Implement explicit text caching in the widget state tree

widget/src/checkbox.rs

@@ -6,12 +6,11 @@ use crate::core::mouse;
 use crate::core::renderer;
 use crate::core::text;
 use crate::core::touch;
-use crate::core::widget::Tree;
+use crate::core::widget;
+use crate::core::widget::tree::{self, Tree};
 use crate::core::{
-    Alignment, Clipboard, Element, Layout, Length, Pixels, Rectangle, Shell,
-    Widget,
+    Clipboard, Element, Layout, Length, Pixels, Rectangle, Shell, Size, Widget,
 };
-use crate::{Row, Text};
 
 pub use iced_style::checkbox::{Appearance, StyleSheet};
 
@@ -45,7 +44,7 @@ where
     width: Length,
     size: f32,
     spacing: f32,
-    text_size: Option<f32>,
+    text_size: Option<Pixels>,
     text_line_height: text::LineHeight,
     text_shaping: text::Shaping,
     font: Option<Renderer::Font>,
@@ -118,7 +117,7 @@ where
 
     /// Sets the text size of the [`Checkbox`].
     pub fn text_size(mut self, text_size: impl Into<Pixels>) -> Self {
-        self.text_size = Some(text_size.into().0);
+        self.text_size = Some(text_size.into());
         self
     }
 
@@ -167,6 +166,14 @@ where
     Renderer: text::Renderer,
     Renderer::Theme: StyleSheet + crate::text::StyleSheet,
 {
+    fn tag(&self) -> tree::Tag {
+        tree::Tag::of::<widget::text::State<Renderer::Paragraph>>()
+    }
+
+    fn state(&self) -> tree::State {
+        tree::State::new(widget::text::State::<Renderer::Paragraph>::default())
+    }
+
     fn width(&self) -> Length {
         self.width
     }
@@ -177,26 +184,35 @@ where
 
     fn layout(
         &self,
+        tree: &Tree,
         renderer: &Renderer,
         limits: &layout::Limits,
     ) -> layout::Node {
-        Row::<(), Renderer>::new()
-            .width(self.width)
-            .spacing(self.spacing)
-            .align_items(Alignment::Center)
-            .push(Row::new().width(self.size).height(self.size))
-            .push(
-                Text::new(&self.label)
-                    .font(self.font.unwrap_or_else(|| renderer.default_font()))
-                    .width(self.width)
-                    .size(
-                        self.text_size
-                            .unwrap_or_else(|| renderer.default_size()),
-                    )
-                    .line_height(self.text_line_height)
-                    .shaping(self.text_shaping),
-            )
-            .layout(renderer, limits)
+        layout::next_to_each_other(
+            &limits.width(self.width),
+            self.spacing,
+            |_| layout::Node::new(Size::new(self.size, self.size)),
+            |limits| {
+                let state = tree
+                    .state
+                    .downcast_ref::<widget::text::State<Renderer::Paragraph>>();
+
+                widget::text::layout(
+                    state,
+                    renderer,
+                    limits,
+                    self.width,
+                    Length::Shrink,
+                    &self.label,
+                    self.text_line_height,
+                    self.text_size,
+                    self.font,
+                    alignment::Horizontal::Left,
+                    alignment::Vertical::Top,
+                    self.text_shaping,
+                )
+            },
+        )
     }
 
     fn on_event(
@@ -244,7 +260,7 @@ where
 
     fn draw(
         &self,
-        _tree: &Tree,
+        tree: &Tree,
         renderer: &mut Renderer,
         theme: &Renderer::Theme,
         style: &renderer::Style,
@@ -283,24 +299,23 @@ where
                 line_height,
                 shaping,
             } = &self.icon;
-            let size = size.unwrap_or(bounds.height * 0.7);
+            let size = size.unwrap_or(Pixels(bounds.height * 0.7));
 
             if self.is_checked {
-                renderer.fill_text(text::Text {
-                    content: &code_point.to_string(),
-                    font: *font,
-                    size,
-                    line_height: *line_height,
-                    bounds: Rectangle {
-                        x: bounds.center_x(),
-                        y: bounds.center_y(),
-                        ..bounds
+                renderer.fill_text(
+                    text::Text {
+                        content: &code_point.to_string(),
+                        font: *font,
+                        size,
+                        line_height: *line_height,
+                        bounds: bounds.size(),
+                        horizontal_alignment: alignment::Horizontal::Center,
+                        vertical_alignment: alignment::Vertical::Center,
+                        shaping: *shaping,
                     },
-                    color: custom_style.icon_color,
-                    horizontal_alignment: alignment::Horizontal::Center,
-                    vertical_alignment: alignment::Vertical::Center,
-                    shaping: *shaping,
-                });
+                    bounds.center(),
+                    custom_style.icon_color,
+                );
             }
         }
 
@@ -311,16 +326,10 @@ where
                 renderer,
                 style,
                 label_layout,
-                &self.label,
-                self.text_size,
-                self.text_line_height,
-                self.font,
+                tree.state.downcast_ref(),
                 crate::text::Appearance {
                     color: custom_style.text_color,
                 },
-                alignment::Horizontal::Left,
-                alignment::Vertical::Center,
-                self.text_shaping,
             );
         }
     }
@@ -348,7 +357,7 @@ pub struct Icon<Font> {
     /// The unicode code point that will be used as the icon.
     pub code_point: char,
     /// Font size of the content.
-    pub size: Option<f32>,
+    pub size: Option<Pixels>,
     /// The line height of the icon.
     pub line_height: text::LineHeight,
     /// The shaping strategy of the icon.