Blank is Black rather

src/main.rs

@@ -4,9 +4,9 @@ use anyhow::Result;
 use clap::{app_from_crate, crate_authors, crate_description, crate_name, crate_version, Arg};
 use io::Write;
 use lasy::{
-    euler_graph_to_euler_circuit, interpolate_euler_circuit, point_graph_to_euler_graph,
-    points_to_segments, segments_to_point_graph, Blanked, InterpolationConfig, IsBlank, Lerp,
-    Position, Weight,
+    blank_segment_points, euler_graph_to_euler_circuit, interpolate_euler_circuit,
+    point_graph_to_euler_graph, points_to_segments, segments_to_point_graph, Blanked,
+    InterpolationConfig, IsBlank, Lerp, Position, Weight,
 };
 
 type InputArrayEntry = (f32, f32, u32);
@@ -50,14 +50,14 @@ impl Position for Point {
 
 impl IsBlank for Point {
     fn is_blank(&self) -> bool {
-        self.color == 0xffffff
+        self.color == 0
     }
 }
 
 impl Blanked for Point {
     fn blanked(&self) -> Self {
         Self {
-            color: 0xffffff,
+            color: 0,
             ..*self
         }
     }
@@ -172,14 +172,55 @@ fn main() -> Result<()> {
             .expect("radians-per-point must be a float")
     }
 
+    let mut last_frames = vec![];
+
     loop {
         let mut line = String::new();
         io::stdin().read_line(&mut line)?;
 
-        serde_json::to_writer(
-            io::stdout(),
-            &optimize_line(default_weight, &line, &config)?,
-        )?;
+        last_frames.push(optimize_line(default_weight, &line, &config)?);
+
+        if last_frames.len() == 2 {
+            let a: Vec<Point> = last_frames
+                .first()
+                .unwrap()
+                .iter()
+                .map(|(x, y, color)| Point {
+                    x: *x,
+                    y: *y,
+                    color: *color,
+                    weight: default_weight,
+                })
+                .collect();
+
+            let b: Vec<Point> = last_frames
+                .last()
+                .unwrap()
+                .iter()
+                .map(|(x, y, color)| Point {
+                    x: *x,
+                    y: *y,
+                    color: *color,
+                    weight: default_weight,
+                })
+                .collect();
+
+            let c: Vec<InputArrayEntry> = a
+                .into_iter()
+                .zip(b.into_iter())
+                .map(|(a, b)| blank_segment_points(a, b, config.blank_delay_points))
+                .flatten()
+                .map(|p| (p.x, p.y, p.color))
+                .collect();
+
+            serde_json::to_writer(io::stdout(), &c)?;
+            io::stdout().write(b"\n")?;
+            io::stdout().flush()?;
+
+            last_frames.remove(0);
+        }
+
+        serde_json::to_writer(io::stdout(), &last_frames.last())?;
         io::stdout().write(b"\n")?;
         io::stdout().flush()?;
     }