Bug 451873 - Temperature page line chart wrong zero last value
Summary: Temperature page line chart wrong zero last value
Status: REOPENED
Alias: None
Product: plasma-systemmonitor
Classification: Applications
Component: general (show other bugs)
Version: 6.0.5
Platform: Neon Linux
: NOR normal
Target Milestone: ---
Assignee: Maxim Egorushkin
URL:
Keywords: usability
Depends on:
Blocks:
 
Reported: 2022-03-25 00:28 UTC by Maxim Egorushkin
Modified: 2024-06-13 14:52 UTC (History)
3 users (show)

See Also:
Latest Commit:
Version Fixed In:
Sentry Crash Report:


Attachments
Temperature page line chart wrong zero last value screenshot (65.92 KB, image/png)
2022-03-25 00:28 UTC, Maxim Egorushkin
Details
System Monitor time series misaligned. (200.17 KB, image/png)
2024-06-12 18:52 UTC, Maxim Egorushkin
Details
System Monitor time series misaligned from the start. (106.75 KB, image/png)
2024-06-12 19:59 UTC, Maxim Egorushkin
Details

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Description Maxim Egorushkin 2022-03-25 00:28:53 UTC
Created attachment 147715 [details]
Temperature page line chart wrong zero last value screenshot

SUMMARY
Temperature page line chart displays last value of every temperature time series as 0°C, which isn't right. 

STEPS TO REPRODUCE
1. Open System Monitor.
2. Navigate to Temperature page.

OBSERVED RESULT
Temperature page default line chart all temperature time series drop to 0°C at the end.

EXPECTED RESULT
The line chart shows correct last measured temperature at the end, not 0°C.

SOFTWARE/OS VERSIONS
Linux/KDE Plasma: KDE neon 5.24
KDE Plasma Version: 5.24.3
KDE Frameworks Version: 5.92.0
Qt Version: 5.15.3

ADDITIONAL INFORMATION
This bug didn't exist in the past, but I didn't notice KDE neon update which broke it.
Comment 1 Arjen Hiemstra 2024-06-07 12:40:23 UTC
This actually is intended behaviour, since there is no data for the rest of the chart a default value is used, which ends up being 0 here.
Comment 2 Maxim Egorushkin 2024-06-12 18:52:02 UTC
Created attachment 170434 [details]
System Monitor time series misaligned.

This current line chart update logic results in time series being being misaligned in the System Monitor. See the attached screenshot of System Monitor where the CPU usage time series line chart is misaligned relative to corresponding temperature and fans time series charts. This is rather undesirable behaviour, I would not intend that onto my neighbour. 

The best practice is to have time series aligned by time, with the rightmost chart edge corresponding to the latest data points at all times. This is easily achieved by always displaying new/later data points as coming from the right edge of the chart, e.g. display chart points and lines from right to left starting with the latest data point.

This way time series chart in System Monitor would stay correctly aligned on the right edge regardless of the length of available time-series history. Such logic I would happily intend onto my neighbour.
Comment 3 Maxim Egorushkin 2024-06-12 19:59:20 UTC
Created attachment 170437 [details]
System Monitor time series misaligned from the start.

Here is another example of time-series charts being misaligned in System Monitor from the start because of different widths of Y-axis tick labels in different charts. That is extremely undesirable and must never happen. 

But it happens because the current line chart update logic doesn't follow the best practices. MSI Afterburner hardware monitor time-series charts is a good example of the best practices to follow.