[mkgmap-dev] Translating command line strings into target charset

Wed Jun 24 21:56:17 BST 2009

My friend, who owns a Garmin GPSMap 60CSx, notified me of a character set
problem in a tile name of my map.  I wasn't aware of the problem, because
my Edge 705 does not display map tile names.  The tile Etelä-Suomi (Southern
Finland) appears as EtelÃ¤-Suomi, where the currency symbol ¤ is displayed
as a black diamond.  Other ä characters in the gmapsupp.img are encoded as
the byte code 304 in octal notation.

The workaround should be simple: in mkgmap.args, write the ä as \304
instead of using UTF-8.  But I would except the parameter to be translated.
After all, the style files are already interpreted as UTF-8.  I think that
the right fix of this bug would be such that \u escape codes are expanded
before utf-8 to target character set translation, and hex and octal escape
codes (\xC4, \304) are expanded after the translation.  That would also
allow us to embed Garmin control characters where desired.

Also, I would like to have some transliteration in the UTF-8 to cp1252
(latin1) translation.  The Garmin displays many latin1 and cp1252 code
points as a black diamond, as I posted some time ago.  We could avoid that
by translating those code points.  I attempted to override the built-in
translation (in the JRE as far as I understood) some time ago, but
I must have patched the wrong place, because my changes had no effect.
Any hints, Steve?

Regards,

	Marko