Rollback drawRect:

Is there any way to quit from drawRect: without refresh the current UIView? For example:

- (void)drawRect:(CGRect)rect {

CGContextRef context = UIGraphicsGetCurrentContext();

CGContextSetRGBStrokeColor(context, 1.0, 1.0, 1.0, 1.0);
CGContextSetLineWidth(context, 2);

CGContextMoveToPoint(context, 10.0, 30.0);
CGContextAddLineToPoint(context, 310.0, 30.0);
CGContextStrokePath(context);


//I w开发者_如何学运维ould like to return from here and rollback all changes in drawRect:

}

Thanks!

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If you haven't started drawing into the context, it might be possible to just return from drawRect:. You'd have to set the clearsContextBeforeDrawing property of the view to NO before.

After starting to draw in the context, the view/layer will always update its content.