OBShapedButton is a UIButton subclass optimized for non-rectangular button shapes. Instances of OBShapedButton respond to touches only in areas where the image that is assigned to the button for UIControlStateNormal is non-transparent.

If possible, you should install OBShapedButton via CocoaPods:

$ edit Podfile
platform :ios
pod 'OBShapedButton'

If you cannot use CocoaPods for whatever reason, manually add OBShapedButton.h, OBShapedButton.m, UIImage+ColorAtPixel.h, and UIImage+ColorAtPixel.m to your Xcode project.

• Design your UI in Interface Builder with UIButtons as usual. Set the Button type to Custom and provide transparent PNG images for the different control states as needed.
• In the Identity Inspector in Interface Builder, set the Class of the button to OBShapedButton. That's it! Your button will now only respond to touches where the PNG image for the normal control state is non-transparent.

Written by Ole Begemann, [email protected]
http://oleb.net/blog/2009/10/obshapedbutton-non-rectangular-buttons-on-the-iphone/
October, 2009

Corrected some serious bugs in April 2011. Thanks to the commenters on my blog and those who posted issues on GitHub for pointing them out, including the fixes.

Contributors:

• balabhadra added support for background images.
• yurkins fixed an issue that only occurred in release builds.
• Steven Zweier fixed an issue that would intermittently result in wrong hit tests.
• jvanakker fixed an issue with images that had a different size than the button.

Copyright (c) 2009 Ole Begemann

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

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