ScalableImage.cs

//-----------------------------------------------------------------------
// <copyright file="ScalableImage.cs" company="Microsoft">
//     Copyright (c) Microsoft Corporation.  All rights reserved.
// </copyright>
// <summary>
// Represents an image that can render as a vector or as a bitmap.
// </summary>
//-----------------------------------------------------------------------

namespace Microsoft.Management.UI.Internal
{
    #region Using Directives

    using System;
    using System.Diagnostics.CodeAnalysis;
    using System.Windows;
    using System.Windows.Automation;
    using System.Windows.Automation.Peers;
    using System.Windows.Data;
    using System.Windows.Media;


    #endregion

    /// <content>
    /// Partial class implementation for ScalableImage control.
    /// </content>
    [SuppressMessage("Microsoft.MSInternal", "CA903:InternalNamespaceShouldNotContainPublicTypes")]
    public partial class ScalableImage : FrameworkElement
    {
        #region Structors

        /// <summary>
        /// Initializes a new instance of the <see cref="Microsoft.Management.UI.Internal.ScalableImage" /> class.
        /// </summary>
        public ScalableImage()
        {
            // This constructor intentionally left blank
        }

        #endregion

        #region Overrides

        /// <summary>
        /// Called when the control is asked to render itself in a given area.
        /// Sets the render size to use all available area when <see cref="Microsoft.Management.UI.Internal.ScalableImageSource.Brush"/> is provided.
        /// </summary>
        /// <param name="finalSize">The final area within the parent that this element should use to arrange itself and its children.</param>
        /// <returns>The actual size used to render the control.</returns>
        protected override Size ArrangeOverride(Size finalSize)
        {
            // If a vector is provided, specify that the control will use all available area \\
            if (this.Source != null && this.Source.Brush != null)
            {
                return finalSize;
            }

            return base.ArrangeOverride(finalSize);
        }

        /// <summary>
        /// Called when the control is being rendered.
        /// Renders the contents of the image as a vector or a bitmap, depending on which is provided.
        /// </summary>
        /// <param name="drawingContext">An instance of <see cref="System.Windows.Media.DrawingContext"/> used to render the control.</param>
        protected override void OnRender(DrawingContext drawingContext)
        {
            Rect renderArea = new Rect(this.RenderSize);

            // No source was provided \\
            if (this.Source == null)
            {
                return;
            }

            // Prefer the vector if it's provided \\
            if (this.Source.Brush != null)
            {
                drawingContext.DrawRectangle(this.Source.Brush, null, renderArea);
            }
            else if (this.Source.Image != null)
            {
                drawingContext.DrawImage(this.Source.Image, renderArea);
            }
        }

        /// <summary>
        /// Override of <seealso cref="UIElement.GetLayoutClip"/>.
        /// Make this control to respect the ClipToBounds attribute value.
        /// </summary>
        /// <param name="layoutSlotSize">An instance of <see cref="System.Windows.Size"/> used for calculating an additional clip.</param>
        /// <returns>Geometry to use as an additional clip in case when element is larger than available space</returns>
        protected override Geometry GetLayoutClip(Size layoutSlotSize)
        {
            return ClipToBounds ? base.GetLayoutClip(layoutSlotSize) : null;
        }

        #endregion

        #region Protected Methods

        partial void OnSourceChangedImplementation(PropertyChangedEventArgs<ScalableImageSource> e)
        {
            if (e.NewValue != null)
            {
                // If a width was provided in the source, use it now \\
                if (!e.NewValue.Size.Width.Equals(Double.NaN))
                {
                    this.Width = e.NewValue.Size.Width;
                }

                // If a height was provided in the source, use it now \\
                if (!e.NewValue.Size.Height.Equals(Double.NaN))
                {
                    this.Height = e.NewValue.Size.Height;
                }

                // Bind the image's accessible name to the one set in the source \\
                Binding accessibleNameBinding = new Binding(ScalableImageSource.AccessibleNameProperty.Name);
                accessibleNameBinding.Source = this.Source;
                this.SetBinding(AutomationProperties.NameProperty, accessibleNameBinding);
            }
        }

        #endregion
    }
}