Re: Long delay in first use of fontconfig features in gd terminal in my MinGW build

[Tatsuro M. <tma...@ya...>]

----- Original Message -----

> From: Mojca Miklavec 
> To: Tatsuro MATSUOKA 
> Cc: gnuplot-beta 
> Date: 2016/2/15, Mon 17:45
> Subject: Re: Long delay in first use of fontconfig features in gd terminal in my MinGW build
> 
> On 15 February 2016 at 09:24, Tatsuro MATSUOKA wrote:
>>  Hello
>> 
>>  This is not a bug but a slightly annoying matter.
>> 
>>  For the gnuplot binaries for windows built by me,
>>  If I use fontconfig features in gd terminal for example
>> 
>>  gnuplot> set term png font 'Times New Roman'
>> 
>>  If it is used for the first time, a long delay happes in first use.
>>  (depending on environment. ca. several ten seconds).
>> 
>>  However, once the fontconfig features is used, delay does not occur.
>> 
>>  For cairo based terminal, this delay does not occur.
>> 
>>  For the binary provided by Bastian, this delay does not occur.
>> 
>>  Have anyone seen the similar issue?
> 
> On all systems with libraries that use fontconfig, fontconfig has to
> scan all system fonts occasionally. On Linux that most likely happens
> semi-automatically somewhere in the background and only once for all
> applications. On Mac and Windows this is a bit more tricky because
> every single piece of software uses its own copy of fontconfig and its
> own database. The described behaviour is a well known "problem". On OS
> X many software packages like MPlayer, VNC, Gimp, ... would display a
> notice when I start them, letting me know that I have to wait until
> the font database gets rebuilt/updated.
> 
> I don't believe that you can entirely avoid that. You can probably
> influence the frequency of updates and location of the database. Maybe
> your build of fontconfig creates a font database at some temporary
> location that Windows deletes when you shut down the computer (that is
> pure guessing). In any case you should not get delays every time you
> start gnuplot.
> 
> I don't understand why the delay happens with gd, but not with cairo
> though (if both use fontconfig). I would expect a delay with every
> terminal that depends on fontconfig, but only once in a while (maybe
> once per month or when you try to use a font that's not in the
> database).
> 
> Mojca


Thanks for your detailed explanation.

> I don't understand why the delay happens with gd, but not with cairo
> though (if both use fontconfig).


For cairo based terminal, it is possible that I might make mistakes.

First I have tried used enhanced text handing on gd terminals.

set term png
set out 'test.png'
set title '{/:Bold A}'
plot sin(x)
set out

First I felt that gnuplot hanged.

For pngcairo

set term pngcairo
set out 'test.png'
set title '{/:Bold A}'
plot sin(x)
set out

worked as expected

But I did not execute

set term pngcairo font 'Times New Roman'

Other fontconfing application like fc-list have long delay in first use.
You explanation is quite right for windows.

Tatsuro