add hsv to rgb, not better looking

Cargo.lock

@@ -2979,6 +2979,12 @@ version = "1.0.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "216080ab382b992234dda86873c18d4c48358f5cfcb70fd693d7f6f2131b628b"
 
+[[package]]
+name = "rgb_hsv"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fec0123e8720dcbc31a22f3ecb7dc5cb41f4b73e361eca37d4acf0b04f572589"
+
 [[package]]
 name = "rustc-demangle"
 version = "0.1.23"
@@ -3366,6 +3372,7 @@ dependencies = [
  "pcap-parser",
  "png",
  "pyo3",
+ "rgb_hsv",
  "serde",
  "tokio",
  "tracing-subscriber",

Cargo.toml

@@ -19,6 +19,7 @@ pcap = { version = "1.2.0", features = ["capture-stream"] }
 pcap-parser = { version = "0.14.1", features = ["data"] }
 png = "0.17.10"
 pyo3 = { version = "0.20.0", "features" = ["extension-module"] }
+rgb_hsv = "1.0.1"
 serde = { version = "1.0.193", features = ["derive", "serde_derive", "alloc"] }
 tokio = { version = "1.36.0", features = ["full"] }
 tracing-subscriber = "0.3.18"

src/stream.rs

@@ -26,6 +26,18 @@ fn pixel_to_celcius(x: u16) -> u16 {
     (t * 256.0) as u16
 }
 
+/// https://en.wikipedia.org/wiki/HSL_and_HSV
+/// convert to the expected dynamic range first. We insert values in [0..256)
+/// h in [0, 360] degrees
+/// s in [0, 1]
+/// v in [0, 1]
+fn once_upon_a_time_hsv2rgb(h: u8, s: u8, v: u8) -> (u8, u8, u8) {
+    let h = (h as f64) / 256.0 * 360.0;
+    let s = (s as f64) / 256.0;
+    let v = (v as f64) / 256.0;
+    (0, 0, 0)
+}
+
 fn main() -> anyhow::Result<()> {
     let args = Args::parse();
     dotenv().ok();
@@ -121,12 +133,13 @@ fn main() -> anyhow::Result<()> {
                         let cutoff = args.red_cutoff.unwrap();
                         let (r, g, b) = if pixel > (256.0 * cutoff) as u16 {
                             let p = pixel - (256.0 * cutoff) as u16;
-                            let p = (p / 256).max(127);
-                            ((128 + p) as u8, 0, 0)
+                            let (r, g, b) = rgb_hsv::hsv_to_rgb((0.0, p as f32, 0.0));
+                            (r as u8, g as u8, b as u8)
                         } else {
-                            let g = frame[i * 2];
-                            let b = frame[i * 2 + 1];
-                            (0, g, b)
+                            let h = frame[i * 2] as f32;
+                            let v = frame[i * 2 + 1] as f32;
+                            let (r, g, b) = rgb_hsv::hsv_to_rgb((h, 0.0, v));
+                            (r as u8, g as u8, b as u8)
                         };
                         let out_i = ((HEIGHT - 1 - y) + (WIDTH - 1 - x) * HEIGHT) * 4;
                         swapped[out_i..out_i + 4].copy_from_slice(&[0, r, g, b]);