To answer my own question: draw to a bitmap offscreen, and then draw that into the UIView rect. The bitmap isn't cleared (unless done explicitly).
brad http://music.columbia.edu/~brad On May 30, 2010, at 2:36 PM, Brad Garton wrote: > Hello cocoa-dev list: > > My apologies if this is incorrect and/or totally misinformed for this list, > but I seem to be missing something obvious. In my application I've > subclassed UIView and use the -drawRect:/-setNeedsDisplay approach to draw > lines into the view. Is there a way to set up the drawing such that it adds > to the existing image instead of redrawing all of it? For example, if I > generate a random line in each -setNeedsDisplay invocation of -drawRect, I'd > like to retain in the resulting image the lines previously drawn. > > thanks-- > > brad > http://music.columbia/edu/~brad > _______________________________________________ Cocoa-dev mailing list ([email protected]) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to [email protected]
