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Manuel Elko
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 Posted: Wed Aug 18, 2004 6:07 am Post subject: Give me a hint on how optimeze or write better... |
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Hi 2 U all first of ALL!
Well, a problem rised in me 2 days ago!
Let me explain U:
I Know that a class derived from TGtraphicControl need the PAINT
method to be redefined to allow right working.....
So I've got a Paint. The problem is that my CONTROL goes on updating
time to time datas that must be painted, but not all datas need to be
repainted, but i need persistency of objects and datas on the
screen....
So, to be faster, and not to Repaint (paint) everything, how can i
implement a fine way to find the solution to this problem?
thank'a.
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DialTone
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| Posted: Wed Aug 18, 2004 8:59 pm Post subject: Re: Give me a hint on how optimeze or write better... |
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| Quote: | So, to be faster, and not to Repaint (paint) everything, how can i
implement a fine way to find the solution to this problem?
thank'a.
|
Not sure I totally understand, but I think what you need is to be
checking ClipRect to determine what needs to be repainted.
Assuming you have a class which has a property called "BackDrop" which is
an instantiated TImage, then you could draw the image onto your class
like this...
procedure TMyControl.Paint;
begin
if (BackDrop.Canvas <> nil) then
Canvas.CopyRect(Canvas.ClipRect, BackDrop.Canvas,
Canvas.ClipRect)
else begin
Canvas.Brush.Color:=clBtnFace;
Canvas.Brush.Style:=bsSolid;
Canvas.FillRect(Canvas.ClipRect);
end;
end;
Also, setting the ControlStyle in the constructor...
constructor TMyControl.Create(AOwner: TComponent);
begin
inherited Create(AOwner);
ControlStyle:=[csCaptureMouse, csClickEvents, csSetCaption,
csDoubleClicks, csOpaque];
end;
Can also help (it's the csOpaque that is important) - this tells VCL that
the control fills its rectangle, so it doesn't bother to try to redraw
controls beneath your control (so you get no flickering)
Not sure if that helps?
Tony
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