Re: Display vs. LockFocus and draw
Re: Display vs. LockFocus and draw
- Subject: Re: Display vs. LockFocus and draw
- From: Marco Binder <email@hidden>
- Date: Tue, 30 Jul 2002 11:32:36 +0200
>
display will also get sub views to draw as well as the parts of it
>
parent view that the view occupies, even if your image/drawing doesn't
>
have any explicit transparency you will probably find you drawing still
>
contains transparency due to aliasing. If you are trying to improve
>
response when dragging try using setNeedsDisplayInRect: and make sure
>
your view takes advantage of the NSRect parameter in drawRect:
Thanks for the response! Still...
the point is, that i DO NOT want the view to redisplay itself! I draw
something ontop of the view while dragging the mouse, and only when dragging
is done, I will have this object added to the elements, my view will draw
from inside its drawRect: method. But still, I need the view to draw its
"old" state just restore the background while dragging. It works nicely with
myView.lockFocus();
myView.drawRect(rect);
myObject.drawRect(rect);
myView.unlockFocus();
myView.setNeedsDisplay(false);
myView.unlockFocus();
myView.displayIfNeeded();
MyObject is only drawn after the displayIfNeeded()-call. So- if I d use
myView.display() or as suggested myView.setNeedsDisplayInRect(rect),
myObject would be erased again, since ist not yet part of the
myView.draw()-method.
So you see, it works the way I did it, but still I wonder WHAT display() is
doing in addition to locking the focus, drawing and unlocking again, as they
say in the docs.
marco
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