Re: [Tuxmath-devel] Prerendered PNG cache for SVG sprites

[David B. <dav...@gm...>]

Hi Wenyuan,

On Fri, Jun 11, 2010 at 7:52 AM, Tim Holy <ho...@wu...> wrote:
> Hi Wenyuan,
>
> On Thursday, June 10, 2010 11:41:45 pm Wenyuan Guo wrote:
>> Do you have write access to your tuxmath install directory (in my
>> case, /usr/local/share/tuxmath) and whether there is enough disk
>> space? The caching PNG files will be written to the same directories
>> where the original SVG sprites are located.
>
> On Linux systems, the typical default (e.g., for distributor-supplied
> packages, or a default make install) is to have the SVGs in some system
> directory, to which users do not have write access.

I agree - the PNG cache can't be located under the install directory,
because that will not be writeable by ordinary users.  This situation
has a lot in common with the "custom word list" tuxtype project from
last summer - ideally, we might want to have an area that is writeable
by tuxmath and readable by all users.  Our high score table has
similar considerations. I found out that this is a thorny problem for
distro packagers - if they are into security, they won't allow any
files that are user-writeable outside of /home.  The traditional way
to handle this is to make the file setgid for games, and put tuxtype
into the games group.  Some distros (e.g. Fedora) didn't even like
that idea, and said we ought to write a dedicated daemon to handle
such file operations.  At that point, I gave up for the time being.

For this case, I think we should just put the cache under ~/.tuxmath.
If tuxmath subsequently gets run by another user, nothing bad will
happen except for the slower startup the first time while the
rescaling takes place.

Cheers,

David Bruce