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// Copyright 2019 The xi-editor 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. //! Events. use crate::kurbo::{Rect, Shape, Size, Vec2}; use druid_shell::{Clipboard, KeyEvent, TimerToken}; use crate::mouse::MouseEvent; use crate::{Command, Target, WidgetId}; /// An event, propagated downwards during event flow. /// /// Events are things that happen that can change the state of widgets. /// An important category is events plumbed from the platform windowing /// system, which includes mouse and keyboard events, but also (in the /// future) status changes such as window focus changes. /// /// Events can also be higher level concepts indicating state changes /// within the widget hierarchy, for example when a widget gains or loses /// focus or "hot" (also known as hover) status. /// /// Events are a key part of what is called "event flow", which is /// basically the propagation of an event through the widget hierarchy /// through the [`event`] widget method. A container widget will /// generally pass the event to its children, mediated through the /// [`WidgetPod`] container, which is where most of the event flow logic /// is applied (especially the decision whether or not to propagate). /// /// This enum is expected to grow considerably, as there are many, many /// different kinds of events that are relevant in a GUI. /// /// [`event`]: trait.Widget.html#tymethod.event /// [`WidgetPod`]: struct.WidgetPod.html #[derive(Debug, Clone)] pub enum Event { /// Sent to all widgets in a given window when that window is first instantiated. /// /// This should always be the first `Event` received, although widgets will /// receive [`LifeCycle::WidgetAdded`] first. /// /// Widgets should handle this event if they need to do some addition setup /// when a window is first created. /// /// [`LifeCycle::WidgetAdded`]: enum.LifeCycle.html#variant.WidgetAdded WindowConnected, /// Called on the root widget when the window size changes. /// /// Discussion: it's not obvious this should be propagated to user /// widgets. It *is* propagated through the RootWidget and handled /// in the WindowPod, but after that it might be considered better /// to just handle it in `layout`. WindowSize(Size), /// Called when a mouse button is pressed. MouseDown(MouseEvent), /// Called when a mouse button is released. MouseUp(MouseEvent), /// Called when the mouse is moved. /// /// The `MouseMove` event is propagated to the active widget, if /// there is one, otherwise to hot widgets (see `HotChanged`). /// If a widget loses its hot status due to `MouseMove` then that specific /// `MouseMove` event is also still sent to that widget. /// /// The `MouseMove` event is also the primary mechanism for widgets /// to set a cursor, for example to an I-bar inside a text widget. A /// simple tactic is for the widget to unconditionally call /// [`set_cursor`] in the MouseMove handler, as `MouseMove` is only /// propagated to active or hot widgets. /// /// [`set_cursor`]: struct.EventCtx.html#method.set_cursor MouseMove(MouseEvent), /// Called when the mouse wheel or trackpad is scrolled. Wheel(MouseEvent), /// Called when a key is pressed. /// /// Note: the intent is for each physical key press to correspond to /// a single `KeyDown` event. This is sometimes different than the /// raw events provided by the platform. In particular, Windows sends /// one or both of WM_KEYDOWN (a raw key code) and WM_CHAR (the /// Unicode value), depending on the actual key. KeyDown(KeyEvent), /// Called when a key is released. /// /// Because of repeat, there may be a number `KeyDown` events before /// a corresponding `KeyUp` is sent. KeyUp(KeyEvent), /// Called when a paste command is received. Paste(Clipboard), /// Called when the trackpad is pinched. /// /// The value is a delta. Zoom(f64), /// Called on a timer event. /// /// Request a timer event through [`EventCtx::request_timer()`]. That will /// cause a timer event later. /// /// Note that timer events from other widgets may be delivered as well. Use /// the token returned from the `request_timer()` call to filter events more /// precisely. /// /// [`EventCtx::request_timer()`]: struct.EventCtx.html#method.request_timer Timer(TimerToken), /// Called with an arbitrary [`Command`], submitted from elsewhere in /// the application. /// /// Commands can be issued when the user triggers a menu item or an /// application-level hotkey, or they can be created dynamically by /// [`Widget`]s, at runtime, with [`EventCtx::submit_command`]. /// /// [`Command`]: struct.Command.html /// [`Widget`]: trait.Widget.html /// [`EventCtx::submit_command`]: struct.EventCtx.html#method.submit_command Command(Command), /// Internal druid event. /// /// This should always be passed down to descendant [`WidgetPod`]s. /// /// [`WidgetPod`]: struct.WidgetPod.html Internal(InternalEvent), } /// Internal events used by druid inside [`WidgetPod`]. /// /// These events are translated into regular [`Event`]s /// and should not be used directly. /// /// [`WidgetPod`]: struct.WidgetPod.html /// [`Event`]: enum.Event.html #[derive(Debug, Clone)] pub enum InternalEvent { /// Sent in some cases when the mouse has left the window. /// /// This is used in cases when the platform no longer sends mouse events, /// but we know that we've stopped receiving the mouse events. MouseLeave, /// A command still in the process of being dispatched. TargetedCommand(Target, Command), /// Used for routing timer events. RouteTimer(TimerToken, WidgetId), } /// Application life cycle events. #[derive(Debug, Clone)] pub enum LifeCycle { /// Sent to a `Widget` when it is added to the widget tree. This should be /// the first message that each widget receives. /// /// Widgets should handle this event in order to do any initial setup. /// /// In addition to setup, this event is also used by the framework to /// track certain types of important widget state. /// /// ## Registering children /// /// Container widgets (widgets which use [`WidgetPod`] to manage children) /// must ensure that this event is forwarded to those children. The [`WidgetPod`] /// itself will handle registering those children with the system; this is /// required for things like correct routing of events. /// /// ## Participating in focus /// /// Widgets which wish to participate in automatic focus (using tab to change /// focus) must handle this event and call [`LifeCycleCtx::register_for_focus`]. /// /// [`LifeCycleCtx::register_child`]: struct.LifeCycleCtx.html#method.register_child /// [`WidgetPod`]: struct.WidgetPod.html /// [`LifeCycleCtx::register_for_focus`]: struct.LifeCycleCtx.html#method.register_for_focus WidgetAdded, /// Called when the size of the widget changes. /// /// The [`Size`] is derived from the [`Rect`] that was set with [`WidgetPod::set_layout_rect`]. /// /// [`Size`]: struct.Size.html /// [`Rect`]: struct.Rect.html /// [`WidgetPod::set_layout_rect`]: struct.WidgetPod.html#method.set_layout_rect Size(Size), /// Called at the beginning of a new animation frame. /// /// On the first frame when transitioning from idle to animating, `interval` /// will be 0. (This logic is presently per-window but might change to /// per-widget to make it more consistent). Otherwise it is in nanoseconds. AnimFrame(u64), /// Called when the "hot" status changes. /// /// This will always be called _before_ the event that triggered it; that is, /// when the mouse moves over a widget, that widget will receive /// `LifeCycle::HotChanged` before it receives `Event::MouseMove`. /// /// See [`is_hot`](struct.EventCtx.html#method.is_hot) for /// discussion about the hot status. HotChanged(bool), /// Called when the focus status changes. /// /// This will always be called immediately after a new widget gains focus. /// The newly focused widget will receive this with `true` and the widget /// that lost focus will receive this with `false`. /// /// See [`EventCtx::is_focused`] for more information about focus. /// /// [`EventCtx::is_focused`]: struct.EventCtx.html#method.is_focused FocusChanged(bool), /// Internal druid lifecycle event. /// /// This should always be passed down to descendant [`WidgetPod`]s. /// /// [`WidgetPod`]: struct.WidgetPod.html Internal(InternalLifeCycle), } /// Internal lifecycle events used by druid inside [`WidgetPod`]. /// /// These events are translated into regular [`LifeCycle`] events /// and should not be used directly. /// /// [`WidgetPod`]: struct.WidgetPod.html /// [`LifeCycle`]: enum.LifeCycle.html #[derive(Debug, Clone)] pub enum InternalLifeCycle { /// Used to route the `WidgetAdded` event to the required widgets. RouteWidgetAdded, /// Used to route the `FocusChanged` event. RouteFocusChanged { /// the widget that is losing focus, if any old: Option<WidgetId>, /// the widget that is gaining focus, if any new: Option<WidgetId>, }, /// Testing only: request the `WidgetState` of a specific widget. /// /// During testing, you may wish to verify that the state of a widget /// somewhere in the tree is as expected. In that case you can dispatch /// this event, specifying the widget in question, and that widget will /// set its state in the provided `Cell`, if it exists. #[cfg(test)] DebugRequestState { widget: WidgetId, state_cell: StateCell, }, #[cfg(test)] DebugInspectState(StateCheckFn), } impl Event { /// Transform the event for the contents of a scrolling container. /// /// the `force` flag is used to ensure an event is delivered even /// if the cursor is out of the viewport, such as if the contents are active /// or hot. pub fn transform_scroll(&self, offset: Vec2, viewport: Rect, force: bool) -> Option<Event> { match self { Event::MouseDown(mouse_event) => { if force || viewport.winding(mouse_event.pos) != 0 { let mut mouse_event = mouse_event.clone(); mouse_event.pos += offset; Some(Event::MouseDown(mouse_event)) } else { None } } Event::MouseUp(mouse_event) => { if force || viewport.winding(mouse_event.pos) != 0 { let mut mouse_event = mouse_event.clone(); mouse_event.pos += offset; Some(Event::MouseUp(mouse_event)) } else { None } } Event::MouseMove(mouse_event) => { if force || viewport.winding(mouse_event.pos) != 0 { let mut mouse_event = mouse_event.clone(); mouse_event.pos += offset; Some(Event::MouseMove(mouse_event)) } else { None } } Event::Wheel(mouse_event) => { if force || viewport.winding(mouse_event.pos) != 0 { let mut mouse_event = mouse_event.clone(); mouse_event.pos += offset; Some(Event::Wheel(mouse_event)) } else { None } } _ => Some(self.clone()), } } } #[cfg(test)] pub(crate) use state_cell::{StateCell, StateCheckFn}; #[cfg(test)] mod state_cell { use crate::core::WidgetState; use crate::WidgetId; use std::{cell::RefCell, rc::Rc}; /// An interior-mutable struct for fetching BasteState. #[derive(Clone, Default)] pub struct StateCell(Rc<RefCell<Option<WidgetState>>>); #[derive(Clone)] pub struct StateCheckFn(Rc<dyn Fn(&WidgetState)>); /// a hacky way of printing the widget id if we panic struct WidgetDrop(bool, WidgetId); impl Drop for WidgetDrop { fn drop(&mut self) { if self.0 { eprintln!("panic in {:?}", self.1); } } } impl StateCell { /// Set the state. This will panic if it is called twice. pub(crate) fn set(&self, state: WidgetState) { assert!( self.0.borrow_mut().replace(state).is_none(), "StateCell already set" ) } #[allow(dead_code)] pub(crate) fn take(&self) -> Option<WidgetState> { self.0.borrow_mut().take() } } impl StateCheckFn { #[cfg(not(target_arch = "wasm32"))] pub(crate) fn new(f: impl Fn(&WidgetState) + 'static) -> Self { StateCheckFn(Rc::new(f)) } pub(crate) fn call(&self, state: &WidgetState) { let mut panic_reporter = WidgetDrop(true, state.id); (self.0)(&state); panic_reporter.0 = false; } } impl std::fmt::Debug for StateCell { fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result { let inner = if self.0.borrow().is_some() { "Some" } else { "None" }; write!(f, "StateCell({})", inner) } } impl std::fmt::Debug for StateCheckFn { fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result { write!(f, "StateCheckFn") } } }