Save the bitmap under the area you will be overwriting before you draw your
bitmap.
To erase, restore the saved bits.
I am not completely familiar w/ the new color capabilities: is it possible
to
define a "transparent" color with the new bitmaps? If not, you will have
to define a separate transparency map and do a bunch of bit-munging
instead of a nice simple API call if you want to have any sort of overlay
capability.
But to erase -- just save the image under the drawing area before you draw.
--
-Richard M. Hartman
[EMAIL PROTECTED]
186,000 mi/sec: not just a good idea, it's the LAW!
revcom wrote in message <7967@palm-dev-forum>...
>
>Hi there, I hope someone can help me...
>
>I have a bitmap that I wish to move around the screen. When in monochrome,
I
>drew it offscreen and used WinCopyRectangle with mode of srcXOR (from
>memory) to alternately draw and erase it.
>
>WIth colour, (bitmap is green and white only) it works fine on a white
>background but the green colour becomes purple when shown against a black
>background.
>
>I've tried all the other winXXX drawing modes and also switched to using
>WinPaintBitmap directly to the screen as the documentation suggests - all
to
>no avail.
>
>Is there some way I can draw and erase a bitmap onto a variety of coloured
>backgrounds whilst still maintaining its original colouring?
>
>Thanks for your help,
>
>
>Robert Crago
>Revelation Computing Pty Limited
>PO Box 459, ASPLEY
>Brisbane, Australia 4034
>
>
>
--
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