,7 +725,7 @@
   <data name="AccessibilityPathEditor" xml:space="preserve">
     <value>{0} {1} Path Editor</value>
     <comment>Editor for File/Directory Path Editor</comment>
-  </data>  
+  </data>
   <data name="ChooseFileOrDirectory" xml:space="preserve">
     <value>Choose a {0}</value>
     <comment>Choose a File or Directory</comment>
@@ -751,7 +751,7 @@
   </data>
   <data name="RemoveVariant" xml:space="preserve">
     <value>Remove Variant</value>
-   </data>  
+   </data>
   <data name="CreateBindingTitle" xml:space="preserve">
     <value>Create Binding</value>
     <comment>Create Binding for Object.Property</comment>
@@ -809,4 +809,41 @@
   <data name="PropertyButtonName" xml:space="preserve">
     <value>Advanced options</value>
   </data>
+  <data name="AutoresizingLeftMarginName" xml:space="preserve">
+    <value>Left margin fixed</value>
+  </data>
+  <data name="Autosizing" xml:space="preserve">
+    <value>Autosizing</value>
+  </data>
+  <data name="Example" xml:space="preserve">
+    <value>Example</value>
+  </data>
+  <data name="AutoresizingBottomMarginName" xml:space="preserve">
+    <value>Bottom margin fixed</value>
+  </data>
+  <data name="AutoresizingRightMarginName" xml:space="preserve">
+    <value>Right margin fixed</value>
+  </data>
+  <data name="AutoresizingSizingHelpText" xml:space="preserve">
+    <value>Cycles through width and height sizable</value>
+  </data>
+  <data name="AutoresizingTopMarginName" xml:space="preserve">
+    <value>Top margin fixed</value>
+  </data>
+  <data name="AutoresizingFixedSized" xml:space="preserve">
+    <value>fixed size</value>
+  </data>
+  <data name="AutoresizingHeightSizable" xml:space="preserve">
+    <value>height sizable</value>
+  </data>
+  <data name="AutoresizingSizingName" xml:space="preserve">
+    <value>Sizing, {0}</value>
+    <comment>Name, {Current State}</comment>
+  </data>
+  <data name="AutoresizingWidthHeightSizable" xml:space="preserve">
+    <value>width and height sizable</value>
+  </data>
+  <data name="AutoresizingWidthSizable" xml:space="preserve">
+    <value>width sizable</value>
+  </data>
 </root>
\ No newline at end of file
diff --git a/Xamarin.PropertyEditing/ViewModels/AutoResizingPropertyViewModel.cs b/Xamarin.PropertyEditing/ViewModels/AutoResizingPropertyViewModel.cs
index 43e965d..2f29af8 100644
--- a/Xamarin.PropertyEditing/ViewModels/AutoResizingPropertyViewModel.cs
+++ b/Xamarin.PropertyEditing/ViewModels/AutoResizingPropertyViewModel.cs
@@ -1,7 +1,7 @@
 using System.Collections.Generic;
-using System.Threading.Tasks;
 using System.Windows.Input;
 using Xamarin.PropertyEditing.Common;
+using Xamarin.PropertyEditing.Drawing;
 
 namespace Xamarin.PropertyEditing.ViewModels
 {
@@ -61,6 +61,64 @@ namespace Xamarin.PropertyEditing.ViewModels
 			set => SetFlag (AutoResizingFlags.FlexibleWidth, value);
 		}
 
+		public CommonRectangle GetPreviewElementRectangle (CommonSize window, AutoResizingFlags flags)
+		{
+			const int Offset = 5;
+			const double multiplier = .75;
+			double width = 10, height = 10;
+			double left;
+			bool fixedLeft = !flags.HasFlag (AutoResizingFlags.FlexibleLeftMargin),
+				fixedRight = !flags.HasFlag (AutoResizingFlags.FlexibleRightMargin);
+
+			if (fixedLeft)
+				left = Offset;
+			else if (fixedRight)
+				left = window.Width - Offset - width;
+			else
+				left = (window.Width / 2) - (width / 2);
+
+			if (flags.HasFlag (AutoResizingFlags.FlexibleWidth)) {
+				if (fixedRight && fixedLeft) {
+					width = window.Width - (Offset * 2);
+				} else if (fixedRight) {
+					left = window.Width - (window.Width * multiplier);
+					width = window.Width - left - Offset;
+				} else if (fixedLeft) {
+					width = (window.Width * multiplier) - Offset;
+				} else {
+					width = window.Width * multiplier;
+					left = (window.Width - width) / 2;
+				}
+			}
+
+			double top;
+			bool fixedTop = !flags.HasFlag (AutoResizingFlags.FlexibleTopMargin),
+				fixedBottom = !flags.HasFlag (AutoResizingFlags.FlexibleBottomMargin);
+
+			if (fixedTop)
+				top = Offset;
+			else if (fixedBottom)
+				top = window.Height - Offset - height;
+			else
+				top = (window.Height / 2) - (height / 2);
+
+			if (flags.HasFlag (AutoResizingFlags.FlexibleHeight)) {
+				if (fixedBottom && fixedTop) {
+					height = window.Height - (Offset * 2);
+				} else if (fixedBottom) {
+					top = window.Height - (window.Height * multiplier);
+					height = window.Height - top - Offset;
+				} else if (fixedTop) {
+					height = (window.Height * multiplier) - Offset;
+				} else {
+					height = window.Height * multiplier;
+					top = (window.Height - height) / 2;
+				}
+			}
+
+			return new CommonRectangle (left, top, width, height);
+		}
+
 		protected override void OnValueChanged ()
 		{
 			base.OnValueChanged ();
-- 
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