Rendering of synthesized bold/italic

Boris Gaertner Boris.Gaertner at gmx.net
Sun Jul 9 07:14:36 UTC 2006


 "Andreas Raab" <andreas.raab at gmx.de> wrote:



> Folks -
Thank you for bringing my attention to this problem.
> 
> I was looking over the pending bugs for 3.9 and this one bothers me 
> greatly: http://bugs.impara.de/view.php?id=3604 . Since none of the 
> rendering code has changed, I have no idea what could possibly cause 
> this regression between 3.8 and 3.9. My best guess is that somehow the 
> fonts themselves got modified but how and where might this have 
> happened? 

Perhaps. To create bold fonts we have to ensure a 1-pixel interspace
between glyphs in the glyphs form. Perhaps we had that earlier and
lost it again when  fonts were moved around between StrikeFonts and
StrikeFontSets.

> Perhaps an accident in the uploaded image? (I didn't update 
> from 3.8 but used a downloaded 3.9 to see if the problem is still there)
> 
> Any ideas anyone? Personally, this is a show-stopper for me.

In earlier times we used StrikeFonts, now we use StrikeFontSets.
There is in fact a minor difference in the code of these classes:
In StrikeFont, we use the method  ensureCleanBold  that adds the
1-pixel interspace when it is not already present. In StrikeFontSet
we do not use that method.

Attached you find a proposal for a preliminary fix. It betters the
situation, but there is still an imperfaction: We do not properly
display the overhang of large italics. I think I remember that 
I fixed that for StrikeFonts some years ago and I will check my
records to find the fix. It was somewhere in CharacterScanner
(That calss underwent a lot of changes in connection with
internationalization support)

I will update the Mantis record as soon as I have a solution for the
overhang problem. The attached file should only give you a hint
where the problem is.

> Cheers,
>    - Boris
> 
PS: I found that MVC is so very damages thatwe should
perhaps drop it altogether. What is the opinion of the
community about that question? (Personally I am a lover
of the old MVC, but I use it in 3.7)



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