.. highlight:: python
   :linenothreshold: 6

.. _examples_taurusplot:

Plot data with Taurus
=====================

This tutorial builds on the example device used in
:doc:`first_gui` and introduces the plotting widgets provided by the
`taurus_pyqtgraph`_ plugin.

Plot spectrum attributes
------------------------

To plot two 1D attributes and watch them update online, create a
:class:`taurus_pyqtgraph.TaurusPlot` and assign the models::

    from taurus_pyqtgraph import TaurusPlot

    panel = TaurusPlot()
    model = ["sys/taurustest/1/abscissas", "sys/taurustest/1/curve"]
    panel.setModel(model)

Each spectrum is plotted against its element index.

Plot Y values against an X attribute
------------------------------------

For a scatter or Y-vs-X plot, provide a tuple containing the X and Y models::

    from taurus_pyqtgraph import TaurusPlot

    panel = TaurusPlot()
    model = [("sys/taurustest/1/abscissas", "sys/taurustest/1/curve")]
    panel.setModel(model)

In this case, ``abscissas`` provides the X values instead of being plotted as a
separate spectrum.

Combine Taurus models with regular PyQtGraph data
--------------------------------------------------

A :class:`taurus_pyqtgraph.TaurusPlot` is also a PyQtGraph plot widget, so you
can combine Taurus models with regular PyQtGraph items::

    from taurus_pyqtgraph import TaurusPlot
    import pyqtgraph as pg
    import numpy

    panel = TaurusPlot()
    model = [("sys/taurustest/1/abscissas,sys/taurustest/1/curve")]
    panel.setModel(model)

    c1 = pg.PlotDataItem(name="pg item", pen="b", fillLevel=0, brush="c")
    c1.setData(numpy.linspace(0, 2, 250))
    panel.addItem(c1)

.. _examples_taurustrend:

Plot a trend
------------

Use :class:`taurus_pyqtgraph.TaurusTrend` when you want to follow how a scalar
attribute changes over time::

    from taurus.qt.qtgui.plot import TaurusTrend

    panel = TaurusTrend()
    model = ["sys/taurustest/1/position"]
    panel.setModel(model)

If the model is a 1D attribute instead of a scalar, ``TaurusTrend`` interprets
it as a collection of scalar values and creates a separate trend line for each
one.

Next steps
----------

For task-oriented plotting options such as zooming, configuration, exporting,
or fixed trend ranges, see :ref:`howto-plotting` and :ref:`howto-trends`.
For background on the plotting backends used by Taurus, see
:ref:`taurusplot_ui`.

.. _taurus_pyqtgraph: https://gitlab.com/taurus-org/taurus_pyqtgraph