Not that this answers your question, but as graham eluded to, there aren't a lot if choices. I'd look into showing a progress indicator or look into tiling. GL
Please excuse mobile typos On May 15, 2013, at 6:44 PM, Graham Cox <graham....@bigpond.com> wrote: > > On 16/05/2013, at 11:29 AM, li shunnian <sonofsky2...@gmail.com> wrote: > >> I implement drawRect of a subclass of UIView. I found view will update whole >> bounds when I switch from another app to myapp. Because I draw a cgimage on >> the view's bounds, it cost lots of time. Are there some properties of view >> or layer to make the update rect not to be whole bounds? > >> My app is a painter, the image is used for back buffering. When dragging, I >> calculate the points between the previous point and now point, and draw a >> small image on the back buffer image. Then update the back buffer image to >> the view. > > > I can't see you have any choice - at times the view will need to refresh its > whole bounds, and if that means drawing the whole image, you will have to do > that, or else end up with blank areas which I'm sure you don't want. If the > view is within a scroller, then it should only ever refresh the visible > portion. > > If it's slow, perhaps you ought to investigate why. Are you scaling or > transforming the image? How do you do the drawing? Show code. > > --Graham > > > > _______________________________________________ > > Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) > > 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: > https://lists.apple.com/mailman/options/cocoa-dev/cody%40servalsoft.com > > This email sent to c...@servalsoft.com _______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) 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: https://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
