Measure tools should support snapping

[Alexandre Prokoudine]

The newly added Measure tool should support snapping to features.

[su_v (suv-lp)]

Related (?) blueprint:
<https://blueprints.launchpad.net/inkscape/+spec/metric>

[Diederik van Lierop (mail-diedenrezi)]

Implemented as of rev. #10377

[su_v (suv-lp)]

Reopening: when e.g. snapping to grid, the labels are no longer centered on the measured distances between intersections of the measuring path and paths/objects on-canvas (does not happen when snapping is off, or the grid not visible).

Also, the mentioned issues with a horizontally constrained measure path (with 'Ctrl' pressed) as described in the comments of bug #796451 are also present (or even worse) if the measuring path snaps e.g. to grid intersections with the same y-coordinate (tested with the second file attached to bug #796451 after turning on the grid).

[su_v (suv-lp)]

@Diederik - did I reopen this report wrongly? Snapping itself with the measure tool does work as intended, and the mentioned issues with the alignment of the labels and flickering results when measuring horizontally constrained probably need to be addressed elsewhere in the measure tool context. Please revert my previous status change if that's the case.

[Diederik van Lierop (mail-diedenrezi)]

That's correct, snapping is working as expected as far as I can tell. This all shouldn't be too difficult to fix, but I'll leave this to Felipe because I don't know what his plans are with the measurement tool.

[Diederik van Lierop (mail-diedenrezi)]

I've subscribed Felipe to inform him about the status