[Lazarus] Smooth scrolling label (marquee)

Luca Olivetti luca at wetron.es
Wed Nov 11 10:49:38 CET 2015

El 11/11/15 a les 10:28, Graeme Geldenhuys ha escrit:

> On 2015-11-11 09:16, Luca Olivetti wrote:
>> Try the attached project.
> LCL inconsistency strikes again.
>     WindowState:=wsMaximized;
> The above line of code has no affect under FreeBSD with LCL-GTK2. I see
> a small borderless window with a button on it.

Thank you for testing.
Yes, but that's not relevant. I put it there just to do the same the 
real app is doing. It also behaves differently with linux-gtk (it 
maximizes) and linux-qt (it doesn't).
Also, on linux-gtk2 I tried up to size 300 and more, while linux-qt 
starts becoming slow at 49.

> Anyway, I tested your project under FreeBSD LCL-GTK2 and Windows 2000.
> Scrolling was smooth (with one exception) and CPU load was idle (< 1%).
> Under Win2000 the application was full-screen, under FreeBSD it wasn't.

OK, windows 2000 probably behaves like windows xp.

> Having the modal quit dialog open did not affect the scrolling speed. I
> also couldn't see any visible change in speed while moving the mouse.

Yes, that's normal, I'm using a timer. The visible change in speed was 
when I was using a thread with synchronize.

> The exception I mentioned was when I run the test project under Win2000
> with the --debug option. There was visible flicker the whole time while
> the application was running.

Strangely (or not) enough, it depends on the theme. With XP I see the 
flickering if I use the classic theme, no flickering with the 
teletubbies one.

Luca Olivetti
Wetron Automation Technology http://www.wetron.es/
Tel. +34 93 5883004 (Ext.3010)  Fax +34 93 5883007

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