Map scale bar

[devemux86]

VTM map scale bar is Mapsforge's old implementation.
It's not dpi aware and works only on Android.

A new implementation should work on all platforms with various unit adapters, like in Mapsforge.

Is having it as layer the best approach or a regular platform view / panel?

[andreynovikov]

Don't think making it a regular view is a good idea. Instead it should be implemented in vector and be drawn by GL like position indicator.

[devemux86]

Why is that?
External map components have usually nothing to do with internal map rendering.

[devemux86]

BTW painting a bitmap scale bar in GL is not vector rendering.

[andreynovikov]

I know, so I propose to make it true vector.

[Longri]

but I think that map scale bar is no external map components

[devemux86]

Map scale bar is actually a component placed on top of a map, e.g. like a location button.
It listens for map changes, it doesn't participate necessarily in map rendering or rotation / tilt.

If you have a true vector map scale bar, please submit a PR.
A true vector one should work on any platform from the start.

Currently the only working available is Mapsforge's and it involves bitmap rendering.

[devemux86]

I integrated Mapsforge's scale bar (Android) in #88.
DPI aware, multiple units, smooth rendering, etc.

I deliberately kept separately the core scale bar classes from the bitmap renderer.
There is the new MapScaleBarLayer for that, see API in action at SimpleMapActivity.

For the rest platforms I need first to enrich VTM graphics API, see #92.

[andreynovikov]

As for me, looks a little bit over-scaled. Otherwise perfect.

[devemux86]

And others in Mapsforge have found it small.
We can never satisfy all, I'll make the scale factor variable.

[devemux86]

After the needed Graphics API refactoring in #92.
The map scale bar moved in vtm module, being now a multi-platform implementation.