Re: x11: slow drawing after set xtics font

[Ethan M. <merritt@u.washington.edu>]

On Thursday 18 June 2009 06:55:45 Daniel J Sebald wrote:
> Petr Mikulik wrote:
> >>'*' as a font name is a disadvantageous choice: the font selection
> >>mechanism of the x-server searches through all the fonts to find
> >>one which matches the name (there is a speed difference between
> >>specifying '*' and the name of a non existent font) and has the
> >>selected font size - in the normal x-server installation first the
> >>bitmapped fonts are searched then the scalable.
> > 
> > 
> > If the drawing gets so slow, it seems that the server searches the font list 
> > for each tic for font "*", right? Cannot this be eliminated?
> > 
> > I think that Octave should produce gnuplot code like:
> > 
> > set terminal x11 font "arial"
> > set title "Hello world" font ",12"
> > 
> > instead of
> > 
> > set terminal x11
> > set title "Hello world" font "*,12"
> 
> I suggest gnuplot be modified slightly to deal with this. 
> Rather than continually searching for the font when '*' is the font name, 

It's not gnuplot that's doing the search, it's the x11 font server.

> x11 terminal should search for the font the first time, 
> record the default font file name to memory, 
> and from there forward use the saved file name, not searching.  

There is no file name.  The font is provided by the x11 font server.


But I am puzzled why Octave would ever want to pass "*" as a font name.
It is true that x11 will eventually resolve this to something, but I
don't think many/any other terminal type will handle it usefully.


Ben Abbott wrote>
> The problem the octave developers have is that identifying a font 
> that reliably works for x11, aqua and windows ... 
> and hopefully works for the other terminals as well.  

I am afraid that is impossible.  Neither Octave nor gnuplot has any
control over what fonts are available on a user's system, and different
terminal types intrinsically use different types of fonts.

The right thing to pass is either no font option at all (which on all
terminals should yield a usable default), or   ",12"   which will 
yield that same default font in a particular size. 




	Ethan