Add apply palette transform

lapix/src/color.rs

@@ -91,6 +91,14 @@ impl ColorF32 {
     pub const fn new(r: f32, g: f32, b: f32, a: f32) -> Self {
         Self { r, g, b, a }
     }
+
+    pub fn dist(&self, other: &Self) -> f32 {
+        ((self.r - other.r).powf(2.)
+            + (self.g - other.g).powf(2.)
+            + (self.b - other.b).powf(2.)
+            + (self.a - other.a).powf(2.))
+        .sqrt()
+    }
 }
 
 impl Color {

lapix/src/lib.rs

@@ -20,7 +20,7 @@ mod util;
 use action::{Action, AtomicAction};
 pub use bitmap::Bitmap;
 pub use canvas::{Canvas, CanvasEffect};
-pub use color::Color;
+pub use color::{Color, ColorF32};
 pub use error::{Error, Result};
 pub use event::Event;
 pub use floating::FreeImage;

lapix/src/state.rs

@@ -328,8 +328,10 @@ impl<IMG: Bitmap + Serialize + for<'de> Deserialize<'de>> State<IMG> {
                 if let Some(Selection::Canvas(_)) = self.selection {
                     self.free_image_from_selection(None);
                 }
+
+                let palette = self.palette().to_vec();
                 if let Some(free_img) = self.free_image.as_mut() {
-                    t.apply(&mut free_img.texture);
+                    t.apply(&mut free_img.texture, palette);
                 }
             }
             Event::NewLayerAbove => {

lapix/src/transform.rs

@@ -1,19 +1,22 @@
 //! Functions that can be applied to an image, modifying it
 
-use crate::{color, Bitmap};
+use crate::Color;
+use crate::{color, Bitmap, ColorF32};
 use serde::{Deserialize, Serialize};
 
 #[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
 pub enum Transform {
     Identity,
     Silhouete,
+    ApplyPalette,
 }
 
 impl Transform {
-    pub fn apply<IMG: Bitmap>(&self, image: &mut IMG) {
+    pub fn apply<IMG: Bitmap>(&self, image: &mut IMG, palette: Vec<Color>) {
         match self {
             Self::Identity => (),
             Self::Silhouete => Self::silhouette(image),
+            Self::ApplyPalette => Self::apply_palette(image, &palette),
         }
     }
 
@@ -28,4 +31,27 @@ impl Transform {
             }
         }
     }
+
+    fn apply_palette<IMG: Bitmap>(image: &mut IMG, palette: &[Color]) {
+        for i in 0..image.width() {
+            for j in 0..image.height() {
+                let p = (i, j).into();
+                let color = image.pixel(p);
+
+                let mut min_dist = f32::MAX;
+                let mut min_index = 0;
+                for (i, palette_color) in palette.iter().enumerate() {
+                    let colorf: ColorF32 = (*palette_color).into();
+                    let dist = colorf.dist(&color.into());
+
+                    if dist < min_dist {
+                        min_dist = dist;
+                        min_index = i;
+                    }
+                }
+
+                image.set_pixel(p, palette[min_index]);
+            }
+        }
+    }
 }

tarsila/src/gui/menu.rs

@@ -165,6 +165,10 @@ impl MenuBar {
                         ui.close_menu();
                         events.push(Event::ApplyTransform(Transform::Silhouete).into());
                     }
+                    if ui.button("Apply palette").clicked() {
+                        ui.close_menu();
+                        events.push(Event::ApplyTransform(Transform::ApplyPalette).into());
+                    }
                 });
             });
         });