GNU bug report logs -
#36315
27.0.50; SVG transparency handling is inaccurate
Previous Next
Reported by: Pip Cet <pipcet <at> gmail.com>
Date: Thu, 20 Jun 2019 20:28:02 UTC
Severity: normal
Found in version 27.0.50
Done: Alan Third <alan <at> idiocy.org>
Bug is archived. No further changes may be made.
Full log
View this message in rfc822 format
> Date: Tue, 25 Jun 2019 08:06:23 +0900
> From: YAMAMOTO Mitsuharu <mituharu <at> math.s.chiba-u.ac.jp>
> Cc: pipcet <at> gmail.com,
> 36315 <at> debbugs.gnu.org
>
> > The patch looks quite large. Do we gain anything significant, apart
> > of the appraisal of librsvg developers?
>
> 1. The current librsvg generates gdk-pixbuf via cairo image surface.
> So we can avoid unnecessarily intermediate data structure and
> roundtrip of alpha-component processing using cairo directly.
> 2. If configured --with-cairo, we can do further shortcut. This is
> included in the patch attached to this mail. Pip's patch is also
> reflected.
> 3. Image transformations can be applied when rendering to the cairo
> surface, not after generating bitmaps. So we can take advantage of
> outline format and get better results of scaling. This is not in
> the patch. Probably it should be done by a separate commit after
> general image transformation code has been stabilized.
Maybe it's just me, but I'm uneasy to bypass librsvg and call Cairo
directly for manipulating SVG images. Why doesn't librsvg provide a
way to do this via its own APIs?
Does anyone else think it's unusual to make such direct calls to what
is essentially a lower-level library?
> > I've built the patch on Windows (you forgot cairo_surface_destroy, so
> > I needed to add it), but the result is strange, or maybe I don't
> > understand what is expected. I don't see any rectangle of color
> > #f00000, I see the entire frame with black background, and a few
> > characters in other colors.
>
> When I tested Pip's test case, I started with emacs -Q -rv to avoid
> text becomes invisible. I could see a red rectangle on X11. Do you
> see such a rectangle without my patch?
Yes, I see an orange rectangle (a square, actually, I think).
This bug report was last modified 3 years and 218 days ago.
Previous Next
GNU bug tracking system
Copyright (C) 1999 Darren O. Benham,
1997,2003 nCipher Corporation Ltd,
1994-97 Ian Jackson.