gd.trm png_state.default_font

[Tait <gnu...@t4...>]

Here's a transcript from a recent CVS:

	Terminal type set to 'windows'
	gnuplot> set term png
	Terminal type set to 'png'
	Options are 'nocrop font arial 12 size 640,480 '
	gnuplot> set term windows
	Terminal type set to 'windows'
	Options are 'color noenhanced'
	gnuplot> set term png
	Terminal type set to 'png'
	gd.trm: caught initialization error
	Options are 'nocrop font arial 12 size 640,480 '
	gnuplot> set term windows
	Terminal type set to 'windows'
	Options are 'color noenhanced'
	gnuplot> set term png
	Terminal type set to 'png'
	Options are 'nocrop font arial 12 size 640,480 '
	gnuplot> set output 'sinx.png'
	gnuplot> plot sin(x)
	gnuplot> unset output
	gnuplot> set term windows enhanced
	Terminal type set to 'windows'
	Options are 'color enhanced'
	gnuplot>


If I attempt to plot after the _first_ "set term png" gnuplot will crash,
every time. If I wait until after the "caught initialization" error as
above, plotting works fine -- valid PNG results and no crash. (There are
certain combinations of options I can give to the PNG terminal to avoid
this crash, but I haven't narrowed down exactly what they are.)

The initialization error seems to come from term/gd.trm when it discovers
the default_font pointer is NULL. A FIXME comment just above this
suggests it should "never happen," from which I surmise this isn't a
known problem. If I force GD_NEED_LOCAL_FONT_POINTERS to be undefined,
the gd.trm initialization error goes away and so does the crashing. I'm
not sure what else, if anything, this breaks.

What does GD_NEED_LOCAL_FONT_POINTERS do? How are font pointers used 
and what does it mean for one to be local?

Tait