Re: Text engine for OpenGL renderer

[Michael Goffioul]

On Sun, Jun 28, 2009 at 7:13 PM, Thomas Treichl<address@hidden> wrote:
> Your example works and the axis labels appear on my Mac OS X 10.4 system.
> But this only works once, if I call "plot", "xlabel" or "title" as a second
> command then Octave crashes. Here is what I mean by example:
>
>  octave-3.2.0:1> backend ("fltk")
>  octave-3.2.0:2> plot (1:10) # does work very well
>  octave-3.2.0:3> plot (1:10)
>  octave-3.2.0:4> error: could not match any font: *-normal-normal-12
>  error: unable to load font:
>  error: ft_render: unable to load appropriate font
>  panic: Segmentation fault -- stopping myself...
>  attempting to save variables to `octave-core'...
>  save to `octave-core' complete
>
> In debug mode I can reproduce the following output:
>
> octave:1> backend ("fltk")
> Reading symbols for shared libraries .... done
> octave:2> plot (1:10) # does work very well
> octave:3> Reading symbols for shared libraries . done
> Reading symbols for shared libraries . done
> Reading symbols for shared libraries . done
> Reading symbols for shared libraries ... done
> Reading symbols for shared libraries . done
> Reading symbols for shared libraries .. done
> Reading symbols for shared libraries . done
> Reading symbols for shared libraries ....... done
> Reading symbols for shared libraries ... done
> Reading symbols for shared libraries . done
> Reading symbols for shared libraries . done
> Reading symbols for shared libraries . done
> Reading symbols for shared libraries . done
> octave:3> plot (1:10)
> octave:4> error: could not match any font: *-normal-normal-12
> error: unable to load font:
> error: ft_render: unable to load appropriate font
> Program received signal EXC_BAD_ACCESS, Could not access memory.
> Reason: KERN_INVALID_ADDRESS at address: 0xfffffffd
> 0x90b40517 in __gnu_cxx::__exchange_and_add ()
> (gdb) where
> #0  0x90b40517 in __gnu_cxx::__exchange_and_add ()
> #1  0x011be99c in input_event_hook () at basic_string.h:226
> #2  0x02ba39a6 in command_editor::event_handler () at cmd-edit.cc:877
> #3  0x00779524 in rl_read_key ()
> #4  0x007610e1 in readline_internal_char ()
> #5  0x007612d5 in readline ()
> #6  0x02ba6ca4 in gnu_readline::do_readline (this=0x364fa50,
> address@hidden, address@hidden) at cmd-edit.cc:255
> #7  0x02ba50e1 in command_editor::readline (address@hidden,
> address@hidden) at cmd-edit.cc:902
> #8  0x011b9a33 in gnu_readline (address@hidden, force_readline=false) at
> input.cc:202
> #9  0x011b9fbe in octave_gets () at input.cc:248
> #10 0x011ba82a in octave_read (buf=0xf5000 "", max_size=8192) at
> input.cc:347
> #11 0x011c1d4d in yy_get_next_buffer () at <stdout>:2879
> #12 0x011cdba3 in octave_lex () at <stdout>:2721
> #13 0x012aad4c in octave_parse () at parse.cc:2234
> #14 0x012fc07b in main_loop () at toplev.cc:566
> #15 0x012983df in octave_main (argc=6, argv=0xbfffda20, embedded=0) at
> octave.cc:886
> #16 0x00006630 in main (argc=-1, argv=0xffffffff) at main.c:35
> #17 0x00005f92 in _start ()
> #18 0x00005eb9 in start ()
> (gdb)
>
> Any ideas? Thanks,

The error you get is quite odd and makes me think about a stack
corruption. I've pushed a changeset that should (hopefully) improve
the situation where a font cannot be loaded. Could you give it a try?

Although in your specific case (as opposed to Ben), I have no idea
why the font cannot be loaded in the second "plot" call. The changeset
I pushed should help to recover from such situation, but won't help to
fix the reason of it (== font not being loaded). You might want to run
octave in gdb and trace what's going on in ft_manager::do_load_font().

Michael.