[Lazarus] TAChart: double-buffering (issue 0012377) questions

[Alexander Klenin]

On Sat, Dec 13, 2008 at 09:57, Mattias Gaertner
<nc-gaertnma at netcologne.de> wrote:
> On Fri, 12 Dec 2008 19:38:55 +1000
> "Alexander Klenin" <klenin at gmail.com> wrote:
>> The only caveat is that TChart is now TWinControl -- can it lead to
>> some undesirable consequences I am not aware of?
>
> All direct TWinControl descendants must be implemented in all widgetsets.
> You can use TCustomControl.

Sorry, I mixed up the mail (but not the patch). I already used TCustomControl.

>> 1) TWinControl.WMPaint already contains double-buffering code, but it
>> is protected
>> by {$ifdef BUFFERED_WMPAINT}. What is the reason of this? Is there
>> some ongoing work to implement double-buffering globally?
>
> It was an idea to implement double buffering, but it does not work on
> all platforms. Gladfully most widgetsets have double buffering themselves.

But, apparently, not Win32, at least on WindowsXP.

>> 2) If double-buffering will be implemented in TAChart itself, it will
>> have some negative
>> performance impact. So, should I make it optional via DoubleBuffer
>> property?

So this question remains. Or should I protect double-buffering with
{$IFDEF WIN32}?

-- 
Alexander S. Klenin
Insight Experts Ltd.