James Chandler Jr wrote:
Hi Giuliano
The Carbon Lazarus works great with invalidate and the OnPaint events,
as far as I've been able to tell. Mac double-buffering on the screen
well-guarantees no flicker. And it is true that invalidate can be
called multiple times before the event loop gets around to calling
OnPaint.
But there is an expense with the double-buffering and 'delayed
flush'-- Sometimes this circuitous route involving many messages, can
cause 'slightly slow' screen updates. If an OnPaint does a lot of
drawing and calculating (which sometimes can't be done in advance),
the new screen draw appears very quick and clean onscreen, but there
is some latency where nothing happens on the screen, before this quick
clean change suddenly appears.
You can invalidate only the area that needs update using
LCLIntf.InvalidateRect. Then you can get the update rect using the
TLMPaint message. With this you can speed the drawing but will require a
more sophisticated algorithm to define what to draw.
Luiz
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