CSS style background-image not always applied when exported to PDF

[SamOxyPlot]

Plugin dw2pdf version: 2021-02-07
Dokuwiki version: Release 2020-07-29 "Hogfather"
OS: Windows 2016

I'm currently using a self-written CSS plugin with a print.css file.

Prerequisites: an Dokuwiki page with following content (see atachment)

Dokuwiki syntax.txt

Print.css containts:

.image {
    background: url(/Wiki/lib/plugins/liscss/images/img.png) no-repeat;
    height: 20px;
    width: 20px;
    display: inline-block;
}

The page is rendered correctly in the browser even in 'print mode'.
However when exporting to PDF the image is only visible in the first DIV. Even in the table the DIV displays no image. In both situations the A element doesn't show the image.

I hope someone can help me find the cause of the problem.

[Klap-in]

I guess it could be a limitation of the mpdf library. The supported css is described here: https://mpdf.github.io/css-stylesheets/supported-css.html

Sometime it has limitations, e.g. maybe the display: inline-block is a challenge for mpdf...?

[Klap-in]

This might be related with #478