"Douglas Handy" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] > "Set up an uncompressed offscreen bitmap, then use WinCopyRectangle to > decompress the first bitmap into the second."
In the end, this is probably the way you will have to go. > The reason I don't want to do that is because what I'm trying to do is access > the color indexes of various pixels in a bitmap resource, even when running on a > non-color device. So I compute the location of the bit(s) in the bit data > portion and read them directly. > > It all works fine when the bitmap is not compressed. When it is compressed, I > figured it easier to try to use BmpCompress() to uncompress it rather than > decode the compression myself. This stands to reason. > I was anticipating that BmpCompress() would run on non-color devices (of at > least OS 3.5) even though I wouldn't expect to be able to make windows with > higher bit depth than the device supports. How can I use WinCopyRectangle() if > I can't get a color depth capable window on non-color devices? > Or can you? Will WinCreateBitmapWindow() allow that? The color depth support is independent of the device capability, so as long as the OS supports greater color depths, you can always create offscreen windows/bitmaps of any color depth you like, provided there is enough memory. > It just seemed like uncompressing the bitmap and then reading the pixels I want > was the most efficient manner of achieving the desired end, but I can't get > BmpCompress() to accept the arguments even though I seem to meet the criteria > specified in the API docs. Is there any possibility that the uncompressed bitmap size exceeds available memory? It's unlikely that is the problem, but I just wanted to make sure. Are you performing your testing on an OS5 device? If so you might want to read about PACE shadow structures. For more information on shadow structures go to http://kb.palmsource.com/cgi-bin/palmsource.cfg/php/enduser/std_alp.php and do a search on 'bitmap', then select the 'OS 5 High Density Overview' white paper, then scroll down to the question titled 'How do I create a bitmap at runtime whose bits I can access directly?' and read. Hope this helps! -Robert -- For information on using the Palm Developer Forums, or to unsubscribe, please see http://www.palmos.com/dev/support/forums/
