Excellent hint! Here is the problem/resolution for these who hit the same
wall (and will search the archives) ;-)
The problem came from a NULL pointer in the form's window structure. The
debug ROMs does not support the Window structure field AddrV20; in the
source code it says it is cleared on purpose to enforce engineers use the
proper API (thanks, Roger).
We needed that field to obtain the address of the memory allocated for the
form so we can perform faster BitBlt there (our own version of DrawBitmap).
The proper way to address the issue seems to be to obtain the pointer to the
bitmap structure for the appropriate window using BmpGetBits().
While working on that one, I also found another something: we use a blank
form to create as a main window, then do our animation inside. Noting
standard is used from that form, besides its physical boundaries and the
creation process. We did not use FrmDrawForm() in the form load event, for
example, because there was nothing there to be drawn; instead, we used to
draw our stuff manually. This had caused crash on the DEBUG ROMs, and the
reason was that the form was not made active! FrmDrawForm(), which is
normally called the first time when the form is loaded, contains a check
whether the form being drawn is currently active and activates it if it is
not. Skipping that call as we used to, will make the DEBUG ROMs unhappy
(forget certification then!). Using FrmSetActiveForm() resolves the problem.
Thanks Aaron, David and Roger
- bobby
-----Original Message-----
From: David Fedor [mailto:[EMAIL PROTECTED]]
Sent: Thursday, January 25, 2001 12:37 PM
To: Palm Developer Forum
Subject: RE: BUG: (OS 4.0 beta, efig & Japanese ROMs) Setting ScrDisplayMo
de depth crashes
Have you tried this on dr3? I know the system works in 2-bit mode in
general, but there could be something else going on. (For example, does
the rom you're running on advertise that it works in 2-bit mode? Does that
same code work on a 3.5 debug rom? I'm not sure what your collection of "20
other roms" includes... other 4.0 debug roms?)
Where's the crash occurring? A stack trace always helps.
-David Fedor
Palm Developer Support
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