[OSM-talk] bug in mapnik UTF8 renderer

Ben Laenen benlaenen at gmail.com
Tue Jan 13 15:51:57 GMT 2009


On Tuesday 13 January 2009, Ed Loach wrote:
> > the parentheses around "Oman" should be reversed.
> > problem in the UTF8 shaper (or lack thereof) ?
> > http://www.openstreetmap.org/?lat=22.08&lon=59.1&zoom=6&layers=
> > B000FTF
>
> It looks like they were removed yesterday from the node which I'm
> guessing is perhaps where the name comes from?
>
> http://www.openstreetmap.org/browse/node/144848937/history
>
> Having said that, none of that nodes history matches what was
> rendered in your permalink, so I don't know whether there is some
> code somewhere that mapped
> name = ????? ????? (Oman)
> to
> name = )Oman( ????? ?????

it's rather the absence of the proper code that makes it look like that 
(remember that what you see on the screen doesn't reflect the order in 
which the letters in the string are stored), and I guess the Mapnik 
renderer doesn't handle text strings with both left-to-right and 
right-to-left very well.

Other obvious bug on current mapnik rendering: the contextual forms 
aren't being used (Arabic letters change shape before and after some 
other letters so they're connected to each other), but that only seems 
to affect only Oman and al-Yaman. The other rendered names are correct, 
so there doesn't seem to be an obvious trigger for that bug...

> Anyway, the parentheses aren't in the name now so they may well
> disappear when the map is next rerendered.

Makes one wonder whether the English or transliterated name is needed. 
Normally you only use the local language and script in the name=* tag.

Ben




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