FreeDATA/gui/src/waterfall

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HTML Canvas/WebSockets Waterfall
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This is a small experiment to create a waterfall plot with HTML Canvas and WebSockets to stream live FFT data from an SDR:

.. image:: img/waterfall.png

``spectrum.js`` contains the main JavaScript source code for the plot, while ``colormap.js`` contains colormaps generated using ``make_colormap.py``.

``index.html``, ``style.css``, ``script.js`` contain an example page that receives FFT data on a WebSocket and plots it on the waterfall plot.

``server.py`` contains a example `Bottle <https://bottlepy.org/docs/dev/>`_ and `gevent-websocket <https://pypi.org/project/gevent-websocket/>`_ server that broadcasts FFT data to connected clients. The FFT data is generated using `GNU radio <https://www.gnuradio.org/>`_ using a USRP but it should be fairly easy to change it to a different SDR.