Bug 17954 – Canvas arc() with radius of 0 throws exception

• Component: DOM
• Status: RESOLVED FIXED

[John Resig]

See the following reduction:
http://ejohn.org/files/bugs/arc/

Which throws the following error:
Error: INDEX_SIZE_ERR: DOM Exception 1
http://ejohn.org/files/bugs/arc/ (line 5)

According to the canvas spec:
http://www.whatwg.org/specs/web-apps/current-work/multipage/section-the-canvas.html

"Negative values for radius must cause the implementation to raise an INDEX_SIZE_ERR exception."

However, that is not the case for arcs with a radius of 0.

[John Resig]

For posterity, here's the reduction:

<canvas width="100" height="100" id="canvas"></canvas>
<script>window.onload = function(){
var c = document.getElementsByTagName("canvas")[0];
var context = c.getContext("2d");
context.arc( 10, 10, 0, 0, 180, false );
};</script>

[Mark Rowe (bdash)]

<rdar://problem/5808318>

[Oliver Hunt]

Landed r31162