1 files changed, 81 insertions, 0 deletions
diff --git a/old/evc/src/helpers/pixel.rs b/old/evc/src/helpers/pixel.rs
new file mode 100644
index 0000000..39fe98c
--- /dev/null
+++ b/old/evc/src/helpers/pixel.rs
@@ -0,0 +1,81 @@
+use crate::format::ser::{Ser, Sink, Source};
+
+#[derive(Copy, Clone, Debug, Default, PartialEq)]
+pub struct Pixel {
+    pub r: u8,
+    pub g: u8,
+    pub b: u8,
+}
+
+impl Ser for Pixel {
+    fn write(&self, sink: &mut impl std::io::Write) -> anyhow::Result<()> {
+        sink.put((self.r, self.g, self.b))
+    }
+
+    fn read(source: &mut impl std::io::Read) -> anyhow::Result<Self> {
+        let (r, g, b) = source.get()?;
+        Ok(Self { r, g, b })
+    }
+}
+
+impl Pixel {
+    pub const BLACK: Pixel = Pixel { r: 0, g: 0, b: 0 };
+    #[inline]
+    pub fn distance(a: Pixel, b: Pixel) -> usize {
+        let (rd, gd, bd) = (
+            a.r.abs_diff(b.r) as usize,
+            a.g.abs_diff(b.g) as usize,
+            a.b.abs_diff(b.b) as usize,
+        );
+        // fast_sqrt(rd * rd + gd * gd + bd * bd)
+        // SQRT[rd + gd + bd]
+        rd + gd + bd
+    }
+
+    #[inline]
+    pub fn average(a: Pixel, b: Pixel) -> Pixel {
+        Pixel {
+            r: ((a.r as u16 + b.r as u16) >> 1) as u8,
+            g: ((a.g as u16 + b.g as u16) >> 1) as u8,
+            b: ((a.b as u16 + b.b as u16) >> 1) as u8,
+        }
+    }
+
+    #[inline]
+    pub fn scale(&self, factor: f32) -> Pixel {
+        Pixel {
+            r: ((self.r as f32) * factor).clamp(0.0, 255.0) as u8,
+            g: ((self.g as f32) * factor).clamp(0.0, 255.0) as u8,
+            b: ((self.b as f32) * factor).clamp(0.0, 255.0) as u8,
+        }
+    }
+}
+
+pub const SQRT: [usize; 256 * 3] = gen_sqrt_lookup();
+
+const fn gen_sqrt_lookup<const N: usize>() -> [usize; N] {
+    let mut arr = [0; N];
+    let mut i = 0;
+    while i < N {
+        arr[i] = sqrt(i as f32) as usize;
+        i += 1;
+    }
+    arr
+}
+
+const fn sqrt(x: f32) -> f32 {
+    let a = 1.0;
+    let a = (a + x / a) * 0.5;
+    let a = (a + x / a) * 0.5;
+    let a = (a + x / a) * 0.5;
+    a
+}
+
+pub fn fast_sqrt(x: usize) -> usize {
+    let a = 1;
+    let a = (a + x / (a + 1)) / 2;
+    let a = (a + x / (a + 1)) / 2;
+    // let a = (a + x / (a + 1)) / 2;
+    // let a = (a + x / (a + 1)) / 2;
+    a
+}