Scrolling line chart

[RGV250]

Hi,
I have been looking at the enviroment monitor demo which is close to what I am looking for. The bit I am not happy with is the line chart as when it is full it carries on showing new data but the x axis compresses so over time it will get unreadable.
I would like to have a scrolling chart of the last x samples, I changed the x axis autoscale to "no" but that just meant that as soon as the chart was full it stopped showing live data.
I have a thought that to do what i require I need to write the data to a FIFO buffer and then write the contents to the chart.
This seems like a lot of work and possibly will make the display very slow so I wondered if I am on the right lines or if anyone has any better solution.

Regards,
Bob

[BenR]

Hi Bob,

Try the historic chart and hopefully that will do what you need.

[chipfryer27]

Hi Ben

Admittedly I'm thicker than a porridge milk shake but I can't see any historic chart option in Web Developer.

Regards

[medelec35]

Hi Iain.
Historic chart is within PC developer, which the environmental monitor demo uses.

[chipfryer27]

Hi Martin

Thanks. Glad to hear I'm not such an idiot after all I really should get back into Web / PC developer as I've not touched it in a long while. It is such a useful feature.

Regards

[RGV250]

Hi Martin,
Unfortunately I need something for the web developer. I am assuming there are technical reasons why this and xy chart and circular buffers are not in web developer.

Regards,
Bob

[RGV250]

Hi Ben,
Is there any chance the historic chart will be available for the web developer. I have thought about string it in a circular buffer but sending over 2000 values every 4 seconds to update the chart does not seem to be a practical solution.

Regards,
Bob

[Steve-Matrix]

Web Developer projects are very different to PC Developer and Embedded projects in Flowcode. We are investigating a scrolling historic chart for Web Developer, but it might be too slow to be useful.

[RGV250]

Hi Steve,
A long time ago I had a chart working for this monitor, it was created in node red and ran on the Pi as far as I can recall.
I can understand it being slow if the web app was loaded onto a mobile phone but not sure if this would be the same problem if the Pi or ESP32 etc is hosting the web app?

Bob

[Steve-Matrix]

My thinking is it's the speed of receiving the data that is the bottleneck rather than the speed of the device hosting the app.

What are your requirements for a scrolling chart in terms of throughput (number of datapoints per second and number of datapoints on the chart as a whole)? That might help guide us when we do some investigating.