Struct ScrollArea 

pub struct ScrollArea { /* private fields */ }

Add vertical and/or horizontal scrolling to a contained Ui.

By default, scroll bars only show up when needed, i.e. when the contents is larger than the container. This is controlled by Self::scroll_bar_visibility.

There are two flavors of scroll areas: solid and floating. Solid scroll bars use up space, reducing the amount of space available to the contents. Floating scroll bars float on top of the contents, covering it. You can change the scroll style by changing the crate::style::Spacing::scroll.

Coordinate system

• content: size of contents (generally large; that’s why we want scroll bars)
• outer: size of scroll area including scroll bar(s)
• inner: excluding scroll bar(s). The area we clip the contents to. Includes content_margin.

If the floating scroll bars settings is turned on then inner == outer.

Example

egui::ScrollArea::vertical().show(ui, |ui| {
    // Add a lot of widgets here.
});

You can scroll to an element using crate::Response::scroll_to_me, Ui::scroll_to_cursor and Ui::scroll_to_rect.

See also

If you want to allow zooming, use crate::Scene.

Implementations

impl ScrollArea

pub fn horizontal() -> ScrollArea

Create a horizontal scroll area.

pub fn vertical() -> ScrollArea

Create a vertical scroll area.

pub fn both() -> ScrollArea

Create a bi-directional (horizontal and vertical) scroll area.

pub fn neither() -> ScrollArea

Create a scroll area where both direction of scrolling is disabled. It’s unclear why you would want to do this.

pub fn new(direction_enabled: impl Into<Vec2b>) -> ScrollArea

Create a scroll area where you decide which axis has scrolling enabled. For instance, ScrollArea::new([true, false]) enables horizontal scrolling.

pub fn max_width(self, max_width: f32) -> ScrollArea

The maximum width of the outer frame of the scroll area.

Use f32::INFINITY if you want the scroll area to expand to fit the surrounding Ui (default).

See also Self::auto_shrink.

pub fn max_height(self, max_height: f32) -> ScrollArea

The maximum height of the outer frame of the scroll area.

Use f32::INFINITY if you want the scroll area to expand to fit the surrounding Ui (default).

See also Self::auto_shrink.

pub fn min_scrolled_width(self, min_scrolled_width: f32) -> ScrollArea

The minimum width of a horizontal scroll area which requires scroll bars.

The ScrollArea will only become smaller than this if the content is smaller than this (and so we don’t require scroll bars).

Default: 64.0.

pub fn min_scrolled_height(self, min_scrolled_height: f32) -> ScrollArea

The minimum height of a vertical scroll area which requires scroll bars.

The ScrollArea will only become smaller than this if the content is smaller than this (and so we don’t require scroll bars).

Default: 64.0.

pub fn scroll_bar_visibility( self, scroll_bar_visibility: ScrollBarVisibility, ) -> ScrollArea

Set the visibility of both horizontal and vertical scroll bars.

With ScrollBarVisibility::VisibleWhenNeeded (default), the scroll bar will be visible only when needed.

pub fn scroll_bar_rect(self, scroll_bar_rect: Rect) -> ScrollArea

Specify within which screen-space rectangle to show the scroll bars.

This can be used to move the scroll bars to a smaller region of the ScrollArea, for instance if you are painting a sticky header on top of it.

pub fn id_source(self, id_salt: impl Hash) -> ScrollArea

👎Deprecated:

Renamed id_salt

A source for the unique Id, e.g. .id_source("second_scroll_area") or .id_source(loop_index).

pub fn id_salt(self, id_salt: impl Hash) -> ScrollArea

A source for the unique Id, e.g. .id_salt("second_scroll_area") or .id_salt(loop_index).

pub fn scroll_offset(self, offset: Vec2) -> ScrollArea

Set the horizontal and vertical scroll offset position.

Positive offset means scrolling down/right.

See also: Self::vertical_scroll_offset, Self::horizontal_scroll_offset, Ui::scroll_to_cursor and Response::scroll_to_me

pub fn vertical_scroll_offset(self, offset: f32) -> ScrollArea

Set the vertical scroll offset position.

Positive offset means scrolling down.

See also: Self::scroll_offset, Ui::scroll_to_cursor and Response::scroll_to_me

pub fn horizontal_scroll_offset(self, offset: f32) -> ScrollArea

Set the horizontal scroll offset position.

Positive offset means scrolling right.

See also: Self::scroll_offset, Ui::scroll_to_cursor and Response::scroll_to_me

pub fn on_hover_cursor(self, cursor: CursorIcon) -> ScrollArea

Set the cursor used when the mouse pointer is hovering over the ScrollArea.

Only applies if Self::scroll_source() has set ScrollSource::drag to true.

Any changes to the mouse cursor made within the contents of the ScrollArea will override this setting.

pub fn on_drag_cursor(self, cursor: CursorIcon) -> ScrollArea

Set the cursor used when the ScrollArea is being dragged.

Only applies if Self::scroll_source() has set ScrollSource::drag to true.

Any changes to the mouse cursor made within the contents of the ScrollArea will override this setting.

pub fn hscroll(self, hscroll: bool) -> ScrollArea

Turn on/off scrolling on the horizontal axis.

pub fn vscroll(self, vscroll: bool) -> ScrollArea

Turn on/off scrolling on the vertical axis.

pub fn scroll(self, direction_enabled: impl Into<Vec2b>) -> ScrollArea

Turn on/off scrolling on the horizontal/vertical axes.

You can pass in false, true, [false, true] etc.

pub fn enable_scrolling(self, enable: bool) -> ScrollArea

👎Deprecated:

Use `ScrollArea::scroll_source()

Control the scrolling behavior.

• If true (default), the scroll area will respond to user scrolling.
• If false, the scroll area will not respond to user scrolling.

This can be used, for example, to optionally freeze scrolling while the user is typing text in a crate::TextEdit widget contained within the scroll area.

This controls both scrolling directions.

pub fn drag_to_scroll(self, drag_to_scroll: bool) -> ScrollArea

👎Deprecated:

Use `ScrollArea::scroll_source()

Can the user drag the scroll area to scroll?

This is useful for touch screens.

If true, the ScrollArea will sense drags.

Default: true.

pub fn scroll_source(self, scroll_source: ScrollSource) -> ScrollArea

What sources does the ScrollArea use for scrolling the contents.

pub fn wheel_scroll_multiplier(self, multiplier: Vec2) -> ScrollArea

The scroll amount caused by a mouse wheel scroll is multiplied by this amount.

Independent for each scroll direction. Defaults to Vec2{x: 1.0, y: 1.0}.

This can invert or effectively disable mouse scrolling.

pub fn auto_shrink(self, auto_shrink: impl Into<Vec2b>) -> ScrollArea

For each axis, should the containing area shrink if the content is small?

• If true, egui will add blank space outside the scroll area.
• If false, egui will add blank space inside the scroll area.

Default: true.

pub fn animated(self, animated: bool) -> ScrollArea

Should the scroll area animate scroll_to_* functions?

Default: true.

pub fn content_margin(self, margin: impl Into<Margin>) -> ScrollArea

Extra margin added around the contents.

The scroll bars will be either on top of this margin, or outside of it, depending on the value of crate::style::ScrollStyle::floating.

Default: crate::style::ScrollStyle::content_margin.

pub fn stick_to_right(self, stick: bool) -> ScrollArea

The scroll handle will stick to the rightmost position even while the content size changes dynamically. This can be useful to simulate text scrollers coming in from right hand side. The scroll handle remains stuck until user manually changes position. Once “unstuck” it will remain focused on whatever content viewport the user left it on. If the scroll handle is dragged all the way to the right it will again become stuck and remain there until manually pulled from the end position.

pub fn stick_to_bottom(self, stick: bool) -> ScrollArea

The scroll handle will stick to the bottom position even while the content size changes dynamically. This can be useful to simulate terminal UIs or log/info scrollers. The scroll handle remains stuck until user manually changes position. Once “unstuck” it will remain focused on whatever content viewport the user left it on. If the scroll handle is dragged to the bottom it will again become stuck and remain there until manually pulled from the end position.

impl ScrollArea

pub fn show<R>( self, ui: &mut Ui, add_contents: impl FnOnce(&mut Ui) -> R, ) -> ScrollAreaOutput<R>

Show the ScrollArea, and add the contents to the viewport.

If the inner area can be very long, consider using Self::show_rows instead.

pub fn show_rows<R>( self, ui: &mut Ui, row_height_sans_spacing: f32, total_rows: usize, add_contents: impl FnOnce(&mut Ui, Range<usize>) -> R, ) -> ScrollAreaOutput<R>

Efficiently show only the visible part of a large number of rows.

let text_style = egui::TextStyle::Body;
let row_height = ui.text_style_height(&text_style);
// let row_height = ui.spacing().interact_size.y; // if you are adding buttons instead of labels.
let total_rows = 10_000;
egui::ScrollArea::vertical().show_rows(ui, row_height, total_rows, |ui, row_range| {
    for row in row_range {
        let text = format!("Row {}/{}", row + 1, total_rows);
        ui.label(text);
    }
});

pub fn show_viewport<R>( self, ui: &mut Ui, add_contents: impl FnOnce(&mut Ui, Rect) -> R, ) -> ScrollAreaOutput<R>

This can be used to only paint the visible part of the contents.

add_contents is given the viewport rectangle, which is the relative view of the content. So if the passed rect has min = zero, then show the top left content (the user has not scrolled).

Trait Implementations

impl Clone for ScrollArea

fn clone(&self) -> ScrollArea

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ScrollArea

fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter.