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Re: Filter Templates

From: Alex Danilo <alex@abbra.com>
Date: Fri, 25 Feb 2011 11:13:09 +1100
Message-Id: <XLC5HL.4VE4HHE6L9DI@abbra.com>
To: Rik Cabanier <cabanier@gmail.com>
Cc: Anthony Grasso <Anthony.Grasso@cisra.canon.com.au>, Dean Jackson <dino@apple.com>, Alistair MacDonald <al@bocoup.com>, Rik Cabanier <cabanier@adobe.com>, Cameron McCormack <cam@mcc.id.au>, Brad Kemper <brad.kemper@gmail.com>, www-style list <www-style@w3.org>, "public-fx@w3.org" <public-fx@w3.org>
Hi Rick,

	Yes, that's correct. In SVG as specified, it could be
<g comp-op="multiply">...</g> or use inline style as you wrote
or applied to individual objects, etc. Although, there's no real
need for 'blend:layer' in your example, but the overall idea is
right.

Alex

--Original Message--:
>
>
>Hi Alex, 
>
>
>
>
>to make sure I'm not confused.
>
>
>This is a filter:
>
><svg version="1.1" xmlns="http://www.w3.org/2000/svg">
> <defs>
>   <filter id="srcLoadedOverlay">
>     <feImage xlink:href="url(#canvas0)" result="img1" />
>     <feImage xlink:href="url(#canvas1)" result="img2" />
>     <feImage xlink:href="url(#canvas2)" result="img3" />
>     <feBlend in="img1" in2="img2" result="blend1" mode="multiply" />
>     <feBlend in="blend1" in2="img3" mode="lighten" />
>   </filter>
> </defs>
></svg>
>
>and this would be a property:
>
><html>
>
>...
>
><body>
>
>.... <- backdrop
>
><div style="blend: layer;"> <- group A
>
>  ... <- text, images, etc
>
>  <div style="blend: multiply;"> <- group B
>
>    .. <- text, images, etc
>
>  </div>
>
></div>
>
>Rik
>
>On Thu, Feb 24, 2011 at 3:53 PM, Alex Danilo <alex@abbra.com> wrote:
>
>Hi Anthony and all,
>
>--Original Message--:
>>Just adding to what Alex said (see below)...
>>
>>
>>>-----Original Message-----
>
>>><snip/>
>>>
>>>Perhaps that should serve as something to look at. This was researched
>>>extensively at the time, and a property works far better than the SVG
>>>filter mechanism when combining a lot of objects for blending.
>>>
>>
>>This is because the background is included twice when using filters to perform compositing. This leads to incorrect results - the output tends to be darker than expected.
>
>Ignoring side-effects, one of the main advantages of a property
>over a filter is no need for any sort of intermediate bitmap.
>
>The object being blended can be rasterized and alpha blended
>with the correct blend mode directly to the canvas. So the
>performance is significantly higher, especially if you are
>trying to composite lots of graphics on top of live HD video
>where memory bandwidth actually matters.
>
>Alex
>
>
>
>
>
Received on Friday, 25 February 2011 01:47:29 GMT

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