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#![warn(missing_docs)] // Let's keep `Context` well-documented.
use std::borrow::Cow;
use std::sync::Arc;
use crate::load::Bytes;
use crate::load::SizedTexture;
use crate::{
animation_manager::AnimationManager, data::output::PlatformOutput, frame_state::FrameState,
input_state::*, layers::GraphicLayers, load::Loaders, memory::Options, os::OperatingSystem,
output::FullOutput, util::IdTypeMap, TextureHandle, *,
};
use epaint::{mutex::*, stats::*, text::Fonts, TessellationOptions, *};
/// Information given to the backend about when it is time to repaint the ui.
///
/// This is given in the callback set by [`Context::set_request_repaint_callback`].
#[derive(Clone, Copy, Debug)]
pub struct RequestRepaintInfo {
/// Repaint after this duration. If zero, repaint as soon as possible.
pub after: std::time::Duration,
/// The current frame number.
///
/// This can be compared to [`Context::frame_nr`] to see if we've already
/// triggered the painting of the next frame.
pub current_frame_nr: u64,
}
// ----------------------------------------------------------------------------
struct WrappedTextureManager(Arc<RwLock<epaint::TextureManager>>);
impl Default for WrappedTextureManager {
fn default() -> Self {
let mut tex_mngr = epaint::textures::TextureManager::default();
// Will be filled in later
let font_id = tex_mngr.alloc(
"egui_font_texture".into(),
epaint::FontImage::new([0, 0]).into(),
Default::default(),
);
assert_eq!(font_id, TextureId::default());
Self(Arc::new(RwLock::new(tex_mngr)))
}
}
// ----------------------------------------------------------------------------
/// Logic related to repainting the ui.
struct Repaint {
/// The current frame number.
///
/// Incremented at the end of each frame.
frame_nr: u64,
/// The duration backend will poll for new events, before forcing another egui update
/// even if there's no new events.
///
/// Also used to suppress multiple calls to the repaint callback during the same frame.
repaint_after: std::time::Duration,
/// While positive, keep requesting repaints. Decrement at the end of each frame.
repaint_requests: u32,
request_repaint_callback: Option<Box<dyn Fn(RequestRepaintInfo) + Send + Sync>>,
requested_repaint_last_frame: bool,
}
impl Default for Repaint {
fn default() -> Self {
Self {
frame_nr: 0,
repaint_after: std::time::Duration::from_millis(100),
// Start with painting an extra frame to compensate for some widgets
// that take two frames before they "settle":
repaint_requests: 1,
request_repaint_callback: None,
requested_repaint_last_frame: false,
}
}
}
impl Repaint {
fn request_repaint(&mut self) {
self.request_repaint_after(std::time::Duration::ZERO);
}
fn request_repaint_after(&mut self, after: std::time::Duration) {
if after == std::time::Duration::ZERO {
// Do a few extra frames to let things settle.
// This is a bit of a hack, and we don't support it for `repaint_after` callbacks yet.
self.repaint_requests = 2;
}
// We only re-call the callback if we get a lower duration,
// otherwise it's already been covered by the previous callback.
if after < self.repaint_after {
self.repaint_after = after;
if let Some(callback) = &self.request_repaint_callback {
let info = RequestRepaintInfo {
after,
current_frame_nr: self.frame_nr,
};
(callback)(info);
}
}
}
fn start_frame(&mut self) {
// We are repainting; no need to reschedule a repaint unless the user asks for it again.
self.repaint_after = std::time::Duration::MAX;
}
// returns how long to wait until repaint
fn end_frame(&mut self) -> std::time::Duration {
// if repaint_requests is greater than zero. just set the duration to zero for immediate
// repaint. if there's no repaint requests, then we can use the actual repaint_after instead.
let repaint_after = if self.repaint_requests > 0 {
self.repaint_requests -= 1;
std::time::Duration::ZERO
} else {
self.repaint_after
};
self.repaint_after = std::time::Duration::MAX;
self.requested_repaint_last_frame = repaint_after.is_zero();
self.frame_nr += 1;
repaint_after
}
}
// ----------------------------------------------------------------------------
#[derive(Default)]
struct ContextImpl {
/// `None` until the start of the first frame.
fonts: Option<Fonts>,
memory: Memory,
animation_manager: AnimationManager,
tex_manager: WrappedTextureManager,
os: OperatingSystem,
input: InputState,
/// State that is collected during a frame and then cleared
frame_state: FrameState,
// The output of a frame:
graphics: GraphicLayers,
output: PlatformOutput,
paint_stats: PaintStats,
repaint: Repaint,
/// Written to during the frame.
layer_rects_this_frame: ahash::HashMap<LayerId, Vec<(Id, Rect)>>,
/// Read
layer_rects_prev_frame: ahash::HashMap<LayerId, Vec<(Id, Rect)>>,
#[cfg(feature = "accesskit")]
is_accesskit_enabled: bool,
#[cfg(feature = "accesskit")]
accesskit_node_classes: accesskit::NodeClassSet,
loaders: Arc<Loaders>,
}
impl ContextImpl {
fn begin_frame_mut(&mut self, mut new_raw_input: RawInput) {
self.repaint.start_frame();
if let Some(new_pixels_per_point) = self.memory.new_pixels_per_point.take() {
new_raw_input.pixels_per_point = Some(new_pixels_per_point);
// This is a bit hacky, but is required to avoid jitter:
let ratio = self.input.pixels_per_point / new_pixels_per_point;
let mut rect = self.input.screen_rect;
rect.min = (ratio * rect.min.to_vec2()).to_pos2();
rect.max = (ratio * rect.max.to_vec2()).to_pos2();
new_raw_input.screen_rect = Some(rect);
}
self.layer_rects_prev_frame = std::mem::take(&mut self.layer_rects_this_frame);
self.memory.begin_frame(&self.input, &new_raw_input);
self.input = std::mem::take(&mut self.input)
.begin_frame(new_raw_input, self.repaint.requested_repaint_last_frame);
self.frame_state.begin_frame(&self.input);
self.update_fonts_mut();
// Ensure we register the background area so panels and background ui can catch clicks:
let screen_rect = self.input.screen_rect();
self.memory.areas.set_state(
LayerId::background(),
containers::area::State {
pivot_pos: screen_rect.left_top(),
pivot: Align2::LEFT_TOP,
size: screen_rect.size(),
interactable: true,
},
);
#[cfg(feature = "accesskit")]
if self.is_accesskit_enabled {
crate::profile_scope!("accesskit");
use crate::frame_state::AccessKitFrameState;
let id = crate::accesskit_root_id();
let mut builder = accesskit::NodeBuilder::new(accesskit::Role::Window);
builder.set_transform(accesskit::Affine::scale(
self.input.pixels_per_point().into(),
));
let mut node_builders = IdMap::default();
node_builders.insert(id, builder);
self.frame_state.accesskit_state = Some(AccessKitFrameState {
node_builders,
parent_stack: vec![id],
});
}
}
/// Load fonts unless already loaded.
fn update_fonts_mut(&mut self) {
crate::profile_function!();
let pixels_per_point = self.input.pixels_per_point();
let max_texture_side = self.input.max_texture_side;
if let Some(font_definitions) = self.memory.new_font_definitions.take() {
crate::profile_scope!("Fonts::new");
let fonts = Fonts::new(pixels_per_point, max_texture_side, font_definitions);
self.fonts = Some(fonts);
}
let fonts = self.fonts.get_or_insert_with(|| {
let font_definitions = FontDefinitions::default();
crate::profile_scope!("Fonts::new");
Fonts::new(pixels_per_point, max_texture_side, font_definitions)
});
{
crate::profile_scope!("Fonts::begin_frame");
fonts.begin_frame(pixels_per_point, max_texture_side);
}
if self.memory.options.preload_font_glyphs {
crate::profile_scope!("preload_font_glyphs");
// Preload the most common characters for the most common fonts.
// This is not very important to do, but may save a few GPU operations.
for font_id in self.memory.options.style.text_styles.values() {
fonts.lock().fonts.font(font_id).preload_common_characters();
}
}
}
#[cfg(feature = "accesskit")]
fn accesskit_node_builder(&mut self, id: Id) -> &mut accesskit::NodeBuilder {
let state = self.frame_state.accesskit_state.as_mut().unwrap();
let builders = &mut state.node_builders;
if let std::collections::hash_map::Entry::Vacant(entry) = builders.entry(id) {
entry.insert(Default::default());
let parent_id = state.parent_stack.last().unwrap();
let parent_builder = builders.get_mut(parent_id).unwrap();
parent_builder.push_child(id.accesskit_id());
}
builders.get_mut(&id).unwrap()
}
}
// ----------------------------------------------------------------------------
/// Your handle to egui.
///
/// This is the first thing you need when working with egui.
/// Contains the [`InputState`], [`Memory`], [`PlatformOutput`], and more.
///
/// [`Context`] is cheap to clone, and any clones refers to the same mutable data
/// ([`Context`] uses refcounting internally).
///
/// ## Locking
/// All methods are marked `&self`; [`Context`] has interior mutability protected by an [`RwLock`].
///
/// To access parts of a `Context` you need to use some of the helper functions that take closures:
///
/// ```
/// # let ctx = egui::Context::default();
/// if ctx.input(|i| i.key_pressed(egui::Key::A)) {
/// ctx.output_mut(|o| o.copied_text = "Hello!".to_string());
/// }
/// ```
///
/// Within such a closure you may NOT recursively lock the same [`Context`], as that can lead to a deadlock.
/// Therefore it is important that any lock of [`Context`] is short-lived.
///
/// These are effectively transactional accesses.
///
/// [`Ui`] has many of the same accessor functions, and the same applies there.
///
/// ## Example:
///
/// ``` no_run
/// # fn handle_platform_output(_: egui::PlatformOutput) {}
/// # fn paint(textures_delta: egui::TexturesDelta, _: Vec<egui::ClippedPrimitive>) {}
/// let mut ctx = egui::Context::default();
///
/// // Game loop:
/// loop {
/// let raw_input = egui::RawInput::default();
/// let full_output = ctx.run(raw_input, |ctx| {
/// egui::CentralPanel::default().show(&ctx, |ui| {
/// ui.label("Hello world!");
/// if ui.button("Click me").clicked() {
/// // take some action here
/// }
/// });
/// });
/// handle_platform_output(full_output.platform_output);
/// let clipped_primitives = ctx.tessellate(full_output.shapes); // create triangles to paint
/// paint(full_output.textures_delta, clipped_primitives);
/// }
/// ```
#[derive(Clone)]
pub struct Context(Arc<RwLock<ContextImpl>>);
impl std::fmt::Debug for Context {
fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
f.debug_struct("Context").finish_non_exhaustive()
}
}
impl std::cmp::PartialEq for Context {
fn eq(&self, other: &Context) -> bool {
Arc::ptr_eq(&self.0, &other.0)
}
}
impl Default for Context {
fn default() -> Self {
Self(Arc::new(RwLock::new(ContextImpl::default())))
}
}
impl Context {
// Do read-only (shared access) transaction on Context
fn read<R>(&self, reader: impl FnOnce(&ContextImpl) -> R) -> R {
reader(&self.0.read())
}
// Do read-write (exclusive access) transaction on Context
fn write<R>(&self, writer: impl FnOnce(&mut ContextImpl) -> R) -> R {
writer(&mut self.0.write())
}
/// Run the ui code for one frame.
///
/// Put your widgets into a [`SidePanel`], [`TopBottomPanel`], [`CentralPanel`], [`Window`] or [`Area`].
///
/// This will modify the internal reference to point to a new generation of [`Context`].
/// Any old clones of this [`Context`] will refer to the old [`Context`], which will not get new input.
///
/// You can alternatively run [`Self::begin_frame`] and [`Context::end_frame`].
///
/// ```
/// // One egui context that you keep reusing:
/// let mut ctx = egui::Context::default();
///
/// // Each frame:
/// let input = egui::RawInput::default();
/// let full_output = ctx.run(input, |ctx| {
/// egui::CentralPanel::default().show(&ctx, |ui| {
/// ui.label("Hello egui!");
/// });
/// });
/// // handle full_output
/// ```
#[must_use]
pub fn run(&self, new_input: RawInput, run_ui: impl FnOnce(&Context)) -> FullOutput {
crate::profile_function!();
self.begin_frame(new_input);
run_ui(self);
self.end_frame()
}
/// An alternative to calling [`Self::run`].
///
/// ```
/// // One egui context that you keep reusing:
/// let mut ctx = egui::Context::default();
///
/// // Each frame:
/// let input = egui::RawInput::default();
/// ctx.begin_frame(input);
///
/// egui::CentralPanel::default().show(&ctx, |ui| {
/// ui.label("Hello egui!");
/// });
///
/// let full_output = ctx.end_frame();
/// // handle full_output
/// ```
pub fn begin_frame(&self, new_input: RawInput) {
crate::profile_function!();
self.write(|ctx| ctx.begin_frame_mut(new_input));
}
}
/// ## Borrows parts of [`Context`]
/// These functions all lock the [`Context`].
/// Please see the documentation of [`Context`] for how locking works!
impl Context {
/// Read-only access to [`InputState`].
///
/// Note that this locks the [`Context`].
///
/// ```
/// # let mut ctx = egui::Context::default();
/// ctx.input(|i| {
/// // ⚠️ Using `ctx` (even from other `Arc` reference) again here will lead to a dead-lock!
/// });
///
/// if let Some(pos) = ctx.input(|i| i.pointer.hover_pos()) {
/// // This is fine!
/// }
/// ```
#[inline]
pub fn input<R>(&self, reader: impl FnOnce(&InputState) -> R) -> R {
self.read(move |ctx| reader(&ctx.input))
}
/// Read-write access to [`InputState`].
#[inline]
pub fn input_mut<R>(&self, writer: impl FnOnce(&mut InputState) -> R) -> R {
self.write(move |ctx| writer(&mut ctx.input))
}
/// Read-only access to [`Memory`].
#[inline]
pub fn memory<R>(&self, reader: impl FnOnce(&Memory) -> R) -> R {
self.read(move |ctx| reader(&ctx.memory))
}
/// Read-write access to [`Memory`].
#[inline]
pub fn memory_mut<R>(&self, writer: impl FnOnce(&mut Memory) -> R) -> R {
self.write(move |ctx| writer(&mut ctx.memory))
}
/// Read-only access to [`IdTypeMap`], which stores superficial widget state.
#[inline]
pub fn data<R>(&self, reader: impl FnOnce(&IdTypeMap) -> R) -> R {
self.read(move |ctx| reader(&ctx.memory.data))
}
/// Read-write access to [`IdTypeMap`], which stores superficial widget state.
#[inline]
pub fn data_mut<R>(&self, writer: impl FnOnce(&mut IdTypeMap) -> R) -> R {
self.write(move |ctx| writer(&mut ctx.memory.data))
}
/// Read-write access to [`GraphicLayers`], where painted [`crate::Shape`]s are written to.
#[inline]
pub(crate) fn graphics_mut<R>(&self, writer: impl FnOnce(&mut GraphicLayers) -> R) -> R {
self.write(move |ctx| writer(&mut ctx.graphics))
}
/// Read-only access to [`PlatformOutput`].
///
/// This is what egui outputs each frame.
///
/// ```
/// # let mut ctx = egui::Context::default();
/// ctx.output_mut(|o| o.cursor_icon = egui::CursorIcon::Progress);
/// ```
#[inline]
pub fn output<R>(&self, reader: impl FnOnce(&PlatformOutput) -> R) -> R {
self.read(move |ctx| reader(&ctx.output))
}
/// Read-write access to [`PlatformOutput`].
#[inline]
pub fn output_mut<R>(&self, writer: impl FnOnce(&mut PlatformOutput) -> R) -> R {
self.write(move |ctx| writer(&mut ctx.output))
}
/// Read-only access to [`FrameState`].
#[inline]
pub(crate) fn frame_state<R>(&self, reader: impl FnOnce(&FrameState) -> R) -> R {
self.read(move |ctx| reader(&ctx.frame_state))
}
/// Read-write access to [`FrameState`].
#[inline]
pub(crate) fn frame_state_mut<R>(&self, writer: impl FnOnce(&mut FrameState) -> R) -> R {
self.write(move |ctx| writer(&mut ctx.frame_state))
}
/// Read-only access to [`Fonts`].
///
/// Not valid until first call to [`Context::run()`].
/// That's because since we don't know the proper `pixels_per_point` until then.
#[inline]
pub fn fonts<R>(&self, reader: impl FnOnce(&Fonts) -> R) -> R {
self.read(move |ctx| {
reader(
ctx.fonts
.as_ref()
.expect("No fonts available until first call to Context::run()"),
)
})
}
/// Read-write access to [`Fonts`].
#[inline]
pub fn fonts_mut<R>(&self, writer: impl FnOnce(&mut Option<Fonts>) -> R) -> R {
self.write(move |ctx| writer(&mut ctx.fonts))
}
/// Read-only access to [`Options`].
#[inline]
pub fn options<R>(&self, reader: impl FnOnce(&Options) -> R) -> R {
self.read(move |ctx| reader(&ctx.memory.options))
}
/// Read-write access to [`Options`].
#[inline]
pub fn options_mut<R>(&self, writer: impl FnOnce(&mut Options) -> R) -> R {
self.write(move |ctx| writer(&mut ctx.memory.options))
}
/// Read-only access to [`TessellationOptions`].
#[inline]
pub fn tessellation_options<R>(&self, reader: impl FnOnce(&TessellationOptions) -> R) -> R {
self.read(move |ctx| reader(&ctx.memory.options.tessellation_options))
}
/// Read-write access to [`TessellationOptions`].
#[inline]
pub fn tessellation_options_mut<R>(
&self,
writer: impl FnOnce(&mut TessellationOptions) -> R,
) -> R {
self.write(move |ctx| writer(&mut ctx.memory.options.tessellation_options))
}
/// If the given [`Id`] has been used previously the same frame at at different position,
/// then an error will be printed on screen.
///
/// This function is already called for all widgets that do any interaction,
/// but you can call this from widgets that store state but that does not interact.
///
/// The given [`Rect`] should be approximately where the widget will be.
/// The most important thing is that [`Rect::min`] is approximately correct,
/// because that's where the warning will be painted. If you don't know what size to pick, just pick [`Vec2::ZERO`].
pub fn check_for_id_clash(&self, id: Id, new_rect: Rect, what: &str) {
let prev_rect = self.frame_state_mut(move |state| state.used_ids.insert(id, new_rect));
if !self.options(|opt| opt.warn_on_id_clash) {
return;
}
let Some(prev_rect) = prev_rect else { return };
// it is ok to reuse the same ID for e.g. a frame around a widget,
// or to check for interaction with the same widget twice:
if prev_rect.expand(0.1).contains_rect(new_rect)
|| new_rect.expand(0.1).contains_rect(prev_rect)
{
return;
}
let show_error = |widget_rect: Rect, text: String| {
let text = format!("🔥 {text}");
let color = self.style().visuals.error_fg_color;
let painter = self.debug_painter();
painter.rect_stroke(widget_rect, 0.0, (1.0, color));
let below = widget_rect.bottom() + 32.0 < self.input(|i| i.screen_rect.bottom());
let text_rect = if below {
painter.debug_text(
widget_rect.left_bottom() + vec2(0.0, 2.0),
Align2::LEFT_TOP,
color,
text,
)
} else {
painter.debug_text(
widget_rect.left_top() - vec2(0.0, 2.0),
Align2::LEFT_BOTTOM,
color,
text,
)
};
if let Some(pointer_pos) = self.pointer_hover_pos() {
if text_rect.contains(pointer_pos) {
let tooltip_pos = if below {
text_rect.left_bottom() + vec2(2.0, 4.0)
} else {
text_rect.left_top() + vec2(2.0, -4.0)
};
painter.error(
tooltip_pos,
format!("Widget is {} this text.\n\n\
ID clashes happens when things like Windows or CollapsingHeaders share names,\n\
or when things like Plot and Grid:s aren't given unique id_source:s.\n\n\
Sometimes the solution is to use ui.push_id.",
if below { "above" } else { "below" })
);
}
}
};
let id_str = id.short_debug_format();
if prev_rect.min.distance(new_rect.min) < 4.0 {
show_error(new_rect, format!("Double use of {what} ID {id_str}"));
} else {
show_error(prev_rect, format!("First use of {what} ID {id_str}"));
show_error(new_rect, format!("Second use of {what} ID {id_str}"));
}
}
// ---------------------------------------------------------------------
/// Use `ui.interact` instead
#[allow(clippy::too_many_arguments)]
pub(crate) fn interact(
&self,
clip_rect: Rect,
item_spacing: Vec2,
layer_id: LayerId,
id: Id,
rect: Rect,
sense: Sense,
enabled: bool,
) -> Response {
let gap = 0.1; // Just to make sure we don't accidentally hover two things at once (a small eps should be sufficient).
// Make it easier to click things:
let interact_rect = rect.expand2(
(0.5 * item_spacing - Vec2::splat(gap))
.at_least(Vec2::splat(0.0))
.at_most(Vec2::splat(5.0)),
);
// Respect clip rectangle when interacting
let interact_rect = clip_rect.intersect(interact_rect);
let mut hovered = self.rect_contains_pointer(layer_id, interact_rect);
// This solves the problem of overlapping widgets.
// Whichever widget is added LAST (=on top) gets the input:
if interact_rect.is_positive() && sense.interactive() {
#[cfg(debug_assertions)]
if self.style().debug.show_interactive_widgets {
Self::layer_painter(self, LayerId::debug()).rect(
interact_rect,
0.0,
Color32::YELLOW.additive().linear_multiply(0.005),
Stroke::new(1.0, Color32::YELLOW.additive().linear_multiply(0.05)),
);
}
#[cfg(debug_assertions)]
let mut show_blocking_widget = None;
self.write(|ctx| {
ctx.layer_rects_this_frame
.entry(layer_id)
.or_default()
.push((id, interact_rect));
if hovered {
let pointer_pos = ctx.input.pointer.interact_pos();
if let Some(pointer_pos) = pointer_pos {
if let Some(rects) = ctx.layer_rects_prev_frame.get(&layer_id) {
for &(prev_id, prev_rect) in rects.iter().rev() {
if prev_id == id {
break; // there is no other interactive widget covering us at the pointer position.
}
if prev_rect.contains(pointer_pos) {
// Another interactive widget is covering us at the pointer position,
// so we aren't hovered.
#[cfg(debug_assertions)]
if ctx.memory.options.style.debug.show_blocking_widget {
// Store the rects to use them outside the write() call to
// avoid deadlock
show_blocking_widget = Some((interact_rect, prev_rect));
}
hovered = false;
break;
}
}
}
}
}
});
#[cfg(debug_assertions)]
if let Some((interact_rect, prev_rect)) = show_blocking_widget {
Self::layer_painter(self, LayerId::debug()).debug_rect(
interact_rect,
Color32::GREEN,
"Covered",
);
Self::layer_painter(self, LayerId::debug()).debug_rect(
prev_rect,
Color32::LIGHT_BLUE,
"On top",
);
}
}
self.interact_with_hovered(layer_id, id, rect, sense, enabled, hovered)
}
/// You specify if a thing is hovered, and the function gives a [`Response`].
pub(crate) fn interact_with_hovered(
&self,
layer_id: LayerId,
id: Id,
rect: Rect,
sense: Sense,
enabled: bool,
hovered: bool,
) -> Response {
let hovered = hovered && enabled; // can't even hover disabled widgets
let highlighted = self.frame_state(|fs| fs.highlight_this_frame.contains(&id));
let mut response = Response {
ctx: self.clone(),
layer_id,
id,
rect,
sense,
enabled,
hovered,
highlighted,
clicked: Default::default(),
double_clicked: Default::default(),
triple_clicked: Default::default(),
dragged: false,
drag_released: false,
is_pointer_button_down_on: false,
interact_pointer_pos: None,
changed: false, // must be set by the widget itself
};
if !enabled || !sense.focusable || !layer_id.allow_interaction() {
// Not interested or allowed input:
self.memory_mut(|mem| mem.surrender_focus(id));
return response;
}
self.check_for_id_clash(id, rect, "widget");
#[cfg(feature = "accesskit")]
if sense.focusable {
// Make sure anything that can receive focus has an AccessKit node.
// TODO(mwcampbell): For nodes that are filled from widget info,
// some information is written to the node twice.
self.accesskit_node_builder(id, |builder| response.fill_accesskit_node_common(builder));
}
let clicked_elsewhere = response.clicked_elsewhere();
self.write(|ctx| {
let memory = &mut ctx.memory;
let input = &mut ctx.input;
if sense.focusable {
memory.interested_in_focus(id);
}
if sense.click
&& memory.has_focus(response.id)
&& (input.key_pressed(Key::Space) || input.key_pressed(Key::Enter))
{
// Space/enter works like a primary click for e.g. selected buttons
response.clicked[PointerButton::Primary as usize] = true;
}
#[cfg(feature = "accesskit")]
{
if sense.click
&& input.has_accesskit_action_request(response.id, accesskit::Action::Default)
{
response.clicked[PointerButton::Primary as usize] = true;
}
}
if sense.click || sense.drag {
memory.interaction.click_interest |= hovered && sense.click;
memory.interaction.drag_interest |= hovered && sense.drag;
response.dragged = memory.interaction.drag_id == Some(id);
response.is_pointer_button_down_on =
memory.interaction.click_id == Some(id) || response.dragged;
for pointer_event in &input.pointer.pointer_events {
match pointer_event {
PointerEvent::Moved(_) => {}
PointerEvent::Pressed { .. } => {
if hovered {
if sense.click && memory.interaction.click_id.is_none() {
// potential start of a click
memory.interaction.click_id = Some(id);
response.is_pointer_button_down_on = true;
}
// HACK: windows have low priority on dragging.
// This is so that if you drag a slider in a window,
// the slider will steal the drag away from the window.
// This is needed because we do window interaction first (to prevent frame delay),
// and then do content layout.
if sense.drag
&& (memory.interaction.drag_id.is_none()
|| memory.interaction.drag_is_window)
{
// potential start of a drag
memory.interaction.drag_id = Some(id);
memory.interaction.drag_is_window = false;
memory.window_interaction = None; // HACK: stop moving windows (if any)
response.is_pointer_button_down_on = true;
response.dragged = true;
}
}
}
PointerEvent::Released { click, button } => {
response.drag_released = response.dragged;
response.dragged = false;
if hovered && response.is_pointer_button_down_on {
if let Some(click) = click {
let clicked = hovered && response.is_pointer_button_down_on;
response.clicked[*button as usize] = clicked;
response.double_clicked[*button as usize] =
clicked && click.is_double();
response.triple_clicked[*button as usize] =
clicked && click.is_triple();
}
}
}
}
}
}
if response.is_pointer_button_down_on {
response.interact_pointer_pos = input.pointer.interact_pos();
}
if input.pointer.any_down() {
response.hovered &= response.is_pointer_button_down_on; // we don't hover widgets while interacting with *other* widgets
}
if memory.has_focus(response.id) && clicked_elsewhere {
memory.surrender_focus(id);
}
if response.dragged() && !memory.has_focus(response.id) {
// e.g.: remove focus from a widget when you drag something else
memory.stop_text_input();
}
});
response
}
/// Get a full-screen painter for a new or existing layer
pub fn layer_painter(&self, layer_id: LayerId) -> Painter {
let screen_rect = self.screen_rect();
Painter::new(self.clone(), layer_id, screen_rect)
}
/// Paint on top of everything else
pub fn debug_painter(&self) -> Painter {
Self::layer_painter(self, LayerId::debug())
}
/// What operating system are we running on?
///
/// When compiling natively, this is
/// figured out from the `target_os`.
///
/// For web, this can be figured out from the user-agent,
/// and is done so by [`eframe`](https://github.com/emilk/egui/tree/master/crates/eframe).
pub fn os(&self) -> OperatingSystem {
self.read(|ctx| ctx.os)
}
/// Set the operating system we are running on.
///
/// If you are writing wasm-based integration for egui you
/// may want to set this based on e.g. the user-agent.
pub fn set_os(&self, os: OperatingSystem) {
self.write(|ctx| ctx.os = os);
}
/// Set the cursor icon.
///
/// Equivalent to:
/// ```
/// # let ctx = egui::Context::default();
/// ctx.output_mut(|o| o.cursor_icon = egui::CursorIcon::PointingHand);
/// ```
pub fn set_cursor_icon(&self, cursor_icon: CursorIcon) {
self.output_mut(|o| o.cursor_icon = cursor_icon);
}
/// Open an URL in a browser.
///
/// Equivalent to:
/// ```
/// # let ctx = egui::Context::default();
/// # let open_url = egui::OpenUrl::same_tab("http://www.example.com");
/// ctx.output_mut(|o| o.open_url = Some(open_url));
/// ```
pub fn open_url(&self, open_url: crate::OpenUrl) {
self.output_mut(|o| o.open_url = Some(open_url));
}
/// Copy the given text to the system clipboard.
///
/// Empty strings are ignored.
///
/// Equivalent to:
/// ```
/// # let ctx = egui::Context::default();
/// ctx.output_mut(|o| o.copied_text = "Copy this".to_owned());
/// ```
pub fn copy_text(&self, text: String) {
self.output_mut(|o| o.copied_text = text);
}
/// Format the given shortcut in a human-readable way (e.g. `Ctrl+Shift+X`).
///
/// Can be used to get the text for [`Button::shortcut_text`].
pub fn format_shortcut(&self, shortcut: &KeyboardShortcut) -> String {
let os = self.os();
let is_mac = matches!(os, OperatingSystem::Mac | OperatingSystem::IOS);
let can_show_symbols = || {
let ModifierNames {
alt,
ctrl,
shift,
mac_cmd,
..
} = ModifierNames::SYMBOLS;
let font_id = TextStyle::Body.resolve(&self.style());
self.fonts(|f| {
let mut lock = f.lock();
let font = lock.fonts.font(&font_id);
font.has_glyphs(alt)
&& font.has_glyphs(ctrl)
&& font.has_glyphs(shift)
&& font.has_glyphs(mac_cmd)
})
};
if is_mac && can_show_symbols() {
shortcut.format(&ModifierNames::SYMBOLS, is_mac)
} else {
shortcut.format(&ModifierNames::NAMES, is_mac)
}
}
/// The current frame number.
///
/// Starts at zero, and is incremented at the end of [`Self::run`] or by [`Self::end_frame`].
///
/// Between calls to [`Self::run`], this is the frame number of the coming frame.
pub fn frame_nr(&self) -> u64 {
self.read(|ctx| ctx.repaint.frame_nr)
}
/// 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.
///
/// If called from outside the UI thread, the UI thread will wake up and run,
/// provided the egui integration has set that up via [`Self::set_request_repaint_callback`]
/// (this will work on `eframe`).
pub fn request_repaint(&self) {
// request two frames of repaint, just to cover some corner cases (frame delays):
self.write(|ctx| ctx.repaint.request_repaint());
}
/// Request repaint after at most the specified duration elapses.
///
/// The backend can chose to repaint sooner, for instance if some other code called
/// this method with a lower duration, or if new events arrived.
///
/// The function can be multiple times, but only the *smallest* duration will be considered.
/// So, if the function is called two times with `1 second` and `2 seconds`, egui will repaint
/// after `1 second`
///
/// This is primarily useful for applications who would like to save battery by avoiding wasted
/// redraws when the app is not in focus. But sometimes the GUI of the app might become stale
/// and outdated if it is not updated for too long.
///
/// Lets say, something like a stop watch widget that displays the time in seconds. You would waste
/// resources repainting multiple times within the same second (when you have no input),
/// just calculate the difference of duration between current time and next second change,
/// and call this function, to make sure that you are displaying the latest updated time, but
/// not wasting resources on needless repaints within the same second.
///
/// NOTE: only works if called before `Context::end_frame()`. to force egui to update,
/// use `Context::request_repaint()` instead.
///
/// ### Quirk:
/// Duration begins at the next frame. lets say for example that its a very inefficient app
/// and takes 500 milliseconds per frame at 2 fps. The widget / user might want a repaint in
/// next 500 milliseconds. Now, app takes 1000 ms per frame (1 fps) because the backend event
/// timeout takes 500 milliseconds AFTER the vsync swap buffer.
/// So, its not that we are requesting repaint within X duration. We are rather timing out
/// during app idle time where we are not receiving any new input events.
pub fn request_repaint_after(&self, duration: std::time::Duration) {
// Maybe we can check if duration is ZERO, and call self.request_repaint()?
self.write(|ctx| ctx.repaint.request_repaint_after(duration));
}
/// For integrations: this callback will be called when an egui user calls [`Self::request_repaint`].
///
/// This lets you wake up a sleeping UI thread.
///
/// Note that only one callback can be set. Any new call overrides the previous callback.
pub fn set_request_repaint_callback(
&self,
callback: impl Fn(RequestRepaintInfo) + Send + Sync + 'static,
) {
let callback = Box::new(callback);
self.write(|ctx| ctx.repaint.request_repaint_callback = Some(callback));
}
/// 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 set_fonts(&self, font_definitions: FontDefinitions) {
let update_fonts = self.fonts_mut(|fonts| {
if let Some(current_fonts) = fonts {
// NOTE: this comparison is expensive since it checks TTF data for equality
current_fonts.lock().fonts.definitions() != &font_definitions
} else {
true
}
});
if update_fonts {
self.memory_mut(|mem| mem.new_font_definitions = Some(font_definitions));
}
}
/// The [`Style`] used by all subsequent windows, panels etc.
pub fn style(&self) -> Arc<Style> {
self.options(|opt| opt.style.clone())
}
/// Mutate the [`Style`] used by all subsequent windows, panels etc.
///
/// Example:
/// ```
/// # let mut ctx = egui::Context::default();
/// ctx.style_mut(|style| {
/// style.spacing.item_spacing = egui::vec2(10.0, 20.0);
/// });
/// ```
pub fn style_mut(&self, mutate_style: impl FnOnce(&mut Style)) {
self.options_mut(|opt| mutate_style(std::sync::Arc::make_mut(&mut opt.style)));
}
/// The [`Style`] used by all new windows, panels etc.
///
/// You can also change this using [`Self::style_mut]`
///
/// You can use [`Ui::style_mut`] to change the style of a single [`Ui`].
pub fn set_style(&self, style: impl Into<Arc<Style>>) {
self.options_mut(|opt| opt.style = style.into());
}
/// 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:
/// ```
/// # let mut ctx = egui::Context::default();
/// ctx.set_visuals(egui::Visuals::light()); // Switch to light mode
/// ```
pub fn set_visuals(&self, visuals: crate::Visuals) {
self.options_mut(|opt| std::sync::Arc::make_mut(&mut opt.style).visuals = visuals);
}
/// The number of physical pixels for each logical point.
#[inline(always)]
pub fn pixels_per_point(&self) -> f32 {
self.input(|i| i.pixels_per_point())
}
/// 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 `eframe` on web, the browsers native zoom level will always be used.
pub fn set_pixels_per_point(&self, pixels_per_point: f32) {
if pixels_per_point != self.pixels_per_point() {
self.request_repaint();
self.memory_mut(|mem| mem.new_pixels_per_point = Some(pixels_per_point));
}
}
/// Useful for pixel-perfect rendering
pub(crate) fn round_to_pixel(&self, point: f32) -> f32 {
let pixels_per_point = self.pixels_per_point();
(point * pixels_per_point).round() / pixels_per_point
}
/// Useful for pixel-perfect rendering
pub(crate) fn round_pos_to_pixels(&self, pos: Pos2) -> Pos2 {
pos2(self.round_to_pixel(pos.x), self.round_to_pixel(pos.y))
}
/// Useful for pixel-perfect rendering
pub(crate) fn round_vec_to_pixels(&self, vec: Vec2) -> Vec2 {
vec2(self.round_to_pixel(vec.x), self.round_to_pixel(vec.y))
}
/// Useful for pixel-perfect rendering
pub(crate) fn round_rect_to_pixels(&self, rect: Rect) -> Rect {
Rect {
min: self.round_pos_to_pixels(rect.min),
max: self.round_pos_to_pixels(rect.max),
}
}
/// Allocate a texture.
///
/// This is for advanced users.
/// Most users should use [`crate::Ui::image`] or [`Self::try_load_texture`]
/// instead.
///
/// In order to display an image you must convert it to a texture using this function.
/// The function will hand over the image data to the egui backend, which will
/// upload it to the GPU.
///
/// ⚠️ Make sure to only call this ONCE for each image, i.e. NOT in your main GUI code.
/// The call is NOT immediate safe.
///
/// The given name can be useful for later debugging, and will be visible if you call [`Self::texture_ui`].
///
/// For how to load an image, see [`ImageData`] and [`ColorImage::from_rgba_unmultiplied`].
///
/// ```
/// struct MyImage {
/// texture: Option<egui::TextureHandle>,
/// }
///
/// impl MyImage {
/// fn ui(&mut self, ui: &mut egui::Ui) {
/// let texture: &egui::TextureHandle = self.texture.get_or_insert_with(|| {
/// // Load the texture only once.
/// ui.ctx().load_texture(
/// "my-image",
/// egui::ColorImage::example(),
/// Default::default()
/// )
/// });
///
/// // Show the image:
/// ui.image((texture.id(), texture.size_vec2()));
/// }
/// }
/// ```
///
/// See also [`crate::ImageData`], [`crate::Ui::image`] and [`crate::Image`].
pub fn load_texture(
&self,
name: impl Into<String>,
image: impl Into<ImageData>,
options: TextureOptions,
) -> TextureHandle {
let name = name.into();
let image = image.into();
let max_texture_side = self.input(|i| i.max_texture_side);
crate::egui_assert!(
image.width() <= max_texture_side && image.height() <= max_texture_side,
"Texture {:?} has size {}x{}, but the maximum texture side is {}",
name,
image.width(),
image.height(),
max_texture_side
);
let tex_mngr = self.tex_manager();
let tex_id = tex_mngr.write().alloc(name, image, options);
TextureHandle::new(tex_mngr, tex_id)
}
/// Low-level texture manager.
///
/// In general it is easier to use [`Self::load_texture`] and [`TextureHandle`].
///
/// You can show stats about the allocated textures using [`Self::texture_ui`].
pub fn tex_manager(&self) -> Arc<RwLock<epaint::textures::TextureManager>> {
self.read(|ctx| ctx.tex_manager.0.clone())
}
// ---------------------------------------------------------------------
/// Constrain the position of a window/area so it fits within the provided boundary.
///
/// If area is `None`, will constrain to [`Self::available_rect`].
pub(crate) fn constrain_window_rect_to_area(&self, window: Rect, area: Option<Rect>) -> Rect {
let mut area = area.unwrap_or_else(|| self.available_rect());
if window.width() > area.width() {
// Allow overlapping side bars.
// This is important for small screens, e.g. mobiles running the web demo.
let screen_rect = self.screen_rect();
(area.min.x, area.max.x) = (screen_rect.min.x, screen_rect.max.x);
}
if window.height() > area.height() {
// Allow overlapping top/bottom bars:
let screen_rect = self.screen_rect();
(area.min.y, area.max.y) = (screen_rect.min.y, screen_rect.max.y);
}
let mut pos = window.min;
// Constrain to screen, unless window is too large to fit:
let margin_x = (window.width() - area.width()).at_least(0.0);
let margin_y = (window.height() - area.height()).at_least(0.0);
pos.x = pos.x.at_most(area.right() + margin_x - window.width()); // move left if needed
pos.x = pos.x.at_least(area.left() - margin_x); // move right if needed
pos.y = pos.y.at_most(area.bottom() + margin_y - window.height()); // move right if needed
pos.y = pos.y.at_least(area.top() - margin_y); // move down if needed
pos = self.round_pos_to_pixels(pos);
Rect::from_min_size(pos, window.size())
}
}
impl Context {
/// Call at the end of each frame.
#[must_use]
pub fn end_frame(&self) -> FullOutput {
crate::profile_function!();
if self.input(|i| i.wants_repaint()) {
self.request_repaint();
}
let textures_delta = self.write(|ctx| {
ctx.memory.end_frame(&ctx.input, &ctx.frame_state.used_ids);
let font_image_delta = ctx.fonts.as_ref().unwrap().font_image_delta();
if let Some(font_image_delta) = font_image_delta {
ctx.tex_manager
.0
.write()
.set(TextureId::default(), font_image_delta);
}
ctx.tex_manager.0.write().take_delta()
});
#[cfg_attr(not(feature = "accesskit"), allow(unused_mut))]
let mut platform_output: PlatformOutput = self.output_mut(|o| std::mem::take(o));
#[cfg(feature = "accesskit")]
{
crate::profile_scope!("accesskit");
let state = self.frame_state_mut(|fs| fs.accesskit_state.take());
if let Some(state) = state {
let has_focus = self.input(|i| i.raw.focused);
let root_id = crate::accesskit_root_id().accesskit_id();
let nodes = self.write(|ctx| {
state
.node_builders
.into_iter()
.map(|(id, builder)| {
(
id.accesskit_id(),
builder.build(&mut ctx.accesskit_node_classes),
)
})
.collect()
});
platform_output.accesskit_update = Some(accesskit::TreeUpdate {
nodes,
tree: Some(accesskit::Tree::new(root_id)),
focus: has_focus.then(|| {
let focus_id = self.memory(|mem| mem.focus());
focus_id.map_or(root_id, |id| id.accesskit_id())
}),
});
}
}
let repaint_after = self.write(|ctx| ctx.repaint.end_frame());
let shapes = self.drain_paint_lists();
FullOutput {
platform_output,
repaint_after,
textures_delta,
shapes,
}
}
fn drain_paint_lists(&self) -> Vec<ClippedShape> {
crate::profile_function!();
self.write(|ctx| ctx.graphics.drain(ctx.memory.areas.order()).collect())
}
/// Tessellate the given shapes into triangle meshes.
pub fn tessellate(&self, shapes: Vec<ClippedShape>) -> Vec<ClippedPrimitive> {
crate::profile_function!();
// A tempting optimization is to reuse the tessellation from last frame if the
// shapes are the same, but just comparing the shapes takes about 50% of the time
// it takes to tessellate them, so it is not a worth optimization.
// here we expect that we are the only user of context, since frame is ended
self.write(|ctx| {
let pixels_per_point = ctx.input.pixels_per_point();
let tessellation_options = ctx.memory.options.tessellation_options;
let texture_atlas = ctx
.fonts
.as_ref()
.expect("tessellate called before first call to Context::run()")
.texture_atlas();
let (font_tex_size, prepared_discs) = {
let atlas = texture_atlas.lock();
(atlas.size(), atlas.prepared_discs())
};
let paint_stats = PaintStats::from_shapes(&shapes);
let clipped_primitives = {
crate::profile_scope!("tessellator::tessellate_shapes");
tessellator::tessellate_shapes(
pixels_per_point,
tessellation_options,
font_tex_size,
prepared_discs,
shapes,
)
};
ctx.paint_stats = paint_stats.with_clipped_primitives(&clipped_primitives);
clipped_primitives
})
}
// ---------------------------------------------------------------------
/// Position and size of the egui area.
pub fn screen_rect(&self) -> Rect {
self.input(|i| i.screen_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 available_rect(&self) -> Rect {
self.frame_state(|s| s.available_rect())
}
/// How much space is used by panels and windows.
pub fn used_rect(&self) -> Rect {
self.read(|ctx| {
let mut used = ctx.frame_state.used_by_panels;
for window in ctx.memory.areas.visible_windows() {
used = used.union(window.rect());
}
used
})
}
/// 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 used_size(&self) -> Vec2 {
self.used_rect().max - Pos2::ZERO
}
// ---------------------------------------------------------------------
/// Is the pointer (mouse/touch) over any egui area?
pub fn is_pointer_over_area(&self) -> bool {
let pointer_pos = self.input(|i| i.pointer.interact_pos());
if let Some(pointer_pos) = pointer_pos {
if let Some(layer) = self.layer_id_at(pointer_pos) {
if layer.order == Order::Background {
!self.frame_state(|state| state.unused_rect.contains(pointer_pos))
} else {
true
}
} else {
false
}
} else {
false
}
}
/// 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 wants_pointer_input(&self) -> bool {
self.is_using_pointer()
|| (self.is_pointer_over_area() && !self.input(|i| i.pointer.any_down()))
}
/// 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 is_using_pointer(&self) -> bool {
self.memory(|m| m.interaction.is_using_pointer())
}
/// If `true`, egui is currently listening on text input (e.g. typing text in a [`TextEdit`]).
pub fn wants_keyboard_input(&self) -> bool {
self.memory(|m| m.interaction.focus.focused().is_some())
}
/// Highlight this widget, to make it look like it is hovered, even if it isn't.
///
/// The highlight takes on frame to take effect if you call this after the widget has been fully rendered.
///
/// See also [`Response::highlight`].
pub fn highlight_widget(&self, id: Id) {
self.frame_state_mut(|fs| fs.highlight_next_frame.insert(id));
}
/// Is an egui context menu open?
pub fn is_context_menu_open(&self) -> bool {
self.data(|d| {
d.get_temp::<crate::menu::BarState>(menu::CONTEXT_MENU_ID_STR.into())
.map_or(false, |state| state.has_root())
})
}
}
// Ergonomic methods to forward some calls often used in 'if let' without holding the borrow
impl Context {
/// Latest reported pointer position.
///
/// When tapping a touch screen, this will be `None`.
#[inline(always)]
pub fn pointer_latest_pos(&self) -> Option<Pos2> {
self.input(|i| i.pointer.latest_pos())
}
/// If it is a good idea to show a tooltip, where is pointer?
#[inline(always)]
pub fn pointer_hover_pos(&self) -> Option<Pos2> {
self.input(|i| i.pointer.hover_pos())
}
/// If you detect a click or drag and wants to know where it happened, use this.
///
/// Latest position of the mouse, but ignoring any [`Event::PointerGone`]
/// if there were interactions this frame.
/// When tapping a touch screen, this will be the location of the touch.
#[inline(always)]
pub fn pointer_interact_pos(&self) -> Option<Pos2> {
self.input(|i| i.pointer.interact_pos())
}
/// Calls [`InputState::multi_touch`].
pub fn multi_touch(&self) -> Option<MultiTouchInfo> {
self.input(|i| i.multi_touch())
}
}
impl Context {
/// Move all the graphics at the given layer.
///
/// Can be used to implement drag-and-drop (see relevant demo).
pub fn translate_layer(&self, layer_id: LayerId, delta: Vec2) {
if delta != Vec2::ZERO {
self.graphics_mut(|g| g.list(layer_id).translate(delta));
}
}
/// Top-most layer at the given position.
pub fn layer_id_at(&self, pos: Pos2) -> Option<LayerId> {
self.memory(|mem| {
mem.layer_id_at(pos, mem.options.style.interaction.resize_grab_radius_side)
})
}
/// Moves the given area to the top in its [`Order`].
///
/// [`Area`]:s and [`Window`]:s also do this automatically when being clicked on or interacted with.
pub fn move_to_top(&self, layer_id: LayerId) {
self.memory_mut(|mem| mem.areas.move_to_top(layer_id));
}
pub(crate) fn rect_contains_pointer(&self, layer_id: LayerId, rect: Rect) -> bool {
rect.is_positive() && {
let pointer_pos = self.input(|i| i.pointer.interact_pos());
if let Some(pointer_pos) = pointer_pos {
rect.contains(pointer_pos) && self.layer_id_at(pointer_pos) == Some(layer_id)
} else {
false
}
}
}
// ---------------------------------------------------------------------
/// Whether or not to debug widget layout on hover.
#[cfg(debug_assertions)]
pub fn debug_on_hover(&self) -> bool {
self.options(|opt| opt.style.debug.debug_on_hover)
}
/// Turn on/off whether or not to debug widget layout on hover.
#[cfg(debug_assertions)]
pub fn set_debug_on_hover(&self, debug_on_hover: bool) {
self.style_mut(|style| style.debug.debug_on_hover = debug_on_hover);
}
}
/// ## Animation
impl Context {
/// 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.
///
/// The animation time is taken from [`Style::animation_time`].
pub fn animate_bool(&self, id: Id, value: bool) -> f32 {
let animation_time = self.style().animation_time;
self.animate_bool_with_time(id, value, animation_time)
}
/// Like [`Self::animate_bool`] but allows you to control the animation time.
pub fn animate_bool_with_time(&self, id: Id, target_value: bool, animation_time: f32) -> f32 {
let animated_value = self.write(|ctx| {
ctx.animation_manager
.animate_bool(&ctx.input, animation_time, id, target_value)
});
let animation_in_progress = 0.0 < animated_value && animated_value < 1.0;
if animation_in_progress {
self.request_repaint();
}
animated_value
}
/// Smoothly animate an `f32` value.
///
/// At the first call the value is written to memory.
/// When it is called with a new value, it linearly interpolates to it in the given time.
pub fn animate_value_with_time(&self, id: Id, target_value: f32, animation_time: f32) -> f32 {
let animated_value = self.write(|ctx| {
ctx.animation_manager
.animate_value(&ctx.input, animation_time, id, target_value)
});
let animation_in_progress = animated_value != target_value;
if animation_in_progress {
self.request_repaint();
}
animated_value
}
/// Clear memory of any animations.
pub fn clear_animations(&self) {
self.write(|ctx| ctx.animation_manager = Default::default());
}
}
impl Context {
/// Show a ui for settings (style and tessellation options).
pub fn settings_ui(&self, ui: &mut Ui) {
use crate::containers::*;
CollapsingHeader::new("🎑 Style")
.default_open(true)
.show(ui, |ui| {
self.style_ui(ui);
});
CollapsingHeader::new("✒ Painting")
.default_open(true)
.show(ui, |ui| {
let prev_tessellation_options = self.tessellation_options(|o| *o);
let mut tessellation_options = prev_tessellation_options;
tessellation_options.ui(ui);
ui.vertical_centered(|ui| reset_button(ui, &mut tessellation_options));
if tessellation_options != prev_tessellation_options {
self.tessellation_options_mut(move |o| *o = tessellation_options);
}
});
}
/// Show the state of egui, including its input and output.
pub fn inspection_ui(&self, ui: &mut Ui) {
use crate::containers::*;
ui.label(format!("Is using pointer: {}", self.is_using_pointer()))
.on_hover_text(
"Is egui currently using the pointer actively (e.g. dragging a slider)?",
);
ui.label(format!("Wants pointer input: {}", self.wants_pointer_input()))
.on_hover_text("Is egui currently interested in the location of the pointer (either because it is in use, or because it is hovering over a window).");
ui.label(format!(
"Wants keyboard input: {}",
self.wants_keyboard_input()
))
.on_hover_text("Is egui currently listening for text input?");
ui.label(format!(
"Keyboard focus widget: {}",
self.memory(|m| m.interaction.focus.focused())
.as_ref()
.map(Id::short_debug_format)
.unwrap_or_default()
))
.on_hover_text("Is egui currently listening for text input?");
let pointer_pos = self
.pointer_hover_pos()
.map_or_else(String::new, |pos| format!("{pos:?}"));
ui.label(format!("Pointer pos: {pointer_pos}"));
let top_layer = self
.pointer_hover_pos()
.and_then(|pos| self.layer_id_at(pos))
.map_or_else(String::new, |layer| layer.short_debug_format());
ui.label(format!("Top layer under mouse: {top_layer}"));
ui.add_space(16.0);
ui.label(format!(
"There are {} text galleys in the layout cache",
self.fonts(|f| f.num_galleys_in_cache())
))
.on_hover_text("This is approximately the number of text strings on screen");
ui.add_space(16.0);
CollapsingHeader::new("📥 Input")
.default_open(false)
.show(ui, |ui| {
let input = ui.input(|i| i.clone());
input.ui(ui);
});
CollapsingHeader::new("📊 Paint stats")
.default_open(false)
.show(ui, |ui| {
let paint_stats = self.read(|ctx| ctx.paint_stats);
paint_stats.ui(ui);
});
CollapsingHeader::new("🖼 Textures")
.default_open(false)
.show(ui, |ui| {
self.texture_ui(ui);
});
CollapsingHeader::new("🔠 Font texture")
.default_open(false)
.show(ui, |ui| {
let font_image_size = self.fonts(|f| f.font_image_size());
crate::introspection::font_texture_ui(ui, font_image_size);
});
}
/// Show stats about the allocated textures.
pub fn texture_ui(&self, ui: &mut crate::Ui) {
let tex_mngr = self.tex_manager();
let tex_mngr = tex_mngr.read();
let mut textures: Vec<_> = tex_mngr.allocated().collect();
textures.sort_by_key(|(id, _)| *id);
let mut bytes = 0;
for (_, tex) in &textures {
bytes += tex.bytes_used();
}
ui.label(format!(
"{} allocated texture(s), using {:.1} MB",
textures.len(),
bytes as f64 * 1e-6
));
let max_preview_size = vec2(48.0, 32.0);
ui.group(|ui| {
ScrollArea::vertical()
.max_height(300.0)
.auto_shrink([false, true])
.show(ui, |ui| {
ui.style_mut().override_text_style = Some(TextStyle::Monospace);
Grid::new("textures")
.striped(true)
.num_columns(4)
.spacing(vec2(16.0, 2.0))
.min_row_height(max_preview_size.y)
.show(ui, |ui| {
for (&texture_id, meta) in textures {
let [w, h] = meta.size;
let mut size = vec2(w as f32, h as f32);
size *= (max_preview_size.x / size.x).min(1.0);
size *= (max_preview_size.y / size.y).min(1.0);
ui.image(SizedTexture::new(texture_id, size))
.on_hover_ui(|ui| {
// show larger on hover
let max_size = 0.5 * ui.ctx().screen_rect().size();
let mut size = vec2(w as f32, h as f32);
size *= max_size.x / size.x.max(max_size.x);
size *= max_size.y / size.y.max(max_size.y);
ui.image(SizedTexture::new(texture_id, size));
});
ui.label(format!("{w} x {h}"));
ui.label(format!("{:.3} MB", meta.bytes_used() as f64 * 1e-6));
ui.label(format!("{:?}", meta.name));
ui.end_row();
}
});
});
});
}
/// Shows the contents of [`Self::memory`].
pub fn memory_ui(&self, ui: &mut crate::Ui) {
if ui
.button("Reset all")
.on_hover_text("Reset all egui state")
.clicked()
{
self.memory_mut(|mem| *mem = Default::default());
}
let (num_state, num_serialized) = self.data(|d| (d.len(), d.count_serialized()));
ui.label(format!(
"{num_state} widget states stored (of which {num_serialized} are serialized)."
));
ui.horizontal(|ui| {
ui.label(format!(
"{} areas (panels, windows, popups, …)",
self.memory(|mem| mem.areas.count())
));
if ui.button("Reset").clicked() {
self.memory_mut(|mem| mem.areas = Default::default());
}
});
ui.indent("areas", |ui| {
ui.label("Visible areas, ordered back to front.");
ui.label("Hover to highlight");
let layers_ids: Vec<LayerId> = self.memory(|mem| mem.areas.order().to_vec());
for layer_id in layers_ids {
let area = self.memory(|mem| mem.areas.get(layer_id.id).copied());
if let Some(area) = area {
let is_visible = self.memory(|mem| mem.areas.is_visible(&layer_id));
if !is_visible {
continue;
}
let text = format!("{} - {:?}", layer_id.short_debug_format(), area.rect(),);
// TODO(emilk): `Sense::hover_highlight()`
if ui
.add(Label::new(RichText::new(text).monospace()).sense(Sense::click()))
.hovered
&& is_visible
{
ui.ctx()
.debug_painter()
.debug_rect(area.rect(), Color32::RED, "");
}
}
}
});
ui.horizontal(|ui| {
ui.label(format!(
"{} collapsing headers",
self.data(|d| d.count::<containers::collapsing_header::InnerState>())
));
if ui.button("Reset").clicked() {
self.data_mut(|d| d.remove_by_type::<containers::collapsing_header::InnerState>());
}
});
ui.horizontal(|ui| {
ui.label(format!(
"{} menu bars",
self.data(|d| d.count::<menu::BarState>())
));
if ui.button("Reset").clicked() {
self.data_mut(|d| d.remove_by_type::<menu::BarState>());
}
});
ui.horizontal(|ui| {
ui.label(format!(
"{} scroll areas",
self.data(|d| d.count::<scroll_area::State>())
));
if ui.button("Reset").clicked() {
self.data_mut(|d| d.remove_by_type::<scroll_area::State>());
}
});
ui.horizontal(|ui| {
ui.label(format!(
"{} resize areas",
self.data(|d| d.count::<resize::State>())
));
if ui.button("Reset").clicked() {
self.data_mut(|d| d.remove_by_type::<resize::State>());
}
});
ui.shrink_width_to_current(); // don't let the text below grow this window wider
ui.label("NOTE: the position of this window cannot be reset from within itself.");
ui.collapsing("Interaction", |ui| {
let interaction = self.memory(|mem| mem.interaction.clone());
interaction.ui(ui);
});
}
}
impl Context {
/// Edit the active [`Style`].
pub fn style_ui(&self, ui: &mut Ui) {
let mut style: Style = (*self.style()).clone();
style.ui(ui);
self.set_style(style);
}
}
/// ## Accessibility
impl Context {
/// Call the provided function with the given ID pushed on the stack of
/// parent IDs for accessibility purposes. If the `accesskit` feature
/// is disabled or if AccessKit support is not active for this frame,
/// the function is still called, but with no other effect.
///
/// No locks are held while the given closure is called.
#[allow(clippy::unused_self)]
#[inline]
pub fn with_accessibility_parent(&self, _id: Id, f: impl FnOnce()) {
// TODO(emilk): this isn't thread-safe - another thread can call this function between the push/pop calls
#[cfg(feature = "accesskit")]
self.frame_state_mut(|fs| {
if let Some(state) = fs.accesskit_state.as_mut() {
state.parent_stack.push(_id);
}
});
f();
#[cfg(feature = "accesskit")]
self.frame_state_mut(|fs| {
if let Some(state) = fs.accesskit_state.as_mut() {
assert_eq!(state.parent_stack.pop(), Some(_id));
}
});
}
/// If AccessKit support is active for the current frame, get or create
/// a node builder with the specified ID and return a mutable reference to it.
/// For newly created nodes, the parent is the node with the ID at the top
/// of the stack managed by [`Context::with_accessibility_parent`].
///
/// The `Context` lock is held while the given closure is called!
///
/// Returns `None` if acesskit is off.
// TODO: consider making both RO and RW versions
#[cfg(feature = "accesskit")]
pub fn accesskit_node_builder<R>(
&self,
id: Id,
writer: impl FnOnce(&mut accesskit::NodeBuilder) -> R,
) -> Option<R> {
self.write(|ctx| {
ctx.frame_state
.accesskit_state
.is_some()
.then(|| ctx.accesskit_node_builder(id))
.map(writer)
})
}
/// Enable generation of AccessKit tree updates in all future frames.
///
/// If it's practical for the egui integration to immediately run the egui
/// application when it is either initializing the AccessKit adapter or
/// being called by the AccessKit adapter to provide the initial tree update,
/// then it should do so, to provide a complete AccessKit tree to the adapter
/// immediately. Otherwise, it should enqueue a repaint and use the
/// placeholder tree update from [`Context::accesskit_placeholder_tree_update`]
/// in the meantime.
#[cfg(feature = "accesskit")]
pub fn enable_accesskit(&self) {
self.write(|ctx| ctx.is_accesskit_enabled = true);
}
/// Return a tree update that the egui integration should provide to the
/// AccessKit adapter if it cannot immediately run the egui application
/// to get a full tree update after running [`Context::enable_accesskit`].
#[cfg(feature = "accesskit")]
pub fn accesskit_placeholder_tree_update(&self) -> accesskit::TreeUpdate {
use accesskit::{NodeBuilder, Role, Tree, TreeUpdate};
let root_id = crate::accesskit_root_id().accesskit_id();
self.write(|ctx| TreeUpdate {
nodes: vec![(
root_id,
NodeBuilder::new(Role::Window).build(&mut ctx.accesskit_node_classes),
)],
tree: Some(Tree::new(root_id)),
focus: None,
})
}
}
/// ## Image loading
impl Context {
/// Associate some static bytes with a `uri`.
///
/// The same `uri` may be passed to [`Ui::image`] later to load the bytes as an image.
///
/// By convention, the `uri` should start with `bytes://`.
/// Following that convention will lead to better error messages.
pub fn include_bytes(&self, uri: impl Into<Cow<'static, str>>, bytes: impl Into<Bytes>) {
self.loaders().include.insert(uri, bytes);
}
/// Returns `true` if the chain of bytes, image, or texture loaders
/// contains a loader with the given `id`.
pub fn is_loader_installed(&self, id: &str) -> bool {
let loaders = self.loaders();
loaders.bytes.lock().iter().any(|l| l.id() == id)
|| loaders.image.lock().iter().any(|l| l.id() == id)
|| loaders.texture.lock().iter().any(|l| l.id() == id)
}
/// Add a new bytes loader.
///
/// It will be tried first, before any already installed loaders.
///
/// See [`load`] for more information.
pub fn add_bytes_loader(&self, loader: Arc<dyn load::BytesLoader + Send + Sync + 'static>) {
self.loaders().bytes.lock().push(loader);
}
/// Add a new image loader.
///
/// It will be tried first, before any already installed loaders.
///
/// See [`load`] for more information.
pub fn add_image_loader(&self, loader: Arc<dyn load::ImageLoader + Send + Sync + 'static>) {
self.loaders().image.lock().push(loader);
}
/// Add a new texture loader.
///
/// It will be tried first, before any already installed loaders.
///
/// See [`load`] for more information.
pub fn add_texture_loader(&self, loader: Arc<dyn load::TextureLoader + Send + Sync + 'static>) {
self.loaders().texture.lock().push(loader);
}
/// Release all memory and textures related to the given image URI.
///
/// If you attempt to load the image again, it will be reloaded from scratch.
pub fn forget_image(&self, uri: &str) {
use load::BytesLoader as _;
crate::profile_function!();
let loaders = self.loaders();
loaders.include.forget(uri);
for loader in loaders.bytes.lock().iter() {
loader.forget(uri);
}
for loader in loaders.image.lock().iter() {
loader.forget(uri);
}
for loader in loaders.texture.lock().iter() {
loader.forget(uri);
}
}
/// Release all memory and textures related to images used in [`Ui::image`] or [`Image`].
///
/// If you attempt to load any images again, they will be reloaded from scratch.
pub fn forget_all_images(&self) {
use load::BytesLoader as _;
crate::profile_function!();
let loaders = self.loaders();
loaders.include.forget_all();
for loader in loaders.bytes.lock().iter() {
loader.forget_all();
}
for loader in loaders.image.lock().iter() {
loader.forget_all();
}
for loader in loaders.texture.lock().iter() {
loader.forget_all();
}
}
/// Try loading the bytes from the given uri using any available bytes loaders.
///
/// Loaders are expected to cache results, so that this call is immediate-mode safe.
///
/// This calls the loaders one by one in the order in which they were registered.
/// If a loader returns [`LoadError::NotSupported`][not_supported],
/// then the next loader is called. This process repeats until all loaders have
/// been exhausted, at which point this returns [`LoadError::NotSupported`][not_supported].
///
/// # Errors
/// This may fail with:
/// - [`LoadError::NotSupported`][not_supported] if none of the registered loaders support loading the given `uri`.
/// - [`LoadError::Loading`][custom] if one of the loaders _does_ support loading the `uri`, but the loading process failed.
///
/// ⚠ May deadlock if called from within a `BytesLoader`!
///
/// [not_supported]: crate::load::LoadError::NotSupported
/// [custom]: crate::load::LoadError::Loading
pub fn try_load_bytes(&self, uri: &str) -> load::BytesLoadResult {
crate::profile_function!();
let loaders = self.loaders();
let bytes_loaders = loaders.bytes.lock();
// Try most recently added loaders first (hence `.rev()`)
for loader in bytes_loaders.iter().rev() {
match loader.load(self, uri) {
Err(load::LoadError::NotSupported) => continue,
result => return result,
}
}
Err(load::LoadError::NoMatchingBytesLoader)
}
/// Try loading the image from the given uri using any available image loaders.
///
/// Loaders are expected to cache results, so that this call is immediate-mode safe.
///
/// This calls the loaders one by one in the order in which they were registered.
/// If a loader returns [`LoadError::NotSupported`][not_supported],
/// then the next loader is called. This process repeats until all loaders have
/// been exhausted, at which point this returns [`LoadError::NotSupported`][not_supported].
///
/// # Errors
/// This may fail with:
/// - [`LoadError::NoImageLoaders`][no_image_loaders] if tbere are no registered image loaders.
/// - [`LoadError::NotSupported`][not_supported] if none of the registered loaders support loading the given `uri`.
/// - [`LoadError::Loading`][custom] if one of the loaders _does_ support loading the `uri`, but the loading process failed.
///
/// ⚠ May deadlock if called from within an `ImageLoader`!
///
/// [no_image_loaders]: crate::load::LoadError::NoImageLoaders
/// [not_supported]: crate::load::LoadError::NotSupported
/// [custom]: crate::load::LoadError::Loading
pub fn try_load_image(&self, uri: &str, size_hint: load::SizeHint) -> load::ImageLoadResult {
crate::profile_function!();
let loaders = self.loaders();
let image_loaders = loaders.image.lock();
if image_loaders.is_empty() {
return Err(load::LoadError::NoImageLoaders);
}
// Try most recently added loaders first (hence `.rev()`)
for loader in image_loaders.iter().rev() {
match loader.load(self, uri, size_hint) {
Err(load::LoadError::NotSupported) => continue,
result => return result,
}
}
Err(load::LoadError::NoMatchingImageLoader)
}
/// Try loading the texture from the given uri using any available texture loaders.
///
/// Loaders are expected to cache results, so that this call is immediate-mode safe.
///
/// This calls the loaders one by one in the order in which they were registered.
/// If a loader returns [`LoadError::NotSupported`][not_supported],
/// then the next loader is called. This process repeats until all loaders have
/// been exhausted, at which point this returns [`LoadError::NotSupported`][not_supported].
///
/// # Errors
/// This may fail with:
/// - [`LoadError::NotSupported`][not_supported] if none of the registered loaders support loading the given `uri`.
/// - [`LoadError::Loading`][custom] if one of the loaders _does_ support loading the `uri`, but the loading process failed.
///
/// ⚠ May deadlock if called from within a `TextureLoader`!
///
/// [not_supported]: crate::load::LoadError::NotSupported
/// [custom]: crate::load::LoadError::Loading
pub fn try_load_texture(
&self,
uri: &str,
texture_options: TextureOptions,
size_hint: load::SizeHint,
) -> load::TextureLoadResult {
crate::profile_function!();
let loaders = self.loaders();
let texture_loaders = loaders.texture.lock();
// Try most recently added loaders first (hence `.rev()`)
for loader in texture_loaders.iter().rev() {
match loader.load(self, uri, texture_options, size_hint) {
Err(load::LoadError::NotSupported) => continue,
result => return result,
}
}
Err(load::LoadError::NoMatchingTextureLoader)
}
/// The loaders of bytes, images, and textures.
pub fn loaders(&self) -> Arc<Loaders> {
crate::profile_function!();
self.read(|this| this.loaders.clone())
}
}
#[test]
fn context_impl_send_sync() {
fn assert_send_sync<T: Send + Sync>() {}
assert_send_sync::<Context>();
}