Friends:

GIMP allows us to constrain a crop so that the cropped image is 1:1 or 4:3 or whatever.

I need to constrain a Transform.

I am photographing art and using transform to fix parallax errors. This is how I am doing it:

1. Add a vertical guideline that intersects the first corner. 2. Add a horizontal guideline that intersects the first corner. 3. With the Handle Transform too, mark the first corner. 4. With the Handle Transform too, mark the second corner. 5. Add a vertical guideline that intersects the third corner. 6. Add a horizontal guideline that intersects the third corner. 7. With the Handle Transform too, mark the third corner. 8. With the Handle Transform too, mark the fourth corner.

With that prep, I can now transform to make my image squared-up by moving the marks on the second and fourth corners to the intersection of the guidelines.

The problem is that this usually creates a squashed or stretched image. In other words, after doing it, if I Crop set to constrain to 1:1, the crop will not align with all four edges.

I am able to fix this by repeating my Handle Transform such that the four edges align with the constrained crop--but what I would really like to be able to do is to constrain my handle transform. Or draw guidelines that comport to constrained settings (like 1:1 for a square).

Can anyone help?

Thanks!

-MS