Markers with viewBox attribute have a border applied around the viewBox automatically

[michaellisitsa]

There is an issue where markers with a viewBox attribute are showing with a rectangular border in >v55

Browsers do not have this behaviour see https://codepen.io/michaellisitsa/pen/xxmBbye and couldn't find anything in the https://www.w3.org/TR/SVG/painting.html#RenderingMarkers

Investigation of bug
The bug only surfaced at v55.0 where a fix was made to the viewBox for markers 607f26f

A check occurs in svg/__init__.py file for the viewBox attribute on the marker node, and as a results a clip box is created on

WeasyPrint/weasyprint/svg/__init__.py

Line 544 in 4dfe607

clip_box = (

Further down, a check is done for the clip_box and a rectangle is drawn. I believe this shouldn't be the case.

WeasyPrint/weasyprint/svg/__init__.py

Line 589 in 4dfe607

self.stream.rectangle(*clip_box)

Reproducable example

<svg
          width="600"
          height="217"
          role="img"
          viewBox="0 0 600 217"
          style="pointer-events: all; width: 100%; height: 100%"
        >
          <defs>
            <marker
            id="circle"
              viewBox="0 0 10 10"
              refX="10"
              refY="5"
              markerWidth="15"
              markerHeight="15"
              orient="auto"
              stroke="none"
            >
              <circle cx="2.5" cy="7.5" r="2.0" stroke="red" fill="transparent" stroke-width="1"/>
            </marker>
          </defs>
            <path
              d="M102.86664121071314,106.99999999999997L102.86664121071314,59"
              style="
                fill: none;
                stroke: black;
                pointer-events: stroke;
                marker-end: url(#circle);
                stroke-width: 2;
              "
              role="presentation"
              shape-rendering="auto"
            ></path>
        </svg>

[liZe]

Hi!

Thanks for the report.

We should add self.stream.end() after clipping, otherwise the rectangle will be used during the drawing. The push/pop state is probably also useless. I’ll push the fix as soon as I find the time to add some related tests!

[liZe]

This problem is fixed and some tests have been added, but there are probably many problems left with markers and their wonderful list of available attributes. Don’t hesitate to report more issues if needed!