Plotly.Net generated SVGs misinterpreted

[jaguarxii]

Describe the bug
Some SVGs generated from Plotly.Net that contain "newline" in text are misinterpreted.

To Reproduce
Using the following samples

after embeding to a document:

    column.Item().Border(2, Unit.Mil).Padding(2, Unit.Millimetre)
        .AlignCenter()
        .Width(150, Unit.Millimetre)
        .Svg(svgBarChart)
        ;

    column.Item().Border(2, Unit.Mil).Padding(2, Unit.Millimetre)
        .AlignCenter()
        .Width(100, Unit.Millimetre)
        .Svg(svgPieChart)
        ;

the images should mantain its structure, but the labels are not quite right

Expected behavior

I have found that the tags that include "em" untis, are misinterpreted

<tspan class="line" dy="0em" x="250" y="250">Simple</tspan>
<tspan class="line" dy="1.3em" x="250" y="250">pie chart</tspan>

If I change them by removing its units I get the right result:

<tspan class="line" dy="0em" x="250" y="250">Simple</tspan>
<tspan class="line" dy="50" x="250" y="250">pie chart</tspan>

Environment
QuestPDF 2024.3.10
Window 11 / Debian 12
dotnet 8

Aditional
Also, the font described in the chart "Nunnito" is not embeded in the file, as it was described in the issue #777

[MarcinZiabek]

This behavior could be:

• a corner case not supported by the Skia SVG engine,
• an option invalid in the SVG specification and therefore not supported by the Skia SVG engine, but correctly displayed in web browsers as they have less strict rules.

I am unable to check as the W3C SVG validator is not working at this moment.

[jaguarxii]

Hi, indeed it seems that relative units (em) are not quite supported by Skia SVG.

Using the Example Units SVG from the W3 SVG Recommendation, that should look like this:

After embedding into my test PDF document, looks like this:

[MarcinZiabek]

Thank you for checking this behavior. Although Skia SVG is quite a mature engine, it surely does not support every feature. SVG is just a surprisingly complex standard 😢