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// Copyright 2020 The Druid Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//! The context types that are passed into various widget methods.
use std::{
any::{Any, TypeId},
collections::{HashMap, VecDeque},
ops::{Deref, DerefMut},
rc::Rc,
time::Duration,
};
use tracing::{error, trace, warn};
use crate::commands::SCROLL_TO_VIEW;
use crate::core::{CommandQueue, CursorChange, FocusChange, WidgetState};
use crate::env::KeyLike;
use crate::menu::ContextMenu;
use crate::piet::{Piet, PietText, RenderContext};
use crate::shell::text::Event as ImeInvalidation;
use crate::shell::Region;
use crate::text::{ImeHandlerRef, TextFieldRegistration};
use crate::{
commands, sub_window::SubWindowDesc, widget::Widget, Affine, Command, Cursor, Data, Env,
ExtEventSink, Insets, Menu, Notification, Point, Rect, Scale, SingleUse, Size, Target,
TimerToken, Vec2, WidgetId, WindowConfig, WindowDesc, WindowHandle, WindowId,
};
/// A macro for implementing methods on multiple contexts.
///
/// There are a lot of methods defined on multiple contexts; this lets us only
/// have to write them out once.
macro_rules! impl_context_method {
($ty:ty, { $($method:item)+ } ) => {
impl $ty { $($method)+ }
};
( $ty:ty, $($more:ty),+, { $($method:item)+ } ) => {
impl_context_method!($ty, { $($method)+ });
impl_context_method!($($more),+, { $($method)+ });
};
}
/// A macro for implementing context traits for multiple contexts.
macro_rules! impl_context_trait {
($tr:ty => $ty:ty, { $($method:item)+ } ) => {
impl $tr for $ty { $($method)+ }
};
($tr:ty => $ty:ty, $($more:ty),+, { $($method:item)+ } ) => {
impl_context_trait!($tr => $ty, { $($method)+ });
impl_context_trait!($tr => $($more),+, { $($method)+ });
};
}
/// Static state that is shared between most contexts.
pub(crate) struct ContextState<'a> {
pub(crate) command_queue: &'a mut CommandQueue,
pub(crate) ext_handle: &'a ExtEventSink,
pub(crate) window_id: WindowId,
pub(crate) window: &'a WindowHandle,
pub(crate) text: PietText,
/// The id of the widget that currently has focus.
pub(crate) focus_widget: Option<WidgetId>,
pub(crate) root_app_data_type: TypeId,
pub(crate) timers: &'a mut HashMap<TimerToken, WidgetId>,
pub(crate) text_registrations: &'a mut Vec<TextFieldRegistration>,
}
/// A mutable context provided to event handling methods of widgets.
///
/// Widgets should call [`request_paint`] whenever an event causes a change
/// in the widget's appearance, to schedule a repaint.
///
/// [`request_paint`]: #method.request_paint
pub struct EventCtx<'a, 'b> {
pub(crate) state: &'a mut ContextState<'b>,
pub(crate) widget_state: &'a mut WidgetState,
pub(crate) notifications: &'a mut VecDeque<Notification>,
pub(crate) is_handled: bool,
pub(crate) is_root: bool,
}
/// A mutable context provided to the [`lifecycle`] method on widgets.
///
/// Certain methods on this context are only meaningful during the handling of
/// specific lifecycle events; for instance [`register_child`]
/// should only be called while handling [`LifeCycle::WidgetAdded`].
///
/// [`lifecycle`]: Widget::lifecycle
/// [`register_child`]: #method.register_child
/// [`LifeCycle::WidgetAdded`]: crate::LifeCycle::WidgetAdded
pub struct LifeCycleCtx<'a, 'b> {
pub(crate) state: &'a mut ContextState<'b>,
pub(crate) widget_state: &'a mut WidgetState,
}
/// A mutable context provided to data update methods of widgets.
///
/// Widgets should call [`request_paint`] whenever a data change causes a change
/// in the widget's appearance, to schedule a repaint.
///
/// [`request_paint`]: #method.request_paint
pub struct UpdateCtx<'a, 'b> {
pub(crate) state: &'a mut ContextState<'b>,
pub(crate) widget_state: &'a mut WidgetState,
pub(crate) prev_env: Option<&'a Env>,
pub(crate) env: &'a Env,
}
/// A context provided to layout-handling methods of widgets.
///
/// As of now, the main service provided is access to a factory for
/// creating text layout objects, which are likely to be useful
/// during widget layout.
pub struct LayoutCtx<'a, 'b> {
pub(crate) state: &'a mut ContextState<'b>,
pub(crate) widget_state: &'a mut WidgetState,
}
/// Z-order paint operations with transformations.
pub(crate) struct ZOrderPaintOp {
pub z_index: u32,
pub paint_func: Box<dyn FnOnce(&mut PaintCtx) + 'static>,
pub transform: Affine,
}
/// A context passed to paint methods of widgets.
///
/// In addition to the API below, [`PaintCtx`] derefs to an implementation of
/// the [`RenderContext`] trait, which defines the basic available drawing
/// commands.
pub struct PaintCtx<'a, 'b, 'c> {
pub(crate) state: &'a mut ContextState<'b>,
pub(crate) widget_state: &'a WidgetState,
/// The render context for actually painting.
pub render_ctx: &'a mut Piet<'c>,
/// The z-order paint operations.
pub(crate) z_ops: Vec<ZOrderPaintOp>,
/// The currently visible region.
pub(crate) region: Region,
/// The approximate depth in the tree at the time of painting.
pub(crate) depth: u32,
}
/// The state of a widget and its global context.
pub struct State<'a> {
// currently the only method using the State struct is set_origin.
// the context state could be included into this struct to allow changes to context state
// changes from Context traits
// pub(crate) state: &'a mut ContextState<'b>,
pub(crate) widget_state: &'a mut WidgetState,
}
/// Convenience trait for code generic over contexts.
///
/// Methods that deal with commands and timers.
/// Available to all contexts but [`PaintCtx`].
pub trait ChangeCtx {
/// Submit a [`Command`] to be run after this event is handled. See [`submit_command`].
///
/// [`submit_command`]: EventCtx::submit_command
fn submit_command(&mut self, cmd: impl Into<Command>);
/// Returns an [`ExtEventSink`] for submitting commands from other threads. See ['get_external_handle'].
///
/// [`get_external_handle`]: EventCtx::get_external_handle
fn get_external_handle(&self) -> ExtEventSink;
/// Request a timer event. See [`request_timer`]
///
/// [`request_timer`]: EventCtx::request_timer
fn request_timer(&mut self, deadline: Duration) -> TimerToken;
/// Returns the state of the widget.
///
/// This method should only be used by the framework to do mergeups.
fn state(&mut self) -> State;
}
/// Convenience trait for invalidation and request methods available on multiple contexts.
///
/// These methods are available on [`EventCtx`], [`LifeCycleCtx`], and [`UpdateCtx`].
pub trait RequestCtx: ChangeCtx {
/// Request a [`paint`] pass. See ['request_paint']
///
/// ['request_paint']: EventCtx::request_paint
/// [`paint`]: Widget::paint
fn request_paint(&mut self);
/// Request a [`paint`] pass for redrawing a rectangle. See [`request_paint_rect`].
///
/// [`request_paint_rect`]: EventCtx::request_paint_rect
/// [`paint`]: Widget::paint
fn request_paint_rect(&mut self, rect: Rect);
/// Request a layout pass. See [`request_layout`].
///
/// [`request_layout`]: EventCtx::request_layout
fn request_layout(&mut self);
/// Request an animation frame. See [`request_anim_frame`].
///
/// [`request_anim_frame`]: EventCtx::request_anim_frame
fn request_anim_frame(&mut self);
/// Indicate that your children have changed. See [`children_changed`].
///
/// [`children_changed`]: EventCtx::children_changed
fn children_changed(&mut self);
/// Create a new sub-window. See [`new_sub_window`].
///
/// [`new_sub_window`]: EventCtx::new_sub_window
fn new_sub_window<W: Widget<U> + 'static, U: Data>(
&mut self,
window_config: WindowConfig,
widget: W,
data: U,
env: Env,
) -> WindowId;
/// Change the disabled state of this widget. See [`set_disabled`].
///
/// [`set_disabled`]: EventCtx::set_disabled
fn set_disabled(&mut self, disabled: bool);
/// Indicate that text input state has changed. See [`invalidate_text_input`].
///
/// [`invalidate_text_input`]: EventCtx::invalidate_text_input
fn invalidate_text_input(&mut self, event: ImeInvalidation);
/// Scrolls this widget into view.
///
/// [`scroll_to_view`]: EventCtx::scroll_to_view
fn scroll_to_view(&mut self);
/// Scrolls the area into view. See [`scroll_area_to_view`].
///
/// [`scroll_area_to_view`]: EventCtx::scroll_area_to_view
fn scroll_area_to_view(&mut self, area: Rect);
}
impl_context_trait!(
ChangeCtx => EventCtx<'_, '_>, UpdateCtx<'_, '_>, LifeCycleCtx<'_, '_>, LayoutCtx<'_, '_>,
{
fn submit_command(&mut self, cmd: impl Into<Command>) {
Self::submit_command(self, cmd)
}
fn get_external_handle(&self) -> ExtEventSink {
Self::get_external_handle(self)
}
fn request_timer(&mut self, deadline: Duration) -> TimerToken {
Self::request_timer(self, deadline)
}
fn state(&mut self) -> State {
State {
//state: &mut *self.state,
widget_state: &mut *self.widget_state,
}
}
}
);
impl_context_trait!(
RequestCtx => EventCtx<'_, '_>, UpdateCtx<'_, '_>, LifeCycleCtx<'_, '_>,
{
fn request_paint(&mut self) {
Self::request_paint(self)
}
fn request_paint_rect(&mut self, rect: Rect) {
Self::request_paint_rect(self, rect)
}
fn request_layout(&mut self) {
Self::request_layout(self)
}
fn request_anim_frame(&mut self) {
Self::request_anim_frame(self)
}
fn children_changed(&mut self) {
Self::children_changed(self)
}
fn new_sub_window<W: Widget<U> + 'static, U: Data>(
&mut self,
window_config: WindowConfig,
widget: W,
data: U,
env: Env,
) -> WindowId {
Self::new_sub_window(self, window_config, widget, data, env)
}
fn set_disabled(&mut self, disabled: bool) {
Self::set_disabled(self, disabled)
}
fn invalidate_text_input(&mut self, event: ImeInvalidation) {
Self::invalidate_text_input(self, event)
}
fn scroll_to_view(&mut self) {
Self::scroll_to_view(self)
}
fn scroll_area_to_view(&mut self, area: Rect) {
Self::scroll_area_to_view(self, area)
}
}
);
// methods on everyone
impl_context_method!(
EventCtx<'_, '_>,
UpdateCtx<'_, '_>,
LifeCycleCtx<'_, '_>,
PaintCtx<'_, '_, '_>,
LayoutCtx<'_, '_>,
{
/// get the `WidgetId` of the current widget.
pub fn widget_id(&self) -> WidgetId {
self.widget_state.id
}
/// Returns a reference to the current `WindowHandle`.
pub fn window(&self) -> &WindowHandle {
self.state.window
}
/// Get the `WindowId` of the current window.
pub fn window_id(&self) -> WindowId {
self.state.window_id
}
/// Get an object which can create text layouts.
pub fn text(&mut self) -> &mut PietText {
&mut self.state.text
}
/// The current window's [`Scale`].
///
/// The returned [`Scale`] is a copy and thus its information will be stale after
/// the platform changes the window's scale. This means you can only rely on it
/// until the next [`Event::WindowScale`] event happens.
///
/// [`Scale`]: crate::Scale
/// [`Event::WindowScale`]: crate::Event::WindowScale
pub fn scale(&self) -> Scale {
self.state.window.get_scale().unwrap_or_default()
}
}
);
// methods on everyone but layoutctx
impl_context_method!(
EventCtx<'_, '_>,
UpdateCtx<'_, '_>,
LifeCycleCtx<'_, '_>,
PaintCtx<'_, '_, '_>,
{
/// The layout size.
///
/// This is the layout size as ultimately determined by the parent
/// container, on the previous layout pass.
///
/// Generally it will be the same as the size returned by the child widget's
/// [`layout`] method.
///
/// [`layout`]: Widget::layout
pub fn size(&self) -> Size {
self.widget_state.size()
}
/// The origin of the widget in window coordinates, relative to the top left corner of the
/// content area.
pub fn window_origin(&self) -> Point {
self.widget_state.window_origin()
}
/// Convert a point from the widget's coordinate space to the window's.
///
/// The returned point is relative to the content area; it excludes window chrome.
pub fn to_window(&self, widget_point: Point) -> Point {
self.window_origin() + widget_point.to_vec2()
}
/// Convert a point from the widget's coordinate space to the screen's.
/// See the [`Screen`] module
///
/// [`Screen`]: crate::shell::Screen
pub fn to_screen(&self, widget_point: Point) -> Point {
let insets = self.window().content_insets();
let content_origin = self.window().get_position() + Vec2::new(insets.x0, insets.y0);
content_origin + self.to_window(widget_point).to_vec2()
}
/// Query the "hot" state of the widget.
///
/// See [`WidgetPod::is_hot`] for additional information.
///
/// [`WidgetPod::is_hot`]: crate::WidgetPod::is_hot
pub fn is_hot(&self) -> bool {
self.widget_state.is_hot
}
/// Query the "active" state of the widget.
///
/// See [`WidgetPod::is_active`] for additional information.
///
/// [`WidgetPod::is_active`]: crate::WidgetPod::is_active
pub fn is_active(&self) -> bool {
self.widget_state.is_active
}
/// The focus status of a widget.
///
/// Returns `true` if this specific widget is focused.
/// To check if any descendants are focused use [`has_focus`].
///
/// Focus means that the widget receives keyboard events.
///
/// A widget can request focus using the [`request_focus`] method.
/// It's also possible to register for automatic focus via [`register_for_focus`].
///
/// If a widget gains or loses focus it will get a [`LifeCycle::FocusChanged`] event.
///
/// Only one widget at a time is focused. However due to the way events are routed,
/// all ancestors of that widget will also receive keyboard events.
///
/// [`request_focus`]: EventCtx::request_focus
/// [`register_for_focus`]: LifeCycleCtx::register_for_focus
/// [`LifeCycle::FocusChanged`]: crate::LifeCycle::FocusChanged
/// [`has_focus`]: #method.has_focus
pub fn is_focused(&self) -> bool {
self.state.focus_widget == Some(self.widget_id())
}
/// The (tree) focus status of a widget.
///
/// Returns `true` if either this specific widget or any one of its descendants is focused.
/// To check if only this specific widget is focused use [`is_focused`],
///
/// [`is_focused`]: crate::EventCtx::is_focused
pub fn has_focus(&self) -> bool {
self.widget_state.has_focus
}
/// The disabled state of a widget.
///
/// Returns `true` if this widget or any of its ancestors is explicitly disabled.
/// To make this widget explicitly disabled use [`set_disabled`].
///
/// Disabled means that this widget should not change the state of the application. What
/// that means is not entirely clear but in any it should not change its data. Therefore
/// others can use this as a safety mechanism to prevent the application from entering an
/// illegal state.
/// For an example the decrease button of a counter of type `usize` should be disabled if the
/// value is `0`.
///
/// [`set_disabled`]: crate::EventCtx::set_disabled
pub fn is_disabled(&self) -> bool {
self.widget_state.is_disabled()
}
}
);
impl_context_method!(EventCtx<'_, '_>, UpdateCtx<'_, '_>, {
/// Set the cursor icon.
///
/// This setting will be retained until [`clear_cursor`] is called, but it will only take
/// effect when this widget is either [`hot`] or [`active`]. If a child widget also sets a
/// cursor, the child widget's cursor will take precedence. (If that isn't what you want, use
/// [`override_cursor`] instead.)
///
/// [`clear_cursor`]: crate::EventCtx::clear_cursor
/// [`override_cursor`]: crate::EventCtx::override_cursor
/// [`hot`]: crate::EventCtx::is_hot
/// [`active`]: crate::EventCtx::is_active
pub fn set_cursor(&mut self, cursor: &Cursor) {
trace!("set_cursor {:?}", cursor);
self.widget_state.cursor_change = CursorChange::Set(cursor.clone());
}
/// Override the cursor icon.
///
/// This setting will be retained until [`clear_cursor`] is called, but it will only take
/// effect when this widget is either [`hot`] or [`active`]. This will override the cursor
/// preferences of a child widget. (If that isn't what you want, use [`set_cursor`] instead.)
///
/// [`clear_cursor`]: crate::EventCtx::clear_cursor
/// [`set_cursor`]: crate::EventCtx::set_cursor
/// [`hot`]: crate::EventCtx::is_hot
/// [`active`]: crate::EventCtx::is_active
pub fn override_cursor(&mut self, cursor: &Cursor) {
trace!("override_cursor {:?}", cursor);
self.widget_state.cursor_change = CursorChange::Override(cursor.clone());
}
/// Clear the cursor icon.
///
/// This undoes the effect of [`set_cursor`] and [`override_cursor`].
///
/// [`override_cursor`]: crate::EventCtx::override_cursor
/// [`set_cursor`]: crate::EventCtx::set_cursor
pub fn clear_cursor(&mut self) {
trace!("clear_cursor");
self.widget_state.cursor_change = CursorChange::Default;
}
});
// methods on event, update and layout.
impl_context_method!(EventCtx<'_, '_>, UpdateCtx<'_, '_>, LayoutCtx<'_, '_>, {
/// Indicate that your [`ViewContext`] has changed.
///
/// This event is sent after layout is done and before paint is called. Note that you can still
/// receive this event even if there was no prior call to layout.
///
/// Widgets must call this method after changing the clip region of their children.
/// Changes to the other parts of [`ViewContext`] (cursor position and global origin) are tracked
/// internally.
///
/// [`ViewContext`]: crate::ViewContext
pub fn view_context_changed(&mut self) {
self.widget_state.view_context_changed = true;
}
});
// methods on event, update, and lifecycle
impl_context_method!(EventCtx<'_, '_>, UpdateCtx<'_, '_>, LifeCycleCtx<'_, '_>, {
/// Request a [`paint`] pass. This is equivalent to calling
/// [`request_paint_rect`] for the widget's [`paint_rect`].
///
/// [`paint`]: Widget::paint
/// [`request_paint_rect`]: #method.request_paint_rect
/// [`paint_rect`]: crate::WidgetPod::paint_rect
pub fn request_paint(&mut self) {
trace!("request_paint");
self.widget_state.invalid.set_rect(
self.widget_state.paint_rect() - self.widget_state.layout_rect().origin().to_vec2(),
);
}
/// Request a [`paint`] pass for redrawing a rectangle, which is given
/// relative to our layout rectangle.
///
/// [`paint`]: Widget::paint
pub fn request_paint_rect(&mut self, rect: Rect) {
trace!("request_paint_rect {}", rect);
self.widget_state.invalid.add_rect(rect);
}
/// Request a layout pass.
///
/// A Widget's [`layout`] method is always called when the widget tree
/// changes, or the window is resized.
///
/// If your widget would like to have layout called at any other time,
/// (such as if it would like to change the layout of children in
/// response to some event) it must call this method.
///
/// [`layout`]: Widget::layout
pub fn request_layout(&mut self) {
trace!("request_layout");
self.widget_state.needs_layout = true;
}
/// Request an [`AnimFrame`] event.
///
/// Receiving [`AnimFrame`] does not inherently mean a `paint` invocation will follow.
/// If you want something actually painted you need to explicitly call [`request_paint`]
/// or [`request_paint_rect`] when handling the [`AnimFrame`] event.
///
/// Note that not requesting paint when handling the [`AnimFrame`] event and then
/// recursively requesting another [`AnimFrame`] can lead to rapid event fire,
/// which is probably not what you want and would most likely be wasted compute cycles.
///
/// [`AnimFrame`]: crate::Event::AnimFrame
/// [`request_paint`]: #method.request_paint
/// [`request_paint_rect`]: #method.request_paint_rect
pub fn request_anim_frame(&mut self) {
trace!("request_anim_frame");
self.widget_state.request_anim = true;
}
/// Indicate that your children have changed.
///
/// Widgets must call this method after adding a new child, removing a child or changing which
/// children are hidden (see [`should_propagate_to_hidden`]).
///
/// [`should_propagate_to_hidden`]: crate::Event::should_propagate_to_hidden
pub fn children_changed(&mut self) {
trace!("children_changed");
self.widget_state.children_changed = true;
self.widget_state.update_focus_chain = true;
self.request_layout();
}
/// Set the disabled state for this widget.
///
/// Setting this to `false` does not mean a widget is not still disabled; for instance it may
/// still be disabled by an ancestor. See [`is_disabled`] for more information.
///
/// Calling this method during [`LifeCycle::DisabledChanged`] has no effect.
///
/// [`LifeCycle::DisabledChanged`]: crate::LifeCycle::DisabledChanged
/// [`is_disabled`]: EventCtx::is_disabled
pub fn set_disabled(&mut self, disabled: bool) {
// widget_state.children_disabled_changed is not set because we want to be able to delete
// changes that happened during DisabledChanged.
self.widget_state.is_explicitly_disabled_new = disabled;
}
/// Indicate that text input state has changed.
///
/// A widget that accepts text input should call this anytime input state
/// (such as the text or the selection) changes as a result of a non text-input
/// event.
pub fn invalidate_text_input(&mut self, event: ImeInvalidation) {
let payload = commands::ImeInvalidation {
widget: self.widget_id(),
event,
};
let cmd = commands::INVALIDATE_IME
.with(payload)
.to(Target::Window(self.window_id()));
self.submit_command(cmd);
}
/// Create a new sub-window.
///
/// The sub-window will have its app data synchronised with caller's nearest ancestor [`WidgetPod`].
/// 'U' must be the type of the nearest surrounding [`WidgetPod`]. The 'data' argument should be
/// the current value of data for that widget.
///
/// [`WidgetPod`]: crate::WidgetPod
// TODO - dynamically check that the type of the pod we are registering this on is the same as the type of the
// requirement. Needs type ids recorded. This goes wrong if you don't have a pod between you and a lens.
pub fn new_sub_window<W: Widget<U> + 'static, U: Data>(
&mut self,
window_config: WindowConfig,
widget: W,
data: U,
env: Env,
) -> WindowId {
trace!("new_sub_window");
let req = SubWindowDesc::new(self.widget_id(), window_config, widget, data, env);
let window_id = req.window_id;
self.widget_state
.add_sub_window_host(window_id, req.host_id);
self.submit_command(commands::NEW_SUB_WINDOW.with(SingleUse::new(req)));
window_id
}
/// Scrolls this widget into view.
///
/// If this widget is only partially visible or not visible at all because of [`Scroll`]s
/// it is wrapped in, they will do the minimum amount of scrolling necessary to bring this
/// widget fully into view.
///
/// If the widget is [`hidden`], this method has no effect.
///
/// This functionality is achieved by sending a [`SCROLL_TO_VIEW`] notification.
///
/// [`Scroll`]: crate::widget::Scroll
/// [`hidden`]: crate::Event::should_propagate_to_hidden
/// [`SCROLL_TO_VIEW`]: crate::commands::SCROLL_TO_VIEW
pub fn scroll_to_view(&mut self) {
self.scroll_area_to_view(self.size().to_rect())
}
});
// methods on everyone but paintctx
impl_context_method!(
EventCtx<'_, '_>,
UpdateCtx<'_, '_>,
LifeCycleCtx<'_, '_>,
LayoutCtx<'_, '_>,
{
/// Submit a [`Command`] to be run after this event is handled.
///
/// Commands are run in the order they are submitted; all commands
/// submitted during the handling of an event are executed before
/// the [`update`] method is called; events submitted during [`update`]
/// are handled after painting.
///
/// [`Target::Auto`] commands will be sent to the window containing the widget.
///
/// [`update`]: Widget::update
pub fn submit_command(&mut self, cmd: impl Into<Command>) {
trace!("submit_command");
self.state.submit_command(cmd.into())
}
/// Returns an [`ExtEventSink`] that can be moved between threads,
/// and can be used to submit commands back to the application.
pub fn get_external_handle(&self) -> ExtEventSink {
trace!("get_external_handle");
self.state.ext_handle.clone()
}
/// Request a timer event.
///
/// The return value is a token, which can be used to associate the
/// request with the event.
pub fn request_timer(&mut self, deadline: Duration) -> TimerToken {
trace!("request_timer deadline={:?}", deadline);
self.state.request_timer(self.widget_state.id, deadline)
}
}
);
impl EventCtx<'_, '_> {
/// Submit a [`Notification`].
///
/// The provided argument can be a [`Selector`] or a [`Command`]; this lets
/// us work with the existing API for adding a payload to a [`Selector`].
///
/// If the argument is a `Command`, the command's target will be ignored.
///
/// # Examples
///
/// ```
/// # use druid::{Event, EventCtx, Selector};
/// const IMPORTANT_EVENT: Selector<String> = Selector::new("druid-example.important-event");
///
/// fn check_event(ctx: &mut EventCtx, event: &Event) {
/// if is_this_the_event_we_were_looking_for(event) {
/// ctx.submit_notification(IMPORTANT_EVENT.with("That's the one".to_string()))
/// }
/// }
///
/// # fn is_this_the_event_we_were_looking_for(event: &Event) -> bool { true }
/// ```
///
/// [`Selector`]: crate::Selector
pub fn submit_notification(&mut self, note: impl Into<Command>) {
trace!("submit_notification");
let note = note.into().into_notification(self.widget_state.id);
self.notifications.push_back(note);
}
/// Submit a [`Notification`] without warning.
///
/// In contrast to [`submit_notification`], calling this method will not result in an
/// "unhandled notification" warning.
///
/// [`submit_notification`]: crate::EventCtx::submit_notification
pub fn submit_notification_without_warning(&mut self, note: impl Into<Command>) {
trace!("submit_notification");
let note = note
.into()
.into_notification(self.widget_state.id)
.warn_if_unused(false);
self.notifications.push_back(note);
}
/// Set the "active" state of the widget.
///
/// See [`EventCtx::is_active`](struct.EventCtx.html#method.is_active).
pub fn set_active(&mut self, active: bool) {
trace!("set_active({})", active);
self.widget_state.is_active = active;
// TODO: plumb mouse grab through to platform (through druid-shell)
}
/// Create a new window.
/// `T` must be the application's root `Data` type (the type provided to [`AppLauncher::launch`]).
///
/// [`AppLauncher::launch`]: crate::AppLauncher::launch
pub fn new_window<T: Any>(&mut self, desc: WindowDesc<T>) {
trace!("new_window");
if self.state.root_app_data_type == TypeId::of::<T>() {
self.submit_command(
commands::NEW_WINDOW
.with(SingleUse::new(Box::new(desc)))
.to(Target::Global),
);
} else {
debug_panic!("EventCtx::new_window<T> - T must match the application data type.");
}
}
/// Show the context menu in the window containing the current widget.
/// `T` must be the application's root `Data` type (the type provided to [`AppLauncher::launch`]).
///
/// [`AppLauncher::launch`]: crate::AppLauncher::launch
pub fn show_context_menu<T: Any>(&mut self, menu: Menu<T>, location: Point) {
trace!("show_context_menu");
if self.state.root_app_data_type == TypeId::of::<T>() {
let menu = ContextMenu { menu, location };
self.submit_command(
commands::SHOW_CONTEXT_MENU
.with(SingleUse::new(Box::new(menu)))
.to(Target::Window(self.state.window_id)),
);
} else {
debug_panic!(
"EventCtx::show_context_menu<T> - T must match the application data type."
);
}
}
/// Set the event as "handled", which stops its propagation to other
/// widgets.
pub fn set_handled(&mut self) {
trace!("set_handled");
self.is_handled = true;
}
/// Determine whether the event has been handled by some other widget.
pub fn is_handled(&self) -> bool {
self.is_handled
}
/// Request keyboard focus.
///
/// Because only one widget can be focused at a time, multiple focus requests
/// from different widgets during a single event cycle means that the last
/// widget that requests focus will override the previous requests.
///
/// See [`is_focused`] for more information about focus.
///
/// [`is_focused`]: struct.EventCtx.html#method.is_focused
pub fn request_focus(&mut self) {
trace!("request_focus");
// We need to send the request even if we're currently focused,
// because we may have a sibling widget that already requested focus
// and we have no way of knowing that yet. We need to override that
// to deliver on the "last focus request wins" promise.
let id = self.widget_id();
self.widget_state.request_focus = Some(FocusChange::Focus(id));
}
/// Transfer focus to the widget with the given `WidgetId`.
///
/// See [`is_focused`] for more information about focus.
///
/// [`is_focused`]: struct.EventCtx.html#method.is_focused
pub fn set_focus(&mut self, target: WidgetId) {
trace!("set_focus target={:?}", target);
self.widget_state.request_focus = Some(FocusChange::Focus(target));
}
/// Transfer focus to the next focusable widget.
///
/// This should only be called by a widget that currently has focus.
///
/// See [`is_focused`] for more information about focus.
///
/// [`is_focused`]: struct.EventCtx.html#method.is_focused
pub fn focus_next(&mut self) {
trace!("focus_next");
if self.has_focus() {
self.widget_state.request_focus = Some(FocusChange::Next);
} else {
warn!(
"focus_next can only be called by the currently \
focused widget or one of its ancestors."
);
}
}
/// Transfer focus to the previous focusable widget.
///
/// This should only be called by a widget that currently has focus.
///
/// See [`is_focused`] for more information about focus.
///
/// [`is_focused`]: struct.EventCtx.html#method.is_focused
pub fn focus_prev(&mut self) {
trace!("focus_prev");
if self.has_focus() {
self.widget_state.request_focus = Some(FocusChange::Previous);
} else {
warn!(
"focus_prev can only be called by the currently \
focused widget or one of its ancestors."
);
}
}
/// Give up focus.
///
/// This should only be called by a widget that currently has focus.
///
/// See [`is_focused`] for more information about focus.
///
/// [`is_focused`]: struct.EventCtx.html#method.is_focused
pub fn resign_focus(&mut self) {
trace!("resign_focus");
if self.has_focus() {
self.widget_state.request_focus = Some(FocusChange::Resign);
} else {
warn!(
"resign_focus can only be called by the currently focused widget \
or one of its ancestors. ({:?})",
self.widget_id()
);
}
}
/// Request an update cycle.
///
/// After this, `update` will be called on the widget in the next update cycle, even
/// if there's not a data change.
///
/// The use case for this method is when a container widget synthesizes data for its
/// children. This is appropriate in specialized cases, but before reaching for this
/// method, consider whether it might be better to refactor to be more idiomatic, in
/// particular to make that data available in the app state.
pub fn request_update(&mut self) {
trace!("request_update");
self.widget_state.request_update = true;
}
/// Scrolls the area into view.
///
/// If the area is only partially visible or not visible at all because of [`Scroll`]s
/// this widget is wrapped in, they will do the minimum amount of scrolling necessary to
/// bring the area fully into view.
///
/// If the widget is [`hidden`], this method has no effect.
///
/// [`Scroll`]: crate::widget::Scroll
/// [`hidden`]: crate::Event::should_propagate_to_hidden
pub fn scroll_area_to_view(&mut self, area: Rect) {
//TODO: only do something if this widget is not hidden
self.submit_notification_without_warning(
SCROLL_TO_VIEW.with(area + self.window_origin().to_vec2()),
);
}
}
impl UpdateCtx<'_, '_> {
/// Returns `true` if this widget or a descendent as explicitly requested
/// an update call.
///
/// This should only be needed in advanced cases;
/// see [`EventCtx::request_update`] for more information.
///
/// [`EventCtx::request_update`]: EventCtx::request_update
pub fn has_requested_update(&mut self) -> bool {
self.widget_state.request_update
}
/// Returns `true` if the current [`Env`] has changed since the previous
/// [`update`] call.
///
/// [`update`]: Widget::update
pub fn env_changed(&self) -> bool {
self.prev_env.is_some()
}
/// Returns `true` if the given key has changed since the last [`update`]
/// call.
///
/// The argument can be anything that is resolveable from the [`Env`],
/// such as a [`Key`] or a [`KeyOrValue`].
///
/// [`update`]: Widget::update
/// [`Key`]: crate::Key
/// [`KeyOrValue`]: crate::KeyOrValue
pub fn env_key_changed<T>(&self, key: &impl KeyLike<T>) -> bool {
match self.prev_env.as_ref() {
Some(prev) => key.changed(prev, self.env),
None => false,
}
}
/// Scrolls the area into view.
///
/// If the area is only partially visible or not visible at all because of [`Scroll`]s
/// this widget is wrapped in, they will do the minimum amount of scrolling necessary to
/// bring the area fully into view.
///
/// If the widget is [`hidden`], this method has no effect.
///
/// [`Scroll`]: crate::widget::Scroll
/// [`hidden`]: crate::Event::should_propagate_to_hidden
pub fn scroll_area_to_view(&mut self, area: Rect) {
//TODO: only do something if this widget is not hidden
self.submit_command(Command::new(
SCROLL_TO_VIEW,
area + self.window_origin().to_vec2(),
self.widget_id(),
));
}
}
impl LifeCycleCtx<'_, '_> {
/// Registers a child widget.
///
/// This should only be called in response to a `LifeCycle::WidgetAdded` event.
///
/// In general, you should not need to call this method; it is handled by
/// the `WidgetPod`.
pub fn register_child(&mut self, child_id: WidgetId) {
trace!("register_child id={:?}", child_id);
self.widget_state.children.add(&child_id);
}
/// Register this widget to be eligible to accept focus automatically.
///
/// This should only be called in response to a [`LifeCycle::BuildFocusChain`] event.
///
/// See [`EventCtx::is_focused`] for more information about focus.
///
/// [`LifeCycle::BuildFocusChain`]: crate::LifeCycle::BuildFocusChain
/// [`EventCtx::is_focused`]: EventCtx::is_focused
pub fn register_for_focus(&mut self) {
trace!("register_for_focus");
self.widget_state.focus_chain.push(self.widget_id());
}
/// Register this widget as accepting text input.
pub fn register_text_input(&mut self, document: impl ImeHandlerRef + 'static) {
let registration = TextFieldRegistration {
document: Rc::new(document),
widget_id: self.widget_id(),
};
self.state.text_registrations.push(registration);
}
/// Scrolls the area into view.
///
/// If the area is only partially visible or not visible at all because of [`Scroll`]s
/// this widget is wrapped in, they will do the minimum amount of scrolling necessary to
/// bring the area fully into view.
///
/// If the widget is [`hidden`], this method has no effect.
///
/// [`Scroll`]: crate::widget::Scroll
/// [`hidden`]: crate::Event::should_propagate_to_hidden
pub fn scroll_area_to_view(&mut self, area: Rect) {
//TODO: only do something if this widget is not hidden
self.submit_command(
SCROLL_TO_VIEW
.with(area + self.window_origin().to_vec2())
.to(self.widget_id()),
);
}
}
impl<'a, 'b> LayoutCtx<'a, 'b> {
/// Set explicit paint [`Insets`] for this widget.
///
/// You are not required to set explicit paint bounds unless you need
/// to paint outside of your layout bounds. In this case, the argument
/// should be an [`Insets`] struct that indicates where your widget
/// needs to overpaint, relative to its bounds.
///
/// For more information, see [`WidgetPod::paint_insets`].
///
/// [`WidgetPod::paint_insets`]: crate::WidgetPod::paint_insets
pub fn set_paint_insets(&mut self, insets: impl Into<Insets>) {
let insets = insets.into();
trace!("set_paint_insets {:?}", insets);
self.widget_state.paint_insets = insets.nonnegative();
}
/// Set an explicit baseline position for this widget.
///
/// The baseline position is used to align widgets that contain text,
/// such as buttons, labels, and other controls. It may also be used
/// by other widgets that are opinionated about how they are aligned
/// relative to neighbouring text, such as switches or checkboxes.
///
/// The provided value should be the distance from the *bottom* of the
/// widget to the baseline.
pub fn set_baseline_offset(&mut self, baseline: f64) {
trace!("set_baseline_offset {}", baseline);
self.widget_state.baseline_offset = baseline
}
}
impl PaintCtx<'_, '_, '_> {
/// The depth in the tree of the currently painting widget.
///
/// This may be used in combination with [`paint_with_z_index`] in order
/// to correctly order painting operations.
///
/// The `depth` here may not be exact; it is only guaranteed that a child will
/// have a greater depth than its parent.
///
/// [`paint_with_z_index`]: #method.paint_with_z_index
#[inline]
pub fn depth(&self) -> u32 {
self.depth
}
/// Returns the region that needs to be repainted.
#[inline]
pub fn region(&self) -> &Region {
&self.region
}
/// Creates a temporary `PaintCtx` with a new visible region, and calls
/// the provided function with that `PaintCtx`.
///
/// This is used by containers to ensure that their children have the correct
/// visible region given their layout.
pub fn with_child_ctx(&mut self, region: impl Into<Region>, f: impl FnOnce(&mut PaintCtx)) {
let mut child_ctx = PaintCtx {
render_ctx: self.render_ctx,
state: self.state,
widget_state: self.widget_state,
z_ops: Vec::new(),
region: region.into(),
depth: self.depth + 1,
};
f(&mut child_ctx);
self.z_ops.append(&mut child_ctx.z_ops);
}
/// Saves the current context, executes the closures, and restores the context.
///
/// This is useful if you would like to transform or clip or otherwise
/// modify the drawing context but do not want that modification to
/// effect other widgets.
///
/// # Examples
///
/// ```
/// # use druid::{Env, PaintCtx, RenderContext, theme};
/// # struct T;
/// # impl T {
/// fn paint(&mut self, ctx: &mut PaintCtx, _data: &T, env: &Env) {
/// let clip_rect = ctx.size().to_rect().inset(5.0);
/// ctx.with_save(|ctx| {
/// ctx.clip(clip_rect);
/// ctx.stroke(clip_rect, &env.get(theme::PRIMARY_DARK), 5.0);
/// });
/// }
/// # }
/// ```
pub fn with_save(&mut self, f: impl FnOnce(&mut PaintCtx)) {
if let Err(e) = self.render_ctx.save() {
error!("Failed to save RenderContext: '{}'", e);
return;
}
f(self);
if let Err(e) = self.render_ctx.restore() {
error!("Failed to restore RenderContext: '{}'", e);
}
}
/// Allows to specify order for paint operations.
///
/// Larger `z_index` indicate that an operation will be executed later.
pub fn paint_with_z_index(
&mut self,
z_index: u32,
paint_func: impl FnOnce(&mut PaintCtx) + 'static,
) {
let current_transform = self.render_ctx.current_transform();
self.z_ops.push(ZOrderPaintOp {
z_index,
paint_func: Box::new(paint_func),
transform: current_transform,
})
}
}
impl<'a> ContextState<'a> {
pub(crate) fn new<T: 'static>(
command_queue: &'a mut CommandQueue,
ext_handle: &'a ExtEventSink,
window: &'a WindowHandle,
window_id: WindowId,
focus_widget: Option<WidgetId>,
timers: &'a mut HashMap<TimerToken, WidgetId>,
text_registrations: &'a mut Vec<TextFieldRegistration>,
) -> Self {
ContextState {
command_queue,
ext_handle,
window,
window_id,
focus_widget,
timers,
text_registrations,
text: window.text(),
root_app_data_type: TypeId::of::<T>(),
}
}
fn submit_command(&mut self, command: Command) {
trace!("submit_command");
self.command_queue
.push_back(command.default_to(self.window_id.into()));
}
fn request_timer(&mut self, widget_id: WidgetId, deadline: Duration) -> TimerToken {
trace!("request_timer deadline={:?}", deadline);
let timer_token = self.window.request_timer(deadline);
self.timers.insert(timer_token, widget_id);
timer_token
}
}
impl<'c> Deref for PaintCtx<'_, '_, 'c> {
type Target = Piet<'c>;
fn deref(&self) -> &Self::Target {
self.render_ctx
}
}
impl<'c> DerefMut for PaintCtx<'_, '_, 'c> {
fn deref_mut(&mut self) -> &mut Self::Target {
self.render_ctx
}
}