ImGui Knobs: rotary knobs for numeric values, in several styles (tick, dot, wiper, stepped, space...).
knob(label, value, v_min, v_max) returns (changed, new_value); knob_int() is its integer version.
Upstream repository · The book’s page
Modules¶
In imgui_bundle (from imgui_bundle import imgui_knobs):
imgui_knobs: 4 functions, 2 classes, 2 enums · the C++ view
Demos using it¶
The demos of the catalog that use it (the pictures link to their code and to the playground).
A parametric curve¶
Turn the knobs, or click Random: the curve follows at once.
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At every frame, the GUI function draws the plot with ImPlot and the knobs with imgui-knobs, and reads their values right there. No callbacks, no widget objects: that is the immediate mode.
Uses: ImPlot, knobs
Simple harmonic motion¶
A mass on a spring, a pendulum, a vibrating string: they all follow the same equation.
More
It is the equation of simple harmonic motion (for the pendulum, at small angles). Adjust the mass and the spring stiffness, and watch how the motion changes.
Uses: ImPlot, knobs
Double pendulum¶
A double pendulum is a chaotic system: tiny changes in its initial conditions lead to wildly different trajectories.
More
Drag the angles to set initial positions, then release and watch chaos unfold.
Uses: ImPlot, knobs, toggles
Fourier epicycles¶
Any closed curve can be approximated by a sum of rotating circles (a Fourier series).
More
Adjust the number of circles to see how the approximation improves.
Uses: ImPlot, knobs, toggles
Medical imaging: a chest CT, its windows, a segmentation¶
A real chest CT, explored as a radiologist would: its slices, its windows, and a region grown from a click.
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Choose a window preset or drag its bounds on the histogram. Click a structure: the region grows across the slices, and the app measures it and shows it in 3D. A second tab finds the blood vessels of a retina. For research and teaching, not for diagnosis.
Uses: ImPlot, ImPlot3D, ImmVision, knobs, ImGuiKit, OpenCV
Gravitational lensing: a ring, arcs, the Einstein Cross¶
A mass in the foreground bends the light of a galaxy behind it.
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The left sky shows the galaxy as it is, the right one what we see through the lens. Drag the galaxy (yellow) and the lens (blue), turn the knobs, or start from a preset: an Einstein ring, two images, a giant arc, the Einstein Cross. The thin lines are the critical curve, where the magnification diverges, and its map in the source plane, the caustic: as the galaxy crosses it, images are born or merge. Hover a pixel of the observed sky to see where its light comes from.
Uses: ImPlot, knobs, toggles
Knobs, toggles, spinners and more¶
Knobs, toggle switches, spinners, a command palette, a dock-like cool bar: widgets beyond Dear ImGui’s own.
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They come from the libraries in the bundle: imgui-knobs, imgui_toggle, imspinner, imgui
Uses: knobs, toggles, spinners, cool bar, command palette, file dialogs
WebAudio synthesizer¶
A small synthesizer written in Python: play the piano with the mouse or the computer keyboard, or let it play a tune.
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Pick a waveform, add some echo, and watch the scope. Pyodide only: it plays through the browser’s WebAudio API, via Pyodide’s js interop.
Browser only
Uses: knobs, browser APIs