XML/SVG/viewport

establishing a new viewport

<?xml version="1.0" encoding="iso-8859-1"?>
<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 20010904//EN" 
  "http://www.w3.org/TR/2001/REC-SVG-20010904/DTD/svg10.dtd">
<svg width="600" height="300"
     xmlns="http://www.w3.org/2000/svg">
  <rect width="200" height="100" fill="red"/>
  <!-- establishing a new viewport -->
  <svg x="50%" y="50%" width="50%" height="50%">
     <rect width="200" height="100" fill="blue"/>
  </svg>
</svg>

SVG viewports

<?xml version="1.0" encoding="iso-8859-1"?>
<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 20001102//EN"
 "http://www.w3.org/TR/2000/CR-SVG-20001102/DTD/svg-20001102.dtd">
<svg width="800" height="400" viewBox="0 0 800 400">
  <g>
    <rect style="fill:red;" x="0" y="0" width="100" height="50" />
    <line x1="0" y1="24" x2="100" y2="24"
      style="stroke:white;stroke-width:2" />
    <line x1="49" y1="0" x2="49" y2="50"
      style="stroke:white;stroke-width:2" />
  </g>
</svg>