Re: canvas: globalAlpha should not throw

Ian Hickson wrote:
> On Tue, 19 May 2009, Simon Pieters wrote:
>> The spec doesn't call out NaN and Infinity for globalAlpha. I think 
>> globalAlpha should be handled consistently with the other canvas 
>> attributes and not throw an exception.
>>
>> http://www.whatwg.org/specs/web-apps/current-work/multipage/the-canvas-element.html#dom-context-2d-globalalpha
> 
> The spec says:
> 
>    Unless otherwise stated, for the 2D context interface, any method call 
>    with a numeric argument whose value is infinite or a NaN value must be 
>    ignored.
> 
> ...and doesn't appear to contradict this in the definition of globalAlpha. 
> Am I missing something?

Unless I'm missing something: globalAlpha isn't a method call.

("Common conformance requirements" differentiates "DOM attribute" 
assignment from "method" calling, so I presume that distinction is real, 
and the bit you quoted from the spec only talks about method calls.)

-- 
Philip Taylor
pjt47@cam.ac.uk

Received on Wednesday, 10 June 2009 16:58:35 UTC