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<!DOCTYPE language SYSTEM "klayout_doc.dtd">

<doc>

  <title>Shapewise Boolean Operations</title>
  <keyword name="Boolean operations"/>
  <keyword name="Shapewise boolean operations"/>
  <keyword name="Merge"/>
  <keyword name="Intersection"/>
  <keyword name="Subtraction"/>

  <p>
  Boolean operations are also available on selected shape sets. 
  These operations use the concept of "primary" and "secondary" selection. The primary selection contains all shapes that
  are selected in the first step. The secondary selection contains all shapes that are selected in additional steps using the
  "Shift" modifier key.
  </p>

  <p>
  The following operations are available in the "Selection" submenu of the "Edit" menu:
  </p>

  <ul>
  <li><b>Merge</b>: merge all shapes in the primary and secondary selection and write the results to the layer of the primary selection.</li>
  <li><b>Intersection</b>: Compute the intersection (AND) of primary and secondary selection and write the results to the layer of the primary selection.</li>
  <li><b>Subtraction</b>: Compute the difference (A NOT B) of primary (A) and secondary (B) selection and write the results to the layer of the primary selection.</li>
  </ul>

</doc>

