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Re: Question for 2d.composite.operation.darker

From: Ms2ger <ms2ger@gmail.com>
Date: Fri, 15 Jun 2012 11:18:03 +0200
Message-ID: <4FDAFDCB.7020503@gmail.com>
To: public-html-testsuite@w3.org
On 06/15/2012 04:36 AM, 이근용 wrote:
> Hello
>
> I am browser engineer in Samsung Electronics.
>
> I have a question for "2d.composite.operation.darker" test.
>
> This test check whether 'darker' operation is the unrecognized operation.
>
> However, W3C Spec define globalcompositeoperation as follows
>
> |source-atop|
>      AatopB.Display the source image wherever both images are opaque. Display the
>      destination image wherever the destination image is opaque but the source
>      image is transparent. Display transparency elsewhere.
> |source-in|
>      AinB.Display the source image wherever both the source image and destination
>      image are opaque. Display transparency elsewhere.
> |source-out|
>      AoutB.Display the source image wherever the source image is opaque and the
>      destination image is transparent. Display transparency elsewhere.
> |source-over|(default)
>      AoverB.Display the source image wherever the source image is opaque. Display
>      the destination image elsewhere.
> |destination-atop|
>      BatopA.Same as|source-atop
>      <http://www.w3.org/TR/2012/WD-2dcontext-20120329/#gcop-source-atop>|but
>      using the destination image instead of the source image and vice versa.
> |destination-in|
>      BinA.Same as|source-in
>      <http://www.w3.org/TR/2012/WD-2dcontext-20120329/#gcop-source-in>|but using
>      the destination image instead of the source image and vice versa.
> |destination-out|
>      BoutA.Same as|source-out
>      <http://www.w3.org/TR/2012/WD-2dcontext-20120329/#gcop-source-out>|but using
>      the destination image instead of the source image and vice versa.
> |destination-over|
>      BoverA.Same as|source-over
>      <http://www.w3.org/TR/2012/WD-2dcontext-20120329/#gcop-source-over>|but
>      using the destination image instead of the source image and vice versa.
> |lighter|
>      AplusB.Display the sum of the source image and destination image, with color
>      values approaching 255 (100%) as a limit.
> |copy|
>      A(Bis ignored).Display the source image instead of the destination image.
> |xor|
>      AxorB.Exclusive OR of the source image and destination image.
> |vendorName-operationName|
>      Vendor-specific extensions to the list of composition operators should use
>      this syntax
>
>      Currently, Webkit support "darker","lighter" operation as vender specific
>      extension.

"lighter" clearly isn't an extension, as you list it in the quote from 
the specification above.

>      Although W3C Spec describe vender extension operation, browsers based on
>      Webkit should get "fail" in this test case.
>
>      I think that this test case should be modified or removed.

WebKit violates the specification, and the test correctly tests for that 
violation. (Gecko used to fail this test as well, with a different 
implementation of "darker".) I object to modifications to this test that 
would make WebKit not fail it.

HTH
Ms2ger
Received on Friday, 15 June 2012 09:18:41 GMT

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