Overlapping axis labels in Sitemap graphs in openHAB App

[dandjo]

Expected Behavior

Readable aligned horizontal labeling in graphs.

Current Behavior

Overlapping text in labels in graphs on the x-axis using openHAB App (latest from Play-Store on Android).

Your Environment

• Version used: openHAB 5.0.0 Build 4558

runtimeInfo:
  version: 5.0.0
  buildString: "Build #4558"
locale: en-AT
systemInfo:
  configFolder: /etc/openhab
  userdataFolder: /var/lib/openhab
  logFolder: /var/log/openhab
  javaVersion: 21.0.6
  javaVendor: Ubuntu
  osName: Linux
  osVersion: 6.8.0-1020-raspi
  osArchitecture: aarch64
  availableProcessors: 4
  freeMemory: 311492568
  totalMemory: 471859200
  uptime: 1310
  startLevel: 100
addons:
  - automation-jsscripting
  - binding-enigma2
  - binding-http
  - binding-mielecloud
  - binding-modbus
  - binding-mqtt
  - binding-netatmo
  - binding-tado
  - misc-openhabcloud
  - persistence-influxdb
  - persistence-mapdb
  - persistence-rrd4j
  - transformation-jsonpath
  - transformation-regex
  - ui-basic
clientInfo:
  device:
    ios: false
    android: false
    androidChrome: false
    desktop: true
    iphone: false
    ipod: false
    ipad: false
    edge: false
    ie: false
    firefox: false
    macos: false
    windows: false
    cordova: false
    phonegap: false
    electron: false
    nwjs: false
    webView: false
    webview: false
    standalone: false
    pixelRatio: 1
    prefersColorScheme: dark
  isSecureContext: false
  locationbarVisible: true
  menubarVisible: true
  navigator:
    cookieEnabled: true
    deviceMemory: N/A
    hardwareConcurrency: 12
    language: en-GB
    languages:
      - en-GB
      - en-US
      - en
      - de
    onLine: true
    platform: Linux x86_64
  screen:
    width: 3440
    height: 1440
    colorDepth: 24
  support:
    touch: false
    pointerEvents: true
    observer: true
    passiveListener: true
    gestures: false
    intersectionObserver: true
  themeOptions:
    dark: dark
    filled: true
    pageTransitionAnimation: default
    bars: light
    homeNavbar: default
    homeBackground: default
    expandableCardAnimation: default
    blocklyRenderer: geras
  userAgent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like
    Gecko) Chrome/134.0.0.0 Safari/537.36
timestamp: 2025-03-27T13:00:02.603Z

[dandjo]

@lolodomo this also happens with BasicUI when using small graphs.

[lolodomo]

I deduce from your screen capture that your problem is not related to legend but rather to values displayed on the X axis.

Depends on XChart and computed text size.

[dandjo]

Yes, sorry for the confusion. The issue is about the values on the x-axis.

[dandjo]

Updated title and description to avoid further confusions.

@lolodomo I rember a similar issue that was caused by an update of XChart. I guess this is a regression?

openhab/openhab-distro#1556

[holgerfriedrich]

Just to give some background: XChart was upgraded, see #4628.
At least it is not the issue we had before (missing label after upgrade), as this was fixed in the meantime.

After the upgrade, XChart might behave differently, though. IIRC this upgrade covered a few years of development.

[dandjo]

@holgerfriedrich I see. Is this an issue of XChart itself or did the API change and the call to XChart needs to be changed?

[holgerfriedrich]

I am afraid I cannot help here. I just wanted to let you know that we did a major upgrade of XChart. The XChart upgrade is quite a huge step (3.1.0 dated 2016 to 3.8.8 dated 2024). I have not seen any issue on my system (rpi, viewed with Firefox on PC).

btw: besides #4628 (upgrade), there was also #4610 (adding the interpolation settings)

[dandjo]

@holgerfriedrich it depends on the resolution. When using BasicUI with any browser, the calculation seems fine. Especially in the app the is a huge overlap. The calculation there is definitively wrong.

[openhab-bot]

This issue has been mentioned on openHAB Community. There might be relevant details there:

https://community.openhab.org/t/openhab-5-0-milestone-discussion/162686/59

[maniac103]

The calculation there is definitively wrong

The thing is: the app doesn't do any calculation by itself. It just provides a screen density in the URL, which typically will be higher than with BasicUI. Everything else is done in the servlet.

[holgerfriedrich]

It depends on the app setting "diagram scaling". For me, the diagram looked good (setting: "small"); "standard" and "huge" show the overlap. Setting for HD diagrams seems not to make a difference.
Current OH5 snapshot is affected; on 4.3.x all settings work fine.

[dandjo]

My screenshot is with "very small". It gets worse with "small", "default" and "large".

[maniac103]

It depends on the app setting "diagram scaling".

Yes, but all that scaling setting (+ the hi-res charts setting) does is adjusting the DPI. getChartScalingFactor() returns values between 3 (very small) and 1 (large), density is the device's display density (typically in the range of 420-480).

So my expectation would be that an URL like http://<ohserver>:8080/chart?items=MyItem&dpi=420&period=1D&width=1080&height=540 (or a slight variation thereof) should show the same issue in a browser.