[lazarus] Jumping window bug
nc-gaertnma at netcologne.de
Mon Mar 18 05:00:10 EST 2002
On Mon, 18 Mar 2002 10:11:42 +0100
Michal Bukovjan <bukovjan at mbox.dkm.cz> wrote:
> This seems like a good fix (better than I could potentially come up
> with). It could also fix the problem that you cannot resize a form by
> changing its Width in Object Inspector, because for some reason, GTK
> fires resize request with original coords first and only after that a
> second request with new ones. The first request nullifies the effect of
> changing the Width property, effectively setting it back. (This also
> occured before my changes :-)
The gtk queues size messages and it sends size steps messages.
For example: doing 2 SetBounds, results in:
1. lcl sets bounds and sends mesg to gtk
2. lcl sets bounds and sends mesg to gtk
3. gtk sends mesg back for first coord. -> lcl resizes to old
4. gtk sends mesg back for second coord. -> lcl resizes to new
The user can not see this internal flickering. That's why I wrote, that the bugfix is incomplete. see devel list.
> Maybe couple of things :
> - we could move the WMSize / WMMove message back to TWinControl
> altogether (from TControl). It was originally there.
I vote for that.
> - I was thinking about removing WMWindowPosChanged message altogether.
> It is provided because of Windows compatibility, and duplicates WMSize /
> - In addition to BoundsChanged virtual procedure, adding a SizeChanged
> and PosChanged virtual methods for notifications. Thus we could remove
> the WMSize / WMMove entirely and the code would get much more
> straightforward right away (and portable). Sure, it would break some
> compatibility with existing Win32 code, but I noticed that Inprise did
> the same with CLX (no WM* messages anymore) and the compatibility fix
> would be to inherit from these new methods instead of messages. The WM*
> message handling then would move to Win32 interface object, where it
> actually belongs.
I never liked the WM* messages. But removing them, would break compatibility with almost all delphi components. How should the new methods look like?
> Did you notice that although WMSize is declared as protected, TSynEdit
> redeclares it as private, calls inherited, and it *STILL* works? Weird :-)
Normal object pascal behaviour. IMO it's very useful.
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