use crate::Empty;use crate::{ seal::Sealed, AnyElement, AnyModel, AnyWeakModel, AppContext, Bounds, ContentMask, Element, ElementId, Entity, EntityId, Flatten, FocusHandle, FocusableView, GlobalElementId, IntoElement, LayoutId, Model, PaintIndex, Pixels, PrepaintStateIndex, Render, Style, StyleRefinement, TextStyle, ViewContext, VisualContext, WeakModel, WindowContext,};use anyhow::{Context, Result};use refineable::Refineable;use std::mem;use std::{ any::{type_name, TypeId}, fmt, hash::{Hash, Hasher}, ops::Range,}; /// A view is a piece of state that can be presented on screen by implementing the [Render] trait./// Views implement [Element] and can composed with other views, and every window is created with a root view.pub struct View<V> { /// A view is just a [Model] whose type implements `Render`, and the model is accessible via this field. pub model: Model<V>,} impl<V> Sealed for View<V> {} struct AnyViewState { prepaint_range: Range<PrepaintStateIndex>, paint_range: Range<PaintIndex>, cache_key: ViewCacheKey,} #[derive(Default)]struct ViewCacheKey { bounds: Bounds<Pixels>, content_mask: ContentMask<Pixels>, text_style: TextStyle,} impl<V: 'static> Entity<V> for View<V> { type Weak = WeakView<V>; fn entity_id(&self) -> EntityId { self.model.entity_id } fn downgrade(&self) -> Self::Weak { WeakView { model: self.model.downgrade(), } } fn upgrade_from(weak: &Self::Weak) -> Option<Self> where Self: Sized, { let model = weak.model.upgrade()?; Some(View { model }) }} impl<V: 'static> View<V> { /// Convert this strong view reference into a weak view reference. pub fn downgrade(&self) -> WeakView<V> { Entity::downgrade(self) } /// Updates the view's state with the given function, which is passed a mutable reference and a context. pub fn update<C, R>( &self, cx: &mut C, f: impl FnOnce(&mut V, &mut ViewContext<V>) -> R, ) -> C::Result<R> where C: VisualContext, { cx.update_view(self, f) } /// Obtain a read-only reference to this view's state. pub fn read<'a>(&self, cx: &'a AppContext) -> &'a V { self.model.read(cx) } /// Gets a [FocusHandle] for this view when its state implements [FocusableView]. pub fn focus_handle(&self, cx: &AppContext) -> FocusHandle where V: FocusableView, { self.read(cx).focus_handle(cx) }} impl<V: Render> Element for View<V> { type RequestLayoutState = AnyElement; type PrepaintState = (); fn id(&self) -> Option<ElementId> { Some(ElementId::View(self.entity_id())) } fn request_layout( &mut self, _id: Option<&GlobalElementId>, cx: &mut WindowContext, ) -> (LayoutId, Self::RequestLayoutState) { let mut element = self.update(cx, |view, cx| view.render(cx).into_any_element()); let layout_id = element.request_layout(cx); (layout_id, element) } fn prepaint( &mut self, _id: Option<&GlobalElementId>, _: Bounds<Pixels>, element: &mut Self::RequestLayoutState, cx: &mut WindowContext, ) { cx.set_view_id(self.entity_id()); element.prepaint(cx); } fn paint( &mut self, _id: Option<&GlobalElementId>, _: Bounds<Pixels>, element: &mut Self::RequestLayoutState, _: &mut Self::PrepaintState, cx: &mut WindowContext, ) { element.paint(cx); }} impl<V> Clone for View<V> { fn clone(&self) -> Self { Self { model: self.model.clone(), } }} impl<T> std::fmt::Debug for View<T> { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { f.debug_struct(&format!("View<{}>", type_name::<T>())) .field("entity_id", &self.model.entity_id) .finish_non_exhaustive() }} impl<V> Hash for View<V> { fn hash<H: Hasher>(&self, state: &mut H) { self.model.hash(state); }} impl<V> PartialEq for View<V> { fn eq(&self, other: &Self) -> bool { self.model == other.model }} impl<V> Eq for View<V> {} /// A weak variant of [View] which does not prevent the view from being released.pub struct WeakView<V> { pub(crate) model: WeakModel<V>,} impl<V: 'static> WeakView<V> { /// Gets the entity id associated with this handle. pub fn entity_id(&self) -> EntityId { self.model.entity_id } /// Obtain a strong handle for the view if it hasn't been released. pub fn upgrade(&self) -> Option<View<V>> { Entity::upgrade_from(self) } /// Updates this view's state if it hasn't been released. /// Returns an error if this view has been released. pub fn update<C, R>( &self, cx: &mut C, f: impl FnOnce(&mut V, &mut ViewContext<V>) -> R, ) -> Result<R> where C: VisualContext, Result<C::Result<R>>: Flatten<R>, { let view = self.upgrade().context("error upgrading view")?; Ok(view.update(cx, f)).flatten() } /// Assert that the view referenced by this handle has been released. #[cfg(any(test, feature = "test-support"))] pub fn assert_released(&self) { self.model.assert_released() }} impl<V> Clone for WeakView<V> { fn clone(&self) -> Self { Self { model: self.model.clone(), } }} impl<V> Hash for WeakView<V> { fn hash<H: Hasher>(&self, state: &mut H) { self.model.hash(state); }} impl<V> PartialEq for WeakView<V> { fn eq(&self, other: &Self) -> bool { self.model == other.model }} impl<V> Eq for WeakView<V> {} /// A dynamically-typed handle to a view, which can be downcast to a [View] for a specific type.#[derive(Clone, Debug)]pub struct AnyView { model: AnyModel, render: fn(&AnyView, &mut WindowContext) -> AnyElement, cached_style: Option<StyleRefinement>,} impl AnyView { /// Indicate that this view should be cached when using it as an element. /// When using this method, the view's previous layout and paint will be recycled from the previous frame if [ViewContext::notify] has not been called since it was rendered. /// The one exception is when [WindowContext::refresh] is called, in which case caching is ignored. pub fn cached(mut self, style: StyleRefinement) -> Self { self.cached_style = Some(style); self } /// Convert this to a weak handle. pub fn downgrade(&self) -> AnyWeakView { AnyWeakView { model: self.model.downgrade(), render: self.render, } } /// Convert this to a [View] of a specific type. /// If this handle does not contain a view of the specified type, returns itself in an `Err` variant. pub fn downcast<T: 'static>(self) -> Result<View<T>, Self> { match self.model.downcast() { Ok(model) => Ok(View { model }), Err(model) => Err(Self { model, render: self.render, cached_style: self.cached_style, }), } } /// Gets the [TypeId] of the underlying view. pub fn entity_type(&self) -> TypeId { self.model.entity_type } /// Gets the entity id of this handle. pub fn entity_id(&self) -> EntityId { self.model.entity_id() }} impl<V: Render> From<View<V>> for AnyView { fn from(value: View<V>) -> Self { AnyView { model: value.model.into_any(), render: any_view::render::<V>, cached_style: None, } }} impl PartialEq for AnyView { fn eq(&self, other: &Self) -> bool { self.model == other.model }} impl Eq for AnyView {} impl Element for AnyView { type RequestLayoutState = Option<AnyElement>; type PrepaintState = Option<AnyElement>; fn id(&self) -> Option<ElementId> { Some(ElementId::View(self.entity_id())) } fn request_layout( &mut self, _id: Option<&GlobalElementId>, cx: &mut WindowContext, ) -> (LayoutId, Self::RequestLayoutState) { if let Some(style) = self.cached_style.as_ref() { let mut root_style = Style::default(); root_style.refine(style); let layout_id = cx.request_layout(root_style, None); (layout_id, None) } else { let mut element = (self.render)(self, cx); let layout_id = element.request_layout(cx); (layout_id, Some(element)) } } fn prepaint( &mut self, global_id: Option<&GlobalElementId>, bounds: Bounds<Pixels>, element: &mut Self::RequestLayoutState, cx: &mut WindowContext, ) -> Option<AnyElement> { cx.set_view_id(self.entity_id()); if self.cached_style.is_some() { cx.with_element_state::<AnyViewState, _>(global_id.unwrap(), |element_state, cx| { let content_mask = cx.content_mask(); let text_style = cx.text_style(); if let Some(mut element_state) = element_state { if element_state.cache_key.bounds == bounds && element_state.cache_key.content_mask == content_mask && element_state.cache_key.text_style == text_style && !cx.window.dirty_views.contains(&self.entity_id()) && !cx.window.refreshing { let prepaint_start = cx.prepaint_index(); cx.reuse_prepaint(element_state.prepaint_range.clone()); let prepaint_end = cx.prepaint_index(); element_state.prepaint_range = prepaint_start..prepaint_end; return (None, element_state); } } let refreshing = mem::replace(&mut cx.window.refreshing, true); let prepaint_start = cx.prepaint_index(); let mut element = (self.render)(self, cx); element.layout_as_root(bounds.size.into(), cx); element.prepaint_at(bounds.origin, cx); let prepaint_end = cx.prepaint_index(); cx.window.refreshing = refreshing; ( Some(element), AnyViewState { prepaint_range: prepaint_start..prepaint_end, paint_range: PaintIndex::default()..PaintIndex::default(), cache_key: ViewCacheKey { bounds, content_mask, text_style, }, }, ) }) } else { let mut element = element.take().unwrap(); element.prepaint(cx); Some(element) } } fn paint( &mut self, global_id: Option<&GlobalElementId>, _bounds: Bounds<Pixels>, _: &mut Self::RequestLayoutState, element: &mut Self::PrepaintState, cx: &mut WindowContext, ) { if self.cached_style.is_some() { cx.with_element_state::<AnyViewState, _>(global_id.unwrap(), |element_state, cx| { let mut element_state = element_state.unwrap(); let paint_start = cx.paint_index(); if let Some(element) = element { let refreshing = mem::replace(&mut cx.window.refreshing, true); element.paint(cx); cx.window.refreshing = refreshing; } else { cx.reuse_paint(element_state.paint_range.clone()); } let paint_end = cx.paint_index(); element_state.paint_range = paint_start..paint_end; ((), element_state) }) } else { element.as_mut().unwrap().paint(cx); } }} impl<V: 'static + Render> IntoElement for View<V> { type Element = View<V>; fn into_element(self) -> Self::Element { self }} impl IntoElement for AnyView { type Element = Self; fn into_element(self) -> Self::Element { self }} /// A weak, dynamically-typed view handle that does not prevent the view from being released.pub struct AnyWeakView { model: AnyWeakModel, render: fn(&AnyView, &mut WindowContext) -> AnyElement,} impl AnyWeakView { /// Convert to a strongly-typed handle if the referenced view has not yet been released. pub fn upgrade(&self) -> Option<AnyView> { let model = self.model.upgrade()?; Some(AnyView { model, render: self.render, cached_style: None, }) }} impl<V: 'static + Render> From<WeakView<V>> for AnyWeakView { fn from(view: WeakView<V>) -> Self { Self { model: view.model.into(), render: any_view::render::<V>, } }} impl PartialEq for AnyWeakView { fn eq(&self, other: &Self) -> bool { self.model == other.model }} impl std::fmt::Debug for AnyWeakView { fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { f.debug_struct("AnyWeakView") .field("entity_id", &self.model.entity_id) .finish_non_exhaustive() }} mod any_view { use crate::{AnyElement, AnyView, IntoElement, Render, WindowContext}; pub(crate) fn render<V: 'static + Render>( view: &AnyView, cx: &mut WindowContext, ) -> AnyElement { let view = view.clone().downcast::<V>().unwrap(); view.update(cx, |view, cx| view.render(cx).into_any_element()) }} /// A view that renders nothingpub struct EmptyView; impl Render for EmptyView { fn render(&mut self, _cx: &mut ViewContext<Self>) -> impl IntoElement { Empty }}
use crate::Empty;
use crate::{
seal::Sealed, AnyElement, AnyModel, AnyWeakModel, AppContext, Bounds, ContentMask, Element,
ElementId, Entity, EntityId, Flatten, FocusHandle, FocusableView, GlobalElementId, IntoElement,
LayoutId, Model, PaintIndex, Pixels, PrepaintStateIndex, Render, Style, StyleRefinement,
TextStyle, ViewContext, VisualContext, WeakModel, WindowContext,
};
use anyhow::{Context, Result};
use refineable::Refineable;
use std::mem;
use std::{
any::{type_name, TypeId},
fmt,
hash::{Hash, Hasher},
ops::Range,
};
/// A view is a piece of state that can be presented on screen by implementing the [Render] trait.
/// Views implement [Element] and can composed with other views, and every window is created with a root view.
pub struct View<V> {
/// A view is just a [Model] whose type implements `Render`, and the model is accessible via this field.
pub model: Model<V>,
}
impl<V> Sealed for View<V> {}
struct AnyViewState {
prepaint_range: Range<PrepaintStateIndex>,
paint_range: Range<PaintIndex>,
cache_key: ViewCacheKey,
}
#[derive(Default)]
struct ViewCacheKey {
bounds: Bounds<Pixels>,
content_mask: ContentMask<Pixels>,
text_style: TextStyle,
}
impl<V: 'static> Entity<V> for View<V> {
type Weak = WeakView<V>;
fn entity_id(&self) -> EntityId {
self.model.entity_id
}
fn downgrade(&self) -> Self::Weak {
WeakView {
model: self.model.downgrade(),
}
}
fn upgrade_from(weak: &Self::Weak) -> Option<Self>
where
Self: Sized,
{
let model = weak.model.upgrade()?;
Some(View { model })
}
}
impl<V: 'static> View<V> {
/// Convert this strong view reference into a weak view reference.
pub fn downgrade(&self) -> WeakView<V> {
Entity::downgrade(self)
}
/// Updates the view's state with the given function, which is passed a mutable reference and a context.
pub fn update<C, R>(
&self,
cx: &mut C,
f: impl FnOnce(&mut V, &mut ViewContext<V>) -> R,
) -> C::Result<R>
where
C: VisualContext,
{
cx.update_view(self, f)
}
/// Obtain a read-only reference to this view's state.
pub fn read<'a>(&self, cx: &'a AppContext) -> &'a V {
self.model.read(cx)
}
/// Gets a [FocusHandle] for this view when its state implements [FocusableView].
pub fn focus_handle(&self, cx: &AppContext) -> FocusHandle
where
V: FocusableView,
{
self.read(cx).focus_handle(cx)
}
}
impl<V: Render> Element for View<V> {
type RequestLayoutState = AnyElement;
type PrepaintState = ();
fn id(&self) -> Option<ElementId> {
Some(ElementId::View(self.entity_id()))
}
fn request_layout(
&mut self,
_id: Option<&GlobalElementId>,
cx: &mut WindowContext,
) -> (LayoutId, Self::RequestLayoutState) {
let mut element = self.update(cx, |view, cx| view.render(cx).into_any_element());
let layout_id = element.request_layout(cx);
(layout_id, element)
}
fn prepaint(
&mut self,
_id: Option<&GlobalElementId>,
_: Bounds<Pixels>,
element: &mut Self::RequestLayoutState,
cx: &mut WindowContext,
) {
cx.set_view_id(self.entity_id());
element.prepaint(cx);
}
fn paint(
&mut self,
_id: Option<&GlobalElementId>,
_: Bounds<Pixels>,
element: &mut Self::RequestLayoutState,
_: &mut Self::PrepaintState,
cx: &mut WindowContext,
) {
element.paint(cx);
}
}
impl<V> Clone for View<V> {
fn clone(&self) -> Self {
Self {
model: self.model.clone(),
}
}
}
impl<T> std::fmt::Debug for View<T> {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_struct(&format!("View<{}>", type_name::<T>()))
.field("entity_id", &self.model.entity_id)
.finish_non_exhaustive()
}
}
impl<V> Hash for View<V> {
fn hash<H: Hasher>(&self, state: &mut H) {
self.model.hash(state);
}
}
impl<V> PartialEq for View<V> {
fn eq(&self, other: &Self) -> bool {
self.model == other.model
}
}
impl<V> Eq for View<V> {}
/// A weak variant of [View] which does not prevent the view from being released.
pub struct WeakView<V> {
pub(crate) model: WeakModel<V>,
}
impl<V: 'static> WeakView<V> {
/// Gets the entity id associated with this handle.
pub fn entity_id(&self) -> EntityId {
self.model.entity_id
}
/// Obtain a strong handle for the view if it hasn't been released.
pub fn upgrade(&self) -> Option<View<V>> {
Entity::upgrade_from(self)
}
/// Updates this view's state if it hasn't been released.
/// Returns an error if this view has been released.
pub fn update<C, R>(
&self,
cx: &mut C,
f: impl FnOnce(&mut V, &mut ViewContext<V>) -> R,
) -> Result<R>
where
C: VisualContext,
Result<C::Result<R>>: Flatten<R>,
{
let view = self.upgrade().context("error upgrading view")?;
Ok(view.update(cx, f)).flatten()
}
/// Assert that the view referenced by this handle has been released.
#[cfg(any(test, feature = "test-support"))]
pub fn assert_released(&self) {
self.model.assert_released()
}
}
impl<V> Clone for WeakView<V> {
fn clone(&self) -> Self {
Self {
model: self.model.clone(),
}
}
}
impl<V> Hash for WeakView<V> {
fn hash<H: Hasher>(&self, state: &mut H) {
self.model.hash(state);
}
}
impl<V> PartialEq for WeakView<V> {
fn eq(&self, other: &Self) -> bool {
self.model == other.model
}
}
impl<V> Eq for WeakView<V> {}
/// A dynamically-typed handle to a view, which can be downcast to a [View] for a specific type.
#[derive(Clone, Debug)]
pub struct AnyView {
model: AnyModel,
render: fn(&AnyView, &mut WindowContext) -> AnyElement,
cached_style: Option<StyleRefinement>,
}
impl AnyView {
/// Indicate that this view should be cached when using it as an element.
/// When using this method, the view's previous layout and paint will be recycled from the previous frame if [ViewContext::notify] has not been called since it was rendered.
/// The one exception is when [WindowContext::refresh] is called, in which case caching is ignored.
pub fn cached(mut self, style: StyleRefinement) -> Self {
self.cached_style = Some(style);
self
}
/// Convert this to a weak handle.
pub fn downgrade(&self) -> AnyWeakView {
AnyWeakView {
model: self.model.downgrade(),
render: self.render,
}
}
/// Convert this to a [View] of a specific type.
/// If this handle does not contain a view of the specified type, returns itself in an `Err` variant.
pub fn downcast<T: 'static>(self) -> Result<View<T>, Self> {
match self.model.downcast() {
Ok(model) => Ok(View { model }),
Err(model) => Err(Self {
model,
render: self.render,
cached_style: self.cached_style,
}),
}
}
/// Gets the [TypeId] of the underlying view.
pub fn entity_type(&self) -> TypeId {
self.model.entity_type
}
/// Gets the entity id of this handle.
pub fn entity_id(&self) -> EntityId {
self.model.entity_id()
}
}
impl<V: Render> From<View<V>> for AnyView {
fn from(value: View<V>) -> Self {
AnyView {
model: value.model.into_any(),
render: any_view::render::<V>,
cached_style: None,
}
}
}
impl PartialEq for AnyView {
fn eq(&self, other: &Self) -> bool {
self.model == other.model
}
}
impl Eq for AnyView {}
impl Element for AnyView {
type RequestLayoutState = Option<AnyElement>;
type PrepaintState = Option<AnyElement>;
fn id(&self) -> Option<ElementId> {
Some(ElementId::View(self.entity_id()))
}
fn request_layout(
&mut self,
_id: Option<&GlobalElementId>,
cx: &mut WindowContext,
) -> (LayoutId, Self::RequestLayoutState) {
if let Some(style) = self.cached_style.as_ref() {
let mut root_style = Style::default();
root_style.refine(style);
let layout_id = cx.request_layout(root_style, None);
(layout_id, None)
} else {
let mut element = (self.render)(self, cx);
let layout_id = element.request_layout(cx);
(layout_id, Some(element))
}
}
fn prepaint(
&mut self,
global_id: Option<&GlobalElementId>,
bounds: Bounds<Pixels>,
element: &mut Self::RequestLayoutState,
cx: &mut WindowContext,
) -> Option<AnyElement> {
cx.set_view_id(self.entity_id());
if self.cached_style.is_some() {
cx.with_element_state::<AnyViewState, _>(global_id.unwrap(), |element_state, cx| {
let content_mask = cx.content_mask();
let text_style = cx.text_style();
if let Some(mut element_state) = element_state {
if element_state.cache_key.bounds == bounds
&& element_state.cache_key.content_mask == content_mask
&& element_state.cache_key.text_style == text_style
&& !cx.window.dirty_views.contains(&self.entity_id())
&& !cx.window.refreshing
{
let prepaint_start = cx.prepaint_index();
cx.reuse_prepaint(element_state.prepaint_range.clone());
let prepaint_end = cx.prepaint_index();
element_state.prepaint_range = prepaint_start..prepaint_end;
return (None, element_state);
}
}
let refreshing = mem::replace(&mut cx.window.refreshing, true);
let prepaint_start = cx.prepaint_index();
let mut element = (self.render)(self, cx);
element.layout_as_root(bounds.size.into(), cx);
element.prepaint_at(bounds.origin, cx);
let prepaint_end = cx.prepaint_index();
cx.window.refreshing = refreshing;
(
Some(element),
AnyViewState {
prepaint_range: prepaint_start..prepaint_end,
paint_range: PaintIndex::default()..PaintIndex::default(),
cache_key: ViewCacheKey {
bounds,
content_mask,
text_style,
},
},
)
})
} else {
let mut element = element.take().unwrap();
element.prepaint(cx);
Some(element)
}
}
fn paint(
&mut self,
global_id: Option<&GlobalElementId>,
_bounds: Bounds<Pixels>,
_: &mut Self::RequestLayoutState,
element: &mut Self::PrepaintState,
cx: &mut WindowContext,
) {
if self.cached_style.is_some() {
cx.with_element_state::<AnyViewState, _>(global_id.unwrap(), |element_state, cx| {
let mut element_state = element_state.unwrap();
let paint_start = cx.paint_index();
if let Some(element) = element {
let refreshing = mem::replace(&mut cx.window.refreshing, true);
element.paint(cx);
cx.window.refreshing = refreshing;
} else {
cx.reuse_paint(element_state.paint_range.clone());
}
let paint_end = cx.paint_index();
element_state.paint_range = paint_start..paint_end;
((), element_state)
})
} else {
element.as_mut().unwrap().paint(cx);
}
}
}
impl<V: 'static + Render> IntoElement for View<V> {
type Element = View<V>;
fn into_element(self) -> Self::Element {
self
}
}
impl IntoElement for AnyView {
type Element = Self;
fn into_element(self) -> Self::Element {
self
}
}
/// A weak, dynamically-typed view handle that does not prevent the view from being released.
pub struct AnyWeakView {
model: AnyWeakModel,
render: fn(&AnyView, &mut WindowContext) -> AnyElement,
}
impl AnyWeakView {
/// Convert to a strongly-typed handle if the referenced view has not yet been released.
pub fn upgrade(&self) -> Option<AnyView> {
let model = self.model.upgrade()?;
Some(AnyView {
model,
render: self.render,
cached_style: None,
})
}
}
impl<V: 'static + Render> From<WeakView<V>> for AnyWeakView {
fn from(view: WeakView<V>) -> Self {
Self {
model: view.model.into(),
render: any_view::render::<V>,
}
}
}
impl PartialEq for AnyWeakView {
fn eq(&self, other: &Self) -> bool {
self.model == other.model
}
}
impl std::fmt::Debug for AnyWeakView {
fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
f.debug_struct("AnyWeakView")
.field("entity_id", &self.model.entity_id)
.finish_non_exhaustive()
}
}
mod any_view {
use crate::{AnyElement, AnyView, IntoElement, Render, WindowContext};
pub(crate) fn render<V: 'static + Render>(
view: &AnyView,
cx: &mut WindowContext,
) -> AnyElement {
let view = view.clone().downcast::<V>().unwrap();
view.update(cx, |view, cx| view.render(cx).into_any_element())
}
}
/// A view that renders nothing
pub struct EmptyView;
impl Render for EmptyView {
fn render(&mut self, _cx: &mut ViewContext<Self>) -> impl IntoElement {
Empty
}
}