Re: Rotating entire map for gps heading
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Gordon JC Pearce
Jun 28, 2012, 1:02:27 PM6/28/12
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On 27/06/12 15:10, redzero wrote:
> Hi,
>
> how can i rotate all map around its center point?
>
> It can be usefull always showing heading of gps as upside for navigation.
You can't. The map tiles are prerendered squares with all the labels
on. What you *could* do is use cairo to draw the map window and rotate
the cairo surface, but that would make all the writing rotate too. You
could fake it by drawing your own map tiles at various resolutions, and
just having say eight rotations.
The only real way to do it would be to get the planet data and draw a
vector map in real time.
--
Gordonjcp MM0YEQ
> Hi,
>
> how can i rotate all map around its center point?
>
> It can be usefull always showing heading of gps as upside for navigation.
You can't. The map tiles are prerendered squares with all the labels
on. What you *could* do is use cairo to draw the map window and rotate
the cairo surface, but that would make all the writing rotate too. You
could fake it by drawing your own map tiles at various resolutions, and
just having say eight rotations.
The only real way to do it would be to get the planet data and draw a
vector map in real time.
--
Gordonjcp MM0YEQ
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