[Octave-bug-tracker] [bug #43651] special character (diameter sign) in plot produces warning or doesn't show up

[H. G.]

Follow-up Comment #5, bug #43651 (project octave):

* Concerning the (unnecessary) warning from gnuplot I do not like to argue.
The resulting plot is fine nevertheless.

If we keep this aside, I do still see a big misbehavior of FLTK on this Win7
machine:

* For the vast majority of the installed fonts (including the default font) NO
special characters are displayed on screen. I took "alpha" in the example
below. So this misbehavior is not restricted to the rather exotic special
character " ".

* On the very SAME Win7 machine (and therefore with the very same fonts
installed) I do get properly displayed special characters with Matlab, as well
as with the gnuplot engine of the same Octave installation. 

* note: This is even true on my Linux machine: gnuplot displays the "alpha"
and the " " with many many more different font names set, as the fltk frontend
does.

Other observations, that might or might not be giving us a hint to the root
cause here:

* FLTK seems to take the special characters directly from the choosen font
name. With Matlab and with the gnuplot engine of Octave this is NOT the case
(see the attached screenshots). They seem to take the SPECIAL characters
always from the same font, regardless of the specified font name. The
specified font name is only taken for the letters and similar "normal"
characters. (This is also the case under Linux: gnuplot gives me always the
same "alpha" on the screen, where as fltk gives my differently looking
"alpha"s, depending on the chosen font name. And for some fonts fltk does not
give me any "alpha" on screen, where gnuplot still does.)

* Matlab as well as the Gnuplot engine probably take the font "Microsoft Sans
Serif" as default font "*" on this Win7 machine. This font is set as default
font "MS Shell Dlg" via the Windows registry
"HKLM/HKEY_LOCAL_MACHINESoftwareMicrosoftWindows
NTCurrentVersionFontSubstitutes". In contrast, fltk seems to use a different
font as default font "*". Maybe Arial. Have a look at the screenshots
yourself.

I will attach 3 screenshots from the resulting plots in (1) Matlab, (2) Octave
with gnuplot and (3) Octave with fltk respectively. They are all the result of
the very same script, quoted below. I think you can follow my conclusions on
the fltk misbehavior on the basis of those screenshots.


close all;
%graphics_toolkit gnuplot;
graphics_toolkit fltk;

fs=14;

text(0,0.99,'Franz alpha   Roman','fontname','Roman','fontsize',fs)
text(0,0.9,'Franz alpha   Lucida','fontname','Lucida','fontsize',fs)
text(0,0.8,'Franz alpha   Garamond','fontname','Garamond','fontsize',fs)
text(0,0.7,'Franz alpha   Times','fontname','Times','fontsize',fs)
text(0,0.6,'Franz alpha   Tahoma','fontname','Tahoma','fontsize',fs)
text(0,0.5,'Franz alpha   *','fontname','*','fontsize',fs)
text(0,0.4,'Franz alpha   MS SansSerif','fontname','Microsoft Sans
Serif','fontsize',fs)
text(0,0.3,'Franz alpha   Arial','fontname','Arial Standard','fontsize',fs)
text(0,0.2,'Franz alpha   Calibri','fontname','Calibri','fontsize',fs)
text(0,0.1,'Franz alpha   Verdana','fontname','Verdana','fontsize',fs)
text(0,0.01,'Franz alpha   Cambria','fontname','Cambria','fontsize',fs)

text(0.5,0.99,'Franz alpha   Modern','fontname','Modern','fontsize',fs)
text(0.5,0.9,'Franz alpha   MS Reference','fontname','MS Reference Sans Serif
Standard','fontsize',fs)
text(0.5,0.8,'Franz alpha   Trebuchet','fontname','Trebuchet','fontsize',fs)
text(0.5,0.7,'Franz alpha   Mathcad UniMath','fontname','Mathcad
UniMath','fontsize',fs)

axis off;


A last comment: This problematic Win7 PC is not some exotic Windows machine.
It' a clean and fresh install of a standard PC in a big engineering company.
The next couple of thousand PCs will look identical in this company...



(file #32627, file #32628, file #32629)
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Additional Item Attachment:

File name: plot_matlab.jpg                Size:195 KB
File name: plot_gnuplot.jpg               Size:188 KB
File name: plot_fltk.jpg                  Size:70 KB


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