site_archiver@lists.apple.com Delivered-To: cocoa-dev@lists.apple.com On Feb 1, 2011, at 4:32 AM, Roland King wrote:

I have a UIView subclass in my iOS app and the content for that UIView is 3 CALayers, each with a bitmap image for their content, added as sublayers of the UIView's layer. Each of the CALayers is the full size of the UIView's layer (they have transparency to composite them together).

When the UIView is resized the setFrame: method is called and I have a custom implementation of that which sets the bounds of the sublayers so they again fill the UIView's layer, and draws a new bitmap for each of them of the right size and sets it into their contents.

However, when I resize, there's a brief flash of the current content, before it's been redrawn, stretched to fill the new sized window, before the new content replaces it. Nothing I've tried has been able to stop that brief flash and I can't figure out where it's coming from.

I suppose my first question is why not just use UIViews instead? They should already abstract all of what you need to make this work away from you, and you should only need to set the view's contentMode property to UIViewContentModeRedraw to get the behavior you seem to desire. Then it would just be a matter of teaching the UIViews how to draw themselves to generate their own content instead of having the parent UIView do so and push it to them. As for overall, I'm not entirely certain what is happening, but it sounds like you have a timing issue, possibly one where the view's are resized on one runloop invocation and their contents replaced on the next. Instead of overriding -setFrame: you should override -layoutSubViews: which should catch more cases where layout is needed and allow you to do the work you need at the right time. -- David Duncan _______________________________________________ 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: http://lists.apple.com/mailman/options/cocoa-dev/site_archiver%40lists.apple... This email sent to site_archiver@lists.apple.com