Rendering SVG in Emacs is broken when only viewBox attribute is given

[smartmic]

Is this a new report?

Yes

System Info

Void 6.6.11_1 x86_64 AuthenticAMD notuptodate rFF

Package(s) Affected

emacs-gtk3-29.2_1

Does a report exist for this bug with the project's home (upstream) and/or another distro?

No response

Expected behaviour

Rendering SVG images which only have a viewBox specification should work.

Actual behaviour

When I open an SVG file which has only a viewBox attribute and no height or width (perfectly valid SVG, renders fine on any SVG viewer and also with Emacs on other distros/platforms), only a small frame appears and no image is rendered. In buffer *Messages*, this (repeating) message appears:

Invalid image size (see ‘max-image-size’)

I shared more details on Reddit

Steps to reproduce

1. Try to display this SVG as image:

<svg style="font-family: Sans Serif;" xmlns='http://www.w3.org/2000/svg' viewBox="0 0 112.32 76.32">
<path d="M2.16,74.16L110.16,74.16L110.16,2.16L2.16,2.16Z"  style="fill:none;stroke-width:2.16;stroke:rgb(0,0,0);" />
<text x="56.16" y="38.16" text-anchor="middle" fill="rgb(0,0,0)" dominant-baseline="central">Hello</text>
</svg>

It will show only a small empty frame.
2. Change to text mode and add a height attribute with a value to the SVG:

<svg style="font-family: Sans Serif;" xmlns='http://www.w3.org/2000/svg' height="200" viewBox="0 0 112.32 76.32">
<path d="M2.16,74.16L110.16,74.16L110.16,2.16L2.16,2.16Z"  style="fill:none;stroke-width:2.16;stroke:rgb(0,0,0);" />
<text x="56.16" y="38.16" text-anchor="middle" fill="rgb(0,0,0)" dominant-baseline="central">Hello</text>
</svg>

3. Switch back to image mode, it will render fine