Re: Quickly Moving Views

• Subject: Re: Quickly Moving Views
• From: John Randolph <email@hidden>
• Date: Wed, 16 Jul 2003 13:46:30 -0700

- (void)scrollRect:(NSRect)aRect by:(NSSize)offset
Copies the visible portion of the receivers rendered image within aRect and lays that portion down again at offset from aRects origin. This method is useful during scrolling or translation of the coordinate system to efficiently move as much of the receivers rendered image as possible without requiring it to be redrawn, following these steps:
Invoke scrollRect:by: to copy the rendered image.

Move the view objects origin or scroll it within its superview.

Calculate the newly exposed rectangles and invoke either setNeedsDisplay: or setNeedsDisplayInRect: to draw them.

You should rarely need to use this method, however. The scrollPoint:, scrollRectToVisible:, and autoscroll: methods automatically perform optimized scrolling.

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