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<!DOCTYPE language SYSTEM "klayout_doc.dtd">

<doc>

  <title>Doing Measurements</title>
  <keyword name="Rulers"/>
  <keyword name="Measure"/>

  <p>
  A measurement can be performed by clicking on the ruler icon in the 
  toolbar and selecting "Ruler" from the drop-down options.
  Left-click on a point in the layout and then left-click again
  or press the Enter key to set the second point. 
  A ruler will be shown that indicates the distance measured. 
  </p>

  <p>
  While you move the endpoint, you can hold the Shift or Ctrl key
  or both. With only the Shift key pressed, the ruler's direction 
  will be limited to horizontal or vertical only. With only the Ctrl
  key pressed, the direction is limited to horizontal, vertical or
  diagonal. With Ctrl and Shift pressed together, no limitation
  of direction applies.
  </p>

  <p>
  While the ruler is dragged, the current drag distance is indicated
  in three edit fields at the top of the layout view. By pressing the
  Tab key, the input focus changes to these edit fields. You can 
  specify a numerical value for the distances here. Use Tab and
  Shift+Tab to jump between the fields. Press the Escape key to
  leave the edit fields. Pressing the Enter key while
  the cursor is on the "dx" or "dy" field will
  accept the values and apply them to the ruler.
  If you specify a value in the last field labelled "d" and press
  Enter, the ruler will enter "fixed length" mode - in that mode you
  can still define the ruler's direction with the mouse, but the 
  length is fixed to the given value.
  </p>

  <p>
  A convenient way to measure a distance is the single-click measurement
  ruler. Select "Measure" from the drop-down options of the ruler symbol.
  In this mode, a single click will set a ruler to the specified 
  position. This feature will look for edges in the vicinity of the 
  ruler and set the ruler to connect the neighboring edges. The ruler
  is attached perpendicular to the edge next to the initial point.
  </p>

  <p>
  The "Measure Edge" ruler type is also a single-click measurement
  ruler, but measures the length of an edge at the click position.
  </p>

  <p>
  You can mark a position with a single click by selecting the "Cross"
  ruler type. Clicking at a location will place such a ruler. The ruler
  shows the x and y coordinate.
  </p>

  <p>
  The "Multi-Ruler" allows concatenating multiple rulers into a single
  object. Click and the first point to start such a ruler. Then click
  on more points to add new segments to the ruler. Each segment is shown
  as an individual ruler with tick marks and a length. Finish the sequence
  with a double-click or by pressing the Enter key.
  Note that the lengths indicated by the ruler labels are the lengths
  of the individual segments. To get an incremental length (the sum
  of all segment length), change the ruler's label format from "$D" to "$DD" ("DD"
  is variable giving the incremental length).
  See the description of ruler templates below, about how to make this change permanent.
  </p>

  <p>
  The "Angle" ruler allows angle measurements. Three clicks are required
  to define a "V" like arrangement of two rulers. The angle enclosed by the two lines forming the "V"
  is shown in the ruler.
  </p>

  <p>
  Another special ruler, the "Radius" ruler is also a three-click type.
  Specify three points to define a circle. The ruler shows the radius
  of this circle and the circle outline.
  </p>

  <p>
  Rulers can be configured in manifold ways. Use "Rulers And Annotations Setup" 
  in the "Edit" menu to open the ruler configuration dialog. 
  A ruler can be
  made to snap to edges of objects by selecting "Snap to edge/vertex".
  Ruler orientations can be constrained by using the "Angle Constraint"
  options. The number of rulers can be limited using the "Limit 
  number of annotations" setting.
  </p>

  <p>
  While drawing or moving one point of a ruler, the direction constraint
  can be overridden with the Shift and Ctrl keys: pressing Shift while moving the
  mouse will enforce orthogonal constraint, Ctrl will enforce diagonal constraint 
  while pressing both will release any direction constraint.
  </p>

  <p>
  All rulers can be cleared using the "Clear all rulers" function from the
  "Edit" menu.
  </p>

  <p>
  Ruler dragging can be canceled with the "Esc" key or using the "Cancel"
  function from the "Edit" menu.
  </p>

  <p>
  Rulers can be moved by selecting "Move" mode with the speedbar buttons
  in the toolbar or "Move" from the "Mode" sub-menu in the "Edit" menu. Then
  left-click and drag the ruler or the ruler end point that should be changed.
  </p>

  <p>
  Rulers can be deleted selectively by selecting a ruler in "Select" mode and
  pressing "Delete".
  </p>

  <p> 
  Rulers can be modified in a variety of ways. For example, rulers can be shown
  as arrows. To edit the properties of a ruler, double-click the ruler or 
  select it and use "Properties" from the "Edit" menu. 
  See <link href="/manual/ruler_properties.xml"/> for a description of the 
  properties.
  </p>

  <p> 
  Multiple templates can be configured to be available for rulers. Each template defined
  will be shown in the "Ruler" mode toolbar button's drop-down menu.
  If a template is selected, new rulers produced from this template will inherit
  the template's properties. Templates are managed in the 
  ruler setup page ("Setup" from the "File" menu) or "Ruler And Annotation Setup" from the "Edit" menu.
  </p>

</doc>

