dpset

dpset is a small Qt application for visually arranging and configuring monitors on Linux using xrandr and xinput.
It provides an intuitive drag-and-drop interface to set positions, resolutions, orientations, and primary monitors.
The application can also generate a shell script to make monitor setups easily reproducible on reboot.

Note: dpset is not part of the official Sweelinq software. It is an independent utility.

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Table of Contents

• Features
• Requirements
• Building
• Running
• Usage
• Notes

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Features

• 💻 Visual Monitor Layout
  Drag and drop monitors in a 2D scene. They snap to each other when close.

• ⚙️ Context Menu

  • Identify: Temporarily shows an overlay on the physical screen.
  • Primary: Mark a specific monitor as the primary display.
  • Resolution: Select from known resolutions or set a custom resolution.
  • Orientation: Rotate the display (normal, left, right, inverted).
  • Touch Device Mapping: Map a detected xinput device to a particular monitor.
  

• ⏫ Apply or Save

  • Apply: Immediately apply xrandr/xinput changes (non-persistent).
  • Script: Save the configuration as a shell script for easy replication at startup.

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Requirements

1. Qt 6.5 (Core, Gui, Widgets) or higher
2. CMake 3.19 or higher
3. xrandr and xinput command-line tools must be installed and in your PATH
4. A standard C++ compiler (e.g., g++ or clang)

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Building

1. Clone this repository:

git clone https://github.com/Sweelinq/dpset.git

2. Create a build directory and run CMake:

cd dpset mkdir build && cd build cmake ..

This will generate the build system (e.g., Makefiles, Ninja, etc.) based on your environment.

3. Build the project:

cmake --build .

After a successful build, you should have an executable named dpset.

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Running

You have two options to run dpset:

1. Download the latest release as an AppImage

• Locate the .appimage file you downloaded (e.g., dpset.AppImage).
• Make it executable:

  chmod +x dpset.AppImage
  

• Launch it:

  ./dpset.AppImage
  

2. Use your own build

• From the build directory (or wherever you built the executable), run:

  ./dpset
  

If xrandr detects monitors, they appear as draggable items.
If no monitors are detected, an error is shown.

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Usage

1. Arrange Monitors

• Drag monitors around the scene to match your desired physical layout.
• Monitors automatically snap together.

2. Context Menu (Right-click on a monitor)

• Identify: Displays a large label on that actual monitor for easy identification.
• Primary: Toggle whether this monitor is primary.
• Resolution: Choose from detected resolutions or set a custom resolution.
• Orientation: Rotate the monitor (normal, left, right, inverted).
• Touch device: Map a specific touch device (detected by xinput) to this monitor.

3. Apply

• Click Apply to immediately run the necessary xrandr and xinput commands.

4. Script

• Click Script to generate a shell script containing all relevant commands.
• Run this script manually or integrate it into your startup routine (e.g., ~/.profile, ~/.xinitrc, or desktop environment services) to restore the layout after reboot.

An example of a generated script:

#!/bin/bash

xrandr --output HDMI-2 --mode 1600x720 --pos 3840x1440 --rotate normal --output HDMI-1 --mode 3840x2160 --pos 0x0 --rotate normal

find_xinput_device() {
    local target_id_path="$(echo "$1" | xargs)"
    local target_name="$(echo "$2" | xargs)"
    for id in $(xinput list --id-only); do
        local node_line
        node_line=$(xinput list-props "$id" 2>/dev/null | grep "Device Node")
        if [ -z "$node_line" ]; then
            continue
        fi
        local device_node
        device_node=$(echo "$node_line" | sed -n 's/.*"\(\/dev\/input\/[^\"]*\)".*/\1/p')
        if [ -z "$device_node" ]; then
            continue
        fi
        local udev_line
        udev_line=$(udevadm info "$device_node" 2>/dev/null | grep "E: ID_PATH=")
        if [ -z "$udev_line" ]; then
            continue
        fi
        local id_path_value
        id_path_value=$(echo "$udev_line" | cut -d'=' -f2 | xargs)
        if [ "$id_path_value" = "$target_id_path" ]; then
            local dev_name
            dev_name=$(xinput list --name-only "$id" | xargs)
            if [ "$dev_name" = "$target_name" ]; then
                echo "$id"
                return 0
            fi
        fi
    done
    echo "-1"
    return 1
}

#Touch mapping for HDMI-2
DEVICE_ID=$(find_xinput_device "pci-0000:00:14.0-usb-0:1:1.0" "Waveshare  Waveshare")
if [ "$DEVICE_ID" -eq "-1" ]; then
    echo "DEBUG: Could not find touch device for HDMI-2 with id_path pci-0000:00:14.0-usb-0:1:1.0 and name Waveshare  Waveshare" >&2
else
    xinput set-prop $DEVICE_ID 'Coordinate Transformation Matrix' 0.29411765 0 0.70588235 0 0.33333333 0.66666667 0 0 1
fi

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Notes

• Non-persistent
  The changes applied with Apply are not saved permanently. You must reapply them or run the generated script after each reboot.
• Wayland
  Currently relies on xrandr and xinput (X11); it does not support Wayland sessions.

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