Lazarus

Programming => General => Topic started by: fcu on October 20, 2020, 03:47:44 pm

Title: ttrackbar flickering
Post by: fcu on October 20, 2020, 03:47:44 pm
Hi
seems ttrackbar is not benefit from DoubleBuffered option event if its explicitly turned on
its the only component that flickering when resizing the form , the rest of controls is fine
i am using lazarus 2.0.10 & fpc3.2 ( windows7 32bits )

Title: Re: ttrackbar flickering
Post by: jamie on October 20, 2020, 11:01:34 pm
I don't see that on the trunk nor the release., or even older ones I have installed.

This is tested on windows 10...

 the trackbar is a native control so native control so maybe the difference in os ?
Title: Re: ttrackbar flickering
Post by: trev on October 21, 2020, 12:51:49 am
I seem to recall that there was another recent flickering thread about this or another component. Whether the flickering was noticed  depended on the speed of the individual's computer hardware.

Found it: see this thread (https://forum.lazarus.freepascal.org/index.php/topic,50042.msg364389.html#msg364389).
Title: Re: ttrackbar flickering
Post by: jamie on October 21, 2020, 01:59:16 am
I think we need a strip down demo to show this effect.

it could be that it is anchored to other controls and things are going awry
Title: Re: ttrackbar flickering
Post by: fcu on October 21, 2020, 01:51:07 pm
i recorded the issue
https://ibb.co/D5yrkjq
Title: Re: ttrackbar flickering
Post by: fcu on October 21, 2020, 02:04:55 pm
this is really weird
after adding a menu to the main form the trackbar stops flickering and the menu start flickering

https://ibb.co/99HMYtp
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