dom/html: ImageData browser compatibility

[rakudrama]

ImageData is different on different browsers:

var image = context2d.createImageData(100, 200);

Chrome:
image is an ImageData object
image.data member is a CanvasPixelArray

FireFox 11:
image is a raw Object: {width: 100, height: 200, data: xxx}
image.data is a Uint8ClampedArray

We can wrap the image data to ensure the FF version is a valid Dart object. This would be a bit painful since it is also an input and would need to be unwrapped. Since the FF version is a raw object, presumably any object with the three properties would do - we could create a native class that has them but also has a prototype to attach Dart methods.

Not sure what to do to about .data property. To generate good code, dart2js would need to know that this has one of two disjoint types which have 'compatible' native methods.

Next action: explore other browsers.

[vsmenon]

Removed Area-UI label.
Added Area-DOM label.

[DartBot]

This comment was originally written by @bp74

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Chrome 18 + Firefox 12 are working with Uint8ClampedArray.
Internet Explorer 9 still complaints because of a CanvasPixelArray.

Dart Editor Build 7066.

[DartBot]

This comment was originally written by @bp74

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Looks like r7299 fixed it!
All browsers give you an Uint8ClampedArray now.

[rakudrama]

Thanks for verifying, Bernhard.

I'm leaving this bug open to track the problem with the type of the returned ImageData object:

Chrome:
image is an ImageData object

FireFox 11:
image is a raw Object: {width: 100, height: 200, data: xxx}

[DartBot]

This comment was originally written by @bp74

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With dart2js (build 8350) this issue is back.
In Firefox you can't access the "data" property of ImageData.

[kasperl]

Hi Stephen. Do you have any insights into what's happening here?

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cc @rakudrama.

[rakudrama]

Yes, see the initial report 'comment #­0'.
On Firefox we need to wrap every busted ImageData with a class that honours the interface.
The best way to do that is to introduce a general mechanism for handling objects that
need special processing coming from and / or going into the DOM.
This is a big change, but I'd rather fix the general problem.
If there I'd some specific urgency I can fix it by hand.

[rakudrama]

Added this to the M1 milestone.
Marked this as being blocked by #4062.

[iposva-google]

Removed Area-DOM label.
Added Area-HTML label.

[rakudrama]

Set owner to @rakudrama.
Added Started label.

[rakudrama]

Fixed r11193

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Added Fixed label.