DrawingVisual.cs source code in C# .NET

                        Code:
                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / wpf / src / Core / CSharp / System / Windows / Media / DrawingVisual.cs / 1305600 / DrawingVisual.cs
                        
                        
                            //------------------------------------------------------------------------------ 
//  Microsoft Avalon
//  Copyright (c) Microsoft Corporation, 2001
//
//  File:       DrawingVisual.cs 
//-----------------------------------------------------------------------------
 
using System; 
using System.Windows.Threading;
 
using System.Windows.Media;
using System.Windows.Media.Composition;
using System.Diagnostics;
using System.Collections.Generic; 
using MS.Internal;
using MS.Win32; 
using System.Resources; 
using System.Runtime.InteropServices;
 
namespace System.Windows.Media
{
    /// 
    /// A DrawingVisual is a Visual that can be used to render Vector graphics on the screen. 
    /// The content is persistet by the System.
    ///  
    public class DrawingVisual : ContainerVisual 
    {
        // bbox in inner coordinate space. Note that this bbox does not 
        // contain the childrens extent.
        IDrawingContent _content;

        ///  
        /// HitTestCore implements precise hit testing against render contents
        ///  
        protected override HitTestResult HitTestCore(PointHitTestParameters hitTestParameters) 
        {
            if (hitTestParameters == null) 
            {
                throw new ArgumentNullException("hitTestParameters");
            }
 
            if (_content != null)
            { 
                if (_content.HitTestPoint(hitTestParameters.HitPoint)) 
                {
                    return new PointHitTestResult(this, hitTestParameters.HitPoint); 
                }
            }

            return null; 
        }
 
        ///  
        /// HitTestCore implements precise hit testing against render contents
        ///  
        protected override GeometryHitTestResult HitTestCore(GeometryHitTestParameters hitTestParameters)
        {
            if (hitTestParameters == null)
            { 
                throw new ArgumentNullException("hitTestParameters");
            } 
 
            if ((_content != null) && GetHitTestBounds().IntersectsWith(hitTestParameters.Bounds))
            { 
                IntersectionDetail intersectionDetail;

                intersectionDetail = _content.HitTestGeometry(hitTestParameters.InternalHitGeometry);
                Debug.Assert(intersectionDetail != IntersectionDetail.NotCalculated); 

                if (intersectionDetail != IntersectionDetail.Empty) 
                { 
                    return new GeometryHitTestResult(this, intersectionDetail);
                } 

            }

            return null; 
        }
 
 
        /// 
        /// Opens the DrawingVisual for rendering. The returned DrawingContext can be used to 
        /// render into the DrawingVisual.
        /// 
        public DrawingContext RenderOpen()
        { 
            VerifyAPIReadWrite();
 
            return new VisualDrawingContext(this); 
        }
 
        /// 
        /// Called from the DrawingContext when the DrawingContext is closed.
        /// 
        internal override void RenderClose(IDrawingContent newContent) 
        {
            IDrawingContent oldContent; 
 
            //
            // First cleanup the old content and the state associate with this node 
            // related to it's content.
            //

            oldContent = _content; 
            _content = null;
 
            if (oldContent != null) 
            {
                // 
                // Remove the notification handlers.
                //

                oldContent.PropagateChangedHandler(ContentsChangedHandler, false /* remove */); 

 
                // 
                // Disconnect the old content from this visual.
                // 

                DisconnectAttachedResource(
                    VisualProxyFlags.IsContentConnected,
                    ((DUCE.IResource)oldContent)); 
            }
 
 
            //
            // Prepare the new content. 
            //

            if (newContent != null)
            { 
                // Propagate notification handlers.
                newContent.PropagateChangedHandler(ContentsChangedHandler, true /* adding */); 
            } 

            _content = newContent; 


            //
            // Mark the visual dirty on all channels and propagate 
            // the flags up the parent chain.
            // 
 
            SetFlagsOnAllChannels(true, VisualProxyFlags.IsContentDirty);
 
            PropagateFlags(
                this,
                VisualFlags.IsSubtreeDirtyForPrecompute,
                VisualProxyFlags.IsSubtreeDirtyForRender); 

        } 
 
        /// 
        /// Overriding this function to release DUCE resources during Dispose and during removal of a subtree. 
        /// 
        internal override void FreeContent(DUCE.Channel channel)
        {
            Debug.Assert(_proxy.IsOnChannel(channel)); 

            if (_content != null) 
            { 
                if (CheckFlagsAnd(channel, VisualProxyFlags.IsContentConnected))
                { 
                    DUCE.CompositionNode.SetContent(
                        _proxy.GetHandle(channel),
                        DUCE.ResourceHandle.Null,
                        channel); 

                    SetFlags( 
                        channel, 
                        false,
                        VisualProxyFlags.IsContentConnected); 

                    ((DUCE.IResource)_content).ReleaseOnChannel(channel);
                }
            } 

            // Call the base method too 
            base.FreeContent(channel); 
        }
 
        /// 
        /// Returns the bounding box of the content.
        /// 
        internal override Rect GetContentBounds() 
        {
            if (_content != null) 
            { 
                Rect resultRect = Rect.Empty;
                MediaContext mediaContext = MediaContext.From(Dispatcher); 
                BoundsDrawingContextWalker ctx = mediaContext.AcquireBoundsDrawingContextWalker();

                resultRect = _content.GetContentBounds(ctx);
                mediaContext.ReleaseBoundsDrawingContextWalker(ctx); 

                return resultRect; 
            } 
            else
            { 
                return Rect.Empty;
            }
        }
 
        /// 
        /// WalkContent - method which walks the content (if present) and calls out to the 
        /// supplied DrawingContextWalker. 
        /// 
        ///  
        ///   DrawingContextWalker - the target of the calls which occur during
        ///   the content walk.
        /// 
        internal void WalkContent(DrawingContextWalker walker) 
        {
            VerifyAPIReadOnly(); 
 
            if (_content != null)
            { 
                _content.WalkContent(walker);
            }
        }
 
        /// 
        /// RenderContent is implemented by derived classes to hook up their 
        /// content. The implementer of this function can assert that the _hCompNode 
        /// is valid on a channel when the function is executed.
        ///  
        internal override void RenderContent(RenderContext ctx, bool isOnChannel)
        {
            DUCE.Channel channel = ctx.Channel;
 
            Debug.Assert(!CheckFlagsAnd(channel, VisualProxyFlags.IsContentConnected));
            Debug.Assert(_proxy.IsOnChannel(channel)); 
 

            // 
            // Create the content on the channel.
            //

            if (_content != null) 
            {
                DUCE.CompositionNode.SetContent( 
                    _proxy.GetHandle(channel), 
                    ((DUCE.IResource)_content).AddRefOnChannel(channel),
                    channel); 

                SetFlags(
                    channel,
                    true, 
                    VisualProxyFlags.IsContentConnected);
            } 
            else if (isOnChannel) /*_content == null*/ 
            {
                DUCE.CompositionNode.SetContent( 
                    _proxy.GetHandle(channel),
                    DUCE.ResourceHandle.Null,
                    channel);
            } 
        }
 
        ///  
        /// GetDrawing - Returns the drawing content of this Visual.
        ///  
        /// 
        /// Changes to this DrawingGroup will not be propagated to the Visual's content.
        /// This method is called by both the Drawing property, and VisualTreeHelper.GetDrawing()
        ///  
        internal override DrawingGroup GetDrawing()
        { 
            // 

 
            VerifyAPIReadOnly();

            DrawingGroup drawingGroupContent = null;
 
            // Convert our content to a DrawingGroup, if content exists
            if (_content != null) 
            { 
                drawingGroupContent = DrawingServices.DrawingGroupFromRenderData((RenderData) _content);
            } 

            return drawingGroupContent;
        }
 
        /// 
        /// Drawing - Returns the drawing content of this Visual. 
        ///  
        /// 
        /// Changes to this DrawingGroup will not propagated to the Visual's content. 
        /// 
        public DrawingGroup Drawing
        {
            get 
            {
                return GetDrawing(); 
            } 
        }
    } 
}


// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
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DrawingVisual.cs source code in C# .NET

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