Closes #163: Show raster and snap icons

[dreng]

Closes #163: Show raster and snap icons

This PR adds an option to set a grid size. For sizes > 0 a grid will be shown in the topology view. If the grid is active all icons snap to the grid when being dragged and dropped.

The grid size may be set as an individual option.

show_raster_and_snap_icons_preview.mp4

[mattieserver]

Should the grid size be something you set for the whole plugin and not only your user?

If I for example set the grid size to 2 and my colleagues to 5 it might result in some strange aligned icons.

[dreng]

Should the grid size be something you set for the whole plugin and not only your user?

If I for example set the grid size to 2 and my colleagues to 5 it might result in some strange aligned icons.

I get your point but I think that this is not a problem of the plugin but a problem of team organization. It's somewhat similar to software developers who have to agree on coding conventions.

Even if you set this as a general option, it is possible that it comes to a different decision later ending in a different grid size. That would be the same result. Another scenario could be a colleague that doesn't use the grid at all while another one uses a fixed grid size and wonders why the icons are not placed on the grid anymore.

I see this feature as a helper to align and nicely arrange icons.

Another idea would be to hard code the size but personally I think that the decision which grid size is the right one should be on the user side.