I'm using Core Image filters to apply real-time effects to vector objects. I've run into the problem of determining just how much space I need to accommodate any given effect. Currently I just add a fixed percentage to the bounds I start with, but it's actually inadequate to do this for many effects, which frequently end up running off the edges of the space allotted.
The vector objects have a defined bounds which fully encloses all drawing that they do. When these objects are altered, that bounds is used to refresh just that part of the view as needed. When a CI Filter is applied, I use that bounds, multiply it by some scaling factor, and use that to create an offscreen image into which the vector object plus its CI effect is rendered. The resulting image is then drawn in the view. The needed space for a given effect varies depending on the effect and its parameters, but I see no way to compute that reliably. If I make the bounds some enormous scale-up of the original bounds to accommodate any potential effect, performance suffers dramatically because of all the wasted area of the view that has to be updated. Is there any way to preflight a Core Image filter effect so I know how much space I'll need to draw it? --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: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
