[changeset] fontsize with fontname="*" (was: Octave 3.1.55: printing to pdf)

[Ben Abbott]

On Apr 5, 2009, at 2:58 PM, Ben Abbott wrote:

> On Apr 5, 2009, at 2:14 PM, Ethan A Merritt wrote:
>
>> On Sunday 05 April 2009, Ben Abbott wrote:
>>>
>>> On Apr 5, 2009, at 3:47 AM, Petr Mikulik wrote:
>>>
>>>> Printing to pdf (via gnuplot backend) is broken in Octave 3.1.55
>>>> even though
>>>> gnuplot accepts "set term pdf" via "pdfcairo" terminal.
>>>>
>>>>> plot(1:100); print a.pdf -dpdf
>>>>
>>>> error: gnuplot_drawnow: the gnuplot terminal, "pdf", is not  
>>>> available.
>>>> error: called from:
>>>> error:
>>>> /opt/octave/octave-3.1.55/share/octave/3.1.55/m/plot/
>>>> gnuplot_drawnow.m at
>>>> line 72, column 7
>>>>
>>>> It seems that gnuplot_drawnow.m requires exact match of terminal
>>>> names in
>>>> 3.1.55. However, gnuplot names the pdf terminal "pdf" or "pdfcairo"
>>>> according to the library it was compiled against. In both cases  
>>>> "set
>>>> term
>>>> pdf" works.
>>>>
>>>> I think gnuplot_drawnow.m should test presence of "pdfcairo" if
>>>> "pdf" has
>>>> not been found.
>>>>
>>>> If I try
>>>> 	print zz.png -dpngcairo
>>>> 	print zz.pdf -dpdfcairo
>>>> it produces these two files:
>>>> 	pngcairo:zz.png
>>>> 	pdfcairo:zz.pdf
>>>> Why the prefix there?
>>>>
>>>> ---
>>>> PM
>>>
>>> Petr,
>>>
>>> For "set term png" if there is no "png" present does gnuplot
>>> substitute "pngcairo" as well?
>>
>> yes
>>
>>> I notice the cairo terminals default options are different from the
>>> non-cairo terminals. Specifically, there is no default font-name
>>> specified, in GPVAL_TERMOPTIONS, for the cairo terminals. This will
>>> interfere with the rendering of different font-sizes when the
>>> anonymous font-name "*" is associated to an Octave text object.
>>
>> The cairo terminals default to font "Sans".
>> Why does this make a difference?
>
> Octave would prefer to specify the font-name and font-size for all  
> text objects. Unfortunately, Octave has no way to determining that  
> font-names are available to a particular gnuplot terminal. If a font- 
> name is specified that a terminal does not have access to, errors/ 
> warnings result. In addition, the text generally does not show up.
>
> To alleviate this, the current implementation of Octave uses an  
> anonymous default font-name, "*". When this anonymous font-name is  
> associated with a text object,  neither the font-name or font-size  
> are passed on to gnuplot. The exceptions to this are the x11 and wxt  
> terminals which apparently have no problem with the fontname "*".
>
>> Would you like this to be echoed back by "show term"?
>> All gnuplot terminals should accept a font-size request with a  
>> blank font
>> name as referring to the current (perhaps default) font.
>> E.g.
>>    set term png enhanced font ",11"
>>    set title "Big Title" font ",20"
>> should give you the default font in size 11 points, and a title in  
>> the
>> same font with size 20 points.
>
> Ok! I'll prepare a changeset to fix how Octave handles a font-name  
> of "*".
>
> Thanks for the information. This will simplify things quite a bit.
>
> Ben


I've attached a changeset that permits the text associated with a  
"fontsize" property to rendered as desired when the fontname property  
is set to the anonymous name "*".

I ran "rundemos plot" with gnuplot-4.2.4 and gnuplot-4.3.0 (recent  
copy). I encountered no problems.

I'll push this change later today.

Ben

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