[whatwg] Canvas - Exception on arc with negative radius
vbs85 at gmx.de
Fri Mar 27 12:50:47 PDT 2009
why does the spec want an INDEX_SIZE_ERR exception on arc's with a
negative radius? This blocks further drawings.
Here is a short example:
var canvas = document.getElementById("canvas");
var ctx = canvas.getContext("2d");
//arc(x, y, radius, startAngle, endAngle, anticlockwise)
ctx.arc(30, 30,-20, 0, 2*Math.PI, false);
<canvas id="canvas" width="100" height="60">
The circle, drawn by the arc, has a negative radius. A negative radius
doesn't make sense for circles, but an INDEX_SIZE_ERR exception stops
further drawing of the rect, even if the code is ok there.
Another example is: http://blahbleh.com/molecools.php?name=1,2%
If you turn the molecule a bit, the circles disappear with a
Isn't it better to just ignore the arc and go on with the drawing, like
Firefox does? And perhaps the same for arcTo?
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