Save UIElement as PNG in Silverlight 3

We don’t have printing feature in SL 3 (SL 4 has that feature though ) so here’s the workaround solution – create a bitmap file of that UIElement then Save that file to user local machine.

Code get from here http://forums.silverlight.net/forums/p/114691/446894.aspx

public static void GenerateImage(UIElement toPrint,double ActualHeight, double ActualWidth )
        {
            WriteableBitmap bitmap = new System.Windows.Media.Imaging.WriteableBitmap(Convert.ToInt32(ActualWidth),
                                                                                    Convert.ToInt32(ActualHeight));

            bitmap.Render(toPrint, new TranslateTransform());
            bitmap.Invalidate();
            SaveFile(bitmap);
        }

        #region Save file

        private static void SaveFile(WriteableBitmap wb)
        {
            SaveFileDialog saveFileDialog = new SaveFileDialog();

            saveFileDialog.DefaultExt = "png";
            saveFileDialog.Filter = "PNG Files (*.png)|*.png|All files (*.*)|*.*";
            saveFileDialog.FilterIndex = 1;

            if (saveFileDialog.ShowDialog() == true)
            {

                using (Stream stream = saveFileDialog.OpenFile())
                {

                    byte[] buffer = GetBuffer(wb);
                    stream.Write(buffer, 0, buffer.Length);

                    stream.Close();
                }

            }
        }

        private static byte[] GetBuffer(WriteableBitmap bitmap)
        {
            int width = bitmap.PixelWidth;
            int height = bitmap.PixelHeight;

            MemoryStream ms = new MemoryStream();

            #region BMP File Header(14 bytes)
            //the magic number(2 bytes):BM
            ms.WriteByte(0x42);
            ms.WriteByte(0x4D);

            //the size of the BMP file in bytes(4 bytes)
            long len = bitmap.Pixels.Length * 4 + 0x36;

            ms.WriteByte((byte)len);
            ms.WriteByte((byte)(len >> 8));
            ms.WriteByte((byte)(len >> 16));
            ms.WriteByte((byte)(len >> 24));

            //reserved(2 bytes)
            ms.WriteByte(0x00);
            ms.WriteByte(0x00);

            //reserved(2 bytes)
            ms.WriteByte(0x00);
            ms.WriteByte(0x00);

            //the offset(4 bytes)
            ms.WriteByte(0x36);
            ms.WriteByte(0x00);
            ms.WriteByte(0x00);
            ms.WriteByte(0x00);
            #endregion

            #region Bitmap Information(40 bytes:Windows V3)
            //the size of this header(4 bytes)
            ms.WriteByte(0x28);
            ms.WriteByte(0x00);
            ms.WriteByte(0x00);
            ms.WriteByte(0x00);

            //the bitmap width in pixels(4 bytes)
            ms.WriteByte((byte)width);
            ms.WriteByte((byte)(width >> 8));
            ms.WriteByte((byte)(width >> 16));
            ms.WriteByte((byte)(width >> 24));

            //the bitmap height in pixels(4 bytes)
            ms.WriteByte((byte)height);
            ms.WriteByte((byte)(height >> 8));
            ms.WriteByte((byte)(height >> 16));
            ms.WriteByte((byte)(height >> 24));

            //the number of color planes(2 bytes)
            ms.WriteByte(0x01);
            ms.WriteByte(0x00);

            //the number of bits per pixel(2 bytes)
            ms.WriteByte(0x20);
            ms.WriteByte(0x00);

            //the compression method(4 bytes)
            ms.WriteByte(0x00);
            ms.WriteByte(0x00);
            ms.WriteByte(0x00);
            ms.WriteByte(0x00);

            //the image size(4 bytes)
            ms.WriteByte(0x00);
            ms.WriteByte(0x00);
            ms.WriteByte(0x00);
            ms.WriteByte(0x00);

            //the horizontal resolution of the image(4 bytes)
            ms.WriteByte(0x00);
            ms.WriteByte(0x00);
            ms.WriteByte(0x00);
            ms.WriteByte(0x00);

            //the vertical resolution of the image(4 bytes)
            ms.WriteByte(0x00);
            ms.WriteByte(0x00);
            ms.WriteByte(0x00);
            ms.WriteByte(0x00);

            //the number of colors in the color palette(4 bytes)
            ms.WriteByte(0x00);
            ms.WriteByte(0x00);
            ms.WriteByte(0x00);
            ms.WriteByte(0x00);

            //the number of important colors(4 bytes)
            ms.WriteByte(0x00);
            ms.WriteByte(0x00);
            ms.WriteByte(0x00);
            ms.WriteByte(0x00);
            #endregion

            #region Bitmap data
            for (int y = height - 1; y >= 0; y--)
            {
                for (int x = 0; x < width; x++)
                {
                    int pixel = bitmap.Pixels[width * y + x];

                    ms.WriteByte((byte)(pixel & 0xff)); //B
                    ms.WriteByte((byte)((pixel >> 8) & 0xff)); //G
                    ms.WriteByte((byte)((pixel >> 0x10) & 0xff)); //R
                    ms.WriteByte(0x00); //reserved
                }
            }
            #endregion


            return ms.GetBuffer();
        }

        #endregion 

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