I think Jesse has provided sufficient information for you. Well, you can also refer the following codes which also include the design time methods.
If you are also trying to create a design time control, the method would give you a better looking object when you are designing on VS2008.
#region ===== Copy Graphics =====
/// <summary>
/// Copy source <see cref="System.Drawing.Graphics"/> to destination <see cref="System.Drawing.Graphics"/> with specified width and height
/// </summary>
/// <param name="gxSrc">The soruce graphic object</param>
/// <param name="gxDst">The destination graphic object</param>
/// <param name="width">The copy width</param>
/// <param name="height">The copy height</param>
public static void CopyTo(this Graphics gxSrc, Graphics gxDst, int width, int height)
{
gxSrc.CopyTo(gxDst, new Rectangle(0,0,width,height));
}
/// <summary>
/// Copy source <see cref="System.Drawing.Graphics"/> to destination <see cref="System.Drawing.Graphics"/> with specified width and height
/// </summary>
/// <param name="gxSrc">The soruce graphic object</param>
/// <param name="gxDst">The destination graphic object</param>
/// <param name="bounds">The copy bounds</param>
public static void CopyTo(this Graphics gxSrc, Graphics gxDst, Rectangle bounds)
{
IntPtr dstDc = gxDst.GetHdc();
IntPtr srcDc = gxSrc.GetHdc();
if (Environment.OSVersion.Platform == PlatformID.WinCE)
NativeMethods.BitBltCE(dstDc, 0, 0, bounds.Width, bounds.Height, srcDc, bounds.X, bounds.Y, (uint)TernaryRasterOperations.SRCCOPY);
else
NativeMethods.BitBltWin(dstDc, 0, 0, bounds.Width, bounds.Height, srcDc, bounds.X, bounds.Y, (uint)TernaryRasterOperations.SRCCOPY);
gxSrc.ReleaseHdc(srcDc);
gxDst.ReleaseHdc(dstDc);
}
#endregion
#region ===== Draw Alpha =====
/// <summary>
/// Draws an image with opacity
/// </summary>
/// <param name="gxDst">The destination graphics</param>
/// <param name="image">The sourece image</param>
/// <param name="opacity">The opacity value</param>
/// <param name="x">The drawing x location</param>
/// <param name="y">The drawing y location</param>
public static void DrawAlpha(this Graphics gxDst, Image image, byte opacity, int x, int y)
{
gxDst.DrawAlpha(image, opacity, new Rectangle(x, y, image.Width, image.Height));
}
/// <summary>
/// Draws an image with opacity
/// </summary>
/// <param name="gxDst">The destination graphics</param>
/// <param name="image">The sourece image</param>
/// <param name="opacity">The opacity value</param>
/// <param name="destRect">The destination rectangle. The image will fit into this rectangle.</param>
public static void DrawAlpha(this Graphics gxDst, Image image, byte opacity, Rectangle destRect)
{
if (Environment.OSVersion.Platform == PlatformID.WinCE)
{
try
{
using (Graphics gxSrc = Graphics.FromImage(image))
{
IntPtr hdcDst = gxDst.GetHdc();
IntPtr hdcSrc = gxSrc.GetHdc();
BlendFunction blendFunction = new BlendFunction
{
BlendOp = (byte)BlendOperation.AC_SRC_OVER, // Only supported blend operation
BlendFlags = (byte)BlendFlags.Zero, // Documentation says put 0 here
SourceConstantAlpha = opacity, // Constant alpha factor
AlphaFormat = (byte)0 // Don't look for per pixel alpha
};
NativeMethods.AlphaBlendCE(
hdcDst, destRect.X, destRect.Y, destRect.Width, destRect.Height,
hdcSrc, 0, 0, image.Width, image.Height,
blendFunction);
gxDst.ReleaseHdc(hdcDst); // Required cleanup to GetHdc()
gxSrc.ReleaseHdc(hdcSrc); // Required cleanup to GetHdc()
return;
}
}
catch (Exception ex)
{
throw new BCD.ComponentModel.Win32Exception(ex);
}
}
DrawAlphaWin(gxDst, image, opacity, destRect);
}
/// <summary>
/// Draw Alpha Blending in design mode
/// </summary>
/// <param name="gxDst">The destination graphics</param>
/// <param name="image">The sourece image</param>
/// <param name="opacity">The opacity value</param>
/// <param name="destRect">The destination rectangle. The image will fit into this rectangle.</param>
internal static void DrawAlphaWin(this Graphics gxDst, Image image, byte opacity, Rectangle destRect)
{
// cheat the design time to create a bitmap with an alpha channel
using (Bitmap tempBitmap = new Bitmap(image.Width, image.Height, (PixelFormat)PixelFormatID.PixelFormat32bppARGB))
{
// copy the original image
using (Graphics tempGx = Graphics.FromImage(tempBitmap))
{
tempGx.DrawImage(image, 0, 0);
}
// Lock the bitmap's bits.
Rectangle rect = new Rectangle(0, 0, tempBitmap.Width, tempBitmap.Height);
System.Drawing.Imaging.BitmapData bmpData =
tempBitmap.LockBits(rect, System.Drawing.Imaging.ImageLockMode.ReadWrite,
(PixelFormat)PixelFormatID.PixelFormat32bppARGB);
// Get the address of the first line.
IntPtr ptr = bmpData.Scan0;
// Declare an array to hold the bytes of the bitmap.
// This code is specific to a bitmap with 32 bits per pixels.
int bytes = tempBitmap.Width * tempBitmap.Height * 4;
byte[] argbValues = new byte[bytes];
// Copy the ARGB values into the array.
System.Runtime.InteropServices.Marshal.Copy(ptr, argbValues, 0, bytes);
// Set every alpha value to the given transparency.
for (int counter = 3; counter < argbValues.Length; counter += 4)
{
argbValues[counter] = opacity;
}
// Copy the ARGB values back to the bitmap
System.Runtime.InteropServices.Marshal.Copy(argbValues, 0, ptr, bytes);
// Unlock the bits.
tempBitmap.UnlockBits(bmpData);
using (ImageAttributes attr = new ImageAttributes())
{
attr.SetColorKey(Color.Black, Color.Black);
//gxDst.DrawImage(tempBitmap, x, y);
gxDst.DrawImage(
tempBitmap,
new Rectangle(destRect.X, destRect.Y, destRect.Width, destRect.Height),
0, 0, tempBitmap.Width, tempBitmap.Height,
GraphicsUnit.Pixel, attr);
}
}
}
How to copy original graphics to a temporary graphics?
