Create a bottom panel.

The id_salt only needs to be unique among the panels of the same parent Ui, e.g. "my_bottom_panel".

By default this is NOT resizable.

The initial wrapping width of the Panel, including margins.

Enforce this exact size, including margins.

Change the background color, margins, etc.

Create a left panel.

The id_salt only needs to be unique among the panels of the same parent Ui, e.g. "my_left_panel".

Maximum size of the panel, including margins.

Minimum size of the panel, including margins.

Can panel be resized by dragging the edge of it?

Default is True.

If you want your panel to be resizable you also need to make the ui use the available space.

This can be done by using Ui.take_available_space, or using a widget in it that takes up more space as you resize it, such as: * Wrapping text (Ui.horizontal_wrapped). * A egui.ScrollArea. * A egui.Separator. * A egui.TextEdit. * …

Create a right panel.

The id_salt only needs to be unique among the panels of the same parent Ui, e.g. "my_right_panel".

Show the panel inside a Ui.

Renamed to egui.Panel.show_switched.

Note: egui.Panel.show_switched takes is_expanded by &mut (to allow drag-to-collapse / drag-to-expand to flip it) and passes a bool to add_contents instead of an float animation fraction. To opt in, migrate to the new name.

Renamed to egui.Panel.show_collapsible.

Note: egui.Panel.show_collapsible takes is_expanded by &mut so it can flip it to False when the user drags the panel closed. To opt in, migrate to the new name.

Show the panel if *is_expanded is True, otherwise hide it, with a slide animation in between.

During the animation add_contents runs against the real panel, and the panel slides off-screen toward its fixed edge (clipped against the parent). The parent only reserves the visible portion, so neighboring widgets follow.

is_expanded is taken by &mut so the panel can flip it to False when the user drags the resize handle past the panel's minimum size, and back to True if the user drags the handle outward while the panel is closed. When egui.Panel.resizable is True, double-clicking the resize edge also flips *is_expanded.

A fully collapsed panel keeps a thin grab handle at its fixed edge, so the user can drag it back open. See egui.Panel.drag_to_open to opt out.

Renamed to egui.Panel.show.

Show a separator line, even when not interacting with it?

The separator line sits on the panel's inner edge, i.e. the edge facing the rest of the ui. It is painted outside the Frame's outline, in room the panel reserves for it in the frame's Frame.outer_margin, so that going from the panel contents outwards you get:

contents | Frame.inner_margin | Frame.stroke | separator line | Frame.outer_margin

Turning this off removes that reserved room too, so the panel gets no permanent gap along that edge.

A resizable panel still shows a line while hovered or dragged, regardless of this setting. With this setting off there is no room reserved for it, so that transient line is painted just outside the frame's outline, overlapping the Frame.outer_margin.

Default: True.

Show either a collapsed or expanded panel, with a nice slide animation between.

The collapsed_panel is shown only when fully collapsed; during the animation, the expanded_panel slides in/out toward its fixed edge, interpolating its visible size between the two panels' sizes. add_contents receives expanded = True whenever the expanded panel is rendered (including mid-animation), and False for the collapsed view.

Give the two panels distinct ids so their persisted sizes don't overwrite each other.

Drag-to-collapse / drag-to-expand

The user can resize the panel by dragging its edge. Pulling that edge past the size limits flips *is_expanded:

• .resizable(True) on the expanded panel enables drag-to-collapse: shrinking past min_size sets *is_expanded = False.
• .resizable(True) on the collapsed panel enables drag-to-expand: growing past max_size sets *is_expanded = True. (Use egui.Panel.exact_size or egui.Panel.max_size to set a tight cap so a small outward drag is enough to trigger the swap.)

Both panels share a single resize-handle widget under the hood (keyed to the expanded panel's id), so a single uninterrupted drag can collapse and re-expand the panel without releasing.

Double-clicking the resize edge also flips *is_expanded (whichever panel is currently shown is the one whose edge you click).

The allowable size range for the panel, including margins.

Create a top panel.

The id_salt only needs to be unique among the panels of the same parent Ui, e.g. "my_top_panel".

By default this is NOT resizable.