mathematical operations in Value entry widgets

[dcberg]

When you move an object or set a guideline, quite often
you want to move it by a certain distance but not to a
certain spot.
It would be great if I could move a guideline from
34.46 over to the right by 19.25 units by just typing
34.46+19.25 in the dialog. It would also help a lot for
deviding the page into a layout grid, if I could move a
line from 210mm to 210 / 3 mm. See where I'm getting
at? Just allowing simple mathematical operations
(+,-,*,/) in these dialogs would be wonderful. Maybe
even allowing more than just one operation along the
line of (34.46+19.25)/2 mm.
I know that you can use the simple (one operation)
stuff in Adobe, and I know that in Corel you can't. I
never really understood this, since it can't be all
that heard to implement and is a great help for
layouting and designing.

[Horkana-users (horkana-users)]

(Bug hunters: This has NOTHING TO DO WITH MATHML!
changed the summary in an attempt to clarify)

you wouldn't happen to know if any other GTK applications
(like the gimp) support this kind of behaviour?
I'm thinking it might be a feature that would need to be added
to the Toolkit rather than Inkscape specifically.

[Bertrand Petit (bp-lp)]

This is a great idea.

Let me expand it a "little": We could use constraints programming to compute attributes of SVG elements. Using this paradign we could specify that the top of object B should be 10 mm from the bottom of object A and that the left side of object C should be 12 mm from the right of object B and that B and C should be flushed top. With such a set of constraints when one resizes object A then location of the two depedent object B and C are also implicitely changed.

For more informations one could have a look at the Gecode library (http://www.gecode.org/).

[su_v (suv-lp)]

Linking as duplicate to bug #171282 “Calculator in input fields” which has seen recent activity and initial implementation of an expression evaluator for entry fields and spinboxes.

Please revert the change if you think this was done in error.