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cocoacalayer

Getting the "LightTable" sample code working

I'd like to get the "LightTable" sample code from Apple's website going (https://developer.apple.com/library/mac/#samplecode/LightTable/Introduction/Intro.html). It all compiles fine but dragging an image onto the running program window results in this error message being logged in the console:

** Canceling drag because exception 'CALayerInvalidGeometry' (reason 'CALayer position contains NaN: [nan nan]') was raised during a dragging session

and nothing happens.

I'm using Xcode 4.6.1 and OSX 10.8.3 The problem seems to be in the "LTMaskLayer" class. Specifically the setFrame function but after some tinkering I still can't get the app to work properly.

Seems like a good app, with lots of things to learn from, not just touch gestures and I'd really like to get it working. Many thanks to anyone who can help.

Solution

  • You're correct, the bug seems to be in -[LTMaskLayer setFrame:].

    This experiment worked for me. Change:

    if (!CGSizeEqualToSize(oldFrame.size, frame.size)) {

    to

    if (!CGSizeEqualToSize(oldFrame.size, frame.size) && !CGSizeEqualToSize(oldFrame.size, CGSizeZero)) {

    It's entirely possible there's a better fix, but this should get you a little farther.