Add sampler

src/main.rs

@@ -7,6 +7,7 @@ mod vec;
 mod array;
 mod surface;
 mod animation;
+mod sampler;
 
 #[derive(Parser)]
 #[clap(author = "Rico Riedel", version = "0.1.0", about = "Wipe your terminal with a random animation.")]

src/sampler.rs

@@ -0,0 +1,104 @@
+use crossterm::style::Color;
+use crate::animation::Animation;
+use crate::char::CharSampler;
+use crate::color::ColorSampler;
+use crate::fill::FillMode;
+use crate::vec::Vector;
+
+pub enum Sample {
+    Keep,
+    Draw { char: char, color: Color },
+    Clear,
+}
+
+pub trait Sampler {
+    fn sample(&self, step: f32, pos: Vector) -> Sample;
+}
+
+pub struct ComposedSampler {
+    animation: Box<dyn Animation>,
+    fill: Box<dyn FillMode>,
+    color: Box<dyn ColorSampler>,
+    char: Box<dyn CharSampler>,
+}
+
+impl ComposedSampler {
+    pub fn new(animation: Box<dyn Animation>,
+               fill: Box<dyn FillMode>,
+               color: Box<dyn ColorSampler>,
+               char: Box<dyn CharSampler>) -> Self {
+        Self { animation, fill, color, char }
+    }
+}
+
+impl Sampler for ComposedSampler {
+    fn sample(&self, step: f32, pos: Vector) -> Sample {
+        let level = self.animation.sample(step, pos);
+
+        if level > 1.0 {
+            Sample::Keep
+        } else if level > 0.0 {
+            let char = self.char.sample(level);
+            let fill = self.fill.sample(level, pos);
+            let color = self.color.sample(fill);
+
+            Sample::Draw { char, color }
+        } else {
+            Sample::Clear
+        }
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use crate::char::SimpleCharSampler;
+    use super::*;
+
+    struct MockAnimation;
+    struct MockFillMode;
+    struct MockColorSampler;
+
+    impl Animation for MockAnimation {
+        fn sample(&self, step: f32, pos: Vector) -> f32 {
+            step + pos.x + pos.y
+        }
+    }
+    impl FillMode for MockFillMode {
+        fn sample(&self, level: f32, pos: Vector) -> f32 {
+            level + pos.x + pos.y
+        }
+    }
+    impl ColorSampler for MockColorSampler {
+        fn sample(&self, fill: f32) -> Color {
+            if fill > 0.5 {
+                Color::Green
+            } else {
+                Color::Red
+            }
+        }
+    }
+
+    fn create_sampler() -> ComposedSampler {
+        let anim = Box::new(MockAnimation { });
+        let fill = Box::new(MockFillMode { });
+        let color = Box::new(MockColorSampler { });
+        let char = Box::new(SimpleCharSampler::new("0123456789".to_string()));
+
+        ComposedSampler::new(anim, fill, color, char)
+    }
+
+    #[test]
+    fn sample_keep() {
+        assert!(matches!(create_sampler().sample(0.7, Vector::new(0.3, 0.1)), Sample::Keep));
+    }
+
+    #[test]
+    fn sample_draw() {
+        assert!(matches!(create_sampler().sample(0.4, Vector::new(0.1, 0.1)), Sample::Draw { char: '6', color: Color::Green }));
+    }
+
+    #[test]
+    fn sample_clear() {
+        assert!(matches!(create_sampler().sample(-1.0, Vector::new(0.4, 0.5)), Sample::Clear));
+    }
+}