[GRASS-dev] iconv a required dependency for using Freetype?

[Paul Kelly]

On Sun, 6 May 2007, Glynn Clements wrote:

>
> Paul Kelly wrote:
>
>>> FWIW, the robust way to check whether two paths are equivalent is to
>>> stat() (or lstat()) both of them, and check whether the device and
>>> inode numbers match.
>>
>> Interesting; here we are comparing the directory the fonts are stored in
>> rather than the font files themselves but perhaps still of use?
>
> Yes; in the case of COM_Font_get(), you would need to remove the last
> part of the path and check whether the directory part refers to the
> same device/inode as $GISBASE/fonts.

OK well it doesn't work on Windows anyway. The device number corresponds 
to the drive letter but it appears the inode number is always 0. So I 
suppose we can just keep the string comparison of the directory names. Or 
remove the option of specifying the full path to a GRASS stroke font - I 
generally feel unhappy with the idea of removing functionality but maybe 
it is the best option here?

>>> Also, I'd guess that using a colon as the field separator is likely to
>>> be problematic on Windows.
>>
>> Yes, that was it. If I use a semi-colon instead all works great - maybe we
>> could change mkftcap to generate a file with semi-colon separators? And
>> change parse_freetypecap() to handle both for backwards compatibility? Is
>> the last character on a line in freetypecap always a separator character?
>> If so that would be a quick way to check. Or could scan the first line and
>> whichever appeared first between : and ; use that as the separator?
>
> If it's going to be changed, one option is to use a vertical bar
> (which isn't a legal filename character on Windows), and make the face
> index a separate column.

I can't see an easy way though of keeping old freetypecap files compatible 
with the current reading code that way though - just recognising an 
alternative separator character doesn't seem to be too disruptive (apart 
from adding extra code and requiring it to be kept there for ever.)

> That would eliminate the possibility of using a non-zero index when
> specifying a font by a pathname, but that's problematic for other

Yes but that's quite neat and an easy and simple way of specifying a 
non-zero index if you need to, I thought.

> reasons (e.g. gisprompt = "old_file,..." should probably check for
> file existence, which would rule out the option of using something
> which is "almost" a filename).

Yes if the font was being specified through a module like d.font - I 
suppose an extra parameter could be added to specify the index. But when 
the font is just being read from an environment variable then it's more 
complicated and anyway the parser isn't going to be involved here so as 
far as I can see the check for file existence needs to be done manually 
anyway as it currently is.

> AFAIK, the trailing separator is an artifact of the time that style
> information (colour, size) was included in the freetypecap file.
>
> BTW, the encoding field isn't used either (d.font.freetype and
> d.text.freetype used it, but the driver doesn't).
>
> Note that d.font has code which parses the freetypecap file in order
> to generate the option list for font=, and to implement the -l switch,
> so that will need to be updated if the format changes.
>
> d.font.freetype and d.text.freetype have similar code, but they no
> longer need to be maintained; they have been replaced by scripts which
> call d.font and d.text (which is actually d.text.new) respectively.

OK. Well here is my current proposal, which can be easily added to both 
d.font and libdriver: dynamically generate the format conversion string 
(containing either a : or ; as separator) based on the relative position 
of : and ; characters in the first line of the file that contains either 
of them.
The code looks like below; it is complicated but I can't see how to make 
it simpler without losing backwards compatibility. I'm not quite happy 
enough with it to commit it yet. It can be easily included in both d.font 
and libdriver as-is, though.

char format[16] = "";

while(fgets(buf, sizeof(buf), fp) && !feof(fp))
{
 	char *p;

 	p = strchr(buf, '#');
 	if(p)
 		*p = 0;

 	if (!*format)
 	{
 		char *first_colon = strchr(buf, ':');
 		char *first_semi = strchr(buf, ';');

 		if (first_colon || first_semi)
 		{
 			char sep_char;

 			if (first_colon == NULL)
 				sep_char = ';';
 			else if (first_semi == NULL)
 				sep_char = ':';
 			else
 				sep_char = (first_colon < first_semi)? ':' : ';';

 			sprintf(format, "%%[^%c]%c%%[^%c]", sep_char, sep_char, sep_char);
 		}
 		else
 			continue;
 	}

 	if(sscanf(buf, format, iname, ipath) != 2)
 		continue;