automatic color mapping

examples/bitmask-slice.toml

@@ -117,6 +117,10 @@ delays = [10, 20]
 [map_icon]
 # The name of the icon_state the resulting generated icon will use
 icon_state_name = "map_icon"
+# Attempt to automatically derive colors from the input icon
+# if true, base_color, text_color, and outer_border will be ignored
+# Optional, defaults to false if omitted
+automatic = false
 # The base color to use for the icon
 # Accepts any hex color
 base_color = "#FFFFFF"

hypnagogic_core/src/config/blocks/generators.rs

@@ -1,6 +1,7 @@
 use crate::generation::rect::{Border, BorderStyle};
 use crate::generation::text::Alignment;
 use crate::util::color::Color;
+use crate::util::icon_ops::pick_contrasting_colors;
 use serde::{Deserialize, Serialize};
 
 #[derive(Debug, Clone, Copy, Eq, PartialEq, Default, Serialize, Deserialize)]
@@ -41,6 +42,8 @@ fn default_alignment() -> Alignment {
 #[derive(Debug, Clone, Eq, PartialEq, Serialize, Deserialize)]
 pub struct MapIcon {
     pub icon_state_name: String,
+    #[serde(default)]
+    pub automatic: bool,
     #[serde(default = "white")]
     pub base_color: Color,
     #[serde(default)]
@@ -61,6 +64,7 @@ impl Default for MapIcon {
     fn default() -> Self {
         Self {
             icon_state_name: "map_icon".to_string(),
+            automatic: false,
             base_color: Color::new(255, 255, 255, 255),
             text: Some("DEF".to_string()),
             text_color: Color::new(0, 0, 0, 255),
@@ -74,3 +78,18 @@ impl Default for MapIcon {
         }
     }
 }
+
+impl MapIcon {
+    pub fn gen_colors(&mut self, colors: &[Color]) {
+        if !self.automatic {
+            return;
+        }
+        let sorted_colors = pick_contrasting_colors(colors);
+        self.base_color = sorted_colors.0;
+        self.text_color = sorted_colors.1;
+        self.outer_border = Some(Border {
+            style: BorderStyle::Solid,
+            color: sorted_colors.1,
+        });
+    }
+}

hypnagogic_core/src/util/color.rs

@@ -95,6 +95,11 @@ impl Color {
             self.red, self.green, self.blue, self.alpha
         )
     }
+
+    #[must_use]
+    pub fn luminance(&self) -> f32 {
+        (0.299 * self.red as f32 + 0.587 * self.green as f32 + 0.114 * self.blue as f32) / 255.0
+    }
 }
 
 impl Serialize for Color {

hypnagogic_core/src/util/icon_ops.rs

@@ -1,5 +1,6 @@
+use crate::util::color::Color;
 use dmi::icon::IconState;
-use image::DynamicImage;
+use image::{DynamicImage, GenericImageView};
 
 // Removes duplicate frames from the icon state's animation, if it has any
 #[must_use]
@@ -54,3 +55,34 @@ pub fn dedupe_frames(icon_state: IconState) -> IconState {
         ..icon_state
     }
 }
+
+#[must_use]
+pub fn colors_in_image(image: &DynamicImage) -> Vec<Color> {
+    let mut colors = Vec::new();
+    for pixel in image.pixels() {
+        let color = pixel.2;
+        if !colors.contains(&color) {
+            colors.push(color);
+        }
+    }
+    colors
+        .iter()
+        .map(|c| Color::new(c.0[0], c.0[1], c.0[2], c.0[3]))
+        .collect()
+}
+
+pub fn sort_colors_by_luminance(colors: &mut Vec<Color>) {
+    colors.sort_by(|a, b| a.luminance().partial_cmp(&b.luminance()).unwrap());
+}
+
+#[must_use]
+pub fn pick_contrasting_colors(colors: &[Color]) -> (Color, Color) {
+    let mut sorted_colors = colors.to_vec();
+    sort_colors_by_luminance(&mut sorted_colors);
+    let len_as_f32 = colors.len() as f32;
+    let first = 0.10 * len_as_f32;
+    let first_index = (first.floor() as usize).saturating_sub(1);
+    let second = 0.90 * len_as_f32;
+    let second_index = (second.floor() as usize).saturating_sub(1);
+    (sorted_colors[first_index], sorted_colors[second_index])
+}