C# Int32Rect.ToDrawingRectangle方法代码示例

        /// <summary>
        /// Gets a System.Drawing.Bitmap from a BitmapSource.
        /// </summary>
        /// <param name="source">The source image from which to create our Bitmap.</param>
        /// <param name="transparencyKey">The transparency key. This is used by the DragDropHelper
        /// in rendering transparent pixels.</param>
        /// <returns>An instance of Bitmap which is a copy of the BitmapSource's image.</returns>
        private static Bitmap GetBitmapFromBitmapSource(BitmapSource source, Color transparencyKey)
        {
            // Copy at full size
            Int32Rect sourceRect = new Int32Rect(0, 0, source.PixelWidth, source.PixelHeight);

            // Convert to our destination pixel format
            DrawingPixelFormat pxFormat = ConvertPixelFormat(source.Format);

            // Create the Bitmap, full size, full rez
            Bitmap bmp = new Bitmap(sourceRect.Width, sourceRect.Height, pxFormat);
            // If the format is an indexed format, copy the color palette
            if ((pxFormat & DrawingPixelFormat.Indexed) == DrawingPixelFormat.Indexed)
                ConvertColorPalette(bmp.Palette, source.Palette);

            // Get the transparency key as a System.Drawing.Color
            DrawingColor transKey = transparencyKey.ToDrawingColor();

            // Lock our Bitmap bits, we need to write to it
            BitmapData bmpData = bmp.LockBits(
                sourceRect.ToDrawingRectangle(),
                ImageLockMode.ReadWrite,
                pxFormat);
            {
                // Copy the source bitmap data to our new Bitmap
                source.CopyPixels(sourceRect, bmpData.Scan0, bmpData.Stride * sourceRect.Height, bmpData.Stride);

                // The drag image seems to work in full 32-bit color, except when
                // alpha equals zero. Then it renders those pixels at black. So
                // we make a pass and set all those pixels to the transparency key
                // color. This is only implemented for 32-bit pixel colors for now.
                if ((pxFormat & DrawingPixelFormat.Alpha) == DrawingPixelFormat.Alpha)
                    ReplaceTransparentPixelsWithTransparentKey(bmpData, transKey);
            }
            // Done, unlock the bits
            bmp.UnlockBits(bmpData);

            return bmp;
        }