BitmapVisualManager.cs source code in C# .NET

                        Code:
                         / DotNET / DotNET / 8.0 / untmp / WIN_WINDOWS / lh_tools_devdiv_wpf / Windows / wcp / Core / System / Windows / Media / Imaging / BitmapVisualManager.cs / 1 / BitmapVisualManager.cs
                        
                        
                            //------------------------------------------------------------------------------ 
//  Microsoft Avalon
//  Copyright (c) Microsoft Corporation, 2003
//
//  File:       BitmapVisualManager.cs 
//
//----------------------------------------------------------------------------- 
using System; 
using System.Windows;
using System.Threading; 
using System.Windows.Threading;
using System.Diagnostics;
using System.Collections;
using System.Runtime.InteropServices; 
using System.IO;
using MS.Internal; 
using System.Security; 
using System.Security.Permissions;
using System.Windows.Media; 
using System.Windows.Media.Composition;
using SR=MS.Internal.PresentationCore.SR;
using SRID=MS.Internal.PresentationCore.SRID;
using MS.Win32.PresentationCore; 

namespace System.Windows.Media.Imaging 
{ 
    #region public class BitmapVisualManager
    ///  
    /// BitmapVisualManager holds state and context for a drawing a visual to an bitmap.
    /// 
    internal class BitmapVisualManager : DispatcherObject
    { 
        #region Constructors
        private BitmapVisualManager() 
        { 
        }
 
        /// 
        /// Create an BitmapVisualManager for drawing a visual to the bitmap.
        /// 
        /// Where the resulting bitmap is rendered 
        public BitmapVisualManager(RenderTargetBitmap bitmapTarget)
        { 
            if (bitmapTarget == null) 
            {
                throw new ArgumentNullException("bitmapTarget"); 
            }

            if (bitmapTarget.IsFrozen)
            { 
                throw new ArgumentException(SR.Get(SRID.Image_CantBeFrozen, null));
            } 
 
            _bitmapTarget = bitmapTarget;
        } 

        #endregion

        #region Public methods 
        /// 
        /// Render visual to printer. 
        ///  
        /// Root of the visual to render
        public void Render(Visual visual) 
        {
            Render(visual, Matrix.Identity, Rect.Empty, false);
        }
 
        /// 
        /// Render visual to printer. 
        ///  
        /// Root of the visual to render
        /// World transform to apply to the root visual 
        /// The window clip of the outermost window or Empty
        /// True if we are rendering the visual
        /// to apply an effect to it
        /// 
        /// 
        /// Critical - Deals with bitmap handles 
        /// TreatAsSafe - validates all parameters, uses safe wrappers 
        /// 
        [SecurityCritical,SecurityTreatAsSafe] 
        internal void Render(Visual visual, Matrix worldTransform, Rect windowClip, bool fRenderForBitmapEffect)
        {
            if (visual == null)
            { 
                throw new ArgumentNullException("visual");
            } 
 
            // If the bitmapTarget we're writing to is frozen then we can't proceed.  Note that
            // it's possible for the BitmapVisualManager to be constructed with a mutable BitmapImage 
            // and for the app to later freeze it.  Such an application is misbehaving if
            // they subsequently try to render to the BitmapImage.
            if (_bitmapTarget.IsFrozen)
            { 
                throw new ArgumentException(SR.Get(SRID.Image_CantBeFrozen));
            } 
 
            int sizeX = _bitmapTarget.PixelWidth;
            int sizeY = _bitmapTarget.PixelHeight; 
            double dpiX = _bitmapTarget.DpiX;
            double dpiY = _bitmapTarget.DpiY;

            Debug.Assert ((sizeX > 0) && (sizeY > 0)); 
            Debug.Assert ((dpiX > 0) && (dpiY > 0));
 
            // validate the data 
            if ((sizeX <= 0) || (sizeY <= 0))
            { 
                return; // nothing to draw
            }

            if ((dpiX <= 0) || (dpiY <= 0)) 
            {
                dpiX = 96; 
                dpiY = 96; 
            }
 
            SafeMILHandle renderTargetBitmap = _bitmapTarget.MILRenderTarget;
            Debug.Assert (renderTargetBitmap != null, "Render Target is null");

            IntPtr pIRenderTargetBitmap = IntPtr.Zero; 

            try 
            { 
                //
                // Allocate a fresh synchronous channel. 
                //

                MediaContext mctx = MediaContext.CurrentMediaContext;
                DUCE.Channel channel = mctx.AllocateSyncChannel(); 

 
                // 
                // Acquire the target bitmap.
                // 

                Guid iidRTB = MILGuidData.IID_IMILRenderTargetBitmap;

                HRESULT.Check(UnsafeNativeMethods.MILUnknown.QueryInterface( 
                    renderTargetBitmap,
                    ref iidRTB, 
                    out pIRenderTargetBitmap)); 

 
                //
                // Render the visual on the synchronous channel.
                //
 
                Renderer.Render(
                    pIRenderTargetBitmap, 
                    channel, 
                    visual,
                    sizeX, 
                    sizeY,
                    dpiX,
                    dpiY,
                    worldTransform, 
                    windowClip,
                    fRenderForBitmapEffect); 
 
                //
                // Release the synchronous channel. This way we can 
                // re-use that channel later.
                //

                mctx.ReleaseSyncChannel(channel); 
            }
            finally 
            { 
                UnsafeNativeMethods.MILUnknown.ReleaseInterface(ref pIRenderTargetBitmap);
            } 

            _bitmapTarget.RenderTargetContentsChanged();
        }
        #endregion 

        #region Member Variables 
        private RenderTargetBitmap _bitmapTarget = null; 
        #endregion
    } 
    #endregion
}

 

 

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.
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