ScrDrawChars is an undocumented, low-level function that doesn't appear to be
used any more. Instead, the OS now takes a different path from WinDrawChars to
the low-level character drawing routines. Merely recompiling with the 3.5 SDK
will not change anything.
Not that I can recommend patching traps, but why not patch WinDrawChars instead?
-- Keith
[EMAIL PROTECTED] on 07/06/2000 01:09:12 AM
Please respond to "Palm Developer Forum" <[EMAIL PROTECTED]>
Sent by: [EMAIL PROTECTED]
To: "Palm Developer Forum" <[EMAIL PROTECTED]>
cc: (Keith Rollin/US/PALM)
Subject: Patching a trap in OS 3.5 vs. OS 3.0
Hi,
I hope I'm not repeating anything already discussed here.
I have a piece of code that used to patch ScrDrawChars trap for me. The problem
is, it's not working on PalmOS 3.5 anymore. When I try to debug my source codes,
the program never enters MyScrDrawChars() now, i.e. standard trap is being used.
Might be a stupid question, but: Do I need to recompile my project using SDK 3.5
for it to work on OS 3.5? And if I do so, will the
application still work on the older OS versions? Or is there something else that
I'm doing wrong.
Thanks,
Sebastian
--------------------------------------------------------
void (*OldScrTrap)(WinPtr, SWord, SWord,
SWord, SWord, SWord,
SWord, SWord, SWord,
CharPtr, Word, FontPtr);
extern void MyScrDrawChars(WinPtr pWindow, SWord xLoc, SWord yLoc,
SWord xExtent, SWord yExtent, SWord clipTop,
SWord clipLeft, SWord clipBottom, SWord clipRight,
CharPtr chars, Word len, FontPtr fontPtr)
{
// ...
// do some operations on chars
// ... and call the standard function:
(*OldScrTrap)(pWindow, xLoc, yLoc,
xExtent, yExtent, clipTop,
clipLeft, clipBottom, clipRight,
chars, len, fontPtr);
}
--------------------------------------------------------
// and this patches the trap at the beginning of my app
(VoidPtr)OldScrTrap = SysGetTrapAddress(sysTrapScrDrawChars); //0xa0ed
SysSetTrapAddress(sysTrapScrDrawChars, &MyScrDrawChars);
--------------------------------------------------------
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