Re: [PATCH] system: grub: Convert grub background using rsvg-convert

[Mark H Weaver <mhw@netris.org>]

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Hi Luis, thanks for the quick response.

Luis Felipe López Acevedo <felipe.lopez@openmailbox.org> writes:

> On 2015-08-27 16:19, ludo@gnu.org wrote:
>> Mark H Weaver <mhw@netris.org> skribis:
>>
>>> The main difficulty here was that our SVG artwork is partially
>>> transparent, and includes a "Background" layer with a checker-board
>>> pattern.  I guess this layer is for convenience when editing in
>>> Inkscape, and apparently Inkscape excludes the "Background" layer when
>>> exporting to png.  Other tools render all layers.  Therefore, avoiding
>>> Inkscape required code to remove that layer before conversion to png.
>>
>> Fun.  :-)
>>
>> If possible, I would rather remove said layer directly in the
>> guix-artwork repo, or somehow make that layer invisible to
>> rsvg-convert.  Luis Felipe: What’s your take on this?
>
> If I understand correctly, the problem is transparency, right? I don't
> understand why transparency would be an issue when exporting PNG
> images, but I don't know how rsvg works.
>
> In any case, the SVG has transparency in several parts:
>
> - The logo.
> - The checkerboard pattern (which is part of the design as in the slim
> login screen).

Ah, okay, so my guesses were incorrect.  I guess the problem is actually
that rsvg-convert (from librsvg) fails to render these SVG files
correctly.  Here's how it renders grub/GuixSD-fully-black-4-3.svg on a
black background:

rsvg-convert --width 640 --height 480 --background-color black \
             --format png --output ~/grub-background.png \
             grub/GuixSD-fully-black-4-3.svg


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> Modifying the first to be fully opaque is time consuming, but can be
> done.

No need, we should keep the source file in the preferred form for
editing.  I'll see if I can figure out what librsvg is doing wrong,
and in the meantime we can keep using inkscape to do the conversion.

Thanks again,

    Mark