From b31ac29deb505b80546640fec2e6686979099b10 Mon Sep 17 00:00:00 2001
From: Franz Dietrich <dietrich@teilgedanken.de>
Date: Sat, 18 Oct 2025 22:19:02 +0200
Subject: [PATCH] add clock and bezier example

---
 turtle-lib/Cargo.toml         |  1 +
 turtle-lib/examples/bezier.rs | 56 +++++++++++++++++++++
 turtle-lib/examples/clock.rs  | 91 +++++++++++++++++++++++++++++++++++
 3 files changed, 148 insertions(+)
 create mode 100644 turtle-lib/examples/bezier.rs
 create mode 100644 turtle-lib/examples/clock.rs

diff --git a/turtle-lib/Cargo.toml b/turtle-lib/Cargo.toml
index 89d51b3..4fe1171 100644
--- a/turtle-lib/Cargo.toml
+++ b/turtle-lib/Cargo.toml
@@ -19,3 +19,4 @@ crossbeam = "0.8"
 # For examples and testing
 tracing-subscriber = { version = "0.3", features = ["env-filter", "fmt"] }
 dialog = "*"
+chrono = "0.4"
diff --git a/turtle-lib/examples/bezier.rs b/turtle-lib/examples/bezier.rs
new file mode 100644
index 0000000..34fd65e
--- /dev/null
+++ b/turtle-lib/examples/bezier.rs
@@ -0,0 +1,56 @@
+//! Cubic Bézier curve example
+//! <https://en.wikipedia.org/wiki/B%C3%A9zier_curve>
+
+use turtle_lib::{turtle_main, vec2};
+
+struct CubicBezier {
+    point0: (f32, f32),
+    point1: (f32, f32),
+    point2: (f32, f32),
+    point3: (f32, f32),
+}
+
+impl CubicBezier {
+    /// Returns the value of this curve at the given parameter t (0.0 to 1.0)
+    pub fn at(&self, t: f64) -> (f32, f32) {
+        let t = t as f32;
+        let mt = 1.0 - t; // (1 - t)
+
+        // Cubic Bézier formula from Wikipedia
+        let p0_weight = mt.powi(3);
+        let p1_weight = 3.0 * mt.powi(2) * t;
+        let p2_weight = 3.0 * mt * t.powi(2);
+        let p3_weight = t.powi(3);
+
+        (
+            self.point0.0 * p0_weight
+                + self.point1.0 * p1_weight
+                + self.point2.0 * p2_weight
+                + self.point3.0 * p3_weight,
+            self.point0.1 * p0_weight
+                + self.point1.1 * p1_weight
+                + self.point2.1 * p2_weight
+                + self.point3.1 * p3_weight,
+        )
+    }
+}
+
+#[turtle_main("Bézier Curve")]
+fn draw(turtle: &mut TurtlePlan) {
+    let curve = CubicBezier {
+        point0: (-200.0, -100.0),
+        point1: (-100.0, 400.0),
+        point2: (100.0, -500.0),
+        point3: (300.0, 200.0),
+    };
+
+    let start = curve.at(0.0);
+    turtle.pen_up().go_to(vec2(start.0, start.1)).pen_down();
+
+    let samples = 100;
+    for i in 0..samples {
+        let t = f64::from(i) / f64::from(samples);
+        let point = curve.at(t);
+        turtle.go_to(vec2(point.0, point.1));
+    }
+}
diff --git a/turtle-lib/examples/clock.rs b/turtle-lib/examples/clock.rs
new file mode 100644
index 0000000..9ca3198
--- /dev/null
+++ b/turtle-lib/examples/clock.rs
@@ -0,0 +1,91 @@
+//! Animated clock example
+//!
+//! This example draws an animated clock that shows the current time.
+//! The clock updates every second to reflect the actual time.
+
+use chrono::{Local, Timelike};
+use macroquad::prelude::{clear_background, is_key_pressed, next_frame, KeyCode, WHITE};
+use turtle_lib::{create_turtle_plan, vec2, DirectionalMovement, Turnable, TurtleApp};
+
+#[macroquad::main("Clock")]
+async fn main() {
+    const HOURS: i32 = 12;
+    const MINUTES: f32 = 60.0;
+    const SECONDS: f32 = 60.0;
+    const FULL_CIRCLE: f32 = 360.0;
+
+    let mut app = TurtleApp::new();
+    let mut last_update = Local::now();
+
+    loop {
+        clear_background(WHITE);
+
+        let now = Local::now();
+
+        // Only redraw when the time changes
+        if now.second() != last_update.second() {
+            let mut turtle = create_turtle_plan();
+            turtle.reset().set_speed(1100).left(90.0); // Instant mode for smooth updates
+
+            // Draw the clock circle and hour markers
+            for i in 1..=HOURS {
+                turtle
+                    .pen_up()
+                    .go_to(vec2(0.0, 0.0))
+                    .right(FULL_CIRCLE / HOURS as f32)
+                    .forward(205.0);
+
+                let pen_size = if (i) % 3 == 0 { 7.0 } else { 2.0 };
+                turtle
+                    .set_pen_width(pen_size)
+                    .pen_down()
+                    .forward(10.0)
+                    .right(90.0)
+                    .write_text(format!("{i}"), 2 * pen_size as i32 + 10)
+                    .left(90.0);
+            }
+
+            // Draw the hour hand
+            turtle
+                .pen_up()
+                .go_to(vec2(0.0, 0.0))
+                .set_heading(90.0)
+                .right(FULL_CIRCLE / HOURS as f32 * (now.hour() % 12) as f32)
+                .set_pen_width(5.0)
+                .pen_down()
+                .forward(120.0);
+
+            // Draw the minute hand
+            turtle
+                .pen_up()
+                .go_to(vec2(0.0, 0.0))
+                .set_heading(90.0)
+                .right(FULL_CIRCLE / MINUTES * now.minute() as f32)
+                .set_pen_width(3.0)
+                .pen_down()
+                .forward(150.0);
+
+            // Draw the second hand
+            turtle
+                .pen_up()
+                .go_to(vec2(0.0, 0.0))
+                .set_heading(90.0)
+                .right(FULL_CIRCLE / SECONDS * now.second() as f32)
+                .set_pen_width(1.0)
+                .pen_down()
+                .forward(180.0);
+
+            app = TurtleApp::new().with_commands(turtle.build());
+            last_update = now;
+        }
+
+        app.update();
+        app.render();
+
+        if is_key_pressed(KeyCode::Escape) || is_key_pressed(KeyCode::Q) {
+            break;
+        }
+
+        next_frame().await;
+    }
+}