F2F/Seattle 2011/Agenda/FilterEffects

Filter effects 1.0

Latest version of the spec: https://dvcs.w3.org/hg/FXTF/raw-file/tip/filters/publish/Filters.html

The specification defines two serializations, one being the svg markup syntax and the other a subset of the markup syntax with some of the most commonly used effects in CSS.

Issues to discuss

• Naming of what was previously called SVG filters
• Arbitrary image processing via a shading language
  • proposed by Adobe in http://lists.w3.org/Archives/Public/public-fx/2011AprJun/0109.html
  • What language? GLSL?
• Hit-testing with filter effect
  • Hit-testing without regard to filters
    • Pros: fast
    • Cons: doesn't always match what the user sees
  • Hit-testing with the filter region
    • Pros: fast
    • Cons: doesn't always match what the user sees
  • Hit-testing with the filter output (with alpha threshold)
    • Pros: Can find the affected pixels/element precisely
    • Cons: high performance cost, possible security risk ISSUE-2071
• Deprecating enable-background
  • Proposal: let the optional x,y,width,height values in enable-background: new [ <x> <y> <width> <height> ] be ignored by UA's. Instead the UA should find an optimal region for the element that the filter is applied to. The optional arguments are currently defined to establish a clipping rectangle of the given size, acting as a temporary canvas.

 <svg enable-background="new 0 0 1600 1200">
   <g filter="url(#effect)">
      <circle r="20" .../>
   </g>
 </svg>

• A filter() function uses as an <image> generator
  • eg. filter( url(something.png), blur(5px) )
• New <image> generators
  • noise
  • turbulence
  • checkerboard
  • halo
• Keyword for "dropshadow" effect
• Experimenting with new effects
  • Prefixing new function names
  • List of potential effects given in spec
• New filter "wave"
  • Proposed http://msdn.microsoft.com/en-us/library/ms533091(v=vs.85).aspx
• Open issues: http://www.w3.org/Graphics/SVG/WG/track/products/12 and http://www.w3.org/Graphics/fx/track/products/1
• 'filter' property and CSSOM
  • Relates to the inclusion of CSS properties defined in SVG in the CSSOM spec, [1]
• Publishing working draft