Update taffy example

examples/taffy.rs

@@ -1,65 +1,127 @@
 use xilem::{view::View, App, AppLauncher};
 
+#[derive(Debug, Clone, PartialEq, Eq, Hash)]
+struct AppState {
+    count: u32,
+}
+
+impl AppState {
+    fn new() -> Self {
+        Self { count: 1 }
+    }
+}
+
 #[cfg(not(feature = "taffy"))]
-fn app_logic(_data: &mut i32) -> impl View<i32> {
+fn app_logic(_data: &mut AppState) -> impl View<AppState> {
     "Error: this example requires the 'taffy' feature to be enabled"
 }
 
 #[cfg(feature = "taffy")]
-fn app_logic(data: &mut i32) -> impl View<i32> {
-    use taffy::style::{AlignItems, JustifyContent};
+fn app_logic(state: &mut AppState) -> impl View<AppState> {
+    use taffy::style::{AlignItems, FlexWrap, JustifyContent};
     use taffy::style_helpers::length;
     use vello::peniko::Color;
     use xilem::view::{button, div, flex_column, flex_row};
 
-    // here's some logic, deriving state for the view from our state
-    let label = if *data == 1 {
-        "clicked 1 time".to_string()
+    const COLORS: [Color; 4] = [
+        Color::LIGHT_GREEN,
+        Color::BLACK,
+        Color::AZURE,
+        Color::HOT_PINK,
+    ];
+
+    // Some logic, deriving state for the view from our app state
+    let label = if state.count == 1 {
+        "Square count: 1".to_string()
     } else {
-        format!("clicked {data} times")
+        format!("Square count: {}", state.count)
     };
 
     // The actual UI Code starts here
     flex_column((
-        button(label, |data| {
-            println!("clicked");
-            *data += 1;
-        }),
-        flex_row((
-            button("decrease", |data| {
-                println!("clicked decrease");
-                *data -= 1;
-            }),
-            button("reset", |data| {
-                println!("clicked reset");
-                *data = 0;
+
+        // Header
+        div(String::from("Xilem Example"))
+            .with_background_color(Color::RED)
+            .with_style(|s| s.padding = length(20.0)),
+
+        // Body 
+        flex_column((
+
+            // Counter control buttons
+            flex_row((
+                label,
+                button("increase", |state: &mut AppState| {
+                    println!("clicked increase");
+                    state.count += 1;
+                }),
+                button("decrease", |state: &mut AppState| {
+                    println!("clicked decrease");
+                    if state.count > 0 {
+                        state.count -= 1;
+                    }
+                }),
+                button("reset", |state: &mut AppState| {
+                    println!("clicked reset");
+                    state.count = 1;
+                }),
+            ))
+            .with_background_color(Color::BLUE_VIOLET)
+            .with_style(|s| {
+                s.gap.width = length(20.0);
+                s.padding = length(20.0);
+                s.justify_content = Some(JustifyContent::Start);
+                s.align_items = Some(AlignItems::Center);
             }),
+
+            // Description text
+            div(String::from("The number of squares below is controlled by the counter above.\n\nTry clicking \"increase\" until the square count increases enough that the view becomes scrollable."))
+                .with_background_color(Color::RED)
+                .with_style(|s| s.padding = length(20.0)),
+
+            // Lorem Ipsum text
+            div(String::from("Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum."))
+                .with_background_color(Color::RED)
+                .with_style(|s| s.padding = length(20.0)),
+
+            // Wrapping container (number of children controlled by counter)
+            flex_row(
+                (0..state.count).map(|i| {
+                    div(())
+                        .with_background_color(COLORS[(i % 4) as usize])
+                        .with_style(|s| {
+                            s.size.width = length(200.0);
+                            s.size.height = length(200.0);
+                        })
+                }).collect::<Vec<_>>()
+            )
+                .with_background_color(Color::FOREST_GREEN)
+                .with_style(|s| {
+                    s.flex_grow = 1.0;
+                    s.flex_wrap = FlexWrap::Wrap;
+                    s.gap = length(20.0);
+                    s.padding = length(20.0);
+                }),
+
         ))
-        .with_background_color(Color::BLUE_VIOLET)
         .with_style(|s| {
-            s.gap.width = length(20.0);
-            s.flex_grow = 1.0;
-            s.justify_content = Some(JustifyContent::Center);
-            s.align_items = Some(AlignItems::Center);
-        }),
-        div(String::from("Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum."))
-            .with_background_color(Color::RED)
-            .with_style(|s| s.padding = length(20.0)),
-        div(())
-            .with_background_color(Color::FOREST_GREEN)
-            .with_style(|s| s.flex_grow = 1.0),
-    ))
-    .with_style(|s| {
-        s.gap.height = length(20.0);
+            s.gap.height = length(20.0);
+            s.padding.left = length(20.0);
+            s.padding.right = length(20.0);
+            s.padding.top = length(20.0);
+            s.padding.bottom = length(20.0);
+        })
+        .with_background_color(Color::WHITE)
+    )).with_style(|s| {
         s.padding.left = length(20.0);
         s.padding.right = length(20.0);
         s.padding.top = length(20.0);
         s.padding.bottom = length(20.0);
     })
-    .with_background_color(Color::WHITE)
+    .with_background_color(Color::DARK_GRAY)
 }
 
 fn main() {
-    let app = App::new(0, app_logic);
+    let app = App::new(AppState::new(), app_logic);
     AppLauncher::new(app).run()
 }