Implement modifier keys for dragged handles

[MewPurPur]

What I'm currently thinking of is the following:

SHIFT = Move things along one axis compared to their original position, with a visual indicator on it. For the auxiliary handles of ellipses and rects, which can only move in one direction, force the aspect ratio to be the same as the one when you started dragging. For circles, V path commands, and H path commands, don't do anything.

CTRL = Aligning path handles at an angle to a previous one. I'm thinking of enabling this for each 15 degrees. This would work in limited situations:

• LineTo path command if it's after another line-drawing path command (not including Z), for example to force a 45 degrees angle compared to the previous line.
• Q or C command's first control, if the previous path command is S, C, T, or Q. This should also make #524 easier.

[ajreckof]

Could also be good to have one for toggling snapping.

[MewPurPur]

I agree in theory, but I don't know how this would be implemented.

[ajreckof]

You would need to first separate snap into two separate parameteres "snap_enabled" and "snap_increment". Then when moving in place of checking "snap_enabled" you also check for the key modifier. If you wish I could implement it.

[MewPurPur]

The implementation details aren't what I don't know about, I mean how it would work. Shift is commonly known to be axis-aligned moving and resizing things with preserved aspect ratio. Ctrl is commonly for snapping, but here I was thinking of something with aligning handles, both of which I find quite important to implement.

[ajreckof]

maybe you can put the new behavior on another key modifier like ALT?

[MewPurPur]

I don't like ALT, but yeah that's the only thing that comes to mind.