Donald C. Kirker wrote:
Does anyone have any suggestions?
I have tried to retrieve the window's bitmap with WinGetBitmap and then
compressing the bitmap that it returns, but it seems that whenever I try to
draw to it I get a fatal exception.
There seem to be restrictions on what you can do with windows backed
by compressed bitmaps. For instance, the documentation for
WinCopyRectangle() says this:
If the destination bitmap is compressed, the mode parameter
must be winPaint, and the destination coordinates must be (0,0).
If the width of the destination rectangle is less than 16 pixels
or if the destination coordinates are not (0,0), then this function
turns off compression for the destination bitmap. Normally, you do
not copy to a compressed bitmap. Instead, you copy to an
uncompressed bitmap and compress it afterwards.
To me, this implies that whatever routines draw to windows (and write
to the underlying bitmaps) don't handle the general case.
It seems like a valid sequence would be something like this:
1. create offscreen bitmap, uncompressed.
2. wrap with a window by using WinCreateBitmapWindow().
3. do all the drawing you need to do.
4. remove the window wrapping by doing WinDeleteWindow().
5. call BmpCompress() on the resulting bitmap.
This is not going to be suitable for all purposes, but it should
work in cases where you want to create the bitmap and then leave
it alone for some reason (like if you were drawing a map or
something along those lines).
- Logan
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