80 lines
2.5 KiB
ReStructuredText
80 lines
2.5 KiB
ReStructuredText
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===============
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Metric Displays
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===============
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OVMS V3 is based on metrics. Metrics can be single numerical or textual values or complex values
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like sets and arrays. The web framework keeps all metrics in a global object, which can be read
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simply by e.g. ``metrics["v.b.soc"]``.
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Metrics updates (as well as other updates) are sent to all DOM elements having the
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``receiver`` class. To hook into these updates, simply add an event listener for
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``msg:metrics``.
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Listening to the event is not necessary though if all you need is some metrics
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display. This is covered by the ``metric`` widget class family as shown here.
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----------------------
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Single Values & Charts
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----------------------
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.. image:: metrics.png
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:scale: 50%
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:align: right
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The following example covers…
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- Text (String) displays
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- Number displays
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- Progress bars (horizontal light weight bar charts)
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- Gauges
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- Charts
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Gauges & charts use the HighCharts library, which is included in the web server. The other widgets
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are simple standard Bootstrap widgets extended by an automatic metrics value update mechanism.
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Highcharts is a highly versatile charting system. For inspiration, have a look at:
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- https://www.highcharts.com/demo
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- https://www.highcharts.com/docs
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We're using `styled mode <https://www.highcharts.com/docs/chart-design-and-style/style-by-css>`_
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so some options don't apply, but everything can be styled by standard CSS.
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Install the example as a web page plugin:
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:download:`metrics.htm <../dev/metrics.htm>` (hint: right click, save as)
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.. literalinclude:: ../dev/metrics.htm
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:language: html
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:linenos:
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-------------
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Vector Tables
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-------------
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.. image:: metrics-table.png
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:scale: 50%
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:align: right
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Some metrics, for example the battery cell voltages or the TPMS tyre health data, may contain
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vectors of arbitrary size. Besides rendering into charts, these can also be displayed by their
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textual values in form of a table.
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The following example shows a live view of the battery cell voltages along with their recorded
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minimum, maximum, maximum deviation and current warning/alert state. Alert states 0-2 are translated
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into icons.
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The metric table widget uses the DataTables library, which is included in the web server. The
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DataTables Javascript library offers a wide range of options to create tabular views into
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datasets.
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Install the example as a web page plugin:
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:download:`metrics-table.htm <../dev/metrics-table.htm>` (hint: right click, save as)
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.. literalinclude:: ../dev/metrics-table.htm
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:language: html
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:linenos:
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