At 12:00am -0700 00-09-27, Palm Developer Forum digest wrote:
>Subject: exact specification for image compression types needed
>From: Bill Janssen <[EMAIL PROTECTED]>
>Date: Tue, 26 Sep 2000 19:00:54 PDT
>X-Message-Number: 94
>
>Hi. I'm working on a project which would create Palm Tbmp images. We
>need to know the specifics of the ScanLine and RLE compression
>formats. Can anyone point me to a specification? If not, can someone
>please state the specification of these two compression types?
>Thanks.
Code for the scanline compression scheme is at
<ftp://ftp.transpac.com/bitmaps>, in the BitmapUtil.c source file.
The RLE compression is a simple sequence of <repeat count><byte of
data>, where the repeat count byte will be 1...255. I believe support
for RLE compression was added in 3.5.
While only the scanline compression algorithm requires that
compression be done scanline-by-scanline, in practice both process
scanlines as chunks - which means that bitmaps using the RLE
compression won't collapse a sequence of identical bytes across a
scanline boundary.
-- Ken
Ken Krugler
TransPac Software, Inc.
<http://www.transpac.com>
+1 530-470-9200
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