Font sizing (was Re: [dia] Windows created diagrams are no longer readable)

[Hans Breuer <Hans Breuer org>]

At 14:14 14.05.04, Lars Clausen wrote:
> On Thu, 2004-05-13 at 22:15, Federico Maggi wrote:
> >       hi,
> > I am sorry if some similar post already exists.
> >

There were many posts, but none of them had such a misleading subject yet ;)
[For me "are no longer readable" sounds like a much more serious problem 
than just some size mismatch.]

> > I am using the same dia version (0.92.2) both on Windows (XP) and Linux
> > (GNU/Linux, debian/testing).
> Once the Windows version of it comes out, try 0.93, it uses font-config,
> so may agree more on fonts.

even if there would be a font-config based build it wont solve the problem 
which is (part of, but also read below) :

_different fonts_ provide by any system will generate different sized 
bounding boxes. There is no magic in Pango or font-config to resolve this 
issue long time known in Dia land.
Note: this is not a matter of the platform you are running Dia on but a 
matter of concrete font files. Ensure they are the same, and appropriately 
mapped/named in you font configuation and the problem is gone.

By default Dia currently uses very weak hints to the font system which font 
to use, like 'sans', 'serif', 'monospace' - that is : the first font in the 
systems enumeration which is classified as being of the respective type. 
Depending on your system for e.g. sans-serif this may be :

'Helvetica - on common Linux (if there is such)
'Luxi Sans' - with osx/X11
'Arial' - with win32 (either Pango/FT2 or Pango/win32 based)

> > If I create a diagram with Windows Version and then go open it with Linux
> > Version I see a 'crazy situation': all the anchor points are scrambled.
> >

you should be able to reduce (if not eliminate) the issue by having the 
same font files installed on both systems _and_ explicit select the desired 
font in Dias font properties.

> > I just need to point-n-click every anchor to solve this problem but it 
> is a
> > very long-and-boring job!
>
> You can Ctrl+A to select all, and then just move it back and forth a
> bit, that should resolve most of it.
>
> It is, however, a problematic issue.  Problem is that Win32 and Pango
> don't agree on how to render fonts, so they have slightly different
> widths, which in turn determines the size of the boxes.  Haven't found a
> good solution yet.

Sorry Lars - but I've a different understanding of the problem. I've tried 
Dia on win32 with both backends Pango/win32 and default 
font-config/Pango/FT2 and beside marginal different aliasing the sizes were 
exactly the same.
Also aren't you comparing apples to elephants (Pango and Win32)? Shouldn't 
that read FT2 and win32 font rendering ? Or did you mean font-configs font 
list compared to the one provided by win32::EnumFontFamilies() ?

UPDATE: Repeating my test with 0.93 (they were originally done some month 
ago with some 0.92 or even 0.91 ?) did show a IMO serious regression 
though. Font sizes between the backends are no longer the same.
To test yourself try the attached UML-Test (original from Dias 
distribution, I've put in an additional layer showing the UML Class box 
sizes with Dia-0.90-win32.
Loading the file with 0.93(Pango/win32) shows some small deviation, some 
few percent as expected. But loading the same file into .93(Pango/FT2) 
shows that the boxes - and thus the reported text length - are about 30% 
smaller. To me this looks like an unacceptable regression - I simply have 
too much diagrams done with 0.90 ...

Confused (-;
        Hans

Attachment: UML-demo-2002-01-07.dia
Description: Binary data

-------- Hans "at" Breuer "dot" Org -----------
Tell me what you need, and I'll tell you how to
get along without it.                -- Dilbert