How exactly to make a CGImageRef from an image on disk

iphone jpeg quartz-graphics gif cgimage
Alexander picture Alexander · Aug 23, 2010 · Viewed 15.6k times · Source

I've looked around everywhere to no avail. I'm doing some image loading in a thread and since UIKit is not thread safe I'm going to have to store the images as CGImageRefs but I can't figure out how to do this. I haven't played with any of the Quartz stuff before so it's confusing me. Basically I just need to load a JPG from the disk into a CGImageRef. Also for bonus points, is there anyway to load a GIF into a CGImageRef?

Answer

Jerry Jones picture Jerry Jones · Aug 23, 2010

gcamp is more or less correct, you are pretty safe to use this on a background thread, but to answer your question, I believe the following would work.

CGDataProviderRef dataProvider = CGDataProviderCreateWithFilename("file");
CGImageRef image = CGImageCreateWithPNGDataProvider(dataProvider, NULL, NO, kCGRenderingIntentDefault);

There is also a function for jpg images, CGImageCreateWithJPEGDataProvider.

(be sure to release the data provider and image when done)

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