DSResize

HighQuality Image Scaling / Resizing using vImage.

Usage

@interface UIImage (HQResize)
-(UIImage*) hqScaleToSize:(CGSize)size usingMode:(UIViewContentMode) mode;
@end

Comparison with Reference Images

Images are resized to identical sizes.

Core Graphics	vImage

Computation Time

Core Graphics	vImage	Image Resolution	slower by
0.014590	0.024121	2130x2900	1.65 times
0.167856	0.317625	3072x2304	1.89 times
0.003484	0.001751	64x64	0.50 times
0.074183	0.146807	1000x1247	1.97 times
0.342612	1.761384	3744x5616	5.14 times

The slowness of hq image is apparent, but the absolute time it takes for even image is quite small.

References

[http://www.galloway.me.uk/2012/01/uiimageorientation-exif-orientation-sample-images/][1] [http://stackoverflow.com/questions/10068095/uiimage-become-fuzzy-when-it-was-scaled-whyios-5-0][2] [https://github.com/Nyx0uf/NYXImagesKit][3]