> On Nov 14, 2017, at 8:11 PM, Rick Mann <rm...@latencyzero.com> wrote: > > Maybe, at least for the bonus question. The bigger question is around the > copy.
Where pixmaps live is a pretty complex issue — ideally they live in the GPU’s address space as textures so they can be blitted efficiently, and that’s often (depending on your hardware) not accessible to the CPU at all. But there’s a lot of logic in CoreGraphics and the underlying graphics engines to shuffle the pixmaps back and forth so software can read and write them. Another factor is that the pixmap may be rescaled or translated into different color spaces to optimize rendering it. So there may not exist a default rendering of it at the time you request one, meaning CG will generate a new pixmap for you. (Also, I dunno about UIImage, but NSImage supports image formats like PDF that don’t have a native pixmap representation at all.) I’m not super into graphics, but my gut feeling is that, if you care about optimization details like whether pixmaps are being copied, you should really be using a lower-level graphics API than UIImage, which is mostly a cheap-and-cheerful convenience layer for apps that just need to splat a few PNGs into their GUI. —Jens _______________________________________________ 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
