[Plplot-devel] How do you specify special symbols and Greek letters with TrueType fonts?

[Alan W. I. <ir...@be...>]

For the -dev png plots I am preparing for publication, I have been
attempting to use the TrueType fonts that are available with the png device
and the -drvopt text,smooth option.  Normal characters that are on the line,
superscripted, or subscripted in either 2D and 3D plots seems to work. The
only trouble I am having is with special symbols and Greek letters.

Andrew (Roach), how do you specify the gradient sign with TrueType fonts?
With Hershey fonts I use #(2266) (as indicated with the correspondence
between numbers and symbols in example 7). I have the same question for
capital Greek Delta (which for Hershey fonts is specified with #gD).  When I
try #gD with TrueType fonts, it just seems to make a short vertical mark,
and there is also the following error message

*** PLPLOT ERROR *** plscol0: Invalid RGB color: 252, 250, 256, aborting
operation

*** PLPLOT ERROR ***
plscol0: Invalid RGB color: 256, 252, 252, aborting operation

A related question is how do you find out what the correspondence is between
the #(nnnn) notation and particular symbols?  Examples 6 and 7 are supposed
to do that, but it appears with -dev png -drvopt text,smooth option that
only the outer labels for the tables are printed with TrueType, but the
symbols within the tables are still done with the Hershey fonts. Andrew, can
you fix this?

System Details:

Debian stable.  CVS version of PLplot.  Currently I am using the default
TrueType fonts, which if you look at the plfreetype.c code are

static char *default_font_names[]={"Arial.ttf","Times_New_Roman.ttf",
"Times_New_Roman_Italic.ttf","Comic_Sans_MS.ttf","Arial.ttf"};

Here are the TrueType fonts (these are the downloadable core MS fonts)
available on my system:

ls /usr/share/fonts/truetype/
Andale_Mono.ttf              Impact.ttf
Arial.ttf                    Times_New_Roman.ttf
Arial_Black.ttf              Times_New_Roman_Bold.ttf
Arial_Bold.ttf               Times_New_Roman_Bold_Italic.ttf
Arial_Bold_Italic.ttf        Times_New_Roman_Italic.ttf
Arial_Italic.ttf             Trebuchet_MS.ttf
Comic_Sans_MS.ttf            Trebuchet_MS_Bold.ttf
Comic_Sans_MS_Bold.ttf       Trebuchet_MS_Bold_Italic.ttf
Courier_New.ttf              Trebuchet_MS_Italic.ttf
Courier_New_Bold.ttf         Verdana.ttf
Courier_New_Bold_Italic.ttf  Verdana_Bold.ttf
Courier_New_Italic.ttf       Verdana_Bold_Italic.ttf
Georgia.ttf                  Verdana_Italic.ttf
Georgia_Bold.ttf             Webdings.ttf
Georgia_Bold_Italic.ttf      ms-fonts
Georgia_Italic.ttf

I can change the environment variables, PLPLOT_NORMAL_FONT,
PLPLOT_ROMAN_FONT, PLPLOT_ITALIC_FONT, PLPLOT_SCRIPT_FONT, and
PLPLOT_SYMBOL_FONT to point to any of these, but in order to properly
explore the font options, the tabulated symbols in examples 6 and 7 have to
be generated with TrueType fonts when those are specified by the user using
the -dev png -drvopt text,smooth options.

Andrew, if the modifications to examples 6 and 7 will take some discussion
and time, and meanwhile you know the specific answer to how to specify the
gradient symbol and Greek letters, please let me know since the gradient
symbol and Greek letters will take care of my immediate publication needs
for a while.

Alan
__________________________
Alan W. Irwin
email: ir...@be...
phone: 250-727-2902

Astronomical research affiliation with Department of Physics and Astronomy,
University of Victoria (astrowww.phys.uvic.ca).

Programming affiliations with the PLplot scientific plotting software
package (plplot.org), the Yorick front-end to PLplot (yplot.sf.net), the
Loads of Linux Links project (loll.sf.net), and the Linux Brochure Project
(lbproject.sf.net).
__________________________

Linux-powered Science
__________________________