Learn PyQt: EqualizerBar — Visualize audio frequency changes

This custom PyQt5/PySide2-compatible widget provides a frequency visualizer output for audio applications. It is completely configurable from the number of bars, the number of segments and colours to the animated decay. It's ready to drop into your Python-Qt5 applications.

The download package includes a demo animation using random data and some custom colour configuration so you can explore how the widget works.

Basic setup

To create an Equalizer object pass in the number of bars and a number of segments per bar.

python

equalizer = Equalizer(5, 10)

The default appearance of the widget.

The default range for each of the equalizer bars is 0...100. This can be adjusted using .setRange.

python

equalizer.setRange(0, 1000)

Decay animation

The equalizer bar includes a decay animation where peaks of values slowly fade over time. This is created by gradually subtracting a set value from the current value of each bar, using a recurring timer.

The frequency of the decay timer (in milliseconds) can be configured using .setDecayFrequencyMs. The default value is 100ms.

python

equalizer.setDecayFrequencyMs()

Passing 0 will disable the decay mechanism.

On each tick a set value is removed from the current value of each bar. This is configured by using .setDecay. Adjust this based on your equalizer's range of possible values.

python

equalizer.setDecay(0, 1000)

Bar style configuration

The number of bars to display and the number of segments in the bars/the colours of those bars are defined at startup.

python

equalizer = EqualizerBar(10,  ["#2d004b", "#542788", "#8073ac", "#b2abd2", "#d8daeb", "#f7f7f7", "#fee0b6", "#fdb863", "#e08214", "#b35806", "#7f3b08"])

Purple Orange theme with 10 bars

To set the colours after startup, either provide a list of colors (QColor or hex values) at startup, or use the .setColors method. Passing a list of colours to this method will change the number of segments to match the colours provided.

python

equalizer.setColors(["#810f7c", "#8856a7", "#8c96c6", "#b3cde3", "#edf8fb"])

You can also use .setColor to set a single colour for all segments, without changing the number of bars.

python

equalizer.setColor('red')

The spacing around the equalizer graphic is configured with .setBarPadding providing an integer value to add in pixels.

python

equalizer.setBarPadding(20)

The proportion of each segment in the bar which is solid/empty is configured using .setBarSolidPercent with a float value between 0...1.

python

equalizer.setBarSolidPercent(0.4)

Finally, the background colour can be configured using .setBackgroundColor

python

equalizer.setBackgroundColor('#0D1F2D')

Customising bar padding and sizing.

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