I would be surprised if QuickLook is bothering to use anything lower-level. The raw truth of it is that CGImageSource is intended to be the fastest image-decoding library on the Mac. Quick Look should have a possible benefit in raw speed because it might have already cached a file's thumbnail.
Of course, once you get into image manipulation, the story might change. What's your end goal here? On 7 Sep 2012, at 13:02, Oleg Krupnov <oleg.krup...@gmail.com> wrote: > I guess I should have asked "Is QuickLook implemented upon > CGImageSource/CGImage or lower-level libraries under the hood?" I > mean, the question is not I CGImageSource vs. CGImage, but rather > CGImageSource/CGImage vs. lower-level libraries like libjpeg etc. > > I tried to measure the performance of QuickLook vs CGImageSource but > it's hard to make a clean experiment. I keep getting different figures > each time. At superficial glance, it seems that they show nearly equal > performance. > > But it would be really curious what libraries QuickLook uses under the hood. > > Thanks! > > On Fri, Sep 7, 2012 at 2:09 PM, Mike Abdullah <cocoa...@mikeabdullah.net> > wrote: >> Your question in the subject makes little sense. CGImageSource is a means to >> create CGImages. Quick Look likely uses both therefore. >> >> Ultimately, you need to test different image loading routes to see which >> suits your needs. >> >> CGImageSourceCreateImageAtIndex >> Generates full-size images as fast as it can >> >> QLThumbnailImageCreate >> Generates thumbnails >> Might have the thumbnail already cached for speed >> Is going to spend a little time in cross-process communication >> Logs warnings if used on the main thread in my experience >> Can handle any file type, not just images >> >> CGImageSourceCreateThumbnailAtIndex >> Generates thumbnails >> Very fast >> >> On 7 Sep 2012, at 10:21, Oleg Krupnov <oleg.krup...@gmail.com> wrote: >> >> And what is the fastest method for image loading, >> QLThumbnailImageCreate or CGImageSourceCreateImageAtIndex? >> >> Thanks! >> _______________________________________________ >> >> 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/cocoadev%40mikeabdullah.net >> >> This email sent to cocoa...@mikeabdullah.net >> >> _______________________________________________ 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
