GRKImageCrop

A UIImage category which provides "visible" pixel cropping capabilities.

A given image can be rectangularly cropped based on calculated insets to "visible" pixels. Visible pixels are those whose alpha component are greater than or equal to a given alpha threshold.

Installing

If you're using CocoPods it's as simple as adding this to your Podfile:

pod 'GRKImageCrop'

otherwise, simply add the contents of the GRKImageCrop subdirectory to your project.

Documentation

To use, simply import UIImage+GRKImageCrop.h:

#import "UIImage+GRKImageCrop.h"

Then you can use the category to create a cropped image from a given image:

[image cropImageBelowAlphaThreshold:0.0f completion:^(UIImage *croppedImage, NSError *error) {
	if (croppedImage)
	{
		//Use croppedImage
	}
	else
	{
		//Hanlde error
	}
}];

The only expected error would be memory related.

Additional documentation is available in UIImage+GRKImageCrop.h and example usage can be found in the GRKImageCropTestApp.

Disclaimer and Licence

• Inspiration was taken from:
  • https://developer.apple.com/library/mac/qa/qa1509/_index.html
  • http://stackoverflow.com/a/1262893/397210
  • http://stackoverflow.com/a/12617031/397210
  • https://github.com/wrep/UIImage-Trim
• I have made use of image cropping code from http://stackoverflow.com/a/25293588/397210
• This work is licensed under the Creative Commons Attribution 3.0 Unported License. Please see the included LICENSE.txt for complete details.

About

A professional iOS engineer by day, my name is Levi Brown. Authoring a blog grokin.gs, I am reachable via:

Twitter @levigroker
App.net @levigroker
Email [email protected]

Your constructive comments and feedback are always welcome.