[Okular-devel] [PATCH] Fix rendering of DVI documents

[Albert Astals Cid]

A Dissabte, 3 d'octubre de 2009, Benoit Jacob va escriure:
> 2009/10/2 Albert Astals Cid <aacid at kde.org>:
> > A Divendres, 2 d'octubre de 2009, Benoit Jacob va escriure:
> >> 2009/10/2 Albert Astals Cid <aacid at kde.org>:
> >> > A Divendres, 2 d'octubre de 2009, Elvis Stansvik va escriure:
> >> >> 2009/10/2 Albert Astals Cid <aacid at kde.org>:
> >> >> > A Divendres, 2 d'octubre de 2009, Benoit Jacob va escriure:
> >> >> >> Hi List,
> >> >> >>
> >> >> >> I noticed that the rendering of DVI documents was broken exactly
> >> >> >> in the same way as what I observed with PDF documents, namely, it
> >> >> >> used auto-hinting which looks especially bad with TeX fonts.
> >> >> >>
> >> >> >> Attached is a 1-line patch that changes it. I need your permission
> >> >> >> to commit.
> >> >> >>
> >> >> >> Screenshots:
> >> >> >> * original :
> >> >> >>  http://picasaweb.google.ca/lh/photo/fry54ANy23UesNpFhbWanA?feat=d
> >> >> >>ire ctl ink * fixed :
> >> >> >>  http://picasaweb.google.ca/lh/photo/OjQIZ7Of6wP74k7fKUwXTw?feat=d
> >> >> >>ire ctl ink
> >> >> >>
> >> >> >> Here are some comments before one objects that disabling hinting
> >> >> >> is just a matter of taste, etc.
> >> >> >>
> >> >> >> First, it's obvious that the "original" screenshot linked above is
> >> >> >> horrible and that the "fixed" is the one that looks good.
> >> >> >>
> >> >> >> Second, it is a consensus on the Poppler/PDF side that one should
> >> >> >> use no hinting, and then, there's no reason why DVI should be any
> >> >> >> different. To summarize the situation on the PDF side:
> >> >> >> * poppler/cairo (hence Evince) 's code completely disables hinting
> >> >> >> * poppler/splash (hence Okular) 's code _meant_ to completely
> >> >> >> disable hinting (actually only auto-hinting, but in the context of
> >> >> >> DVI that's really the same because almost all DVI files use Type 1
> >> >> >> fonts, and bytecode only exists in TrueType fonts). It was a clear
> >> >> >> bug in the code, where it was clear that the code didn't do what
> >> >> >> it intended, that resulted in hinted fonts being used.
> >> >> >>
> >> >> >> Third, the old KDVI used to not do any hinting, I'm completely
> >> >> >> sure of that because I've spent hundreds of hours looking at
> >> >> >> documents in it. I remember distinctly the (imho beautiful)
> >> >> >> slightly fuzzy look of the TeX fonts in it, that is characteristic
> >> >> >> of non-hinted text, although at that time I didn't know about
> >> >> >> hinting. That said, I used "svn annotate" to see who enabled
> >> >> >> hinting in the C++ code, and it turns out to be Stefan Kebekus
> >> >> >> himself in an old revision (240000-something). I am puzzled about
> >> >> >> that, but I still maintain that KDVI didn't use hinting on all the
> >> >> >> Linux systems that I tried. My best guess is that Stefan Kebekus
> >> >> >> _thought_ that he had enabled hinting but for some reason it
> >> >> >> wasn't used. I haven't investigated further as this is quite
> >> >> >> intricate, and of course I only have Okular's code at hand, I
> >> >> >> haven't looked at the actual KDVI code.
> >> >> >>
> >> >> >> OK to commit?
> >> >> >
> >> >> > No, actually what it is clear that *you* don't like hinting, and
> >> >> > you have a certain amount of followers, the problem is that
> >> >> > typically people that is happy with a setting is not much active
> >> >> > defending it because they are happy in their sofas.
> >> >> >
> >> >> > My suggestion is adding a configuration option that lets the user
> >> >> > choose between "No Hinting", "Hinting" and "Hinting as set in KDE
> >> >> > settings". For KDE 4.3.x we can add it, it set in "Hinting" and the
> >> >> > only configuration option will be thought non GUI as we can't add
> >> >> > translatable texts. For KDE 4.4.x we can default to "No Hinting" if
> >> >> > others here (basically Pino, Brad, Tokoe) agree.
> >> >>
> >> >> I'm not one of those three, but I'll just chime in anyway and say
> >> >> that I agree with Benoit that, at least in the example he gave, it's
> >> >> very obvious that the non-hinted version looks much better. I'm not
> >> >> trying to troll here, but come on, in some places the hinted one is
> >> >> hardly readable, the characters are all jumpy; e.g. the 'T' in the
> >> >> very first word. I don't know if this is a bug in the hinting or just
> >> >> the way it's supposed to look.
> >> >>
> >> >> Anyway, this doesn't make me a "follower" of Benoit; I'm just calling
> >> >> it like I see it ;)
> >> >
> >> > That's one PDF in one hundred, and i've already felt too many times
> >> > people hating me becuase I changed something I considered mintor but
> >> > was critical for them, so for me it's a setting all the way.
> >>
> >> You miss the point, it's not a PDF, it's a DVI, and that makes all the
> >> difference, because as I explained in my previous email, 95% of DVI
> >> files use the same TeX font, so if I show you a bad screenshot with
> >> this font, it's to be taken seriously.
> >>
> >> Albert, seriously. I've fixed one of the top bugs in Okular, that
> >> makes it useless to half of people as far as PDF is concerned, and to
> >> everybody as far as DVI is concerned, and you don't even acknowledge
> >> the bug.
> >
> > Man, you are starting to repeat yourself
> >
> >> Let alone say thank you. Instead, you answer like I'm just an
> >> angry user who wants to steer Okular his own way. The bug wasn't hard
> >> to fix, you just need to acknowledge that while hinting can
> >> *sometimes* increase the crispness, it *always* degrades the fidelity
> >> of the rendering, and, regardless of "sometimes" versus "always", in
> >> the PARTICULAR setting of a PDF/DVI viewer, it should be OBVIOUS that
> >> fidelity is more important than crispness.
> >
> > You want a thanks?
> >
> > THANKS
> >  THANKS
> >  THANKS
> 
> Sigh. Am I really ridiculous, as you imply, for having expected a
> little "thanks" ?

Sincerely, yes, saying thanks is a good manner that is being gradually lost 
(at lest here in Barcelona), and that's bad. So i'm sorry to only find 
problems in your contributions and not be positive about your findings.

> 
> > Here you have three, please try to be constructive.
> 
> Constructive?
>  - I fix a bug in poppler and one in Okular
>  - I provide explanations of my findings
>  - I provide rationalizations of my opinions
> what more can i do. seriously?
> 
> > We have reached the situation in which it seems hinting is the culprit
> > for some bad font rendering.
> 
> Yes.
> 
> > Trust me in the fact that i know some people like
> > hinting, if you can't trust me, bad luck, but i'm the core developer
> > here.
> 
> Again, here I was submitting a patch that affects only DVI rendering.
> Only TeX fonts. I explained in the previous mail how this makes all
> the difference.
> 
> > I even gave you the default value, but you want to win so much that you
> > don't even want the option to exist? I don't really see what your problem
> > is.
> 
> I never said that. As soon as I read about your proposal to introduce
> the option, I was satisfied. It is useless for DVI, but it doesn't
> disturb me. And I understand that you want only one GUI for
> configuration, not one per file format. 

Exact, the option might be of not much use for DVI, but an option per format 
sucks a lot

> All is OK and for the rest, I
> was only replying point by point to your replies.
> 
> Again, let's not end this discussion on bad feelings. I don't know how
> such a technical discussion about patches could lead to bad moods but
> let's make sure it's over now. I never meant to offend you or attack
> you personnally, I was only criticizing existing code.

No problem, it sometimes gets too much personal when it shouldn't, i'm not 
angry and you are not, everyone's happy :-)

> Thanks for listening,

Thanks for the patch, serious.

Albert

> Benoit
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