Open Radar

 
Summary:
The subset of CoreImage filters available in iOS 5 do not include the Mac filter CIRandomGenerator. CIRandomGenerator can be used to generate noise in images, which is an extremely important design element if when creating user interface elements. Adding CIRandomGenerator would allow entire UI elements to be drawn via code in a resolution-independent manner, instead of relying on large image resources that have to be optimized for every possible resolution.

Steps to Reproduce:
Running `[CIFilter filterWithName:@"CIRandomGenerator"]`.

Expected Results:
Running `[CIFilter filterWithName:@"CIRandomGenerator"]` would return an instance of the CIRandomGenerator filter.

Actual Results:
Running the aforementioned method  on all builds of iOS 5 returns `nil`.

Regression:
This has never worked on iOS, however it does work correctly on Mac OS X since 10.4.

Notes:
Noise is truly the last piece of most UI elements that cannot be replicated (efficiently) programmatically. With three separate screen resolutions to make apps for, resolution-independent UI elements are much more efficient in many cases than including three separately-optimized images in the application's bundle. All other traditional effects that graphic designers employ in Photoshop (blend modes, layer styles, etc.) can be replicated with the CoreGraphics, CoreImage, and CoreAnimation APIs, so the addition of a viable noise generator would finally close the feature gap.