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ui.rs
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ui.rs
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// #![warn(missing_docs)]
use epaint::mutex::{Arc, RwLock, RwLockReadGuard, RwLockWriteGuard};
use std::hash::Hash;
use crate::{
color::*, containers::*, epaint::text::Fonts, layout::*, menu::MenuState, placer::Placer,
widgets::*, *,
};
// ----------------------------------------------------------------------------
/// This is what you use to place widgets.
///
/// Represents a region of the screen with a type of layout (horizontal or vertical).
///
/// ```
/// # egui::__run_test_ui(|ui| {
/// ui.add(egui::Label::new("Hello World!"));
/// ui.label("A shorter and more convenient way to add a label.");
/// ui.horizontal(|ui| {
/// ui.label("Add widgets");
/// if ui.button("on the same row!").clicked() {
/// /* … */
/// }
/// });
/// # });
/// ```
pub struct Ui {
/// ID of this ui.
/// Generated based on id of parent ui together with
/// another source of child identity (e.g. window title).
/// Acts like a namespace for child uis.
/// Should be unique and persist predictably from one frame to next
/// so it can be used as a source for storing state (e.g. window position, or if a collapsing header is open).
id: Id,
/// This is used to create a unique interact ID for some widgets.
/// This value is based on where in the hierarchy of widgets this Ui is in,
/// and the value is increment with each added child widget.
/// This works as an Id source only as long as new widgets aren't added or removed.
/// They are therefore only good for Id:s that has no state.
next_auto_id_source: u64,
/// Specifies paint layer, clip rectangle and a reference to `Context`.
painter: Painter,
/// The `Style` (visuals, spacing, etc) of this ui.
/// Commonly many `Ui`:s share the same `Style`.
/// The `Ui` implements copy-on-write for this.
style: Arc<Style>,
/// Handles the `Ui` size and the placement of new widgets.
placer: Placer,
/// If false we are unresponsive to input,
/// and all widgets will assume a gray style.
enabled: bool,
/// Indicates whether this Ui belongs to a Menu.
menu_state: Option<Arc<RwLock<MenuState>>>,
}
impl Ui {
// ------------------------------------------------------------------------
// Creation:
/// Create a new `Ui`.
///
/// Normally you would not use this directly, but instead use
/// [`SidePanel`], [`TopBottomPanel`], [`CentralPanel`], [`Window`] or [`Area`].
pub fn new(ctx: Context, layer_id: LayerId, id: Id, max_rect: Rect, clip_rect: Rect) -> Self {
let style = ctx.style();
Ui {
id,
next_auto_id_source: id.with("auto").value(),
painter: Painter::new(ctx, layer_id, clip_rect),
style,
placer: Placer::new(max_rect, Layout::default()),
enabled: true,
menu_state: None,
}
}
/// Create a new `Ui` at a specific region.
pub fn child_ui(&mut self, max_rect: Rect, layout: Layout) -> Self {
self.child_ui_with_id_source(max_rect, layout, "child")
}
/// Create a new `Ui` at a specific region with a specific id.
pub fn child_ui_with_id_source(
&mut self,
max_rect: Rect,
layout: Layout,
id_source: impl Hash,
) -> Self {
crate::egui_assert!(!max_rect.any_nan());
let next_auto_id_source = Id::new(self.next_auto_id_source).with("child").value();
self.next_auto_id_source = self.next_auto_id_source.wrapping_add(1);
let menu_state = self.get_menu_state();
Ui {
id: self.id.with(id_source),
next_auto_id_source,
painter: self.painter.clone(),
style: self.style.clone(),
placer: Placer::new(max_rect, layout),
enabled: self.enabled,
menu_state,
}
}
// -------------------------------------------------
/// A unique identity of this `Ui`.
#[inline]
pub fn id(&self) -> Id {
self.id
}
/// Style options for this `Ui` and its children.
///
/// Note that this may be a different [`Style`] than that of [`Context::style`].
#[inline]
pub fn style(&self) -> &Arc<Style> {
&self.style
}
/// Mutably borrow internal `Style`.
/// Changes apply to this `Ui` and its subsequent children.
///
/// To set the style of all `Ui`:s, use [`Context::set_style`].
///
/// Example:
/// ```
/// # egui::__run_test_ui(|ui| {
/// ui.style_mut().override_text_style = Some(egui::TextStyle::Heading);
/// # });
/// ```
pub fn style_mut(&mut self) -> &mut Style {
Arc::make_mut(&mut self.style) // clone-on-write
}
/// Changes apply to this `Ui` and its subsequent children.
///
/// To set the visuals of all `Ui`:s, use [`Context::set_visuals`].
pub fn set_style(&mut self, style: impl Into<Arc<Style>>) {
self.style = style.into();
}
/// Reset to the default style set in [`Context`].
pub fn reset_style(&mut self) {
self.style = self.ctx().style();
}
/// The current spacing options for this `Ui`.
/// Short for `ui.style().spacing`.
#[inline]
pub fn spacing(&self) -> &crate::style::Spacing {
&self.style.spacing
}
/// Mutably borrow internal `Spacing`.
/// Changes apply to this `Ui` and its subsequent children.
///
/// Example:
/// ```
/// # egui::__run_test_ui(|ui| {
/// ui.spacing_mut().item_spacing = egui::vec2(10.0, 2.0);
/// # });
/// ```
pub fn spacing_mut(&mut self) -> &mut crate::style::Spacing {
&mut self.style_mut().spacing
}
/// The current visuals settings of this `Ui`.
/// Short for `ui.style().visuals`.
#[inline]
pub fn visuals(&self) -> &crate::Visuals {
&self.style.visuals
}
/// Mutably borrow internal `visuals`.
/// Changes apply to this `Ui` and its subsequent children.
///
/// To set the visuals of all `Ui`:s, use [`Context::set_visuals`].
///
/// Example:
/// ```
/// # egui::__run_test_ui(|ui| {
/// ui.visuals_mut().override_text_color = Some(egui::Color32::RED);
/// # });
/// ```
pub fn visuals_mut(&mut self) -> &mut crate::Visuals {
&mut self.style_mut().visuals
}
/// Get a reference to the parent [`Context`].
#[inline]
pub fn ctx(&self) -> &Context {
self.painter.ctx()
}
/// Use this to paint stuff within this `Ui`.
#[inline]
pub fn painter(&self) -> &Painter {
&self.painter
}
/// If `false`, the `Ui` does not allow any interaction and
/// the widgets in it will draw with a gray look.
#[inline]
pub fn is_enabled(&self) -> bool {
self.enabled
}
/// Calling `set_enabled(false)` will cause the `Ui` to deny all future interaction
/// and all the widgets will draw with a gray look.
///
/// Usually it is more convenient to use [`Self::add_enabled_ui`] or [`Self::add_enabled`].
///
/// Calling `set_enabled(true)` has no effect - it will NOT re-enable the `Ui` once disabled.
///
/// ### Example
/// ```
/// # egui::__run_test_ui(|ui| {
/// # let mut enabled = true;
/// ui.group(|ui| {
/// ui.checkbox(&mut enabled, "Enable subsection");
/// ui.set_enabled(enabled);
/// if ui.button("Button that is not always clickable").clicked() {
/// /* … */
/// }
/// });
/// # });
/// ```
pub fn set_enabled(&mut self, enabled: bool) {
self.enabled &= enabled;
if !self.enabled && self.is_visible() {
self.painter
.set_fade_to_color(Some(self.visuals().window_fill()));
}
}
/// If `false`, any widgets added to the `Ui` will be invisible and non-interactive.
#[inline]
pub fn is_visible(&self) -> bool {
self.painter.is_visible()
}
#[deprecated = "Renamed is_visible"]
pub fn visible(&self) -> bool {
self.painter.is_visible()
}
/// Calling `set_visible(false)` will cause all further widgets to be invisible,
/// yet still allocate space.
///
/// The widgets will not be interactive (`set_visible(false)` implies `set_enabled(false)`).
///
/// Calling `set_visible(true)` has no effect.
///
/// ### Example
/// ```
/// # egui::__run_test_ui(|ui| {
/// # let mut visible = true;
/// ui.group(|ui| {
/// ui.checkbox(&mut visible, "Show subsection");
/// ui.set_visible(visible);
/// if ui.button("Button that is not always shown").clicked() {
/// /* … */
/// }
/// });
/// # });
/// ```
pub fn set_visible(&mut self, visible: bool) {
self.set_enabled(visible);
if !visible {
self.painter.set_invisible();
}
}
#[inline]
pub fn layout(&self) -> &Layout {
self.placer.layout()
}
/// Should text wrap in this `Ui`?
///
/// This is determined first by [`Style::wrap`], and then by the layout of this `Ui`.
pub fn wrap_text(&self) -> bool {
if let Some(wrap) = self.style.wrap {
wrap
} else if let Some(grid) = self.placer.grid() {
grid.wrap_text()
} else {
let layout = self.layout();
layout.is_vertical() || layout.is_horizontal() && layout.main_wrap()
}
}
/// Create a painter for a sub-region of this Ui.
///
/// The clip-rect of the returned `Painter` will be the intersection
/// of the given rectangle and the `clip_rect()` of this `Ui`.
pub fn painter_at(&self, rect: Rect) -> Painter {
self.painter().sub_region(rect)
}
/// Use this to paint stuff within this `Ui`.
#[inline]
pub fn layer_id(&self) -> LayerId {
self.painter().layer_id()
}
/// The [`InputState`] of the [`Context`] associated with this [`Ui`].
/// Equivalent to `.ctx().input()`.
///
/// Note that this locks the [`Context`], so be careful with if-let bindings:
///
/// ```
/// # egui::__run_test_ui(|ui| {
/// if let Some(pos) = { ui.input().pointer.hover_pos() } {
/// // This is fine!
/// }
///
/// let pos = ui.input().pointer.hover_pos();
/// if let Some(pos) = pos {
/// // This is also fine!
/// }
///
/// if let Some(pos) = ui.input().pointer.hover_pos() {
/// // ⚠️ Using `ui` again here will lead to a dead-lock!
/// }
/// # });
/// ```
#[inline]
pub fn input(&self) -> RwLockReadGuard<'_, InputState> {
self.ctx().input()
}
/// The [`InputState`] of the [`Context`] associated with this [`Ui`].
/// Equivalent to `.ctx().input_mut()`.
///
/// Note that this locks the [`Context`], so be careful with if-let bindings
/// like for [`Self::input()`].
/// ```
/// # egui::__run_test_ui(|ui| {
/// ui.input_mut().consume_key(egui::Modifiers::default(), egui::Key::Enter);
/// # });
/// ```
#[inline]
pub fn input_mut(&self) -> RwLockWriteGuard<'_, InputState> {
self.ctx().input_mut()
}
/// The [`Memory`] of the [`Context`] associated with this ui.
/// Equivalent to `.ctx().memory()`.
#[inline]
pub fn memory(&self) -> RwLockWriteGuard<'_, Memory> {
self.ctx().memory()
}
/// Stores superficial widget state.
#[inline]
pub fn data(&self) -> RwLockWriteGuard<'_, crate::util::IdTypeMap> {
self.ctx().data()
}
/// The [`PlatformOutput`] of the [`Context`] associated with this ui.
/// Equivalent to `.ctx().output()`.
#[inline]
pub fn output(&self) -> RwLockWriteGuard<'_, PlatformOutput> {
self.ctx().output()
}
/// The [`Fonts`] of the [`Context`] associated with this ui.
/// Equivalent to `.ctx().fonts()`.
#[inline]
pub fn fonts(&self) -> RwLockReadGuard<'_, Fonts> {
self.ctx().fonts()
}
/// The height of text of this text style
pub fn text_style_height(&self, style: &TextStyle) -> f32 {
self.fonts().row_height(&style.resolve(self.style()))
}
/// Screen-space rectangle for clipping what we paint in this ui.
/// This is used, for instance, to avoid painting outside a window that is smaller than its contents.
#[inline]
pub fn clip_rect(&self) -> Rect {
self.painter.clip_rect()
}
/// Screen-space rectangle for clipping what we paint in this ui.
/// This is used, for instance, to avoid painting outside a window that is smaller than its contents.
pub fn set_clip_rect(&mut self, clip_rect: Rect) {
self.painter.set_clip_rect(clip_rect);
}
/// Can be used for culling: if `false`, then no part of `rect` will be visible on screen.
pub fn is_rect_visible(&self, rect: Rect) -> bool {
self.is_visible() && rect.intersects(self.clip_rect())
}
}
// ------------------------------------------------------------------------
/// # Sizes etc
impl Ui {
/// Where and how large the `Ui` is already.
/// All widgets that have been added ot this `Ui` fits within this rectangle.
///
/// No matter what, the final Ui will be at least this large.
///
/// This will grow as new widgets are added, but never shrink.
pub fn min_rect(&self) -> Rect {
self.placer.min_rect()
}
/// Size of content; same as `min_rect().size()`
pub fn min_size(&self) -> Vec2 {
self.min_rect().size()
}
/// New widgets will *try* to fit within this rectangle.
///
/// Text labels will wrap to fit within `max_rect`.
/// Separator lines will span the `max_rect`.
///
/// If a new widget doesn't fit within the `max_rect` then the
/// `Ui` will make room for it by expanding both `min_rect` and `max_rect`.
pub fn max_rect(&self) -> Rect {
self.placer.max_rect()
}
/// Used for animation, kind of hacky
pub(crate) fn force_set_min_rect(&mut self, min_rect: Rect) {
self.placer.force_set_min_rect(min_rect);
}
// ------------------------------------------------------------------------
/// Set the maximum size of the ui.
/// You won't be able to shrink it below the current minimum size.
pub fn set_max_size(&mut self, size: Vec2) {
self.set_max_width(size.x);
self.set_max_height(size.y);
}
/// Set the maximum width of the ui.
/// You won't be able to shrink it below the current minimum size.
pub fn set_max_width(&mut self, width: f32) {
self.placer.set_max_width(width);
}
/// Set the maximum height of the ui.
/// You won't be able to shrink it below the current minimum size.
pub fn set_max_height(&mut self, height: f32) {
self.placer.set_max_height(height);
}
// ------------------------------------------------------------------------
/// Set the minimum size of the ui.
/// This can't shrink the ui, only make it larger.
pub fn set_min_size(&mut self, size: Vec2) {
self.set_min_width(size.x);
self.set_min_height(size.y);
}
/// Set the minimum width of the ui.
/// This can't shrink the ui, only make it larger.
pub fn set_min_width(&mut self, width: f32) {
self.placer.set_min_width(width);
}
/// Set the minimum height of the ui.
/// This can't shrink the ui, only make it larger.
pub fn set_min_height(&mut self, height: f32) {
self.placer.set_min_height(height);
}
// ------------------------------------------------------------------------
/// Helper: shrinks the max width to the current width,
/// so further widgets will try not to be wider than previous widgets.
/// Useful for normal vertical layouts.
pub fn shrink_width_to_current(&mut self) {
self.set_max_width(self.min_rect().width());
}
/// Helper: shrinks the max height to the current height,
/// so further widgets will try not to be wider than previous widgets.
pub fn shrink_height_to_current(&mut self) {
self.set_max_height(self.min_rect().height());
}
/// Expand the `min_rect` and `max_rect` of this ui to include a child at the given rect.
pub fn expand_to_include_rect(&mut self, rect: Rect) {
self.placer.expand_to_include_rect(rect);
}
/// `ui.set_width_range(min..=max);` is equivalent to `ui.set_min_width(min); ui.set_max_width(max);`.
pub fn set_width_range(&mut self, width: std::ops::RangeInclusive<f32>) {
self.set_min_width(*width.start());
self.set_max_width(*width.end());
}
/// `ui.set_height_range(min..=max);` is equivalent to `ui.set_min_height(min); ui.set_max_height(max);`.
pub fn set_height_range(&mut self, height: std::ops::RangeInclusive<f32>) {
self.set_min_height(*height.start());
self.set_max_height(*height.end());
}
/// Set both the minimum and maximum width.
pub fn set_width(&mut self, width: f32) {
self.set_min_width(width);
self.set_max_width(width);
}
/// Set both the minimum and maximum height.
pub fn set_height(&mut self, height: f32) {
self.set_min_height(height);
self.set_max_height(height);
}
/// Ensure we are big enough to contain the given x-coordinate.
/// This is sometimes useful to expand an ui to stretch to a certain place.
pub fn expand_to_include_x(&mut self, x: f32) {
self.placer.expand_to_include_x(x);
}
/// Ensure we are big enough to contain the given y-coordinate.
/// This is sometimes useful to expand an ui to stretch to a certain place.
pub fn expand_to_include_y(&mut self, y: f32) {
self.placer.expand_to_include_y(y);
}
// ------------------------------------------------------------------------
// Layout related measures:
/// The available space at the moment, given the current cursor.
/// This how much more space we can take up without overflowing our parent.
/// Shrinks as widgets allocate space and the cursor moves.
/// A small size should be interpreted as "as little as possible".
/// An infinite size should be interpreted as "as much as you want".
pub fn available_size(&self) -> Vec2 {
self.placer.available_size()
}
pub fn available_width(&self) -> f32 {
self.available_size().x
}
pub fn available_height(&self) -> f32 {
self.available_size().y
}
/// In case of a wrapping layout, how much space is left on this row/column?
pub fn available_size_before_wrap(&self) -> Vec2 {
self.placer.available_rect_before_wrap().size()
}
pub fn available_rect_before_wrap(&self) -> Rect {
self.placer.available_rect_before_wrap()
}
}
/// # `Id` creation
impl Ui {
/// Use this to generate widget ids for widgets that have persistent state in `Memory`.
pub fn make_persistent_id<IdSource>(&self, id_source: IdSource) -> Id
where
IdSource: Hash + std::fmt::Debug,
{
self.id.with(&id_source)
}
pub(crate) fn next_auto_id(&self) -> Id {
Id::new(self.next_auto_id_source)
}
pub(crate) fn auto_id_with<IdSource>(&self, id_source: IdSource) -> Id
where
IdSource: Hash + std::fmt::Debug,
{
Id::new(self.next_auto_id_source).with(id_source)
}
pub fn skip_ahead_auto_ids(&mut self, count: usize) {
self.next_auto_id_source = self.next_auto_id_source.wrapping_add(count as u64);
}
}
/// # Interaction
impl Ui {
/// Check for clicks, drags and/or hover on a specific region of this `Ui`.
pub fn interact(&self, rect: Rect, id: Id, sense: Sense) -> Response {
self.ctx().interact(
self.clip_rect(),
self.spacing().item_spacing,
self.layer_id(),
id,
rect,
sense,
self.enabled,
)
}
/// Is the pointer (mouse/touch) above this rectangle in this `Ui`?
///
/// The `clip_rect` and layer of this `Ui` will be respected, so, for instance,
/// if this `Ui` is behind some other window, this will always return `false`.
pub fn rect_contains_pointer(&self, rect: Rect) -> bool {
self.ctx()
.rect_contains_pointer(self.layer_id(), self.clip_rect().intersect(rect))
}
/// Is the pointer (mouse/touch) above this `Ui`?
/// Equivalent to `ui.rect_contains_pointer(ui.min_rect())`
pub fn ui_contains_pointer(&self) -> bool {
self.rect_contains_pointer(self.min_rect())
}
}
/// # Allocating space: where do I put my widgets?
impl Ui {
/// Allocate space for a widget and check for interaction in the space.
/// Returns a `Response` which contains a rectangle, id, and interaction info.
///
/// ## How sizes are negotiated
/// Each widget should have a *minimum desired size* and a *desired size*.
/// When asking for space, ask AT LEAST for your minimum, and don't ask for more than you need.
/// If you want to fill the space, ask about [`Ui::available_size`] and use that.
///
/// You may get MORE space than you asked for, for instance
/// for justified layouts, like in menus.
///
/// You will never get a rectangle that is smaller than the amount of space you asked for.
///
/// ```
/// # egui::__run_test_ui(|ui| {
/// let response = ui.allocate_response(egui::vec2(100.0, 200.0), egui::Sense::click());
/// if response.clicked() { /* … */ }
/// ui.painter().rect_stroke(response.rect, 0.0, (1.0, egui::Color32::WHITE));
/// # });
/// ```
pub fn allocate_response(&mut self, desired_size: Vec2, sense: Sense) -> Response {
let (id, rect) = self.allocate_space(desired_size);
self.interact(rect, id, sense)
}
/// Returns a `Rect` with exactly what you asked for.
///
/// The response rect will be larger if this is part of a justified layout or similar.
/// This means that if this is a narrow widget in a wide justified layout, then
/// the widget will react to interactions outside the returned `Rect`.
pub fn allocate_exact_size(&mut self, desired_size: Vec2, sense: Sense) -> (Rect, Response) {
let response = self.allocate_response(desired_size, sense);
let rect = self
.placer
.align_size_within_rect(desired_size, response.rect);
(rect, response)
}
/// Allocate at least as much space as needed, and interact with that rect.
///
/// The returned `Rect` will be the same size as `Response::rect`.
pub fn allocate_at_least(&mut self, desired_size: Vec2, sense: Sense) -> (Rect, Response) {
let response = self.allocate_response(desired_size, sense);
(response.rect, response)
}
/// Reserve this much space and move the cursor.
/// Returns where to put the widget.
///
/// ## How sizes are negotiated
/// Each widget should have a *minimum desired size* and a *desired size*.
/// When asking for space, ask AT LEAST for your minimum, and don't ask for more than you need.
/// If you want to fill the space, ask about [`Ui::available_size`] and use that.
///
/// You may get MORE space than you asked for, for instance
/// for justified layouts, like in menus.
///
/// You will never get a rectangle that is smaller than the amount of space you asked for.
///
/// Returns an automatic `Id` (which you can use for interaction) and the `Rect` of where to put your widget.
///
/// ```
/// # egui::__run_test_ui(|ui| {
/// let (id, rect) = ui.allocate_space(egui::vec2(100.0, 200.0));
/// let response = ui.interact(rect, id, egui::Sense::click());
/// # });
/// ```
pub fn allocate_space(&mut self, desired_size: Vec2) -> (Id, Rect) {
// For debug rendering
let original_available = self.available_size_before_wrap();
let too_wide = desired_size.x > original_available.x;
let too_high = desired_size.y > original_available.y;
let rect = self.allocate_space_impl(desired_size);
if self.style().debug.debug_on_hover && self.rect_contains_pointer(rect) {
let painter = self.ctx().debug_painter();
painter.rect_stroke(rect, 4.0, (1.0, Color32::LIGHT_BLUE));
self.placer.debug_paint_cursor(&painter, "next");
}
let debug_expand_width = self.style().debug.show_expand_width;
let debug_expand_height = self.style().debug.show_expand_height;
if (debug_expand_width && too_wide) || (debug_expand_height && too_high) {
self.painter
.rect_stroke(rect, 0.0, (1.0, Color32::LIGHT_BLUE));
let stroke = Stroke::new(2.5, Color32::from_rgb(200, 0, 0));
let paint_line_seg = |a, b| self.painter().line_segment([a, b], stroke);
if debug_expand_width && too_wide {
paint_line_seg(rect.left_top(), rect.left_bottom());
paint_line_seg(rect.left_center(), rect.right_center());
paint_line_seg(
pos2(rect.left() + original_available.x, rect.top()),
pos2(rect.left() + original_available.x, rect.bottom()),
);
paint_line_seg(rect.right_top(), rect.right_bottom());
}
if debug_expand_height && too_high {
paint_line_seg(rect.left_top(), rect.right_top());
paint_line_seg(rect.center_top(), rect.center_bottom());
paint_line_seg(rect.left_bottom(), rect.right_bottom());
}
}
let id = Id::new(self.next_auto_id_source);
self.next_auto_id_source = self.next_auto_id_source.wrapping_add(1);
(id, rect)
}
/// Reserve this much space and move the cursor.
/// Returns where to put the widget.
fn allocate_space_impl(&mut self, desired_size: Vec2) -> Rect {
let item_spacing = self.spacing().item_spacing;
let frame_rect = self.placer.next_space(desired_size, item_spacing);
egui_assert!(!frame_rect.any_nan());
let widget_rect = self.placer.justify_and_align(frame_rect, desired_size);
self.placer
.advance_after_rects(frame_rect, widget_rect, item_spacing);
widget_rect
}
/// Allocate a specific part of the `Ui`.
///
/// Ignore the layout of the `Ui`: just put my widget here!
/// The layout cursor will advance to past this `rect`.
pub fn allocate_rect(&mut self, rect: Rect, sense: Sense) -> Response {
let id = self.advance_cursor_after_rect(rect);
self.interact(rect, id, sense)
}
pub(crate) fn advance_cursor_after_rect(&mut self, rect: Rect) -> Id {
egui_assert!(!rect.any_nan());
let item_spacing = self.spacing().item_spacing;
self.placer.advance_after_rects(rect, rect, item_spacing);
if self.style().debug.debug_on_hover && self.rect_contains_pointer(rect) {
let painter = self.ctx().debug_painter();
painter.rect_stroke(rect, 4.0, (1.0, Color32::LIGHT_BLUE));
self.placer.debug_paint_cursor(&painter, "next");
}
let id = Id::new(self.next_auto_id_source);
self.next_auto_id_source = self.next_auto_id_source.wrapping_add(1);
id
}
pub(crate) fn placer(&self) -> &Placer {
&self.placer
}
pub(crate) fn cursor(&self) -> Rect {
self.placer.cursor()
}
pub(crate) fn set_cursor(&mut self, cursor: Rect) {
self.placer.set_cursor(cursor);
}
/// Where do we expect a zero-sized widget to be placed?
pub(crate) fn next_widget_position(&self) -> Pos2 {
self.placer.next_widget_position()
}
/// Allocated the given space and then adds content to that space.
/// If the contents overflow, more space will be allocated.
/// When finished, the amount of space actually used (`min_rect`) will be allocated.
/// So you can request a lot of space and then use less.
#[inline]
pub fn allocate_ui<R>(
&mut self,
desired_size: Vec2,
add_contents: impl FnOnce(&mut Self) -> R,
) -> InnerResponse<R> {
self.allocate_ui_with_layout(desired_size, *self.layout(), add_contents)
}
/// Allocated the given space and then adds content to that space.
/// If the contents overflow, more space will be allocated.
/// When finished, the amount of space actually used (`min_rect`) will be allocated.
/// So you can request a lot of space and then use less.
#[inline]
pub fn allocate_ui_with_layout<R>(
&mut self,
desired_size: Vec2,
layout: Layout,
add_contents: impl FnOnce(&mut Self) -> R,
) -> InnerResponse<R> {
self.allocate_ui_with_layout_dyn(desired_size, layout, Box::new(add_contents))
}
fn allocate_ui_with_layout_dyn<'c, R>(
&mut self,
desired_size: Vec2,
layout: Layout,
add_contents: Box<dyn FnOnce(&mut Self) -> R + 'c>,
) -> InnerResponse<R> {
crate::egui_assert!(desired_size.x >= 0.0 && desired_size.y >= 0.0);
let item_spacing = self.spacing().item_spacing;
let frame_rect = self.placer.next_space(desired_size, item_spacing);
let child_rect = self.placer.justify_and_align(frame_rect, desired_size);
let mut child_ui = self.child_ui(child_rect, layout);
let ret = add_contents(&mut child_ui);
let final_child_rect = child_ui.min_rect();
self.placer
.advance_after_rects(final_child_rect, final_child_rect, item_spacing);
if self.style().debug.debug_on_hover && self.rect_contains_pointer(final_child_rect) {
let painter = self.ctx().debug_painter();
painter.rect_stroke(frame_rect, 4.0, (1.0, Color32::LIGHT_BLUE));
painter.rect_stroke(final_child_rect, 4.0, (1.0, Color32::LIGHT_BLUE));
self.placer.debug_paint_cursor(&painter, "next");
}
let response = self.interact(final_child_rect, child_ui.id, Sense::hover());
InnerResponse::new(ret, response)
}
/// Allocated the given rectangle and then adds content to that rectangle.
/// If the contents overflow, more space will be allocated.
/// When finished, the amount of space actually used (`min_rect`) will be allocated.
/// So you can request a lot of space and then use less.
pub fn allocate_ui_at_rect<R>(
&mut self,
max_rect: Rect,
add_contents: impl FnOnce(&mut Self) -> R,
) -> InnerResponse<R> {
egui_assert!(max_rect.is_finite());
let mut child_ui = self.child_ui(max_rect, *self.layout());
let ret = add_contents(&mut child_ui);
let final_child_rect = child_ui.min_rect();
self.placer.advance_after_rects(
final_child_rect,
final_child_rect,
self.spacing().item_spacing,
);
let response = self.interact(final_child_rect, child_ui.id, Sense::hover());
InnerResponse::new(ret, response)
}
/// Convenience function to get a region to paint on.
///
/// Note that egui uses screen coordinates for everything.
///
/// ```
/// # use egui::*;
/// # use std::f32::consts::TAU;
/// # egui::__run_test_ui(|ui| {
/// let size = Vec2::splat(16.0);
/// let (response, painter) = ui.allocate_painter(size, Sense::hover());
/// let rect = response.rect;
/// let c = rect.center();
/// let r = rect.width() / 2.0 - 1.0;
/// let color = Color32::from_gray(128);
/// let stroke = Stroke::new(1.0, color);
/// painter.circle_stroke(c, r, stroke);
/// painter.line_segment([c - vec2(0.0, r), c + vec2(0.0, r)], stroke);
/// painter.line_segment([c, c + r * Vec2::angled(TAU * 1.0 / 8.0)], stroke);
/// painter.line_segment([c, c + r * Vec2::angled(TAU * 3.0 / 8.0)], stroke);
/// # });
/// ```
pub fn allocate_painter(&mut self, desired_size: Vec2, sense: Sense) -> (Response, Painter) {
let response = self.allocate_response(desired_size, sense);
let clip_rect = self.clip_rect().intersect(response.rect); // Make sure we don't paint out of bounds
let painter = Painter::new(self.ctx().clone(), self.layer_id(), clip_rect);
(response, painter)
}
/// Adjust the scroll position of any parent [`ScrollArea`] so that the given `Rect` becomes visible.
///
/// If `align` is `None`, it'll scroll enough to bring the cursor into view.
///
/// See also: [`Response::scroll_to_me`], [`Ui::scroll_to_rect`].
///
/// ```
/// # use egui::Align;
/// # egui::__run_test_ui(|ui| {
/// egui::ScrollArea::vertical().show(ui, |ui| {
/// // …
/// let response = ui.button("Center on me.");
/// if response.clicked() {
/// ui.scroll_to_rect(response.rect, Some(Align::Center));
/// }
/// });
/// # });
/// ```
pub fn scroll_to_rect(&self, rect: Rect, align: Option<Align>) {
for d in 0..2 {
let range = rect.min[d]..=rect.max[d];
self.ctx().frame_state().scroll_target[d] = Some((range, align));
}
}
/// Adjust the scroll position of any parent [`ScrollArea`] so that the cursor (where the next widget goes) becomes visible.
///
/// If `align` is not provided, it'll scroll enough to bring the cursor into view.
///
/// See also: [`Response::scroll_to_me`], [`Ui::scroll_to_rect`].
///
/// ```
/// # use egui::Align;
/// # egui::__run_test_ui(|ui| {
/// egui::ScrollArea::vertical().show(ui, |ui| {
/// let scroll_bottom = ui.button("Scroll to bottom.").clicked();
/// for i in 0..1000 {
/// ui.label(format!("Item {}", i));
/// }
///
/// if scroll_bottom {
/// ui.scroll_to_cursor(Some(Align::BOTTOM));
/// }
/// });
/// # });
/// ```
pub fn scroll_to_cursor(&self, align: Option<Align>) {
let target = self.next_widget_position();
for d in 0..2 {
let target = target[d];
self.ctx().frame_state().scroll_target[d] = Some((target..=target, align));
}
}
}
/// # Adding widgets
impl Ui {
/// Add a [`Widget`] to this `Ui` at a location dependent on the current [`Layout`].
///
/// The returned [`Response`] can be used to check for interactions,
/// as well as adding tooltips using [`Response::on_hover_text`].
///
/// See also [`Self::add_sized`] and [`Self::put`].
///
/// ```
/// # egui::__run_test_ui(|ui| {
/// # let mut my_value = 42;
/// let response = ui.add(egui::Slider::new(&mut my_value, 0..=100));
/// response.on_hover_text("Drag me!");
/// # });
/// ```
#[inline]
pub fn add(&mut self, widget: impl Widget) -> Response {
widget.ui(self)
}
/// Add a [`Widget`] to this `Ui` with a given size.
/// The widget will attempt to fit within the given size, but some widgets may overflow.
///
/// To fill all remaining area, use `ui.add_sized(ui.available_size(), widget);`
///
/// See also [`Self::add`] and [`Self::put`].
///
/// ```
/// # let mut my_value = 42;
/// # egui::__run_test_ui(|ui| {
/// ui.add_sized([40.0, 20.0], egui::DragValue::new(&mut my_value));
/// # });
/// ```
pub fn add_sized(&mut self, max_size: impl Into<Vec2>, widget: impl Widget) -> Response {
// TODO: configure to overflow to main_dir instead of centered overflow
// to handle the bug mentioned at https://github.com/emilk/egui/discussions/318#discussioncomment-627578
// and fixed in https://github.com/emilk/egui/commit/035166276322b3f2324bd8b97ffcedc63fa8419f
//