bug#26978: 25.2; incomplete display of SVG image

[Eli Zaretskii <eliz@gnu.org>]

> From: ynyaaa@gmail.com
> Date: Thu, 18 May 2017 13:24:40 +0900
> 
> (1)Texts in SVG are not displayed.
> This sample should show "ABC" in a red square,
> but three rectangles are displayed instead of "ABC".
> 
> <svg xmlns="http://www.w3.org/2000/svg" width="100" height="100">
>   <rect fill="red" width="100" height="100"/>
>   <text x="10" y="60" font-size="40" fill="white">ABC</text>
> </svg>

I cannot reproduce this: I do see "ABC" in a red square.

> (2)External image files may not be displayed.
> Copy emacs-25.2/share/icons/hicolor/16x16/apps/emacs.png
> into the same directory of the sample SVG,
> I can view the scaled emacs icon over a blue square with image-mode.
> 
> If emacs.png and the SVG are saved in the root directory,
> viewing the SVG shows only a blue square.
> 
> If emacs.png is not in the same directory of the SVG nor its descendant
> and the path of xlink:href="..." is rewritten,
> viewing the SVG shows only a blue square.

Is this related to the first or the second SVG in your report?

> If the current buffer is not related to any file
> (i.e. buffer-file-name is nil),
> evaluating (insert-image (create-image data-string 'svg t))
> shows only a blue square.
> 
> <svg xmlns="http://www.w3.org/2000/svg" width="100" height="100"
>      xmlns:xlink="http://www.w3.org/1999/xlink">
>   <rect fill="blue" width="100" height="100"/>
>   <image xlink:href="emacs.png" width="100" height="100"/>
> </svg>

Here I see only a blue square no matter whether this SVG is from a
file or from a buffer string, and no matter what is the directory.
Once again, a full detailed recipe could help establish whether
there's a difference between our systems.

Firefox does show the PNG image on the background of the square.  Can
someone please try the above SVG in Emacs on a Unix or GNU system and
tell what is displayed?

This could be a problem with that particular version of librsvg, which
would make it not an Emacs problem.

> I obtained librsvg-2.40.1-2-w32-bin.zip
> from http://sourceforge.net/projects/ezwinports/files/.

What about the PNG library?  Is it possible you are using one that is
different from what came with librsvg-2.40.1-2-w32-bin.zip?  librsvg
uses libpng internally.