Example
The axis offsets for drawing the marker that are specified by refX and refY are applied before the rotation specified by the orient parameter. Below you can see the effects of various combinations of orient and refX, refY to illustrate this.
<svg width="800px" height="600px">
<defs>
<marker id="marker1"
viewBox="0 0 10 10" refX="0" refY="5" orient="auto" >
<path d="M 0 0 L 10 5 L 0 10 z" />
</marker>
<marker id="marker2"
viewBox="0 0 10 10" refX="0" refY="0" orient="0" >
<path d="M 0 0 L 10 5 L 0 10 z" />
</marker>
<marker id="marker3"
viewBox="0 0 10 10" refX="20" refY="20" orient="0" >
<path d="M 0 0 L 10 5 L 0 10 z" />
</marker>
<marker id="marker4"
viewBox="0 0 10 10" refX="20" refY="20" orient="180" >
<path d="M 0 0 L 10 5 L 0 10 z" />
</marker>
</defs>
<line x1="20" y1="20" x2="100" y2="100" stroke-width="8" stroke="blue" marker-end="url(#marker1)" />
<text x="20" y="150"> refX,Y (0,5) orient (auto) </text>
<line x1="220" y1="20" x2="300" y2="100" stroke-width="8" stroke="blue" marker-end="url(#marker2)" />
<text x="220" y="150"> refX,Y (0,0) orient (0) </text>
<line x1="20" y1="220" x2="100" y2="300" stroke-width="8" stroke="blue" marker-end="url(#marker3)" />
<text x="20" y="390"> refX,Y (20,20) orient (0) </text>
<line x1="220" y1="220" x2="300" y2="300" stroke-width="8" stroke="blue" marker-end="url(#marker4)" />
<text x="220" y="390"> refX,Y (20,20) orient (180) </text>
</svg>
