Spectrum-2D Widget
*********************

A widget that allows plotting multiple spectrum attributes on the y-axis against a single spectrum attribute on the x-axis. 

Widget setting 
==============
The widget allows for multiple spectrum attributes to be specified in a one-to-many configuration; one for the x-axis and many for the y-axis, respectively.
The ``Time Base`` is a spectrum attribute for the x-axis of the oscilloscope. Since the widget supports multiple y-axis spectrum attributes to be added, pressing the "+" sign next to ``Graphs`` will enable the user to specify a spectrum attribute.
Other settings include:

* the option of displaying the ``Label`` or ``Name`` of the attributes being plotted,
* the checkbox for whether or not the title of the plot should be visible (this ``Show Title`` option affects the padding of the plot),
* two checkboxes, one for X- and one for Y-axis, indicating whether the scientific (exponential) notation format should be applied to any axis, 
* two checkboxes, one for X- and one for Y-axis, indicating whether logarithmic scale should be applied on any axis, 
* the option of adjusting the style of plot indicators, possible choices are: ``Linear``, ``Bar Chart``, ``Markers``, ``Linear with markers``.

\ |IMG1|\ 

*The y-axis contains four spectrum attributes representing four dictinct channels and their waveform voltages from an ossiloscope plotted against another spectrum attribute called time-range*

\ |IMG2|  |IMG3| \

*The y-axis, plotted against spectrum attribute called `float_spectrum_ro`, contains:*  

* *two spectrum attributes `float_spectrum_ro` and `double_spectrum_ro` drawn on a Bar Chart plot with scientific notation format and logarithmic scale on y-axis (left),*  
* *one spcetrum attribute `float_spectrum_ro` drawn on a Marker plot (right).*  

Widget design
==============
The plot is rendered using plotly, a robust and interactive graphing library. The plots are re-drawn as they are updated by spectrum attribute data pushed by the respective tango device that the attributes associate with. PLotly, natively provides a couple of tools to interact with the plots. These include, zooming, panning, focusing on specific graph parts, resetting axes and saving snapshots of the graph as Portable Network Graphics(PNG) files. 


\ |IMG4|\ 

*The plot shown above is a sample of a four channel oscilloscope plotted against (psuedo)time-range*

\ |IMG5|\ 

*The plots above, plotted against `float_spectrum_ro`, shows:*

* *spectrum attributes `float_spectrum_ro` with `double_spectrum_ro` drawn on a Bar Chart plot with scientific notation format and logarithmic scale on y-axis  (left),*  
* *spectrum attributes `float_spectrum_ro` drawn on a Marker plot with linear scale on both axes (right)*  

.. bottom of content

.. |IMG1| image:: _static/img/spectrum_2d_settings.png

.. |IMG2| image:: _static/img/spectrum_2d_settings1.png

.. |IMG3| image:: _static/img/spectrum_2d_settings2.png

.. |IMG4| image:: _static/img/spectrum_2d_design.png

.. |IMG5| image:: _static/img/spectrum_2d_plots.png