Circle with small radius, large scaling and opacity < 1 comes out as a square

[alexnoe81]

Description

If an svg file contains a circle with small radius (such as 1) which is referenced in a use element with large scaling and opacity < 1, it doesn't come out as a circle. The circle with radius 1 gets rendered into an image, and then, the resulting image of size 2x2 gets scaled and added to the target renderer.

The thing is that gnuplot using the svg terminal creates these kind of svg files, and technically, it is not wrong to do so.

Example data

The following example shows the problem. It's a real gnuplot output where I removed everything except for one circle. Note r='1', scale(9.45) and opacity='0.58'):

<?xml version="1.0" encoding="utf-8"  standalone="no"?>
<svg 
 width="3840" height="2160"
 viewBox="0 0 3840 2160"
 xmlns="http://www.w3.org/2000/svg"
 xmlns:xlink="http://www.w3.org/1999/xlink"
>

<title>Gnuplot</title>
<desc>Produced by GNUPLOT 5.4 patchlevel 5 </desc>

<g id="gnuplot_canvas">
	<rect x="0" y="0" width="3840" height="2160" fill="none"/>
	<defs>
		<circle id='gpPt5' stroke-width='0.074' stroke='currentColor' cx='0' cy='0' r='1'/>
		<use xlink:href='#gpPt5' id='gpPt6' fill='currentColor' stroke='none'/>
	</defs>
	<use xlink:href='#gpPt6' transform='translate(277.22,196.15) scale(9.45)' color='rgb(  0, 192,   0)' opacity='0.58'/>
	</g>
</svg>

Used Versions

NuGet 3.4.4, used in .NET Framework 4.7.2.