CPU, Memory & GPU Status Widget for KDE Plasma 6

OBS: Developed with AI assistance

A personal lightweight, native, and reactive C++ & QML mini-applet (plasmoid) for the KDE Plasma 6 panel. It monitors and displays real-time CPU temperature, RAM usage, GPU temperature, and VRAM usage in a compact layout, with custom visibility settings and click-to-launch system monitor.

Why?

I wanted a lightweight and minimalist system monitor widget for the KDE Plasma status bar to track CPU, RAM, GPU, and VRAM usage without cluttering the panel.

Features

• Real-Time Monitoring:
  • CPU Temperature (in °C) with dynamic sensor detection.
  • RAM Usage (in GB / Total GB).
  • GPU Temperature (in °C) via nvidia-smi.
  • VRAM Usage (in GB / Total GB) via nvidia-smi.
• Configurable Visibility:
  • Native KDE Plasma 6 configuration page (Right-click ➔ Configure...).
  • Enable or disable CPU, RAM, GPU, and VRAM graphs independently.
  • Automatic fallback placeholder ("Sem monitores") if all graphs are unchecked.
• Resource-Efficient:
  • Written in C++17 reading directly from Linux kernel pseudo-filesystems (/proc/meminfo and /sys/class/hwmon/).
  • Skips hardware calls (like nvidia-smi) for disabled monitors to save system resources.
• Responsive Visuals: Vertical status bars with color gradients (green ➔ yellow ➔ red) and smooth height transition animations.
• System Integration:
  • Click to Launch: Clicking anywhere on the widget launches the default KDE System Monitor (plasma-systemmonitor), with automatic fallback to ksysguard.
  • Native Tooltip: Detailed hovering tooltips showing precise numbers for all active metrics.
• Robust Hardware Detection: Automatic search for CPU-specific thermal sensors on /sys/class/hwmon/ (supporting AMD k10temp/zenpower and Intel coretemp drivers), falling back to /sys/class/thermal/.

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Requirements

To build and run this widget, you need:

• OS: Linux (with /proc and /sys filesystems)
• Desktop Environment: KDE Plasma 6
• Optional: nvidia-smi (for NVIDIA GPU & VRAM monitoring)
• Dependencies (Ubuntu/Debian):

  sudo apt install -y build-essential cmake extra-cmake-modules \
                      libkf6coreaddons-dev libkf6config-dev \
                      libplasma-dev qt6-base-dev qt6-declarative-dev

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Installation

1. Build and Install (Command Line)

To compile and install the widget using your system's native Qt6 and KDE Frameworks:

# 1. Configure the build directory (pointing to system paths)
cmake -B build -S . -DCMAKE_INSTALL_PREFIX=/usr -DCMAKE_BUILD_TYPE=Release

# 2. Compile the plugin library
cmake --build build

# 3. Install the plugin and QML packages to system directories
sudo cmake --install build

2. Restart the Panel

For Plasma to recognize and load the newly compiled C++ plugin binary:

systemctl --user restart plasma-plasmashell.service

3. Add to Panel

Right-click on your Plasma panel ➔ select Add Widgets ➔ search for "CPU & Memory Status" ➔ drag and drop it onto your panel.

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Configuration

Right-click the widget on the panel and select Configure CPU & Memory Status...:

• Toggle visibility for CPU Temperature, RAM Usage, GPU Temperature, and VRAM Usage.

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Development (Qt Creator Setup)

If you are using Qt Creator, make sure you configure it to use your system's native Qt6 compiler rather than a local standalone Kit (e.g. Qt 6.11.x) to avoid ABI version mismatches:

1. Open Qt Creator ➔ Preferences ➔ Kits ➔ Qt Versions.
2. Click Add... and select your system's qmake executable (usually /usr/bin/qmake6 or /usr/lib/qt6/bin/qmake).
3. Under the Kits tab, create or select a kit (e.g. Desktop (System Qt6)) and link it to this system Qt version.
4. Open the project's CMakeLists.txt and use this kit for building.

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Project Structure

• CMakeLists.txt: Build configuration, library target naming (org.kde.plasma.cpumemstatus), and package install directories.
• assets/: Repository images and screenshots.
• package/: QML package files.
  • metadata.json: Applet definition, versioning, minimum Plasma version requirements, and package structure.
  • contents/config/: Configuration metadata (main.xml, config.qml).
  • contents/ui/: Interface views (main.qml, CpuBar.qml, MemBar.qml, GpuBar.qml, VramBar.qml, configGeneral.qml).
• src/: Backend C++ code (cpumemapplet.h/cpp) handling kernel/GPU stats reading and subprocess spawning.

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License

This project is licensed under the GPL-2.0-or-later License - see the package/metadata.json file for details.