[whatwg] [canvas] globalCompositeOperation poorly defined

Henri Sivonen hsivonen at iki.fi
Fri Jul 21 01:14:09 PDT 2006

On Jul 21, 2006, at 00:59, L. David Baron wrote:

> On Friday 2006-06-23 12:30 +0200, Arve Bersvendsen wrote:
>> There are a number of tests for globalCompositeOperation here:
>> <URL:http://testsuite.org/html/elements/canvas/getContext/2d/ 
>> globalCompositeOperation/>
>> These tests are written pretty much to the letter of the  
>> specification,
>> but it would be appreciated if someone tried to verify the tests.
> I don't see how the pass conditions in those tests are derived from  
> the
> little that the specification says.  If someone could explain, perhaps
> they could write better text for the specification?

I gather that a normative reference to the Porter–Duff paper is needed:

Henri Sivonen
hsivonen at iki.fi

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