private DrawingGroup GetDrawingHelper()
{
DrawingGroup drawingGroup = null;
if (_hwnd.Handle != IntPtr.Zero && UnsafeNativeMethods.IsWindow(_hwnd))
{
NativeMethods.RECT rc = new NativeMethods.RECT();
SafeNativeMethods.GetWindowRect(_hwnd, ref rc);
int width = rc.right - rc.left;
int height = rc.bottom - rc.top;
HandleRef hdcScreen = new HandleRef(this, UnsafeNativeMethods.GetDC(new HandleRef(this, IntPtr.Zero)));
if (hdcScreen.Handle != IntPtr.Zero)
{
HandleRef hdcBitmap = new HandleRef(this, IntPtr.Zero);
HandleRef hBitmap = new HandleRef(this, IntPtr.Zero);
try
{
hdcBitmap = new HandleRef(this, UnsafeNativeMethods.CriticalCreateCompatibleDC(hdcScreen));
if (hdcBitmap.Handle != IntPtr.Zero)
{
hBitmap = new HandleRef(this, UnsafeNativeMethods.CriticalCreateCompatibleBitmap(hdcScreen, width, height));
if (hBitmap.Handle != IntPtr.Zero)
{
// Select the bitmap into the DC so that we draw to it.
IntPtr hOldBitmap = UnsafeNativeMethods.CriticalSelectObject(hdcBitmap, hBitmap.Handle);
try
{
// Clear the bitmap to white (so we don't waste toner printing a black bitmap something fails).
NativeMethods.RECT rcPaint = new NativeMethods.RECT(0, 0, width, height);
IntPtr hbrWhite = UnsafeNativeMethods.CriticalGetStockObject(NativeMethods.WHITE_BRUSH);
UnsafeNativeMethods.CriticalFillRect(hdcBitmap.Handle, ref rcPaint, hbrWhite);
// First try to use the PrintWindow API.
bool result = UnsafeNativeMethods.CriticalPrintWindow(_hwnd, hdcBitmap, 0);
if (result == false)
{
// Fall back to sending a WM_PRINT message to the window.
//
// Note: there are known cases where WM_PRINT is not implemented
// to provide visual parity with WM_PAINT. However, since the
// GetDrawing method is virtual, the derived class can override
// this default implementation and provide a better implementation.
UnsafeNativeMethods.SendMessage(_hwnd.Handle, WindowMessage.WM_PRINT, hdcBitmap.Handle, (IntPtr)(NativeMethods.PRF_CHILDREN | NativeMethods.PRF_CLIENT | NativeMethods.PRF_ERASEBKGND | NativeMethods.PRF_NONCLIENT));
}
else
{
// There is a know issue where calling PrintWindow on a window will
// clear all dirty regions (but since it is redirected, the screen
// won't be updated). As a result we can leave unpainted pixels on
// the screen if PrintWindow is called when the window was dirty.
//
// To fix this, we just force the child window to repaint.
//
UnsafeNativeMethods.CriticalRedrawWindow(_hwnd, IntPtr.Zero, IntPtr.Zero, NativeMethods.RDW_INVALIDATE | NativeMethods.RDW_ALLCHILDREN);
}
// Create a DrawingGroup that only contains an ImageDrawing that wraps the bitmap.
drawingGroup = new DrawingGroup();
System.Windows.Media.Imaging.BitmapSource bitmapSource = Imaging.CriticalCreateBitmapSourceFromHBitmap(hBitmap.Handle, IntPtr.Zero, Int32Rect.Empty, null, WICBitmapAlphaChannelOption.WICBitmapIgnoreAlpha);
Rect rectElement = new Rect(RenderSize);
drawingGroup.Children.Add(new ImageDrawing(bitmapSource, rectElement));
drawingGroup.Freeze();
}
finally
{
// Put the old bitmap back into the DC.
UnsafeNativeMethods.CriticalSelectObject(hdcBitmap, hOldBitmap);
}
}
}
}
finally
{
UnsafeNativeMethods.ReleaseDC(new HandleRef(this, IntPtr.Zero), hdcScreen);
hdcScreen = new HandleRef(null, IntPtr.Zero);
if (hBitmap.Handle != IntPtr.Zero)
{
UnsafeNativeMethods.DeleteObject(hBitmap);
hBitmap = new HandleRef(this, IntPtr.Zero);
}
if (hdcBitmap.Handle != IntPtr.Zero)
{
UnsafeNativeMethods.CriticalDeleteDC(hdcBitmap);
hdcBitmap = new HandleRef(this, IntPtr.Zero);
}
}
}
}
return(drawingGroup);
}
private DrawingGroup GetDrawingHelper()
{
SecurityHelper.DemandUIWindowPermission();
DrawingGroup drawingGroup = null;
if (this._hwnd.Handle != IntPtr.Zero && UnsafeNativeMethods.IsWindow(this._hwnd))
{
NativeMethods.RECT rect = default(NativeMethods.RECT);
SafeNativeMethods.GetWindowRect(this._hwnd, ref rect);
int num = rect.right - rect.left;
int num2 = rect.bottom - rect.top;
HandleRef hDC = new HandleRef(this, UnsafeNativeMethods.GetDC(new HandleRef(this, IntPtr.Zero)));
if (hDC.Handle != IntPtr.Zero)
{
HandleRef handleRef = new HandleRef(this, IntPtr.Zero);
HandleRef hObject = new HandleRef(this, IntPtr.Zero);
try
{
handleRef = new HandleRef(this, UnsafeNativeMethods.CriticalCreateCompatibleDC(hDC));
if (handleRef.Handle != IntPtr.Zero)
{
hObject = new HandleRef(this, UnsafeNativeMethods.CriticalCreateCompatibleBitmap(hDC, num, num2));
if (hObject.Handle != IntPtr.Zero)
{
IntPtr obj = UnsafeNativeMethods.CriticalSelectObject(handleRef, hObject.Handle);
try
{
NativeMethods.RECT rect2 = new NativeMethods.RECT(0, 0, num, num2);
IntPtr brush = UnsafeNativeMethods.CriticalGetStockObject(0);
UnsafeNativeMethods.CriticalFillRect(handleRef.Handle, ref rect2, brush);
if (!UnsafeNativeMethods.CriticalPrintWindow(this._hwnd, handleRef, 0))
{
UnsafeNativeMethods.SendMessage(this._hwnd.Handle, WindowMessage.WM_PRINT, handleRef.Handle, (IntPtr)30);
}
else
{
UnsafeNativeMethods.CriticalRedrawWindow(this._hwnd, IntPtr.Zero, IntPtr.Zero, 129);
}
drawingGroup = new DrawingGroup();
BitmapSource imageSource = Imaging.CriticalCreateBitmapSourceFromHBitmap(hObject.Handle, IntPtr.Zero, Int32Rect.Empty, null, WICBitmapAlphaChannelOption.WICBitmapIgnoreAlpha);
Rect rect3 = new Rect(base.RenderSize);
drawingGroup.Children.Add(new ImageDrawing(imageSource, rect3));
drawingGroup.Freeze();
}
finally
{
UnsafeNativeMethods.CriticalSelectObject(handleRef, obj);
}
}
}
}
finally
{
UnsafeNativeMethods.ReleaseDC(new HandleRef(this, IntPtr.Zero), hDC);
hDC = new HandleRef(null, IntPtr.Zero);
if (hObject.Handle != IntPtr.Zero)
{
UnsafeNativeMethods.DeleteObject(hObject);
hObject = new HandleRef(this, IntPtr.Zero);
}
if (handleRef.Handle != IntPtr.Zero)
{
UnsafeNativeMethods.CriticalDeleteDC(handleRef);
handleRef = new HandleRef(this, IntPtr.Zero);
}
}
}
}
return(drawingGroup);
}