[BUG] Drawing to SVG: stroke-linejoin not transferred to SVG

[Mikkel Pedersen]

Hi all,

Version: 4.4.4.

When setting the stroke linejoin to 1 or 2 (round or bevel) in a Polygon, this information is not transferred when saving the Drawing as SVG. 

Here is a minimal example. Notice that the Polygon has strokeLineJoin=1.

from reportlab.graphics.shapes import Drawing, Polygon

from reportlab.lib.colors import Color

from reportlab.graphics import renderSVG

drawing = Drawing(500, 500)

polygon = Polygon(

    [10, 10, 250, 490, 490, 10],

    strokeWidth=5,

    fillColor=Color(0, 0, 0, 0),

    strokeLineJoin=1

)

drawing.add(polygon)

svg_data = drawing.asString('svg')

img_bytes = renderSVG.drawToString(drawing)

with open('output.svg', 'w') as f:

    f.write(img_bytes)

The output is shown below. Since I set the stroke linejoin to 1 (round) I would expect the linejoins to be round. Instead, the default 0 (miter) is used.

Digging into the saved SVG file I found that stroke-linejoin were nowhere to be found. In renderSVG.py I managed to find a solution that at least works for my example. Here are the changes:

Line 32: I added stroke-linejoin.

AREA_STYLES = 'stroke-width stroke-linecap stroke-linejoin stroke stroke-opacity fill fill-opacity stroke-dasharray stroke-dashoffset fill-rule id'.split()

Line 351: I changed stroke-linecap to stroke-linejoin. This is what convinced me that this is a bug. In the method setLineJoin(), it sets the stroke-linecap instead.

self.style['stroke-linejoin'] = vals[v]

Here is the output with these changes. As you can see the linejoins are now rounded.

Here is a GitHub Gist of the modified renderSVG.py: https://gist.github.com/mikkelkp/5dd6a1a21dcffe7feb5d6e90578ef009

Regards,

Mikkel