Re: [Plplot-general] problems while plotting some symbols with cairo drivers

[Elena B. <Ele...@ir...>]

Alan, thanks once more

It was really a problem of the absence of several fonts.

Working 'font package' for CentOS 64 bit is:

  rpm -qa *font*

xorg-x11-font-utils-7.2-11.el6.x86_64
fontconfig-2.8.0-3.el6.x86_64
liberation-sans-fonts-1.05.1.20090721-5.el6.noarch
dejavu-fonts-common-2.30-2.el6.noarch
ghostscript-fonts-5.50-23.1.el6.noarch
libXfont-1.4.1-2.el6_1.x86_64
fontconfig-devel-2.8.0-3.el6.x86_64
dejavu-sans-fonts-2.30-2.el6.noarch
libfontenc-1.0.5-2.el6.x86_64
fontconfig-2.8.0-3.el6.i686
urw-fonts-2.4-10.el6.noarch
fontpackages-filesystem-1.41-1.1.el6.noarch
liberation-fonts-common-1.05.1.20090721-5.el6.noarch


Best regards
Elena

On 01/28/2014 08:33 PM, Alan W. Irwin wrote:
> On 2014-01-28 12:50+0100 Elena Budnik wrote:
>
>> Bonjour,
>>
>> Our installation is CentOS 64 bit, PLplot 5.9.10, cairo-devel v 
>> 1.8.8, pango-devel v 1.28.1.
>>
>> x06c from PlPlot examples:
>>
>>   devices 1-3 - Xlib,  PostScript  - everything is OK.
>>   devices 7-13 - SVG and all cairo drivers - cannot recognize some 
>> symbols
>>
>>  I've attached a PNG to explain the problem.
>>
>>  It seems to be some improper installation  -  what should we check?
>>
>
> Hi Elena:
>
> Thanks for switching your PLplot questions to this list, and thanks
> for a nice demonstration of the issue you have encountered with
> standard example 6.  I just double-checked and cannot replicate it
> here (Debian stable), but I think I know what the problem is on your
> CentOS platform.
>
> First, to give you some background, devices 1-3 use our internal
> Hershey fonts to render those symbols.  Those fonts are normally quite
> limited, but in their limited range (such as example 6) they are
> reliable but ugly.  The cairo (and svg and qt) device drivers access
> system fonts the modern way where the required glyph is specified by
> unicode index.  Normally, the results are much more complete than the
> Hershey fonts.  For example, compare results for -dev xwin and -dev
> xcairo for standard examples 23 and 24.
>
> But if you look carefully at the example 6 results you have sent, that
> cairo device is telling you that glyphs are missing from your system
> fonts for unicode index 25b3, 22c6, and 2299, and I expect you will
> find a number of other missing glyphs (indicated for cairo devices by
> a rectangular box with a unicode index inside) for examples 23 and 24
> as well.  The likely explanation is you need to install additional
> system fonts on your CentOS platform.
>
> To give you some excellent information about what system fonts you
> have currently installed, I strongly suggest you install the gucharmap
> application (if you don't have it installed already).  That gives you
> a very nice GUI demonstration of what glyphs are supplied by your
> system fonts.  Here for gucharmap, if I use the search widget to find
> 25b3, 22c6, and 2299 (white up-pointing triangle, star operator, and
> circled dot operator), they are displayed (as expected) for the
> FreeSans, FreeSerif, and FreeMono system fonts.  Many other system
> fonts I have installed also contain those glyphs.
>
> What happens if you try the same search in gucharmap?  You should find
> the same result (empty glyphs) as for the cairo device driver since
> gucharmap also depends on libcairo, but I would like you to
> double-check that to rule out the possibility there is some obscure or
> subtle problem in the way that the PLplot cairo device driver is using
> that library compared to gucharmap.
>
> Note, that PLplot's modern devices such as the cairo devices never
> look for a specific system font. Instead, they ask the cairo system
> library to look for a generic system font (one of the sans, serif, or
> mono families).  That library, in turn, asks fontconfig to
> automatically find the best glyph choice for the specified unicode
> index for any system font belonging to the specified sans, serif, or
> mono broad category of font.  gucharmap works in a similar way
> although in that case you can ask for specific fonts as well (which
> falls back to the generic search for a glyph if the glyph is not
> present in the non-generic font you have specified).
>
> Assuming that your PLplot and gucharmap results are both telling you
> there are no system fonts with those desired 25b3, 22c6, and 2299
> glyphs, then the likely issue is that your CentOS box just does not
> have many TrueType fonts installed (yet).
>
> So as a next step in the font debugging process, what happens if you
> try to install the FreeSans, FreeSerif, and FreeMono system fonts?
> (Those are general unicode fonts with good looking glyphs that have a
> very large coverage including 25b3, 22c6, and 2299 of the possible
> unicode glyphs.) On Debian, the name of the package that contains
> those system fonts is fonts-freefont-ttf, but on CentOS, the name of
> the package will be different, and you might have to use the rpmfind
> facilities to find what the package name is.  Once you have those system
> fonts installed, then gucharmap should reveal very large numbers
> of glyphs available in most of the unicode index blocks, and examples 6,
> 7, 23, and 24 should show few or no missing glyphs.
>
> Let this list know whether installation of additional system fonts
> solves the problem for you. If that step doesn't solve your system
> font problems, then the possibility also exists that there is some bad
> screwup (e.g., fontconfig not being configured properly) in how CentOS
> installs system fonts.  But I think a lot of CentOS users would be
> loudly complaining if that were the case so I view that possibility as
> fairly unlikely.
>
> Alan
> __________________________
> Alan W. Irwin
>
> Astronomical research affiliation with Department of Physics and 
> Astronomy,
> University of Victoria (astrowww.phys.uvic.ca).
>
> Programming affiliations with the FreeEOS equation-of-state
> implementation for stellar interiors (freeeos.sf.net); the Time
> Ephemerides project (timeephem.sf.net); PLplot scientific plotting
> software package (plplot.sf.net); the libLASi project
> (unifont.org/lasi); the Loads of Linux Links project (loll.sf.net);
> and the Linux Brochure Project (lbproject.sf.net).
> __________________________
>
> Linux-powered Science
> __________________________