[Lazarus] MySQL Access

Terry A. Haimann terry at HaimannOnline.com
Sat Oct 18 17:40:47 CEST 2008


On Sat, Oct 18, 2008 at 22:50, Darius Blaszyk <dhkblaszyk at zeelandnet.nl> wrote:
>> to increase the amount of visible credits, but the the animated area does
>> not grow with the dialog, which looks rather amateurish, if you pardon
>> the expression.
> This was fixed in r17035
I see. Sorry about the noise.
My internet connection is not fast enough to follow Lazarus
development speed ;-)

>The flicker I cannot reproduce myself, not even on windows.
It is more or less known issue, even in Delphi.
It is caused by the fact that Windows (and possibly GTK as well,
judging by the existence of the same issue there)
sends WM_ERASEBKGND message before WM_PAINT message and (sometimes)
displays the control in the state between messages.
To solve this, Delphi has introduced DoubleBuffered(?) form property.
To check this issue, you can use attached (debug-only!) patch which disables
background erasing for AboutFrm. You can see that TImage with
mini-logo stops flickering
and the flicker of page control is reduced (because the control itself
still processes WM_ERASEBKGND).
Of course, this comes at a price of "transparent" form, so it is not a
proper solution.

-- 
Alexander S. Klenin
Insight Experts Ltd.
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