[patch] settable minimal size of "zoom to selection" view

[bilbo]

When you zoom to selection, the bounding box is enlarged by 0.002 degrees in every direction. While this can be good settings while editing large maps, it is very bad when editing in crowded city, as if you select something quite small (cca 50m large or even a single node) and want to zoom to it, zoom is set to area about 400x400 meters around it.

I have attached patch that allows you to set how much is the bbox enlarged when zooming (in advanced settings, key "edit.zoom-enlarge-bbox")

Also, perhaps the default should be changed from 0.002 to something like 0.0005

[bilbo]

settable zoom patch

[xeen]

May I suggest instead trying to auto-determine this dependent on the selection? For example, when correcting keep right bugs it's very possible changing from editing a long highway to a single node. This would certainly improve keep right. I haven't tried the patch, can you judge if the decreased value is still suitable for long highways and the like?

[bilbo]

The zoomed-in area always contain the selection. Just the border is smaller. I think the border was added mainly to solve "zoom to selection with single node selected", so it won't zoom to infinitely small area. The default value of border is IMHO too large, so this patch makes it configurable. There could be some extra value based on percent, but you always need some minimal distance in meters/degrees to avoid problems with zooming to single point.

[stoecker]

(In [2572]) applied #3527 - hidden option for zoom extension