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Re: DOMPoint dictionary problem

From: Dirk Schulze <dschulze@adobe.com>
Date: Tue, 17 Sep 2013 01:45:37 -0700
To: "Tab Atkins Jr." <jackalmage@gmail.com>
CC: "Robert O'Callahan" <robert@ocallahan.org>, Jet Villegas W3C <w3c@junglecode.net>, Cameron McCormack <heycam@gmail.com>, Boris Zbarsky <bzbarsky@mozilla.com>, Doug Schepers <schepers@w3.org>, "public-pointer-events@w3.org" <public-pointer-events@w3.org>, "public-fx@w3.org" <public-fx@w3.org>, www-style <www-style@w3.org>
Message-ID: <CB92366C-AB10-49D5-986E-F028FC11ED28@adobe.com>

On Sep 16, 2013, at 6:42 PM, Tab Atkins Jr. <jackalmage@gmail.com> wrote:

> On Mon, Sep 16, 2013 at 3:46 AM, Robert O'Callahan <robert@ocallahan.org> wrote:
>> Making DOMPoint a dictionary, as currently proposed, is a problem since it
>> means other objects (such as the proposed DOMQuad) can't have DOMPoints as
>> attributes. I'm assuming the WebIDL restriction that attributes can't be
>> dictionaries is not easily removed.
> 
> Yes, this is fine with me.
> 
>> I think we probably should make DOMPoint a regular interface. For methods
>> that take DOMPoints as parameters, we can retain the convenient literal
>> syntax for points by adding a DOMPointLiteral dictionary type and using
>> union types, e.g.
>>  DOMPoint convertPoint((DOMPoint or DOMPointLiteral) point);
> 
> You don't even need to do that - as long as their
> attribute/dict-member names match, a DOMPoint *is* a DOMPointLiteral,
> so you can just write the function signature as:
> 
>    DOMPoint convertPoint(DOMPointLiteral point)

I still think it would be useful to resolve decisions on DOMPoint together with a view to the needs of DOMMatrix which uses a Point definition as well. The current definition of Point in DOMMatrix is a dictionary and should have been compatible with DOMPoint dictionary. It is my understanding that this does not need to be the case with an interface DOMPoint. Difference: DOMPoint just has the attributes 'x' and 'y'. Point in DOMMatrix has at least a third parameter 'z' and possibly a forth 'w' (needs a resolution).

Greetings,
Dirk

> 
> ~TJ
> 
Received on Tuesday, 17 September 2013 08:46:17 UTC

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