How to snap an NSWindow to a grid

How can I snap an NSWindow to a grid? Any good algorithms, tutorials that are rec开发者_C百科ommended?

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If you just want to monitor you app's windows its easy to just monitor the own windows locations and "override" their locations as soon as they come to a grid boundary. You might want to checkout the KVO documentation for observing NSWindow properties.

What I think you actually want to do is monitor ALL windows, including those from other apps. If so, have a look at Apples Accessibility APIs.

Keep in mind when you use AX APIs you have to either enable accessibility support in the system preferences or authorize your app!

Update:

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Example: http://toxicsoftware.com/snappingwindow_cocoa_source_code/