Expose shape fields

examples/dynamic_stroke_size.rs

@@ -0,0 +1,105 @@
+//! Demonstrate surgical changes on the fields of `Shape` (path, fill, stroke).
+//! The triangle changes fill color; the hexagon changes stroke width; and
+//! the node positions of all shapes are extracted from the path to apply different
+//! rotations on size.
+
+use bevy::{color::palettes::css::*, prelude::*};
+use bevy_prototype_lyon::prelude::*;
+
+fn main() {
+    App::new()
+        .add_plugins((DefaultPlugins, ShapePlugin))
+        .add_systems(Startup, setup_system)
+        .add_systems(Update, redraw_line_width)
+        .add_systems(Update, redraw_fill)
+        .add_systems(Update, rotate_shape_by_size)
+        .run();
+}
+
+// Marker traits to uniquely identify entities.
+#[derive(Component)]
+struct HexagonShape;
+#[derive(Component)]
+struct TriangleShape;
+
+/// Walk Path to get the maximum x coordinate.
+fn get_max_x(shape: &Shape) -> f32 {
+    shape
+        .path
+        .iter()
+        .map(|p| p.to().x)
+        .chain(shape.path.iter().map(|p| p.from().x))
+        .fold(0f32, |acc, x| if x - acc > 1e-8 { x } else { acc })
+}
+
+/// Over time, rotate smaller shapes faster.
+fn rotate_shape_by_size(mut query: Query<(&mut Transform, &Shape)>, time: Res<Time>) {
+    let delta = time.delta_secs();
+
+    for (mut transform, shape) in query.iter_mut() {
+        transform.rotate(Quat::from_rotation_z(200. / get_max_x(shape) * delta));
+    }
+}
+
+/// Change line width of the hexagon over time.
+fn redraw_line_width(mut query: Query<&mut Shape, With<HexagonShape>>, time: Res<Time>) {
+    let outline_width = 2.0 + time.elapsed_secs_f64().sin().abs() * 10.0;
+
+    let mut shape = query.single_mut();
+    shape.stroke = shape.stroke.map(|mut s| {
+        s.options.line_width = outline_width as f32;
+        s
+    });
+}
+
+/// Change fill color of the triangle over time.
+fn redraw_fill(mut query: Query<&mut Shape, With<TriangleShape>>, time: Res<Time>) {
+    let hue = (time.elapsed_secs_f64() * 50.0) % 360.0;
+    let color = Color::hsl(hue as f32, 1.0, 0.5);
+
+    let mut shape = query.single_mut();
+    shape.fill = shape.fill.map(|mut f| {
+        f.color = color;
+        f
+    });
+}
+
+fn setup_system(mut commands: Commands) {
+    let triangle = shapes::RegularPolygon {
+        sides: 3,
+        feature: shapes::RegularPolygonFeature::Radius(100.0),
+        ..shapes::RegularPolygon::default()
+    };
+    let hexagon = shapes::RegularPolygon {
+        sides: 6,
+        feature: shapes::RegularPolygonFeature::Radius(200.0),
+        ..shapes::RegularPolygon::default()
+    };
+    let big_square = shapes::RegularPolygon {
+        sides: 4,
+        feature: shapes::RegularPolygonFeature::Radius(300.0),
+        ..shapes::RegularPolygon::default()
+    };
+
+    commands.spawn((Camera2d, Msaa::Sample4));
+    commands.spawn((
+        ShapeBuilder::with(&triangle)
+            .fill(DARK_CYAN)
+            .stroke((BLACK, 10.0))
+            .build(),
+        Transform::default().with_translation(Vec3::new(0., 0., 2.)),
+        TriangleShape,
+    ));
+    commands.spawn((
+        ShapeBuilder::with(&hexagon)
+            .fill(DARK_CYAN)
+            .stroke((BLACK, 10.0))
+            .build(),
+        Transform::default().with_translation(Vec3::new(0., 0., 1.)),
+        HexagonShape,
+    ));
+    commands.spawn((ShapeBuilder::with(&big_square)
+        .fill(ORANGE)
+        .stroke((BLACK, 10.0))
+        .build(),));
+}

src/entity.rs

@@ -41,9 +41,12 @@ impl Default for ShapeBundle {
 #[derive(Component, Default, Clone)]
 #[require(Mesh2d, MeshMaterial2d<ColorMaterial>(color_material_handle), Transform, Visibility)]
 pub struct Shape {
-    path: tess::path::Path,
-    fill: Option<Fill>,
-    stroke: Option<Stroke>,
+    /// Geometry of a shape.
+    pub path: tess::path::Path,
+    /// Fill data, changes are propagated to the mesh.
+    pub fill: Option<Fill>,
+    /// Stroke data, changes are propagated to the mesh.
+    pub stroke: Option<Stroke>,
 }
 
 impl Shape {