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TimeVaryingParameter Extension
==============================

*Example script* (scamp_extensions): `examples/Composition & form/Larger-scale form/time_varying_parameter_example.py <https://github.com/MarcTheSpark/scamp_extensions/blob/main/examples/Composition & form/Larger-scale form/time_varying_parameter_example.py>`__

*Download:* :download:`time_varying_parameter_example.py <downloads/composition_form_larger_scale_form_time_varying_parameter_example/time_varying_parameter_example.py>`

**Requires the** ``scamp_extensions`` **package** (``pip install scamp_extensions``).

A script using the context-sensitive :class:`~expenvelope.envelope.Envelope` wrapper :class:`TimeVaryingParameter`, which reads into the underlying envelope at the current clock   's beat or time when called.

*Topics:* :doc:`Envelopes › As compositional parameters <envelopes>`, :doc:`Composition & form › Larger-scale form <composition_form>`

.. raw:: html

   <div style="margin:0.6em 0"><audio controls preload="none" src="../_static/media/Composition%20%26%20form/Larger-scale%20form/time_varying_parameter_example.mp3" style="width:100%;max-width:520px"></audio></div>

.. code-block:: python

   from scamp import *
   from scamp_extensions.utilities import TimeVaryingParameter


   s = Session()

   piano = s.new_part("piano")


   def play_gesture(center_pitch, width, length):
       pitch_shape = TimeVaryingParameter.from_levels([0, width, -width, -width/2, -width, 0], length=length)
       volume_shape = TimeVaryingParameter([1, 0.4, 1], [length * 0.1, length * 0.9])
       while current_clock().beat < length:
           piano.play_note(int(center_pitch + pitch_shape()), volume_shape(), 0.25)


   width_param = TimeVaryingParameter([4, 20, 0], [30, 30])
   center_pitch_param = TimeVaryingParameter([60, 80, 40, 60], [20, 20, 20])
   length_param = TimeVaryingParameter([10, 1], [60])

   while s.beat < 65:
       fork(play_gesture, args=(center_pitch_param(), width_param(), length_param()), initial_tempo=180)
       wait_for_children_to_finish()