> > On 8 Mar 2014, at 5:02 pm, Trygve Inda <cocoa...@xericdesign.com> wrote: > >> This is slower by about 15%. :( > > > Bummer. > > I'm thinking that two seconds to composite 20 x 1920 x 1080 X 32 bits isn't > too bad actually. That's 165 MB of actual pixel data to iterate over, and at > each pixel it's going to have to perform considerable cubic downsampling and > antialiasing operations for the 10x size reduction (have you tried adjusting > options for image interpolation quality and antialiasing?). > > Is there a way to composite this big image on a background thread or perhaps > composite each contributing image using a different thread so it can at least > spread the load across the available cores? I must admit that can be tricky > because each thread will need its own context, but all sharing the same > underlying destination bitmap buffer (but drawing into a different portion of > it). Or, if the final image is just destined only for the screen, you could > make each source image the content of a CALayer and composite it using Core > Animation, which is then all done in hardware. > > --Graham > > >
Interestingly if I call: CGContextSetInterpolationQuality ([context graphicsPort], kCGInterpolationNone); It results in 10% slower processing. The antialiasing setting does not affect speed at all. Doing multiple threads will require quite a bit of work - I may give that a try too. The destination is both screen and a file so I don't think Core Animation will work. I might be near the limits of what I can do speed-wise here. :( _______________________________________________ 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
