=======
Leaders
=======

.. _props-leader:

Leader Properties
-----------------

.. raw:: html

   <details>
   <summary><a>Show/Hide <b>Leader</b> Attributes</a></summary>

* im 
    PIL image handle, link to the calling program
* at
    Coordinates on object
* angle
    Angle of first extension line, changes leader orientation
* extA
    Length inclined extension line, default 20
* extB
    Length horizontal extension line, default 20
* text
    Dimension text
* font
    Font of the text
* fill
    Line colour
* width
    Line width in pixels 
* arrowhead
    Three integer tuple describing the shape and size of the arrow
* arrow
    position of the arrow on the line, which influences the direction it 
    points.     

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   </details>

|

.. |l315| image:: ../figures/dims/leader315.png
    :width: 120
    :height: 120

.. |l225| image:: ../figures/dims/leader225.png
    :width: 120
    :height: 120

.. |l45| image:: ../figures/dims/leader45.png
    :width: 120
    :height: 120

.. |l135| image:: ../figures/dims/leader135.png
    :width: 120
    :height: 120

..

    +----------------+-----------------+-----------------+-----------------+
    |        **Upper Leader**          |         **Lower Leader**          |
    +================+=================+=================+=================+
    |   |l225|       |    |l315|       |    |l135|       |     |l45|       |
    +----------------+-----------------+-----------------+-----------------+
    | Left position  | Right position  |  Left position  | Right position  |
    |     225°       |      315°       |       135°      |       45°       |
    +----------------+-----------------+-----------------+-----------------+


Leaders allow us to refer to a specific item property not easily shown by 
normal dimensions or general decriptive notes.

The leader example has a single arrow on an angled line with a horizontal
line over which the text is placed.

Changing the angle gives different leader orientations. It is better to
use angles between 30 and 60° in each of the quadrants.

.. container:: toggle

    .. container:: header

        *Show/Hide Code* test_leader.py

    .. literalinclude:: ../examples/dims/test_leader.py