Re: Font height issue

[Marcin Borkowski]

On 2016-02-25, at 20:34, Tassilo Horn <address@hidden> wrote:

> Hi all,
>
> I have the problem that the font I want to use in Emacs (PragmataPro in
> size 10, sizes 9 or 11 seem to be not affected) seems to have slightly
> different heights in the regular and the bold version, or at least Emacs
> thinks so.  As a result, when modes change text to/from regular to bold
> or vice versa dynamically (e.g., show-paren-mode with a bold
> show-paren-match face), the height of the line changes which is
> extremely annoying.
>
> When I searched the net I found many others having this kind of issue
> with different fonts (like DejaVu Sans Mono), too, and I also found this
> workaround
>
>   
> https://www.reddit.com/r/emacs/comments/3zto22/i_sort_of_fixed_a_font_rendering_bug_of_emacs/
>
> suggesting this patch:
>
> --8<---------------cut here---------------start------------->8---
> diff --git a/src/xftfont.c b/src/xftfont.c
> index 110f99a..95e7e52 100644
> --- a/src/xftfont.c
> +++ b/src/xftfont.c
> @@ -395,16 +395,16 @@ xftfont_open (struct frame *f, Lisp_Object entity, int 
> pixel_size)
>  
>    font->ascent = xftfont->ascent;
>    font->descent = xftfont->descent;
> -  if (pixel_size >= 5)
> -    {
> -      /* The above condition is a dirty workaround because
> -        XftTextExtents8 behaves strangely for some fonts
> -        (e.g. "Dejavu Sans Mono") when pixel_size is less than 5. */
> -      if (font->ascent < extents.y)
> -       font->ascent = extents.y;
> -      if (font->descent < extents.height - extents.y)
> -       font->descent = extents.height - extents.y;
> -    }
> +  /* if (pixel_size >= 5) */
> +  /*   { */
> +  /*     /\* The above condition is a dirty workaround because */
> +  /*    XftTextExtents8 behaves strangely for some fonts */
> +  /*    (e.g. "Dejavu Sans Mono") when pixel_size is less than 5. *\/ */
> +  /*     if (font->ascent < extents.y) */
> +  /*   font->ascent = extents.y; */
> +  /*     if (font->descent < extents.height - extents.y) */
> +  /*   font->descent = extents.height - extents.y; */
> +  /*   } */
>    font->height = font->ascent + font->descent;
>  
>    if (XINT (AREF (entity, FONT_SIZE_INDEX)) == 0)
> --8<---------------cut here---------------end--------------->8---
>
> And indeed, that does solve the issue for me.  Now the regular and the
> bold version are displayed with the same height.
>
> I have no idea about font handling, so I cannot tell if the above DTRT.
> However, it fixes an annoying issue that seems to happen only with
> Emacs.  Somewhere on the net I've read that Emacs seems to be the only
> one being correct, i.e., it displays what the font says, and if the bold
> version of a font is higher than the regular one, that's a (mis)feature
> of the font.
>
> Anyhow, since the results can be annoying and apparently not so few
> users are affected, can we have a customize option for that?

+1

I have the same problem.

> Bye,
> Tassilo

Best,

-- 
Marcin Borkowski
http://octd.wmi.amu.edu.pl/en/Marcin_Borkowski
Faculty of Mathematics and Computer Science
Adam Mickiewicz University