Add example illustrating the new arc methods

It draws a simple flower only using arcs, rotations and fills.

Signed-off-by: Paul Mabileau <[email protected]>

examples/flower.rs

@@ -0,0 +1,110 @@
+//! Draws a simple geometric sort of flower with customizable dimensions.
+//!
+//! This example makes extensive use of the turtle arc methods: [`arc_left`] and [`arc_right`].
+//! They both provide the ability to draw a circular arc defined by the given `radius` and `extent`
+//! parameters, while the first makes the turtle draw it to the left and the second to the right.
+
+use turtle::{Angle, Distance, Drawing};
+
+const TURTLE_SPEED: &str = "faster";
+const BOTTOM_MARGIN: Distance = 25.0;
+
+const LEAF_FILL_COLOR: &str = "green";
+const LEAF_BORDER_COLOR: &str = "dark green";
+const LEAF_BORDER_WIDTH: Distance = 1.0;
+const LEFT_LEAF_RADIUS: Distance = 200.0;
+const LEFT_LEAF_EXTENT: Angle = 45.0;
+const RIGHT_LEAF_INCLINATION: Angle = 15.0;
+const RIGHT_LEAF_BOTTOM_RADIUS: Distance = 250.0;
+const RIGHT_LEAF_BOTTOM_EXTENT: Angle = 45.0;
+const RIGHT_LEAF_TOP_RADIUS: Distance = 157.0;
+const RIGHT_LEAF_TOP_EXTENT: Angle = 75.0;
+
+const TRUNK_COLOR: &str = LEAF_BORDER_COLOR;
+const TRUNK_WIDTH: Distance = 3.0;
+const TRUNK_PIECE_COUNT: usize = 4;
+const TRUNK_PIECE_RADIUS: Distance = 500.0;
+const TRUNK_PIECE_EXTENT: Angle = 15.0;
+
+const PETALS_COUNT: usize = 4;
+const PETALS_FILL_COLOR: &str = "purple";
+const PETALS_BORDER_COLOR: &str = "dark purple";
+const PETALS_BORDER_WIDTH: Distance = LEAF_BORDER_WIDTH;
+const PETALS_INIT_LEFT: Angle = 65.0;
+const PETALS_SIDE_RADIUS: Distance = 80.0;
+const PETALS_SIDE_EXTENT: Angle = 90.0;
+const PETALS_SPACE_GAP: Angle = 20.0;
+const PETALS_SPACE_RADIUS: Distance = 40.0;
+const PETALS_SPACE_EXTENT: Angle = 30.0;
+
+fn main() {
+    // Acquiring resources.
+    let mut drawing = Drawing::new();
+    let size = drawing.size();
+    let mut turtle = drawing.add_turtle();
+
+    // Initial positioning.
+    turtle.set_speed("instant");
+    turtle.pen_up();
+    turtle.go_to([
+        -(size.width as f64) / 6.0,
+        -(size.height as f64) / 2.0 + BOTTOM_MARGIN,
+    ]);
+    turtle.pen_down();
+
+    // Setup.
+    turtle.use_degrees();
+    turtle.set_speed(TURTLE_SPEED);
+
+    // Body.
+    turtle.set_fill_color(LEAF_FILL_COLOR);
+    turtle.set_pen_color(LEAF_BORDER_COLOR);
+
+    for _ in 0..TRUNK_PIECE_COUNT {
+        // Leaves:
+        turtle.set_pen_size(LEAF_BORDER_WIDTH);
+        turtle.set_pen_color(LEAF_BORDER_COLOR);
+        turtle.begin_fill();
+
+        // Left leaf.
+        turtle.arc_left(LEFT_LEAF_RADIUS, LEFT_LEAF_EXTENT);
+        turtle.right(LEFT_LEAF_EXTENT);
+        turtle.arc_right(LEFT_LEAF_RADIUS, -LEFT_LEAF_EXTENT);
+        turtle.right(LEFT_LEAF_EXTENT);
+
+        // Right leaf.
+        turtle.right(RIGHT_LEAF_INCLINATION);
+        turtle.arc_right(RIGHT_LEAF_BOTTOM_RADIUS, RIGHT_LEAF_BOTTOM_EXTENT);
+        turtle.right(RIGHT_LEAF_INCLINATION);
+        turtle.arc_right(RIGHT_LEAF_TOP_RADIUS, -RIGHT_LEAF_TOP_EXTENT);
+
+        // Trunk.
+        turtle.end_fill();
+        turtle.set_pen_size(TRUNK_WIDTH);
+        turtle.set_pen_color(TRUNK_COLOR);
+        turtle.arc_right(TRUNK_PIECE_RADIUS, TRUNK_PIECE_EXTENT);
+    }
+
+    // Petals.
+    turtle.set_fill_color(PETALS_FILL_COLOR);
+    turtle.set_pen_color(PETALS_BORDER_COLOR);
+    turtle.set_pen_size(PETALS_BORDER_WIDTH);
+    turtle.left(PETALS_INIT_LEFT);
+    turtle.begin_fill();
+    turtle.arc_right(PETALS_SIDE_RADIUS, PETALS_SIDE_EXTENT);
+
+    for _ in 0..PETALS_COUNT {
+        turtle.left(PETALS_SPACE_GAP);
+        turtle.arc_right(PETALS_SPACE_RADIUS, -PETALS_SPACE_EXTENT);
+        turtle.right(2.0 * PETALS_SPACE_GAP + PETALS_SPACE_EXTENT);
+        turtle.arc_left(PETALS_SPACE_RADIUS, PETALS_SPACE_EXTENT);
+    }
+
+    // Finish petals with error adjustments.
+    turtle.left(PETALS_SPACE_GAP);
+    turtle.arc_left(PETALS_SIDE_RADIUS + 1.0, 3.0 - PETALS_SIDE_EXTENT);
+    turtle.end_fill();
+
+    // Reveal final drawing.
+    turtle.hide();
+}