Inline data URIs for SVG markers are not directly supported in QGIS 3.40.x

[cxcandid]

What is the bug or the crash?

In Sept. 2020 I found out that we can use inline SVG definitions to define a point marker symbol in QGIS: https://gis.stackexchange.com/questions/374223/using-embedded-svg-symbol-in-multiple-layers

In QGIS 3.36.x it was possible to enter the following data URI in Expression Builder to define a SVG marker:

'data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" version="1.1" id="Layer_1" x="0px" y="0px" viewBox="0 0 100 100" enable-background="new 0 0 100 100" xml:space="preserve" height="100px" width="100px"><path fill="param(fill) #000000" d="M50,2.5c-19.2,0-34.8,15-34.8,33.4C15.2,61.3,50,97.5,50,97.5s34.8-36.2,34.8-61.6 C84.8,17.5,69.2,2.5,50,2.5z M50,48.2c-7.1,0-12.9-5.8-12.9-12.9c0-7.1,5.8-12.9,12.9-12.9c7.1,0,12.9,5.8,12.9,12.9 C62.9,42.4,57.1,48.2,50,48.2z"/></svg>'

Unfortunately, this no longer works in QGIS 3.40.x.

In QGIS 3.40.x we also need to convert the data URI to base64 to achieve the same effect:

'base64:'|| to_base64('<svg xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink" version="1.1" id="Layer_1" x="0px" y="0px" viewBox="0 0 100 100" enable-background="new 0 0 100 100" xml:space="preserve" height="100px" width="100px"><path fill="param(fill) #000000" d="M50,2.5c-19.2,0-34.8,15-34.8,33.4C15.2,61.3,50,97.5,50,97.5s34.8-36.2,34.8-61.6 C84.8,17.5,69.2,2.5,50,2.5z M50,48.2c-7.1,0-12.9-5.8-12.9-12.9c0-7.1,5.8-12.9,12.9-12.9c7.1,0,12.9,5.8,12.9,12.9 C62.9,42.4,57.1,48.2,50,48.2z"/></svg>')

QGIS 3.40.x can no longer process inline data URIs for SVG markers directly.

Steps to reproduce the issue

See bug report.

Versions

QGIS 3.40.x Windows

Supported QGIS version

• I'm running a supported QGIS version according to the roadmap.

New profile

• I tried with a new QGIS profile

Additional context

No response

[nyalldawson]

Thanks for reporting this!

It's funny, inline data like this was never formally supported -- it was a happy accident that it worked at all. Anyway, I've fixed it in #59589 and added tests, so you can consider if officially supported now.

[cxcandid]

@nyalldawson many thanks for your support!

Is this a general fix that works everywhere where SVG symbols can be selected (i.e. label background)?

[nyalldawson]

@cxcandid yes, it'll work everywhere