primitive implementations

src/bezpath.rs

@@ -1,6 +1,8 @@
-use bevy::prelude::*;
+use bevy::{math::DVec2, prelude::*};
 use bevy_vello::prelude::*;
 
+use crate::VectorBorder;
+
 use super::VelloVector;
 
 /// Vello Bézier path component.
@@ -137,3 +139,16 @@ fn interp_pathel(p0: kurbo::Point, pathel: kurbo::PathEl, t: f32) -> kurbo::Path
         kurbo::PathEl::ClosePath => kurbo::PathEl::ClosePath,
     }
 }
+
+impl VectorBorder for VelloBezPath {
+    fn border_translation(&self, _time: f32) -> DVec2 {
+        // TODO: def should not unwrap here
+        let p = self.path.iter().last().unwrap().end_point().unwrap_or_default().to_vec2();
+
+        DVec2::new(p.x, p.y)
+    }
+
+    fn border_tangent(&self, _time: f32) -> f64 {
+        self.border_translation(f32::default()).to_angle()
+    }
+}

src/circle.rs

@@ -1,6 +1,8 @@
-use bevy::prelude::*;
+use bevy::{math::DVec2, prelude::*};
 use bevy_vello::prelude::*;
 
+use crate::VectorBorder;
+
 use super::VelloVector;
 
 #[derive(Component, Default, Debug, Clone, Copy)]
@@ -24,3 +26,13 @@ impl VelloVector for VelloCircle {
         kurbo::Circle::new(kurbo::Point::default(), self.radius)
     }
 }
+
+impl VectorBorder for VelloCircle {
+    fn border_translation(&self, _time: f32) -> DVec2 {
+        DVec2::new(0.0, self.radius)
+    }
+
+    fn border_tangent(&self, _time: f32) -> f64 {
+        0.0
+    }
+}

src/head.rs

@@ -1,4 +1,4 @@
-use bevy::{prelude::*, utils::Uuid};
+use bevy::{math::DVec2, prelude::*, utils::Uuid};
 
 use bevy_vello::prelude::*;
 
@@ -9,7 +9,7 @@ pub struct ShapeId(Uuid);
 pub struct Head {
     pub shape_id: ShapeId,
 
-    pub scale: f64,
+    pub scale: f32,
     pub offset: f32,
     pub rotation_offset: f32,
 }
@@ -20,7 +20,8 @@ pub struct Shapes {
 }
 
 pub trait VectorBorder {
-    fn border_translation(&self, time: f32) -> kurbo::Vec2;
-    /// returns the gradient of the tangent to the border
+    /// translation of the chosen "apex"
+    fn border_translation(&self, time: f32) -> DVec2;
+    /// gradient of the tangent to the border
     fn border_tangent(&self, time: f32) -> f64;
 }

src/lib.rs

@@ -39,6 +39,10 @@ impl Plugin for VelloGraphicsPlugin {
                 build_vector::<VelloCircle>(),
                 build_vector::<VelloLine>(),
                 build_vector::<VelloBezPath>(),
+                build_head::<VelloRect>(),
+                build_head::<VelloCircle>(),
+                build_head::<VelloLine>(),
+                build_head::<VelloBezPath>(),
             ),
         );
     }
@@ -70,19 +74,19 @@ pub trait VelloVector {
     }
 }
 
-pub(crate) fn build_vector<
-    Vector: VelloVector + Component,
-    HeadEquipt: VelloVector + VectorBorder + Component,
->() -> SystemConfigs {
+pub(crate) fn build_vector<Vector: VelloVector + Component>() -> SystemConfigs {
     (
-        append_heads::<HeadEquipt>,
         build_fill_only_vector::<Vector>,
         build_stroke_only_vector::<Vector>,
         build_fill_and_stroke_vector::<Vector>,
     )
         .into_configs()
 }
 
+pub(crate) fn build_head<HeadEquipt: VelloVector + VectorBorder + Component>() -> SystemConfigs {
+    append_heads::<HeadEquipt>.into_configs()
+}
+
 #[allow(clippy::type_complexity)]
 fn append_heads<HeadEquipt: VelloVector + VectorBorder + Component>(
     mut q_vectors: Query<
@@ -96,13 +100,14 @@ fn append_heads<HeadEquipt: VelloVector + VectorBorder + Component>(
 
     for (vector, head, mut scene) in q_vectors.iter_mut() {
         let translation = vector.border_translation(time);
+        let translation = kurbo::Vec2::new(translation.x, translation.y);
         let tangent = vector.border_tangent(time);
         let rotation = tangent.atan();
 
         let transform = kurbo::Affine::default()
             .with_translation(translation)
             .then_rotate(rotation)
-            .then_scale(head.scale);
+            .then_scale(head.scale as f64);
 
         let head_scene = shapes.scenes.get(&head.shape_id);
         if let Some(head_scene) = head_scene {

src/line.rs

@@ -1,6 +1,8 @@
 use bevy::{math::DVec2, prelude::*};
 use bevy_vello::prelude::*;
 
+use crate::VectorBorder;
+
 use super::VelloVector;
 
 #[derive(Component, Default, Debug, Clone, Copy)]
@@ -40,3 +42,13 @@ impl VelloVector for VelloLine {
         )
     }
 }
+
+impl VectorBorder for VelloLine {
+    fn border_translation(&self, _time: f32) -> DVec2 {
+        self.p1
+    }
+
+    fn border_tangent(&self, _time: f32) -> f64 {
+        (self.p1.y - self.p0.y) / (self.p1.x - self.p0.x)
+    }
+}

src/rect.rs

@@ -1,6 +1,8 @@
 use bevy::{math::DVec2, prelude::*};
 use bevy_vello::prelude::*;
 
+use crate::VectorBorder;
+
 use super::VelloVector;
 
 #[derive(Component, Default, Debug, Clone, Copy)]
@@ -46,3 +48,13 @@ impl VelloVector for VelloRect {
         )
     }
 }
+
+impl VectorBorder for VelloRect {
+    fn border_translation(&self, _time: f32) -> DVec2 {
+        DVec2::new(self.anchor.x, (1.0 - self.anchor.y) * self.size.y)
+    }
+
+    fn border_tangent(&self, _time: f32) -> f64 {
+        0.0
+    }
+}