first commit

src/lib.rs

@@ -0,0 +1,75 @@
+mod colormaps;
+
+use std::ops::Sub;
+use thiserror::Error;
+
+#[derive(Error, Debug)]
+pub enum ColorcetError {
+    #[error("no colormap with name {0} known")]
+    ColormapNotFound(String),
+}
+
+pub trait Int: Sub + Sized {
+    const MIN: Self;
+    const MAX: Self;
+}
+
+macro_rules! impl_int {
+    ($($t:tt),+ $(,)?) => {
+        $(
+            impl Int for $t {
+                const MIN: Self = $t::MIN;
+                const MAX: Self = $t::MAX;
+            }
+        )*
+    };
+}
+
+impl_int!(
+    u8, i8, u16, i16, u32, i32, u64, i64, u128, i128, isize, usize
+);
+
+pub struct ColorMap([[f64; 3]; 256]);
+
+impl ColorMap {
+    /// get a vector of rgb values, scaled between 0.0 and 1.0
+    pub fn get_colors_f64(&self) -> Vec<Vec<f64>> {
+        self.0.iter().map(|row| row.to_vec()).collect()
+    }
+
+    /// get a vector of rgb values, scaled between T::MIN and T::MAX
+    pub fn get_colors_int<T>(&self) -> Vec<Vec<T>>
+    where
+        T: Int + From<f64>,
+        f64: From<T>,
+    {
+        let a: f64 = T::MIN.into();
+        let b: f64 = T::MAX.into();
+        let c = b - a;
+        self.0
+            .iter()
+            .map(|row| row.iter().map(|&i| ((i - a) / c).round().into()).collect())
+            .collect()
+    }
+}
+
+/// find a colorcet colormap by name, add _r to reverse the colormap
+pub fn get_named_colormap(name: &str) -> Result<ColorMap, ColorcetError> {
+    let (name0, reverse) = if let Some(name) = name.strip_suffix("_r") {
+        (name, true)
+    } else {
+        (name, false)
+    };
+
+    if let Some(&alias) = colormaps::ALIASES.get(name0)
+        && let Some(cmap) = colormaps::COLOR_MAPS.get(alias)
+    {
+        let mut cmap = cmap.to_owned();
+        if reverse {
+            cmap.reverse();
+        }
+        Ok(ColorMap(cmap))
+    } else {
+        Err(ColorcetError::ColormapNotFound(name.into()))
+    }
+}