Re: [dev] Potential bug in st fallback font code

From: Christoph Lohmann <20h_AT_r-36.net>
Date: Tue, 10 Mar 2015 06:39:49 +0100

Greetings.

On Tue, 10 Mar 2015 06:39:49 +0100 Eric Pruitt <eric.pruitt_AT_gmail.com> wrote:
> On Mon, Mar 09, 2015 at 11:17:23PM +0100, Christoph Lohmann wrote:
> > The returned pattern are no duplicates and can’t be compared. I pushed a
> > change to st to store the unicode long too of the glyph. This prevents
> > the code from reloading the default font used to display the missing
> > glyph.
>
> I think your patch is buggy as I have noticed two strange behaviours. I
> recompiled st, launched my music player, and I had some Japanese
> characters that have normally rendered fine for me render as rectangles.
> Upon closing and re-opening st, they rendered correctly again; see
> attached "non-rendering-characters.png". Unfortunately, I can't seem to
> reproduce the problem, but since I've never experienced anything like
> that before and use st with Asian characters on a daily basis, your
> change seems to be the most likely suspect. On top that, the size in
> which st renders the missing-character-rectangles has also spontaneously
> changed*. This is easy to reproduce by reverting the st git repo and
> recompiling st; see attached "font-size-change.png".
>
> * I cannot explain why, in the first screenshot, the rectangles are
> large instead of small.

Why are you throwing half‐baked bug reports at me without doing any de‐
bugging on your own? First of all, this is suckless: Bug reports have to
be opened with a patch attached. Second: Don’t reply to yourself if you
don’t have any new information in it.

The code is open, add as many debug symbols as you like. Most likely you
will need to compile fontconfig to have debug output too. My first guess
is that just checking for the long of the character isn’t enough cache
information.

When I find some way to reproduce the problem I will debug it as needed.

For your line drawing problem: This is an Xft problem. I don’t want to
add specific line‐drawing code to st. It’s the task of the font render‐
ing library to actually produce what I tell it to draw. Maybe it’s time
to move to pango to not have to deal with that bug reports anymore.


Sincerely,

Christoph Lohmann
Received on Tue Mar 10 2015 - 06:39:49 CET