Specifies the area of the back buffer that changed.
Assembly: PresentationCore (in PresentationCore.dll)
The back buffer has not been assigned by a call to the SetBackBuffer method.
One or more of the following conditions is true.
dirtyRect.X < 0
dirtyRect.Y < 0
dirtyRect.Width < 0 or dirtyRect.Width > PixelWidth
dirtyRect.Height < 0 or dirtyRect.Height > PixelHeight
Call the method to indicate changes your code has made to the back buffer. To be rendered, the changed area on the back buffer must have a corresponding changed area on the D3DImage.
Call the Unlock method to copy the changed areas to the front buffer.
After a few calls to the method, the changed areas are merged into a single area. This means you must have valid data outside of the changed areas.
The following code example shows how to call the method to specify the changed region in the back buffer. For more information, see Walkthrough: Hosting Direct3D9 Content in WPF.
d3dimg.Lock(); // Repeatedly calling SetBackBuffer with the same IntPtr is // a no-op. There is no performance penalty. d3dimg.SetBackBuffer(D3DResourceType.IDirect3DSurface9, pSurface); HRESULT.Check(Render()); d3dimg.AddDirtyRect(new Int32Rect(0, 0, d3dimg.PixelWidth, d3dimg.PixelHeight)); d3dimg.Unlock();