Expose reusable `Button` logic

... and reuse it in `iced_pure`!

2 files changed, 52 insertions, 124 deletions

diff --git a/pure/src/widget/button.rs b/pure/src/widget/button.rs
index 198a3af9..89acb7f5 100644
--- a/pure/src/widget/button.rs
+++ b/pure/src/widget/button.rs
@@ -4,15 +4,16 @@ use iced_native::event::{self, Event};
 use iced_native::layout;
 use iced_native::mouse;
 use iced_native::renderer;
-use iced_native::touch;
+use iced_native::widget::button;
 use iced_native::{
-    Background, Clipboard, Color, Hasher, Layout, Length, Padding, Point,
-    Rectangle, Shell, Vector,
+    Clipboard, Hasher, Layout, Length, Padding, Point, Rectangle, Shell,
 };
 use iced_style::button::StyleSheet;
 
 use std::any::Any;
 
+pub use button::State;
+
 pub struct Button<'a, Message, Renderer> {
     content: Element<'a, Message, Renderer>,
     on_press: Option<Message>,
@@ -51,7 +52,7 @@ where
     }
 
     fn state(&self) -> Box<dyn Any> {
-        Box::new(State { is_pressed: false })
+        Box::new(State::new())
     }
 
     fn children(&self) -> &[Element<Message, Renderer>] {
@@ -71,6 +72,8 @@ where
 
         self.tag().hash(state);
         self.width.hash(state);
+        self.height.hash(state);
+        self.padding.hash(state);
         self.content.as_widget().hash_layout(state);
     }
 
@@ -79,20 +82,16 @@ where
         renderer: &Renderer,
         limits: &layout::Limits,
     ) -> layout::Node {
-        let limits = limits
-            .width(self.width)
-            .height(self.height)
-            .pad(self.padding);
-
-        let mut content = self.content.as_widget().layout(renderer, &limits);
-        content.move_to(Point::new(
-            self.padding.left.into(),
-            self.padding.top.into(),
-        ));
-
-        let size = limits.resolve(content.size()).pad(self.padding);
-
-        layout::Node::with_children(size, vec![content])
+        button::layout(
+            renderer,
+            limits,
+            self.width,
+            self.height,
+            self.padding,
+            |renderer, limits| {
+                self.content.as_widget().layout(renderer, &limits)
+            },
+        )
     }
 
     fn on_event(
@@ -105,12 +104,6 @@ where
         clipboard: &mut dyn Clipboard,
         shell: &mut Shell<'_, Message>,
     ) -> event::Status {
-        let state = if let Some(state) = tree.state.downcast_mut::<State>() {
-            state
-        } else {
-            return event::Status::Ignored;
-        };
-
         if let event::Status::Captured = self.content.as_widget_mut().on_event(
             &mut tree.children[0],
             event.clone(),
@@ -123,42 +116,14 @@ where
             return event::Status::Captured;
         }
 
-        match event {
-            Event::Mouse(mouse::Event::ButtonPressed(mouse::Button::Left))
-            | Event::Touch(touch::Event::FingerPressed { .. }) => {
-                if self.on_press.is_some() {
-                    let bounds = layout.bounds();
-
-                    if bounds.contains(cursor_position) {
-                        state.is_pressed = true;
-
-                        return event::Status::Captured;
-                    }
-                }
-            }
-            Event::Mouse(mouse::Event::ButtonReleased(mouse::Button::Left))
-            | Event::Touch(touch::Event::FingerLifted { .. }) => {
-                if let Some(on_press) = self.on_press.clone() {
-                    let bounds = layout.bounds();
-
-                    if state.is_pressed {
-                        state.is_pressed = false;
-
-                        if bounds.contains(cursor_position) {
-                            shell.publish(on_press);
-                        }
-
-                        return event::Status::Captured;
-                    }
-                }
-            }
-            Event::Touch(touch::Event::FingerLost { .. }) => {
-                state.is_pressed = false;
-            }
-            _ => {}
-        }
-
-        event::Status::Ignored
+        button::update(
+            event,
+            layout,
+            cursor_position,
+            shell,
+            &self.on_press,
+            || tree.state_mut::<State>(),
+        )
     }
 
     fn draw(
@@ -170,60 +135,17 @@ where
         cursor_position: Point,
         _viewport: &Rectangle,
     ) {
-        let state = if let Some(state) = tree.state.downcast_ref::<State>() {
-            state
-        } else {
-            return;
-        };
-
         let bounds = layout.bounds();
         let content_layout = layout.children().next().unwrap();
 
-        let is_mouse_over = bounds.contains(cursor_position);
-        let is_disabled = self.on_press.is_none();
-
-        let styling = if is_disabled {
-            self.style_sheet.disabled()
-        } else if is_mouse_over {
-            if state.is_pressed {
-                self.style_sheet.pressed()
-            } else {
-                self.style_sheet.hovered()
-            }
-        } else {
-            self.style_sheet.active()
-        };
-
-        if styling.background.is_some() || styling.border_width > 0.0 {
-            if styling.shadow_offset != Vector::default() {
-                // TODO: Implement proper shadow support
-                renderer.fill_quad(
-                    renderer::Quad {
-                        bounds: Rectangle {
-                            x: bounds.x + styling.shadow_offset.x,
-                            y: bounds.y + styling.shadow_offset.y,
-                            ..bounds
-                        },
-                        border_radius: styling.border_radius,
-                        border_width: 0.0,
-                        border_color: Color::TRANSPARENT,
-                    },
-                    Background::Color([0.0, 0.0, 0.0, 0.5].into()),
-                );
-            }
-
-            renderer.fill_quad(
-                renderer::Quad {
-                    bounds,
-                    border_radius: styling.border_radius,
-                    border_width: styling.border_width,
-                    border_color: styling.border_color,
-                },
-                styling
-                    .background
-                    .unwrap_or(Background::Color(Color::TRANSPARENT)),
-            );
-        }
+        let styling = button::draw(
+            renderer,
+            bounds,
+            cursor_position,
+            self.on_press.is_some(),
+            self.style_sheet.as_ref(),
+            || tree.state::<State>(),
+        );
 
         self.content.as_widget().draw(
             &tree.children[0],
@@ -245,22 +167,14 @@ where
         _viewport: &Rectangle,
         _renderer: &Renderer,
     ) -> mouse::Interaction {
-        let is_mouse_over = layout.bounds().contains(cursor_position);
-        let is_disabled = self.on_press.is_none();
-
-        if is_mouse_over && !is_disabled {
-            mouse::Interaction::Pointer
-        } else {
-            mouse::Interaction::default()
-        }
+        button::mouse_interaction(
+            layout,
+            cursor_position,
+            self.on_press.is_some(),
+        )
     }
 }
 
-#[derive(Debug, Clone)]
-struct State {
-    is_pressed: bool,
-}
-
 impl<'a, Message, Renderer> Into<Element<'a, Message, Renderer>>
     for Button<'a, Message, Renderer>
 where
diff --git a/pure/src/widget/tree.rs b/pure/src/widget/tree.rs
index 2353edc5..1ab6d80b 100644
--- a/pure/src/widget/tree.rs
+++ b/pure/src/widget/tree.rs
@@ -58,4 +58,18 @@ impl Tree {
             *self = Self::new(new);
         }
     }
+
+    pub fn state<T>(&self) -> &T
+    where
+        T: 'static,
+    {
+        self.state.downcast_ref().expect("Downcast widget state")
+    }
+
+    pub fn state_mut<T>(&mut self) -> &mut T
+    where
+        T: 'static,
+    {
+        self.state.downcast_mut().expect("Downcast widget state")
+    }
 }