> > On 8 Mar 2014, at 2:38 pm, Trygve Inda <cocoa...@xericdesign.com> wrote: > >> Profiling this shows lots of time (90%) is spent in drawInRect and it takes >> about 2 seconds to run. Is there a better way to do this that is faster? >> >> Maybe keep everything in CG and only convert to NSImage at the end? > > > Sounds like you answered your own question... > > >> Not sure >> how to do this. > > > Instead of creating canvas as a NSImage, create a NSBitmapImageRep and then a > graphics context from it, using +[NSGraphicsContext > graphicsContextWithBitmapImageRep]. Then you can use CGContextDrawImage with > your CGImageRef data, targetting that context. Once you're done, just add the > bitmap image rep to an NSImage. > > Essentially, you want to avoid copying any image data that you don't need to, > though in fact your original code *may* already be avoiding that and just > wrapping things. Spending 90% of your time in drawInRect is probably a good > sign - it means that only the copy that really needs to happen is taking time. > It might be that you can't do better (though 2 seconds sounds high, but you > haven't said what size these images are). The other thing to ensure is that > everything uses the same colour space throughout - if any conversion is needed > it will hit performance hard. Lesser performance hits can come from mismatched > image buffer formats, so if all your CGImageRefs are the same, use the format > information associated with them to create your NSBitMapImageRep to match. If > format and colour space are the same, the actual bitblit needed should be very > fast as it's just a straight copy, no conversion. > > --Graham
I get the same times doing it this way, but maybe my color spaces are different. The CGImage returned from my AVAsset is: <CGColorSpace 0x100550490> (kCGColorSpaceICCBased; kCGColorSpaceModelRGB; Composite NTSC) I am not really sure what color space to pass into: [NSBitmapImageRep alloc] initWithBitmapDataPlanes:NULL..... Currently I am using NSDeviceRGBColorSpace. Any thoughts? T. _______________________________________________ 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
