[Marble-devel] How to know when all tiles/data needed for rendering are available?

[Torsten Rahn]

Hi Friedrich,

You are touching a topic there that has been on the TODO since long.

It would be great if we had multiple dpi support.

As mentioned already using the tiles from higher zoom levels to create a high 
resolution crisp map would only work for map themes without labels (e.g. the 
satellite map). But it would be great if it would work for those cases (and 
maybe get scaled instead for maps like the openstreetmap map theme).

But as you figured already there are lots of other things rendered by Marble 
that would hugely benefit from dpi-support: Text Labels for GeoData objects, 
Coordinate lines, All kinds of vector data displayed on the map, etc.
It would be cool if there was at least some initial rudimentary support there.

This is your chance to become the Hero of the Marble 1.4 release ;-)

BR,
Torsten



On Montag, 19. März 2012 21:47:42 Friedrich W. H. Kossebau wrote:
> Hi Anders,
> 
> Am Montag, 19. März 2012, 19:42:12 schrieb Anders Lund:
> > Mandag den 19. marts 2012 19:30:06 skrev Friedrich W. H. Kossebau:
> > > Background:
> > > I am currently looking into making the Map shape plugin for Calligra
> > > usable.  E.g. for rendering to the printer or to a PDF document. There
> > > the resolution is much higher than on the screen (Retina display is
> > > not so common yet  ), so other tiles are needed for a proper output.
> > 
> > do not forget that those tiles will differ from the ones in a lower zoom
> > level, it may be better to scale the tiles you have. Map tiles use
> > graphics that are not meant for printing resolutions, eg 16px icons and
> > fonts aimed at screen display.
> 
> Hm, good hint, did not yet think about that, might have hit me next. Higher
> resolution also would mean more detail... (meanwhile also e.g. found and
> read http://wiki.openstreetmap.org/wiki/OSM_on_Paper)
> 
> So indeed scaling the tiles would be better, so the printed output matches
> the screen output.
> 
> But:
> I wonder if at least the things which are rendered inside Marble should
> consider the dpi resolution (and we also all hope for local OSM rendering
> to arrive a day)? A grep for DPI at least did not yield anything
> resolution related. Mh, chance for an improvement that is, no? ;)
> After all in the (already started) future "screen display" could not simply
> be assumed to be ~100 dpi. Okay to file a bug about that?
> 
> And given that I might not be the only one who would like to use Marble to
> also render to paper/higher resolution ideally that scaling of tiles could
> also be provided by Marble::MarbleMap.
> 
> I guess a patch from me is welcome ;) But no hope on me doing that, my WIP
> stack is too high ATM :/ But if someone reading this is working in that
> area and can consider this problem, she/he would help to make the Map
> plugin for Calligra shine in the future :)
> 
> Another usecase I can think of is a Marble plugin for kdenlive, to
> visualize how someone travels between places of a story (e.g. someone
> doing a lovely vacation report "... then we drove to Helsinki...", could
> even use real track data). That rendering also needs to know about having
> all data available and ideally can render as much as possible directly to
> the video format resolution.
> 
> So consider this a real problem for "Marble everywhere" :P
> 
> Cheers
> Friedrich
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