constant-plot.xml

<mugl>
  <window border="0" margin="0" padding="0"/>
  <legend visible="false"/>
  <plotarea marginbottom="50" marginleft="60" marginright="25" margintop="10"/>

  <horizontalaxis highlightstyle="labels" id="x" linewidth="0" max="201207" min="200601" tickmax="0" tickmin="-4" type="datetime">
    <labels>
      <label format="%Y" spacing="100Y 50Y 20Y 10Y 5Y 2Y 1Y "/>
      <label format="%n %y" spacing="6M 3M 2M 1M"/>
    </labels>
    <title anchor="0 5" position="-15 0">Month/Year</title>
    <grid color="0xeeeeee"/>
  </horizontalaxis>
  <verticalaxis highlightstyle="labels" id="y" linewidth="0" max="4.5" min="-4.5" tickmax="0" tickmin="-4">
    <labels>
      <label densityfactor="0.5" format="%1d" spacing="20 10 5 2 1"/>
      <label densityfactor="0.5" format="%.1f" spacing="0.5 0.2 0.1"/>
    </labels>
    <title anchor="0 -4" angle="90" position="-15 0">Some Constant Plots</title>
    
    
    <grid color="0xeeeeee"/>
  </verticalaxis>

  <plot>
    <legend visible="false"/>
    <verticalaxis ref="y"><constant value="0"/></verticalaxis>
    <renderer type="line">
      <option name="linecolor" value="0x999999"/>
      <option name="linewidth" value="1"/>
    </renderer>
  </plot>

  <plot>
    <legend visible="false"/>
    <verticalaxis ref="y"><constant value="2"/></verticalaxis>
    <renderer type="line">
      <option name="linecolor" value="0x990000"/>
      <option name="linewidth" value="1"/>
    </renderer>
  </plot>

  <plot>
    <legend visible="false"/>
    <verticalaxis ref="y"><constant value="-2"/></verticalaxis>
    <renderer type="line">
      <option name="linecolor" value="0x000099"/>
      <option name="linewidth" value="3"/>
    </renderer>
  </plot>

</mugl>