First commit. Version 0.1.0

examples/scroll.rs

@@ -0,0 +1,154 @@
+//! `cargo run --example scroll`
+//!
+//! Demonstrates the two main scroll use cases:
+//!
+//! - **List mode** — a long vertical list inside a `scroll(column(...))`.
+//! - **Grid mode** — a grid of buttons inside a `scroll(grid(4))` (app-drawer style).
+//!
+//! Press the "List" / "Grid" toggle at the top to switch between modes.
+//! Drag the content area to scroll. Esc exits.
+//!
+//! NOTE: ltk is a Wayland layer-shell toolkit. This example requires a running
+//! Wayland compositor (e.g. sway, labwc, or a full desktop session).
+
+use ltk::{
+	App, Element, Keysym, ButtonVariant,
+	button, column, row, text, scroll, grid, spacer,
+};
+
+// ── Messages ──────────────────────────────────────────────────────────────────
+
+#[ derive( Clone ) ]
+enum Message
+{
+	ShowList,
+	ShowGrid,
+	ItemPressed( usize ),
+}
+
+// ── App state ─────────────────────────────────────────────────────────────────
+
+#[ derive( PartialEq ) ]
+enum Mode { List, Grid }
+
+struct ScrollApp
+{
+	mode:         Mode,
+	last_pressed: Option<usize>,
+}
+
+impl ScrollApp
+{
+	fn new() -> Self
+	{
+		Self { mode: Mode::List, last_pressed: None }
+	}
+}
+
+// ── App trait ─────────────────────────────────────────────────────────────────
+
+const ITEM_COUNT: usize = 64;
+
+impl App for ScrollApp
+{
+	type Message = Message;
+
+	fn view( &self ) -> Element<Message>
+	{
+		let palette   = ltk::theme_palette();
+		let primary   = palette.text_primary;
+		let secondary = palette.text_secondary;
+
+		let status = match self.last_pressed
+		{
+			Some( i ) => format!( "Pressed item {}", i + 1 ),
+			None      => String::from( "Drag to scroll  ·  click an item" ),
+		};
+
+		// Top bar: toggle buttons + status
+		let toggle_list = button::<Message>( "List" )
+			.variant( if self.mode == Mode::List { ButtonVariant::Primary } else { ButtonVariant::Secondary } )
+			.on_press( Message::ShowList );
+
+		let toggle_grid = button::<Message>( "Grid" )
+			.variant( if self.mode == Mode::Grid { ButtonVariant::Primary } else { ButtonVariant::Secondary } )
+			.on_press( Message::ShowGrid );
+
+		let top_bar = row::<Message>()
+			.spacing( 8.0 )
+			.push( toggle_list )
+			.push( toggle_grid )
+			.push( spacer() )
+			.push( text( &status ).size( 14.0 ).color( secondary ) );
+
+		// Scrollable content area
+		let content: Element<Message> = match self.mode
+		{
+			Mode::List =>
+			{
+				// A long list of labeled buttons in a scrollable column
+				let mut col = column::<Message>().padding( 8.0 ).spacing( 6.0 );
+				for i in 0..ITEM_COUNT
+				{
+					col = col.push(
+						button::<Message>( format!( "List item {}  —  click me", i + 1 ) )
+							.variant( ButtonVariant::Secondary )
+							.on_press( Message::ItemPressed( i ) ),
+					);
+				}
+				scroll( col ).into()
+			}
+			Mode::Grid =>
+			{
+				// A grid of labeled buttons in a scrollable 4-column grid
+				let mut g = grid::<Message>( 4 ).padding( 8.0 ).spacing( 6.0 );
+				for i in 0..ITEM_COUNT
+				{
+					g = g.push(
+						button::<Message>( format!( "Item {}", i + 1 ) )
+							.variant( ButtonVariant::Secondary )
+							.on_press( Message::ItemPressed( i ) ),
+					);
+				}
+				scroll( g ).into()
+			}
+		};
+
+		column::<Message>()
+			.padding( 16.0 )
+			.spacing( 12.0 )
+			.push( text( "ltk — scroll showcase" ).size( 22.0 ).color( primary ).align_center() )
+			.push( top_bar )
+			.push( content )
+			.push(
+				text( "Drag = scroll  ·  Esc = quit" )
+					.size( 12.0 )
+					.color( secondary )
+					.align_center(),
+			)
+			.into()
+	}
+
+	fn update( &mut self, msg: Message )
+	{
+		match msg
+		{
+			Message::ShowList          => self.mode = Mode::List,
+			Message::ShowGrid          => self.mode = Mode::Grid,
+			Message::ItemPressed( i )  => self.last_pressed = Some( i ),
+		}
+	}
+
+	fn on_key( &mut self, keysym: Keysym ) -> Option<Message>
+	{
+		if keysym == Keysym::Escape { std::process::exit( 0 ); }
+		None
+	}
+}
+
+// ── Entry point ───────────────────────────────────────────────────────────────
+
+fn main()
+{
+	ltk::run( ScrollApp::new() );
+}