I think your going overboard with this. Keep it simple with minimal UI change:
I agree and would be entirely satisfied with a way to change the sizes in the Standard Sizes drop-down
. The fixed size ones (not %) should all be customizable. If you change resize fields values the currently selected size name in the drop-down is saved. Right-click the size name (or push a button) and the size name could be renamed
. Don't want to save it? Leave it on Custom.
"Keep ratio" button is of course indispensable.
I agree "Keep document size" would be better named "Keep print size"
. I don't agree that it should grey-out the print size fields. A minute print size variation always happens if you change the other parameters. The dialogue correctly displays this. The dialogue is also consistent if Keep document (print) size is ticked and one of the screen dimensions is changed: of course one of the print dimensions changes. IMO this is desirable, "Keep print size" should not override or grey-out sizing fields.
I was initially happy with the screen size transformation values being carried from previous operation but now it just confuses me. Previous behaviour, with current screen dims, was better. Fact is that you expect initial status of the dialogue to reflect the status of the image you have on the screen. Anyway this was only half a solution: If the previous resize was a change in print size you still have to input the values before trying another algorithm.
It would be better to have on the drop-down a "Previous resize" size
. If this was second on the list, under Custom, pressing down arrow would restore previous operation. As it is you get 160x120 size.
I think its unnecessary and even undesirable to have radios or checks to "Keep DPI" or "Keep screen size". It really complicates what overrides what and should be really difficult to program. But this is only my opinion.
Anyway, if saved resize sizes are implemented, then "Canvas resize" saved sizes should be implemented
in the same way.