Example SXG file
Prev Appendix A. Scalable X Graphics Next

Example SXG file

The following example creates an image of a circle with a grey border, filled with a small black-and-white checkerboard pattern. 

<sxg>
  <width>32</width>
  <height>32</height>

  <widthmm>10</widthmm>
  <heightmm>10</heightmm>

  <widthfactor>2</widthfactor>
  <heightfactor>2</heightfactor>

  <picture id="grey">
    <type>rgb</type>
    <r>.5</r>
    <g>.5</g>
    <b>.5</b>
  </picture>

  <picture id="checkerboard">
    <size>
      <type>mmrounded</type>
      <factor>.5</factor>
    </size>
    <width>2</width>
    <height>2</height>
  </picture>

  <pixmap id="circle_mask">
    <size>scaled</size>
    <width>32</width>
    <height>32</height>
    <mask />
    <gc id="circle_mask_gc" />
  </pixmap>

  <render id="checkerboard">
    <repeat>normal</repeat>
    <fill>
      <rectangle>
	<x>0</x>
	<y>0</y>
	<width>2</width>
	<height>2</height>
      </rectangle>
    </fill>
    <fill>
      <r>1</r>
      <g>1</g>
      <b>1</b>

      <rectangle>
	<x>0</x>
	<y>0</y>
	<width>1</width>
	<height>1</height>
      </rectangle>
      <rectangle>
	<x>1</x>
	<y>1</y>
	<width>1</width>
	<height>1</height>
      </rectangle>
    </fill>
  </render>

  <gc id="circle_mask_gc">
    <function>set</function>

    <arcs>
      <fill />

      <arc>
	<x>2</x>
	<y>2</y>
	<width>28</width>
	<height>28</height>
	<angle1>0</angle1>
	<angle2>360</angle2>
      </arc>
    </arcs>
  </gc>

  <render id="main">
    <composite>
      <op>src</op>
      <mask>
	<pixmap>circle_mask</pixmap>
	<x>0</x>
	<y>0</y>
      </mask>
      <src>
	<picture>checkerboard</picture>
	<x>0</x>
	<y>0</y>
      </src>
      <x>0</x>
      <y>0</y>
      <width>32</width>
      <height>32</height>
    </composite>
  </render>

  <gc id="circle_mask_gc">
    <function>clear</function>

    <fill>
	<x>0</x>
	<y>0</y>
	<width>32</width>
	<height>32</height>
    </fill>

    <function>set</function>
    <line_width>4</line_width>

    <arcs>
      <arc>
	<x>2</x>
	<y>2</y>
	<width>28</width>
	<height>28</height>
	<angle1>0</angle1>
	<angle2>360</angle2>
      </arc>
    </arcs>
  </gc>

  <render id="main">
    <composite>
      <op>over</op>
      <mask>
	<pixmap>circle_mask</pixmap>
	<x>0</x>
	<y>0</y>
      </mask>
      <src>
	<picture>grey</picture>
	<x>0</x>
	<y>0</y>
      </src>
      <x>0</x>
      <y>0</y>
      <width>32</width>
      <height>32</height>
    </composite>
  </render>
</sxg>

This SXG file defines its nominal size as 10x10 millimeters, using a virtual 32x32 coordinate space. First, a 2x2 pseudo-millimeter-sized picture gets entirely filled with a black color, then two 1x1 white rectangles get drawn, forming the checkerboard pattern.

A mask pixmap gets created, for the full 32x32 virtual coordinate space, and is filled with a circle. This is used as a mask to compose the checkerboard pattern into the main picture.

The mask pixmap is modifying by clearing a 28x28 circle inside it, leaving the mask as only a 4 virtual pixel-wide border. This mask then gets used to compose the grey color on top of the main picture.

Prev Up Next
Picture render commands Table Of Contents Using XInclude with SXG files