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

[ludo@gnu.org (Ludovic Courtès)]

Andy Wingo <wingo@igalia.com> skribis:

> On Fri 28 Aug 2015 19:15, Luis Felipe López Acevedo <felipe.lopez@openmailbox.org> writes:
>
>> Modifying the document background does not affect the design at all,
>> because we are using the dark rectangle on top of it as the background
>> of the image, so it doesn't matter what the background of the document
>> is.
>>
>> Could it be that rsvg-convert is complaining about transparency in the
>> page/document background and not about the transparency of the
>> checkerboard pattern in the "Background" layer? Because it is not
>> complaining about the transparency in the layer that contains the logo
>> (which has transparency as well), is it?
>
> We could use guile-cairo / guile-rsvg to convert, fwiw.  Better to do
> that than to cause our graphics people to modify the image.
>
>   (use-modules (rsvg) (cairo))
>
>   (define (->int x) (inexact->exact (ceiling x)))
>
>   (define (render-to-png in-svg out-png)
>     (let ((svg (rsvg-handle-new-from-file in-svg)))
>       (call-with-values (lambda () (rsvg-handle-get-dimensions svg))
>         (lambda (width height em ex)
>           (let* ((surf (cairo-image-surface-create 'argb32
>                                                    (->int width)
>                                                    (->int height)))
>                  (cr (cairo-create surf)))
>             (rsvg-handle-render-cairo svg cr)
>             (cairo-surface-flush surf)
>             (cairo-surface-write-to-png (cairo-get-target cr) out-png))))))

FWIW I tried this (finally!) and this has the same problem as
‘rsvg-convert’ regarding the checkerboard pattern.

So maybe we need to apply Felipe’s changes anyway?  Thoughts?

Ludo’.