SVG: right-align text at the end of a textPath - html

Question

I'd like to right-lign text at the end of a textPath:
<svg height="300" width="400">
<defs>
<path id="myTextPath" d="M30,160 A175,175 0 0,1 370,160" />
</defs>
<path d="M30,160 A175,175 0 0,1 370,160" style="stroke: black; stroke-width:1; fill:none;" />
<g fill="black" stroke="none">
<text x="0%" y="0" text-anchor="start">
<textPath xlink:href="#myTextPath">Start</textPath>
</text>
<text x="50%" y="0" text-anchor="middle">
<textPath xlink:href="#myTextPath">Middle</textPath>
</text>
<text x="100%" y="0" text-anchor="end">
<textPath xlink:href="#myTextPath">End</textPath>
</text>
</g>
</svg>
You can see this working here: http://jsfiddle.net/7sqdxw11/
The Start text begins right where I'd expect - at the beginning of the textPath.
However, the end text ends well short of the end of the textPath.
(The Middle is also well shy of the middle of the textPath).
Here's a screenshot:
What am I doing wrong? How to I get the End to end at the right end of the textPath arc?

Answer 1

In SVG percentage coordinates generally refer to the either the width of the SVG, or in some cases the width of the parent object.
So in your example the "100%" will result in a value of 400px - the width of your SVG. However your path actually has a length of 466. You can get the length by experimentation, or by using some Javascript:
var len = document.getElementById("myTextPath").getTotalLength();
So if you change the "100%" to "466" you get the effect you wanted.
<svg height="300" width="400">
<defs>
<path id="myTextPath" d="M30,160 A175,175 0 0,1 370,160" />
</defs>
<path d="M30,160 A175,175 0 0,1 370,160" style="stroke: black; stroke-width:1; fill:none;" />
<g fill="black" stroke="none">
<text x="0" y="0" text-anchor="start">
<textPath xlink:href="#myTextPath">Start</textPath>
</text>
<text x="233" y="0" text-anchor="middle">
<textPath xlink:href="#myTextPath">Middle</textPath>
</text>
<text x="466" y="0" text-anchor="end">
<textPath xlink:href="#myTextPath">End</textPath>
</text>
</g>
</svg>