David,
At 12:00am -0800 00-02-12, Palm Developer Forum digest wrote:
>Subject: Color bitmaps on the fly and compression
>From: David Tribble <[EMAIL PROTECTED]>
>Date: Fri, 11 Feb 2000 16:57:38 -1000
>X-Message-Number: 88
>
><disclaimer> I know I'm looking for help on "System Only" stuff =
></disclaimer>
>
>I'm converting GIFs to color BitmapTypes, but can't fit GIFs that are =
>bigger than 250 x 250 pixels (or thereabouts) unless I compress them.
Right...250x250x1 byte/pixel is approximately 64K, thus you're
running up against the max chunk size limit.
>But I can't get the compression to work for me. I set up my version 2 =
>bitmap with flags.compressed =3D 1 and compressionType =3D =
>BitmapCompressionTypeScanLine . I use the ScrCompressScanLine to =
>compress a scan line. But when I try to use WinDrawBitmap, it dies on =
>the emulator with the "just read directly from memory manager =
>structures". Probably my fault, but I should ask: is =
>ScrCompressScanLine ok to use with version 2 bitmaps and is =
>compressionType =3D BitmapCompressionTypeScanLine the right choice?
1. There are definitely some parts of the OS that assume compression
of color bitmaps will be RLE, but I don't know if that's the problem
you're running into.
2. Normally one would use BmpCreate/BmpCompress (available in 3.5),
but that doesn't solve your 64K limit problem, and all of the data
has to be in the dynamic heap - which might be a problem for big
color bitmaps.
3. So then one solution would be to use
ScrCompress(BitmapCompressionTypeRLE, ...) to compress scanline by
scanline. But a question would be why you're compressing on the
device?
-- Ken
Ken Krugler
TransPac Software, Inc.
<http://www.transpac.com>
+1 530-470-9200
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