Add vector

Cargo.lock

@@ -11,6 +11,15 @@ dependencies = [
  "memchr",
 ]
 
+[[package]]
+name = "approx"
+version = "0.5.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "cab112f0a86d568ea0e627cc1d6be74a1e9cd55214684db5561995f6dad897c6"
+dependencies = [
+ "num-traits",
+]
+
 [[package]]
 name = "autocfg"
 version = "1.1.0"
@@ -424,6 +433,7 @@ checksum = "c811ca4a8c853ef420abd8592ba53ddbbac90410fab6903b3e79972a631f7680"
 name = "wipe"
 version = "2.0.0"
 dependencies = [
+ "approx",
  "crossterm",
  "mockall",
 ]

Cargo.toml

@@ -11,3 +11,4 @@ crossterm = "0.24"
 
 [dev-dependencies]
 mockall = "0.11"
+approx = "0.5"

src/main.rs

@@ -1,6 +1,8 @@
 pub mod error;
+mod pattern;
 pub mod printer;
 pub mod term;
+mod vec;
 
 fn main() -> Result<(), error::Error> {
     Ok(())

src/vec.rs

@@ -0,0 +1,69 @@
+use std::ops::Sub;
+
+#[derive(Copy, Clone, PartialEq, Debug)]
+pub struct Vector {
+    pub x: f32,
+    pub y: f32,
+}
+
+impl Vector {
+    pub fn new(x: f32, y: f32) -> Self {
+        Self { x, y }
+    }
+
+    pub fn len(&self) -> f32 {
+        (self.x * self.x + self.y * self.y).sqrt()
+    }
+
+    pub fn center(&self) -> Vector {
+        Self::new(self.x / 2.0, self.y / 2.0)
+    }
+
+    pub fn angle(&self) -> f32 {
+        self.y.atan2(self.x)
+    }
+}
+
+impl Sub for Vector {
+    type Output = Vector;
+
+    fn sub(self, rhs: Self) -> Self::Output {
+        Self::new(self.x - rhs.x, self.y - rhs.y)
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+    use approx::*;
+
+    #[test]
+    fn new() {
+        let v = Vector::new(4.0, 7.0);
+        assert_eq!(4.0, v.x);
+        assert_eq!(7.0, v.y);
+    }
+
+    #[test]
+    fn len() {
+        assert_abs_diff_eq!(8.5, Vector::new(3.0, 8.0).len(), epsilon = 0.1);
+    }
+
+    #[test]
+    fn center() {
+        assert_eq!(Vector::new(4.0, 9.0), Vector::new(8.0, 18.0).center());
+    }
+
+    #[test]
+    fn angle() {
+        assert_abs_diff_eq!(-1.5, Vector::new(2.0, -20.0).angle(), epsilon = 0.1);
+    }
+
+    #[test]
+    fn sub() {
+        assert_eq!(
+            Vector::new(-5.0, 10.0),
+            Vector::new(3.0, 16.0) - Vector::new(8.0, 6.0)
+        );
+    }
+}