/// <summary>
/// Returns a Graphics object representing a buffer.
/// </summary>
private Graphics CreateBuffer(IntPtr src, int offsetX, int offsetY, int width, int height)
{
// Create the compat DC.
_busy = BufferBusyDisposing;
DisposeDC();
_busy = BufferBusyPainting;
_compatDC = UnsafeNativeMethods.CreateCompatibleDC(new HandleRef(null, src));
// Recreate the bitmap if necessary.
if (width > _bufferSize.Width || height > _bufferSize.Height)
{
int optWidth = Math.Max(width, _bufferSize.Width);
int optHeight = Math.Max(height, _bufferSize.Height);
_busy = BufferBusyDisposing;
DisposeBitmap();
_busy = BufferBusyPainting;
IntPtr pvbits = IntPtr.Zero;
_dib = CreateCompatibleDIB(src, IntPtr.Zero, optWidth, optHeight, ref pvbits);
_bufferSize = new Size(optWidth, optHeight);
}
// Select the bitmap.
_oldBitmap = SafeNativeMethods.SelectObject(new HandleRef(this, _compatDC), new HandleRef(this, _dib));
// Create compat graphics.
_compatGraphics = Graphics.FromHdcInternal(_compatDC);
_compatGraphics.TranslateTransform(-_targetLoc.X, -_targetLoc.Y);
_virtualSize = new Size(width, height);
return(_compatGraphics);
}
private Graphics CreateBuffer(IntPtr src, int offsetX, int offsetY, int width, int height)
{
//create the compat DC
busy = BUFFER_BUSY_DISPOSING;
DisposeDC();
busy = BUFFER_BUSY_PAINTING;
compatDC = UnsafeNativeMethods.CreateCompatibleDC(new HandleRef(null, src));
//recreate the bitmap if necessary
if (width > bufferSize.Width || height > bufferSize.Height)
{
Debug.WriteLineIf(DoubleBuffering.TraceInfo, "allocating new bitmap: " + width + " x " + height);
int optWidth = Math.Max(width, bufferSize.Width);
int optHeight = Math.Max(height, bufferSize.Height);
busy = BUFFER_BUSY_DISPOSING;
DisposeBitmap();
busy = BUFFER_BUSY_PAINTING;
Debug.WriteLineIf(DoubleBuffering.TraceInfo, " new size : " + optWidth + " x " + optHeight);
IntPtr pvbits = IntPtr.Zero;
dib = CreateCompatibleDIB(src, IntPtr.Zero, optWidth, optHeight, ref pvbits);
bufferSize = new Size(optWidth, optHeight);
}
//select the bitmap
oldBitmap = SafeNativeMethods.SelectObject(new HandleRef(this, compatDC), new HandleRef(this, dib));
//create compat graphics
Debug.WriteLineIf(DoubleBuffering.TraceInfo, " Create compatGraphics");
compatGraphics = Graphics.FromHdcInternal(compatDC);
compatGraphics.TranslateTransform(-targetLoc.X, -targetLoc.Y);
virtualSize = new Size(width, height);
return(compatGraphics);
}
