How to crop a layer outside doc boundary?

[Joel Stewart]

If I resize a layer so it is larger than the document dimensions (say a texture layer), how can I crop away the rest of the image that is off the edges, to keep the file size down?

In Photoshop I've always done select all, then image, crop (possibly not the best way, but it works). In other iPad apps the info just automatically disappears once a transformation is done (not ideal).

[support]

In paintstorm you can see borders of outside parts in free transform mode, but there is no automatic function to crop by existed part.

[Joel Stewart]

Can I humbly suggest that it should be possible, especially on the iPad where large images are coming up against the limits of the RAM.