I've been going round and round on this. Apparently, my usual muddle-through-the-geometry approach is not working.
I'm just trying to create a perfect "quarter" circle sector in draw.io.
I read through https://desk.draw.io/support/solutions/articles/16000052874-how-to-create-and-edit-shapes-
But it is very vague.
Here is my best attempt, but it isn't right, the edges are too hard:
<shape name="Quarter Circle" h="49" w="49" aspect="variable" strokewidth="inherit">
<connections>
<constraint x="0.5" y="0" perimeter="0" name="N"/>
<constraint x="0.5" y="1" perimeter="0" name="S"/>
</connections>
<background>
<path>
<move x="49" y="0"/>
<line x="0" y="0"/>
<line x="0" y="49"/>
<arc rx="90" ry="90" x-axis-rotation="0" large-arc-flag="0" sweep-flag="0" x="49" y="0"/>
<close/>
</path>
</background>
<foreground>
<fillstroke/>
</foreground>
</shape>
I really want a quarter circle that if you rotate four of them, you end up with a perfect circle.
The arc radii (rx and ry) have to match the shape size to achieve what you want. Just replace your arc line with this:
<arc rx="49" ry="49" x-axis-rotation="0" large-arc-flag="0" sweep-flag="0" x="49" y="0"/>