I am noticing some things that aren't what I expected in terms of bitmap versions and
need some clarification.
1) The documentation (Palm OS Companion pg. 104) says that PalmRez creates version 1
bitmaps unless compression or transparency is specified. However, I noticed that the
same is not true of OS 3.5. When calling WinGetBitmap, it always returns version 2 in
the bitmap field, even though compression and transparency are not specified, and even
if the pixelSize is 1. This bitmap will draw fine on a Palm OS 3.0 device, and even a
Palm OS 2.0 device. So why is the version number set to 2?
2) The doc says the bitmaps in version 1 format are supported by Palm OS 3.0 and
above, but I noticed that trying to draw a bitmap with a bit depth larger than the
window depth will crash the Palm in pre OS 3.5. Which begs the question, what really
does the version number mean if you can create a version 1 bitmap that isn't supported
in Palm OS 3.0? Or is it the version 1 bitmaps REQUIRE a black and white bitmap as the
first bitmap in the bitmap chain.
3) What are the differences between the bitmap version numbers. From the above, and
the doc, here is what I am guessing, but the doc isn't explicit on these.
Version 0: Supports muliple bit depths and chaining of chaining of multiple
bitmaps with multiple bit depths. But you can't just draw a non black & white bitmap
on any device.
Version 1: Supports color tables too.
Version 2: Supports RLE compression and transparencies. Always works in OS 3.5,
and may or may not work in previous OS's depending on the bit depth.
4) What do you have to do to insure that a bitmap will draw on a device? It looks to
me like just examining the version number of the bitmap isn't going to tell you what
you want to know.
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