Ok. So I have some more info on this problem. The problem is that 16-bit transparency does not work properly on OS 5.0. This problem seems to be fixed in OS 5.1.
On OS 5.0, -16-bit transparency only works for black. If you use a non-zero color for the transparency, it will not be honored in WinDrawBitmap or WinPaintBitmap. Workaround: -I found a "less than ideal" workaround for this problem. What I do is create an offscreen window and set the transparency for this window manually using BmpSetTransparency. It seems to take a 16bit value created from an rgb value (5 bits of red, 6 bits of green, 5 bits of blue). I then use WinDrawBitmap or WinPaintBitmap to move the bitmap from my resource to this window. After that, I use WinCopyRect (winPaint mode) to move this bitmap from the offscreen window to the final destination window. WinCopyRect seems to honor the transparency properly. If someone has a better workaround - please let me know. It bothers me to have to alloc an offscreen window just make sure transparency works properly. Thanks to Andy Stewart at PalmSource for his help. -Mark On Thu, Oct 31, 2002 at 11:59:06AM -0800, Mark Palatucci wrote: > Hello, > > I am having an interesting transparency problem when I run my > application on the new Tungsten T device. > > I have certain bitmaps that use (255,0,255) as a transparency > color. On the TT (which I got yesterday), the transparent color is > actually painted over whatever is below it! While this creates some > interesting visuals, it is not quite what I'm looking for..:) > > This problem does not occur in the OS 5 simulator (debug or release > roms) or any color OS 4.x devices. > > Has anyone else encountered this problem? > > Some additional info: > -I am not using any double density bitmaps > -All my bitmaps are 16bit. > -My app only runs on 16bit or higher color devices. > > My guess here is that the blitter that scales the single density > bitmaps does not properly handle the transparency. Since I paint into > an offscreen window (using nativeFormat) first - perhaps my window > type is wrong? > > Any ideas would be most appreciated.. > > -Mark > > -- > For information on using the Palm Developer Forums, or to unsubscribe, please see >http://www.palmos.com/dev/support/forums/ -- For information on using the Palm Developer Forums, or to unsubscribe, please see http://www.palmos.com/dev/support/forums/
