At 6:31 PM +0100 2000/03/07, Aaron Ardiri wrote:
> i am updating some of my programs for os 3.5 (finally got some time)
> and i have noticed that WinDrawBitmap() is terribly slow with os 3.5!
>
> when i use the same code on anything prior to 3.5 - the bitmaps draw
> ultra fast.. however, on 3.5 devices (and roms) the display is done
> as one hugely slow sweepline
Could you be a bit more specific (pardon the pun)? Terms like "terribly slow" and
"hugely slow" are awfully subjective. If you're comparing draw performance at 8 bits
per pixel to 1 bit per pixel, then yes, more bits will require more time.
> has anyone seen this? is there a remedy!?
>
> my Palm III, IIIx and V have been updated to 3.5 - and under all modes,
> (1bpp, 2bpp and 4bpp where available) the drawing is slower!?
An inevitable side-effect of a more "generic" blitter. Maximum speed is obtained when
the source and destination bitmaps use the same number of bits per pixel, share the
same [system] palette, and use the standard copy transfer mode. Any other combination
requires re-mapping every pixel, with varying degrees of "faster" and "slower"
depending on the transforms involved. Currently the blitter is not very optimized, but
we're working on that. Special-casing each combination for maximum performance is, as
you can imagine, a very large and complex task. Code bloat quickly becomes a serious
concern.
Regards,
Jim Schram
Palm Incorporated
Partner Engineering
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