.. only:: html

    .. note::
        :class: sphx-glr-download-link-note

        Click :ref:`here <sphx_glr_download_auto_graphs_plot_graphs_fill_area.py>`     to download the full example code
    .. rst-class:: sphx-glr-example-title

    .. _sphx_glr_auto_graphs_plot_graphs_fill_area.py:


How to fill an area
===================


.. code-block:: default

    # sphinx_gallery_thumbnail_number = 2







In this example, we show how to fill specified area with a given color.


.. code-block:: default

    import openturns as ot
    import openturns.viewer as viewer
    from matplotlib import pylab as plt
    ot.Log.Show(ot.Log.NONE)








We generate a sample from a standard gaussian distribution.


.. code-block:: default

    dist = ot.Normal()
    graph = dist.drawPDF()
    view = viewer.View(graph)




.. image:: /auto_graphs/images/sphx_glr_plot_graphs_fill_area_001.png
    :alt: plot graphs fill area
    :class: sphx-glr-single-img






.. code-block:: default

    def linearSample(xmin,xmax,npoints):
        '''Returns a sample created from a regular grid 
        from xmin to xmax with npoints points.'''
        step = (xmax-xmin)/(npoints-1)
        rg = ot.RegularGrid(xmin, step, npoints)
        vertices = rg.getVertices()
        return vertices










.. code-block:: default

    a = 1.
    b = 2.









.. code-block:: default

    nplot = 100 # Number of points in the plot
    x = linearSample(a,b,nplot)
    y = dist.computePDF(x)









The following function uses the `PolygonArray` class to create a area filled with a given color.


.. code-block:: default

    def drawInTheBounds(vLow,vUp,n_test):
        '''
        Draw the area within the bounds.
        '''
        palette = ot.Drawable.BuildDefaultPalette(2)
        myPaletteColor = palette[1]
        polyData = [[vLow[i], vLow[i+1], vUp[i+1], vUp[i]] for i in range(n_test-1)]
        polygonList = [ot.Polygon(polyData[i], myPaletteColor, myPaletteColor) for i in range(n_test-1)]
        boundsPoly = ot.PolygonArray(polygonList)
        return boundsPoly









Compute the bounds to fill: the lower vertical bound is zero and the upper vertical bound is the PDF.


.. code-block:: default

    vLow = [[x[i,0],0.] for i in range(nplot)] 
    vUp = [[x[i,0],y[i,0]] for i in range(nplot)]









.. code-block:: default

    area = dist.computeCDF(b) - dist.computeCDF(a)









.. code-block:: default

    boundsPoly = drawInTheBounds(vLow,vUp,nplot)
    graph = dist.drawPDF()
    graph.add(boundsPoly)
    graph.setTitle("Area = %.3f" % (area))
    graph.setLegends([""])
    view = viewer.View(graph)
    plt.show()




.. image:: /auto_graphs/images/sphx_glr_plot_graphs_fill_area_002.png
    :alt: Area = 0.136
    :class: sphx-glr-single-img





The CDF difference is equal to the area under the curve.


.. rst-class:: sphx-glr-timing

   **Total running time of the script:** ( 0 minutes  0.179 seconds)


.. _sphx_glr_download_auto_graphs_plot_graphs_fill_area.py:


.. only :: html

 .. container:: sphx-glr-footer
    :class: sphx-glr-footer-example



  .. container:: sphx-glr-download sphx-glr-download-python

     :download:`Download Python source code: plot_graphs_fill_area.py <plot_graphs_fill_area.py>`



  .. container:: sphx-glr-download sphx-glr-download-jupyter

     :download:`Download Jupyter notebook: plot_graphs_fill_area.ipynb <plot_graphs_fill_area.ipynb>`


.. only:: html

 .. rst-class:: sphx-glr-signature

    `Gallery generated by Sphinx-Gallery <https://sphinx-gallery.github.io>`_