Module doesn't work with ImagickBackend

[bummzack]

When using the ImagickBackend instead of the GDBackend for image manipulation, the module crashes because ImagickBackend lacks the crop method.

Not entirely sure if this should be fixed in SilverStripe core instead (eg. extending the Image_Backend interface with some additional methods, such as crop and also implement them in the ImagickBackend)?

[jonom]

Sorry for the delay @bummzack I was taking some time off.

Huh! Yes I think that the Image_Backend interface ideally needs a crop($top, $left, $width, $height) method added as does ImagickBackend.

Adding a new method to an interface would be a breaking change but we could add a crop method to ImagickBackend in the 3 branch as a short term thing. I know @tractorcow was looking at dropping the ImageBackend interface for SS4 and using a third party image manipulation API instead so it may be redundant to implement a fuller solution in 4, but I don't know if that has progressed.

@bummzack Do you want to open a PR on framework (3 branch) for adding a crop method to ImagickBackend? Alternatively if you want to add an extension to this module for ImagickBackend that achieves the same end I'll be happy to accept it.