Add more pixel formats and implement for_each and map for image

src/image.rs

@@ -1,15 +1,6 @@
 pub mod farbfeld;
-
 pub use farbfeld::*;
 
-#[derive(Clone, Copy, Debug, PartialEq)]
-pub struct SRGBA {
-    pub r: f32,
-    pub g: f32,
-    pub b: f32,
-    pub a: f32,
-}
-
 #[derive(Clone, Copy, Debug, Eq, PartialEq)]
 pub struct Extent {
     pub x: usize,
@@ -28,6 +19,28 @@ pub enum Error {
     Io(std::io::Error),
 }
 
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub struct SRGBA {
+    pub r: f32,
+    pub g: f32,
+    pub b: f32,
+    pub a: f32,
+}
+
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub struct SRGB {
+    pub r: f32,
+    pub g: f32,
+    pub b: f32,
+}
+
+#[derive(Clone, Copy, Debug, PartialEq)]
+pub struct LinearRGB {
+    pub r: f32,
+    pub g: f32,
+    pub b: f32,
+}
+
 pub trait Format<P> {
     fn read<I>(input: &mut I) -> Result<Image<P>, Error>
     where
@@ -38,18 +51,6 @@ pub trait Format<P> {
         O: std::io::Write;
 }
 
-impl Extent {
-    pub fn size(&self) -> usize {
-        self.x * self.y
-    }
-}
-
-impl SRGBA {
-    pub fn new(r: f32, g: f32, b: f32, a: f32) -> Self {
-        Self { r, g, b, a }
-    }
-}
-
 pub trait Pixel:
     std::ops::AddAssign
     + std::ops::MulAssign<f32>
@@ -59,6 +60,8 @@ pub trait Pixel:
     + Clone
     + Copy
     + Default
+    + Send
+    + Sync
     + Sized
 {
 }
@@ -72,10 +75,115 @@ impl<P> Pixel for P where
         + Clone
         + Copy
         + Default
+        + Send
+        + Sync
         + Sized
 {
 }
 
+impl Extent {
+    pub fn size(&self) -> usize {
+        self.x * self.y
+    }
+}
+
+impl<P: Pixel> Image<P> {
+    pub fn load<F: Format<P>>(path: &str) -> Result<Image<P>, Error> {
+        let file = std::fs::File::open(path)?;
+        F::read(&mut std::io::BufReader::new(file))
+    }
+
+    pub fn save<F: Format<P>>(&self, path: &str) -> std::io::Result<()> {
+        let file = std::fs::File::create(path)?;
+        F::write(&mut std::io::BufWriter::new(file), self)
+    }
+
+    pub fn with_extent(extent: Extent) -> Self {
+        let mut pixels = Vec::with_capacity(extent.size());
+        pixels.resize(extent.size(), P::default());
+        Self { extent, pixels }
+    }
+
+    pub fn for_each<F>(&mut self, f: F)
+    where
+        F: Fn(usize, usize, &mut P) + Send + Sync,
+    {
+        if let Ok(count) = std::thread::available_parallelism() {
+            self.for_each_parallel(f, count.get())
+        } else {
+            Self::for_each_thread(
+                f,
+                self.pixels.as_mut_slice(),
+                0,
+                self.extent.x,
+            )
+        }
+    }
+
+    pub fn map<F, Q>(&self, f: F) -> Image<Q>
+    where
+        F: Fn(P) -> Q + Send + Sync,
+        Q: Pixel,
+    {
+        let mut img = Image::with_extent(self.extent);
+        img.for_each(|x, y, p| {
+            *p = f(self.pixels[self.extent.x * y + x]);
+        });
+        img
+    }
+
+    fn for_each_parallel<F>(&mut self, f: F, n: usize)
+    where
+        F: Fn(usize, usize, &mut P) + Send + Sync,
+    {
+        let row = self.extent.x;
+        let per_thread = self.extent.size() / n;
+        let rem = self.extent.size() % n;
+
+        std::thread::scope(|scope| {
+            let mut rest = self.pixels.as_mut_slice();
+            let mut buf: &mut [P];
+            {
+                let count = per_thread + rem;
+                (buf, rest) = rest.split_at_mut(count);
+                let fref = &f;
+                scope.spawn(move || Self::for_each_thread(fref, buf, 0, row));
+            }
+            for i in 1..n {
+                (buf, rest) = rest.split_at_mut(per_thread);
+                let start = i * per_thread + rem;
+                let fref = &f;
+                scope.spawn(move || {
+                    Self::for_each_thread(fref, buf, start, row)
+                });
+            }
+        });
+    }
+
+    fn for_each_thread<F>(f: F, pixels: &mut [P], start: usize, row: usize)
+    where
+        F: Fn(usize, usize, &mut P),
+    {
+        for i in 0..pixels.len() {
+            let x = (start + i) % row;
+            let y = (start + i) / row;
+            f(x, y, &mut pixels[i]);
+        }
+    }
+}
+
+impl From<std::io::Error> for Error {
+    fn from(error: std::io::Error) -> Self {
+        Error::Io(error)
+    }
+}
+
+impl SRGBA {
+    pub fn new(r: f32, g: f32, b: f32, a: f32) -> Self {
+        Self { r, g, b, a }
+    }
+}
+
 impl std::ops::AddAssign for SRGBA {
     fn add_assign(&mut self, other: SRGBA) {
         self.r += other.r;
@@ -132,20 +240,156 @@ impl std::default::Default for SRGBA {
     }
 }
 
-impl From<std::io::Error> for Error {
-    fn from(error: std::io::Error) -> Self {
-        Error::Io(error)
+impl SRGB {
+    pub fn new(r: f32, g: f32, b: f32) -> Self {
+        Self { r, g, b }
     }
 }
 
-impl<P> Image<P> {
-    pub fn load<F: Format<P>>(path: &str) -> Result<Image<P>, Error> {
-        let file = std::fs::File::open(path)?;
-        F::read(&mut std::io::BufReader::new(file))
-    }
-
-    pub fn save<F: Format<P>>(&self, path: &str) -> std::io::Result<()> {
-        let file = std::fs::File::create(path)?;
-        F::write(&mut std::io::BufWriter::new(file), self)
+impl std::ops::AddAssign for SRGB {
+    fn add_assign(&mut self, other: SRGB) {
+        self.r += other.r;
+        self.g += other.g;
+        self.b += other.b;
+    }
+}
+
+impl std::ops::MulAssign<f32> for SRGB {
+    fn mul_assign(&mut self, scalar: f32) {
+        self.r *= scalar;
+        self.g *= scalar;
+        self.b *= scalar;
+    }
+}
+
+impl std::ops::DivAssign<f32> for SRGB {
+    fn div_assign(&mut self, scalar: f32) {
+        self.r /= scalar;
+        self.g /= scalar;
+        self.b /= scalar;
+    }
+}
+
+impl std::ops::Mul<f32> for SRGB {
+    type Output = Self;
+
+    fn mul(mut self, scalar: f32) -> Self {
+        self *= scalar;
+        self
+    }
+}
+
+impl std::ops::Div<f32> for SRGB {
+    type Output = Self;
+
+    fn div(mut self, scalar: f32) -> Self {
+        self /= scalar;
+        self
+    }
+}
+
+impl std::default::Default for SRGB {
+    fn default() -> Self {
+        Self {
+            r: 0.0,
+            g: 0.0,
+            b: 0.0,
+        }
+    }
+}
+
+impl LinearRGB {
+    pub fn new(r: f32, g: f32, b: f32) -> Self {
+        Self { r, g, b }
+    }
+}
+
+impl std::ops::AddAssign for LinearRGB {
+    fn add_assign(&mut self, other: LinearRGB) {
+        self.r += other.r;
+        self.g += other.g;
+        self.b += other.b;
+    }
+}
+
+impl std::ops::MulAssign<f32> for LinearRGB {
+    fn mul_assign(&mut self, scalar: f32) {
+        self.r *= scalar;
+        self.g *= scalar;
+        self.b *= scalar;
+    }
+}
+
+impl std::ops::DivAssign<f32> for LinearRGB {
+    fn div_assign(&mut self, scalar: f32) {
+        self.r /= scalar;
+        self.g /= scalar;
+        self.b /= scalar;
+    }
+}
+
+impl std::ops::Mul<f32> for LinearRGB {
+    type Output = Self;
+
+    fn mul(mut self, scalar: f32) -> Self {
+        self *= scalar;
+        self
+    }
+}
+
+impl std::ops::Div<f32> for LinearRGB {
+    type Output = Self;
+
+    fn div(mut self, scalar: f32) -> Self {
+        self /= scalar;
+        self
+    }
+}
+
+impl std::default::Default for LinearRGB {
+    fn default() -> Self {
+        Self {
+            r: 0.0,
+            g: 0.0,
+            b: 0.0,
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn f32_image_created_with_extent_has_all_zeros() {
+        let img = Image::<f32>::with_extent(Extent { x: 10, y: 10 });
+        assert_eq!(img.pixels.len(), 100);
+        for pixel in img.pixels {
+            assert_eq!(pixel, 0.0);
+        }
+    }
+
+    #[test]
+    fn f32_image_for_each() {
+        let mut img = Image::<f32>::with_extent(Extent { x: 10, y: 10 });
+        img.for_each(|x, y, p| *p = (x + y) as f32);
+        for x in 0..img.extent.x {
+            for y in 0..img.extent.y {
+                assert_eq!(img.pixels[y * img.extent.x + x], (x + y) as f32);
+            }
+        }
+    }
+
+    #[test]
+    fn f32_image_map() {
+        let mut img = Image::<f32>::with_extent(Extent { x: 10, y: 10 });
+        for i in 0..img.extent.size() {
+            img.pixels[i] = i as f32;
+        }
+        let res = img.map(|p| p * 2.0);
+        assert_eq!(res.extent, img.extent);
+        for i in 0..res.extent.size() {
+            assert_eq!(res.pixels[i], 2.0 * i as f32);
+        }
     }
 }