A Different Audio Spectrum Analyzer for KDE Plasma

Contents

• Requirements
• Install the required dependencies
  • Arch Linux
  • Ubuntu
• Installation
  • Via KDE Store
  • Via Command Line
  • Via AUR
  • Drag panon widget to your panel
• Shaders
  • Debugging Shaders
• Troubleshooting
• Credits

Requirements

	Minimal version required
OpenGL / GLSL	3.0 / 1.30
QtQuick	2.0

Install the required dependencies

Arch Linux

sudo pacman -S qt5-websockets qt5-3d \
    python-docopt python-numpy python-pillow python-pyaudio python-cffi python-websockets 

Ubuntu

sudo apt-get install qml-module-qt3d qml-module-qt-websockets \
    python3-docopt python3-numpy python3-pyaudio python3-cffi python3-websockets python3-pil 

Installation

Via KDE Store

1. Open the “Add Widgets” dialog of your desktop
2. Go to “Get New Widgets” in the bottom
3. Click “Download New Plasma Widgets”
4. Search for “panon”
5. Click “Install”

Via Command Line

git clone https://github.com/rbn42/panon.git
cd panon/kde
# To install
kpackagetool5 -t Plasma/Applet --install plasmoid
# To upgrade
kpackagetool5 -t Plasma/Applet --upgrade plasmoid

Via AUR

plasma5-applets-panon and plasma5-applets-panon-git are available for ArchLinux.

If you want to modify shaders, installing panon as a system package is not a preferred solution right now, because then the modification will require write permission in /usr/share/plasma/plasmoids/panon.

Drag panon widget to your panel (eg. latte-dock).

Shaders

What is a shader? And a turtorial for beginners.

Shaders are stored in kde/plasmoid/contents/shaders/. If you want to modify the shaders, you can start with solid.frag.

Providing panon is installed in your home directory, you can add your own shader files to ~/.local/share/plasma/plasmoids/panon/contents/shaders/. Panon can detect and load shaders in this folder. The name of a shader file must be ended with .frag.

Shader API and Shadertoy.com

Shadertoy.com is a cross-browser online community and tool for creating and sharing shaders through WebGL, from where you can find many wonderful works shared by kind people. And by default, these works are licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License.

Panon’s shader API is designed to be similar to shadertoy.com. Many of the works can be copied directly to panon, providing you add #version 130 to the shader file’s first line. But all these works were designed to show in browsers, so they won’t look good in tiny space like a panel. example-shadertoy.frag is such an example.

Currently, these shadertoy-like uniforms are provided,

iResolution	width and heigh of the applet	available
iTime		available
iTimeDelta		available
iFrame		available
iMouse	mouse position	available
iChannel0	fixed wave data	coming soon
iChannel1	fixed spectrum data	available

Debugging Shaders

Neither KDE Panel nor Latte-Dock shows the errors caused by the shaders. To catch the error messages, plasma-sdk is required. To debug your shader, you must put your shader file in kde/plasmoid/contents/shaders/, and then start plasmoidviewer in a console.

cd ./kde/
#Providing plasma-sdk is installed
plasmoidviewer --applet ./plasmoid/

In plasmoidviewer, go to the configuration window and pick your own shader. Then plasmoidviewer will run your shader and show the errors, if exist, in the console.

Troubleshooting

Panon shows nothing when you are playing music

1. Please make sure your OpenGL version satisfies the minimum requirement.
2. If you are using pyaudio as panon’s backend, please execute python3 ./test/test_pyaudio.py The script will tell you if pyaudio works or not. If the script failed, this issue can be reported to pyaudio. Alternatively, you may choose to execute ./test/test_python-sounddevice.py and ./test/test_QtMultimedia.py and if one of them works for you, I can add it to panon as another backend choice.

Credits

		LICENSE
source.py and spectrum.py	adapted from PyVisualizer
husl-glsl.fsh	copied from hsluv-glsl
hsv2rgb in utils.fsh	copied from GLSL-color.md
example-shadertoy.frag	copied from shadertoy	CC BY-NC-SA 3.0
pulseaudio.py and pulseaudio.py.h	copied from SoundCard	BSD-3-Clause