Bob, your site is so helpful, thanks for taking the time to organize and share all that stuff

"Bob Powell [MVP]" <bob (AT) _spamkiller_bobpowell (DOT) net>

Hi James,

Here is the C# code, it works fine in VB since you don't need any pointers,
you just modify integers in the pixels array. Don't forget to Free the
handle when you are completely finished with the bitmap. The "pixels" array
is an array of uint (unsigned integer). You can use signed integer but it is
more tricky to deal with the top bit. You can access the blue channel with a
0xFF mask, green with 0xFF00, etc. Or you can use an array of bytes, but
that isn't as fast.

// 4 bytes per pixel, format: ARGB
pixels = new uint[width * height];

// if not pinned the GC can move around the array
handle = GCHandle.Alloc(pixels, GCHandleType.Pinned);
IntPtr pointer = Marshal.UnsafeAddrOfPinnedArrayElement(pixels, 0);
bitmap = new Bitmap(width , height, width * 4,
PixelFormat.Format32bppPArgb, pointer);

To access a pixel on the bitmap at x and y:

pixel at (x,y) = pixels[width * y + x]

Any modification to that array modifies the bitmap directly. No marshall or
copy needed.

Regards,
Frank Hileman

check out VG.net: http://www.vgdotnet.com
Animated vector graphics system
Integrated Visual Studio graphics editor

"James Maeding" <jmaeding (AT) nettaxi (DOT) com> wrote