Re: [Gimp-user] Rotate?

[Noel Stoutenburg <mjolnir ticnet com>]

Erik P. Olsen wrote:

> Why can't I rotate images similarly with Gimp?

and I concur with the answer that BK gave, as far as it went. But to 
expand a bit, there are several ways to rotate an image. For the purpose 
Erik mentioned, I'd use the method BK mentioned:

Image > Transform > Rotate...

This is the equivalent of rotating the substrate upon which the image lies.

There is a second way, useful when one wants to modify some part (or 
all) of the image with respect to the substrate.

Layer > Transform > Rotate...

acts similarly to the method BK described, except that it rotates the 
layer containing the image, or some part of it, with respect to the 
rest. If one has an image that has unequal dimensions, like a rectangle 
or oval, and rotates the layer relative to the substrate (canvas is the 
term GIMP uses), then part of the layer is no longer over the substrate. 
This gives a result similar to what the OP describes: part of the image 
is no longer over substrate, and gets lost.

A third method works similarly to the method of the layer transform: the 
Rotate tool in the toolbox. The rotate tool will rotate a selection of 
the image (which may, but need not necessarily coincide with an image) 
and rotate that selection relative to the remainder of the image. And 
just like the layer transform I describe above, there is a risk that a 
selection with unequal dimensions will lose part of the information.

It turns out, though, that even if one seems to have lost the 
information by choosing layer or selection rotation instead of image 
rotation, that besides undo, there is a convenient way to recover the 
information no longer over substrate. One can resize the canvas. Once 
the canvas is resized with the dimensions of the image again matching 
the dimensions of the rotated part, the full image again becomes visible.

ns