Struct CtxRef 

pub struct CtxRef(/* private fields */);

A wrapper around Arc<Context>. This is how you will normally create and access a Context.

Almost all methods are marked &self, Context has interior mutability (protected by mutexes).

CtxRef is cheap to clone, and any clones refers to the same mutable data.

Example:

let mut ctx = egui::CtxRef::default();

// Game loop:
loop {
    let raw_input = egui::RawInput::default();
    ctx.begin_frame(raw_input);

    egui::CentralPanel::default().show(&ctx, |ui| {
        ui.label("Hello world!");
        if ui.button("Click me").clicked() {
            /* take some action here */
        }
    });

    let (output, shapes) = ctx.end_frame();
    let clipped_meshes = ctx.tessellate(shapes); // create triangles to paint
    handle_output(output);
    paint(clipped_meshes);
}

Implementations

impl CtxRef

pub fn begin_frame(&mut self, new_input: RawInput)

Call at the start of every frame. Match with a call to Context::end_frame.

This will modify the internal reference to point to a new generation of Context. Any old clones of this CtxRef will refer to the old Context, which will not get new input.

Put your widgets into a SidePanel, TopBottomPanel, CentralPanel, Window or Area.

pub fn layer_painter(&self, layer_id: LayerId) -> Painter

Get a full-screen painter for a new or existing layer

pub fn debug_painter(&self) -> Painter

Paint on top of everything else

Methods from Deref<Target = Context>

pub fn available_rect(&self) -> Rect

How much space is still available after panels has been added. This is the “background” area, what egui doesn’t cover with panels (but may cover with windows). This is also the area to which windows are constrained.

pub fn memory(&self) -> AtomicRefMut<'_, Memory>

Stores all the egui state. If you want to store/restore egui, serialize this.

pub fn output(&self) -> AtomicRefMut<'_, Output>

What egui outputs each frame.

pub fn request_repaint(&self)

Call this if there is need to repaint the UI, i.e. if you are showing an animation. If this is called at least once in a frame, then there will be another frame right after this. Call as many times as you wish, only one repaint will be issued.

pub fn input(&self) -> &InputState

pub fn fonts(&self) -> &Fonts

Not valid until first call to CtxRef::begin_frame(). That’s because since we don’t know the proper pixels_per_point until then.

pub fn texture(&self) -> Arc<Texture>

The egui texture, containing font characters etc. Not valid until first call to CtxRef::begin_frame(). That’s because since we don’t know the proper pixels_per_point until then.

pub fn set_fonts(&self, font_definitions: FontDefinitions)

Tell egui which fonts to use.

The default egui fonts only support latin and cyrillic alphabets, but you can call this to install additional fonts that support e.g. korean characters.

The new fonts will become active at the start of the next frame.

pub fn style(&self) -> Arc<Style>

The Style used by all subsequent windows, panels etc.

pub fn set_style(&self, style: impl Into<Arc<Style>>)

The Style used by all new windows, panels etc.

You can also use Ui::style_mut to change the style of a single Ui.

Example:

let mut style: egui::Style = (*ctx.style()).clone();
style.spacing.item_spacing = egui::vec2(10.0, 20.0);
ctx.set_style(style);

pub fn set_visuals(&self, visuals: Visuals)

The Visuals used by all subsequent windows, panels etc.

You can also use Ui::visuals_mut to change the visuals of a single Ui.

Example:

ctx.set_visuals(egui::Visuals::light()); // Switch to light mode

pub fn pixels_per_point(&self) -> f32

The number of physical pixels for each logical point.

pub fn set_pixels_per_point(&self, pixels_per_point: f32)

Set the number of physical pixels for each logical point. Will become active at the start of the next frame.

Note that this may be overwritten by input from the integration via RawInput::pixels_per_point. For instance, when using egui_web the browsers native zoom level will always be used.

pub fn end_frame(&self) -> (Output, Vec<ClippedShape>)

Call at the end of each frame. Returns what has happened this frame crate::Output as well as what you need to paint. You can transform the returned shapes into triangles with a call to Context::tessellate.

pub fn tessellate(&self, shapes: Vec<ClippedShape>) -> Vec<ClippedMesh>

Tessellate the given shapes into triangle meshes.

pub fn used_rect(&self) -> Rect

How much space is used by panels and windows.

pub fn used_size(&self) -> Vec2

How much space is used by panels and windows. You can shrink your egui area to this size and still fit all egui components.

pub fn is_pointer_over_area(&self) -> bool

Is the pointer (mouse/touch) over any egui area?

pub fn wants_pointer_input(&self) -> bool

True if egui is currently interested in the pointer (mouse or touch). Could be the pointer is hovering over a Window or the user is dragging a widget. If false, the pointer is outside of any egui area and so you may be interested in what it is doing (e.g. controlling your game). Returns false if a drag started outside of egui and then moved over an egui area.

pub fn is_using_pointer(&self) -> bool

Is egui currently using the pointer position (e.g. dragging a slider). NOTE: this will return false if the pointer is just hovering over an egui area.

pub fn wants_mouse_input(&self) -> bool

👎Deprecated: Renamed wants_pointer_input

pub fn is_using_mouse(&self) -> bool

👎Deprecated: Renamed is_using_pointer

pub fn wants_keyboard_input(&self) -> bool

If true, egui is currently listening on text input (e.g. typing text in a TextEdit).

pub fn translate_layer(&self, layer_id: LayerId, delta: Vec2)

Move all the graphics at the given layer. Can be used to implement drag-and-drop (see relevant demo).

pub fn layer_id_at(&self, pos: Pos2) -> Option<LayerId>

Top-most layer at the given position.

pub fn debug_on_hover(&self) -> bool

Wether or not to debug widget layout on hover.

pub fn set_debug_on_hover(&self, debug_on_hover: bool)

Turn on/off wether or not to debug widget layout on hover.

pub fn animate_bool(&self, id: Id, value: bool) -> f32

Returns a value in the range [0, 1], to indicate “how on” this thing is.

The first time called it will return if value { 1.0 } else { 0.0 } Calling this with value = true will always yield a number larger than zero, quickly going towards one. Calling this with value = false will always yield a number less than one, quickly going towards zero.

The function will call Self::request_repaint() when appropriate.

pub fn clear_animations(&self)

Clear memory of any animations.

pub fn settings_ui(&self, ui: &mut Ui)

pub fn inspection_ui(&self, ui: &mut Ui)

pub fn memory_ui(&self, ui: &mut Ui)

pub fn style_ui(&self, ui: &mut Ui)

Trait Implementations

impl AsRef<Context> for CtxRef

fn as_ref(&self) -> &Context

Converts this type into a shared reference of the (usually inferred) input type.

impl Borrow<Context> for CtxRef

fn borrow(&self) -> &Context

Immutably borrows from an owned value.

impl Clone for CtxRef

fn clone(&self) -> CtxRef

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Default for CtxRef

fn default() -> CtxRef

Returns the “default value” for a type.

impl Deref for CtxRef

type Target = Context

The resulting type after dereferencing.

fn deref(&self) -> &Context

Dereferences the value.

impl PartialEq for CtxRef

fn eq(&self, other: &CtxRef) -> bool

Tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.