[mkgmap-dev] Character set translations

Wed May 6 23:15:42 BST 2009

On Wed, May 06, 2009 at 11:34:21PM +0300, Marko Mäkelä wrote:
> On Thu, Apr 16, 2009 at 06:08:06PM +0100, Steve Ratcliffe wrote:
> > > Probably, mkgmap should make some effort to automatically write a  
> > > sensible code page -- how are the options latin1, charset and code-page 
> > > meant to work together? Does one affect input, the other output?
> > 
> > Its mostly historical when I didn't fully understand what was required.
> > The two things were selecting between the 6 bit format and the 8 bit format
> > and then getting the correct character set for the 8 bit format.
> 
> Is ENCODING_FORMAT9 the 8-bit format?

Yes it is.

> What is ENCODING_FORMAT10 and which devices do support it?  I just tried
> generating a map with --charset=unicode, but the Garmin Edge 705 appears
> to display non-ASCII characters as if they were UTF-8 encoded strings

Certainly on my Legend there is no difference between format 9 and 10
either but it depends on the firmware for the device as far as I know.

> Where would you implement the fixups for unsupported cp1252 characters?
> I noticed that the code relies on java.nio.charset.Charset for doing the
> translations.  Is it table-driven, and if so, is it possible to tweak the
> translation tables?  Else, is there an efficient Java library function for
> replacing all occurrences of a given character (e.g., replacing
> 0x91 and 0x92 with 0x27)?

Well if we know what is required we can do anything, if need be a new
Charset could be created if the Garmins don't follow an existing one
exactly.

..Steve