Re: issue with line break option PANGO_WRAP_CHAR

[Behdad Esfahbod <behdad behdad org>]

On 13-09-06 08:22 AM, Parth Kanungo wrote:
> Hello,
>
> I am facing an issue with a line break option - PANGO_WRAP_CHAR.
>
> You can see the output (image.bmp)
>
> for my code (main.cpp)
>
> It is clear that "i" can be rendered on the first line after "Th".
>
> However, it is coming on the second line. This is wrong.
>
> Is this a known bug?

There's many things going on here:

1. Unicode line breaking algorithm prohibits breaking before a space.  As such
we try to fit the space after i in the same line.  Normally, after we break
line, we zero the width of the final space on the line (see
pango-layout.c:zero_line_final_space).  We try to account for that when
deciding where to break, but it's possible that we are messing things up,

2. When WRAP_CHAR, we still never break before a space, while sometimes that's
the right thing to do no matter what Unicode says.

In short, that piece of code needs some long overdue love, but I don't know
anyone with the time and expertise to look into it right now.

behdad

> I further debugged and found that
>
> 1. can_break_at() gives false for space character.
>
> 2. break_width contains the width of "Th" only, when it should contain the
> width of "The"
>
>  
>
> But, I am not sure how to fix this.
>
> Moreover, this problem aggravates if we introduce multiple spaces between 2 words.
>
>  
>
> Any pointers in this direction would be helpful.
>
>  
>
> Thanks and regards,
> Parth Kanungo
>
>
>
> _______________________________________________
> gtk-i18n-list mailing list
> gtk-i18n-list gnome org
> https://mail.gnome.org/mailman/listinfo/gtk-i18n-list

-- 
behdad
http://behdad.org/