Re: What is the filter primitive subregion of SourceGraphic?

Hi Ryan,

The responsible specification for filter effects can be found here: https://drafts.fxtf.org/filter-effects/#FilterPrimitiveSubRegion


Especially the subregions chapter is supposed to clarify input and output filter regions better with additional information per filter effect.

I hope this helps. If you see issues, please create issues on GitHub as written in the specification header.

Greetings,
Dirk

On 10. Dec 2017, at 02:35, Ryan Saunders <ryansaun@microsoft.com<mailto:ryansaun@microsoft.com>> wrote:

Hello,

I am working on implementing <feTile>, and I’ve run up against something that seems unspecified in the 1.1 spec. Per http://www.w3.org/TR/SVG11/filters.html#feTileElement<https://na01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww.w3.org%2FTR%2FSVG11%2Ffilters.html%23feTileElement&data=02%7C01%7Cdschulze%40adobe.com%7Cc9d3e0c41a094e97165d08d5407521e2%7Cfa7b1b5a7b34438794aed2c178decee1%7C0%7C0%7C636485794190977665&sdata=b13U%2FTyjamrfy1%2BYWFDHa5XTN83pApGj3tEFrZz5EHI%3D&reserved=0>, “typically the input image has been defined with its own filter primitive subregion…”. What is supposed to happen when the input does NOT have a defined filter primitive subregion, as seems to be the case when the input is SourceGraphic? In other words, what should be the result of this?

<svg version="1..1" baseProfile="basic" preserveAspectRatio="xMidYMid meet" zoomAndPan="magnify" id="svg-root"
  width="100%" height="100%" viewBox="0 0 480 360"
  xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
  <defs>
    <filter id="tile" filterUnits="userSpaceOnUse" primitiveUnits="userSpaceOnUse" x="10" y="10" width="460" height="340">
      <feTile />
    </filter>
  </defs>
  <g filter="url(#tile)">
    <rect x="5" y="5" width="50" height="50" fill="red" />
    <rect x="15" y="15" width="30" height="30" fill="green" />
    <rect x="5" y="5" width="70" height="70" fill="none" stroke="black" />
  </g>
  <rect x="1" y="1" width="478" height="358" fill="none" stroke="blue" />
</svg>

Chrome, IE, Edge, and Inkscape all render this document differently. Note that the <feTile> element is the only element in the filter chain, so it receives SourceGraphic as its input by default. Since there is no previous filter primitive to establish a sub-region, what portion of the <g> element should be tiled?

Ryan

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