Re: [MiNT] fVDI TTF issues

[Frank Naumann <fnaumann@mail.CS.Uni-Magdeburg.De>]

Hello!

> I've been playing with the FreeType engine for the fVDI. I've designed it
> as a wrapper (user space application). Now I know it was totally wrong
> idea to be able to get it work under FreeMiNT.
>
> The problem is that the FreeType (normal SpareMiNT RPM package) uses
> normal system calls to load the font glyphs. These system calls are issued
> from within the interrupt and are performed in the current process
> context. Which means that e.g. Fseek() begins to operate upon a
> filedescriptor that is not known to the current process (each time
> different possibly).
>
> Is there some way how to make the system calls use a specific process
> context?

A system call is per definition executed in the current process context.

> I need to call the freetype from the wrapper application context
> despite the fact that it is hapenning in the interrupt handler (VDI call).

You can't use system calls at all from interrupts. Only specific kernel
routines are interrupt safe and can be used from interrupt handlers.

> If this is not feasible then I can see only one way: Port the engine as a
> kernel module.

I don't think this is a big problem. FreeType is already designed in mind
of portability and use only some simple ANSI-C functions for I/O, or I'm
wrong?


Ciao
   ...Frank

--
ATARI FALCON 040 // MILAN 060
-----------------------------------------
http://www.cs.uni-magdeburg.de/~fnaumann/
e-Mail: fnaumann@freemint.de