const int CBM_INIT = 0x04;// /* initialize bitmap */
public static IntPtr Create32BppBitmap(Image sourceImage)
{
BITMAPV5HEADER bi = new BITMAPV5HEADER();
bi.bV5Size = (uint)Marshal.SizeOf(bi);
bi.bV5Width = sourceImage.Width;
bi.bV5Height = sourceImage.Height;
bi.bV5Planes = 1;
bi.bV5BitCount = 32;
bi.bV5Compression = BI_BITFIELDS;
// The following mask specification specifies a supported 32 BPP
// alpha format for Windows XP.
bi.bV5RedMask = 0x00FF0000;
bi.bV5GreenMask = 0x0000FF00;
bi.bV5BlueMask = 0x000000FF;
bi.bV5AlphaMask = 0xFF000000;
IntPtr hdc = User32.GetDC(IntPtr.Zero);
IntPtr bits = IntPtr.Zero;
// Create the DIB section with an alpha channel.
IntPtr hBitmap = Gdi32.CreateDIBSection(hdc, bi, (uint)DIB.DIB_RGB_COLORS,
out bits, IntPtr.Zero, 0);
var hMemDC = Gdi32.CreateCompatibleDC(hdc);
Gdi32.ReleaseDC(IntPtr.Zero, hdc);
var sourceBits = ((Bitmap) sourceImage).LockBits(
new Rectangle(0, 0, sourceImage.Width, sourceImage.Height), ImageLockMode.ReadOnly,
PixelFormat.Format32bppArgb);
var stride = sourceImage.Width*4;
for (int y = 0; y < sourceImage.Height; y++)
{
IntPtr DstDib = (IntPtr)(bits.ToInt32() + (y * stride));
IntPtr SrcDib = (IntPtr)(sourceBits.Scan0.ToInt32() + ((sourceImage.Height - 1 - y) *
stride));
for (int x = 0; x < sourceImage.Width; x++)
{
Marshal.WriteInt32(DstDib, Marshal.ReadInt32(SrcDib));
DstDib = (IntPtr)(DstDib.ToInt32() + 4);
SrcDib = (IntPtr)(SrcDib.ToInt32() + 4);
}
}
return hBitmap;
}
internal static extern IntPtr CreateDIBSection(IntPtr hdc, [In] BITMAPV5HEADER pbmi,
uint pila, out IntPtr ppvBits, IntPtr hSection, uint dwOffset);
