<?xml version="1.0" encoding="ISO-8859-1"?>

<screensaver name="hilbert" _label="Hilbert">

  <command arg="-root"/>

  <hgroup>
   <vgroup>

    <hgroup>
     <select id="twodee">
      <option id="random"  _label="2D or 3D"/>
      <option id="2D"      _label="2D"               arg-set="-mode 2d"/>
      <option id="3D"      _label="3D"               arg-set="-mode 3d"/>
     </select>

     <select id="closed">
      <option id="random"  _label="Open or closed paths"/>
      <option id="closed"  _label="Closed"           arg-set="-ends closed"/>
      <option id="open"    _label="Open"             arg-set="-ends open"/>
     </select>
    </hgroup>

    <hgroup>
     <vgroup>
      <number id="delay" type="slider" arg="-delay %"
              _label="Frame rate" _low-label="Slow" _high-label="Fast"
              low="0" high="100000" default="30000"
              convert="invert"/>

      <number id="speed" type="slider" arg="-speed %"
              _label="Speed" _low-label="Slow" _high-label="Fast"
              low="0.02" high="10.0" default="1.0"/>
     </vgroup>

     <vgroup>
      <number id="depth" type="slider" arg="-max-depth %"
              _label="Recursion levels" _low-label="2" _high-label="10"
              low="2" high="10" default="5"/>

      <number id="thickness" type="slider" arg="-thickness %"
              _label="Line thickness" _low-label="Thin" _high-label="Thick"
              low="0.01" high="1.0" default="0.25"/>
     </vgroup>
    </hgroup>

    <hgroup>
     <boolean id="wander"  _label="Wander"          arg-set="-wander"/>
     <boolean id="spin"    _label="Spin"            arg-unset="-no-spin"/>
     <boolean id="showfps" _label="Show frame rate" arg-set="-fps"/>
     <boolean id="wire"    _label="Wireframe"       arg-set="-wireframe"/>
    </hgroup>

   </vgroup>
  </hgroup>

  <_description>
This draws the recursive Hilbert space-filling curve, in both 2D and
3D variants.  It incrementally animates the growth and recursion to
the maximum depth, then unwinds it back.

The Hilbert path is a single contiguous line that can fill a volume
without crossing itself.  As a data structure, Hilbert paths are
useful because ordering along the curve preserves locality: points
that close together along the curve are also close together in space.
The converse is often, but not always, true.  The coloration
reflects this.

http://en.wikipedia.org/wiki/Hilbert_curve

Written by Jamie Zawinski; 2011.
  </_description>
</screensaver>
