[web] Added procedural color generation

web/src/contrast.rs

@@ -0,0 +1,72 @@
+#![cfg(feature = "ogp_images")]
+
+use image::{Pixel, Rgb, Rgba};
+use pronouns_today::util::pcg64;
+
+pub fn generate_color_pair(state: &mut u128) -> ([u8; 3], [u8; 3]) {
+	let mut background = random_color(state);
+	let mut foreground;
+	loop {
+		foreground = random_color(state);
+		if meets_criteria(&foreground, &background) {
+			break;
+		}
+		background = random_color(state);
+		if meets_criteria(&foreground, &background) {
+			break;
+		}
+	}
+	(foreground, background)
+}
+
+pub fn generate_color_pair_rgba(state: &mut u128) -> (Rgba<u8>, Rgba<u8>) {
+	let (color1, color2) = generate_color_pair(state);
+
+	let (color1, color2): (Rgb<u8>, Rgb<u8>) = (
+		color1.into(),
+		color2.into(),
+	);
+
+	(color1.to_rgba(), color2.to_rgba())
+}
+
+pub fn relative_lum(color: &[u8; 3]) -> f32 {
+	let color_mapped: Vec<f32> = color.iter()
+		.map(|val| {
+			let val = *val as f32 / 255.0;
+			if val < 0.03928 {
+				val / 12.92
+			} else {
+				((val+0.055)/1.055).powf(2.4)
+			}
+		})
+		.collect();
+	return 0.2126 * color_mapped[0] + 0.7152 * color_mapped[1] + 0.0722 * color_mapped[2]
+}
+
+pub fn check_contrast(color1: &[u8; 3], color2: &[u8; 3]) -> f32 {
+	let a = 0.05 + relative_lum(color1);
+	let b = 0.05 + relative_lum(color2);
+	(a / b).max(b / a)
+}
+
+pub fn get_saturation(color: &[u8; 3]) -> f32 {
+	let chroma_max = *(color.iter().max().unwrap());
+	let chroma_min = *(color.iter().min().unwrap());
+	return ((chroma_max - chroma_min) as f32) / chroma_max as f32;
+}
+
+pub fn random_color(state: &mut u128) -> [u8; 3] {
+	let random = pcg64(state).to_le_bytes();
+	return [
+		random[0],
+		random[1],
+		random[2],
+	]
+}
+
+pub fn meets_criteria(foreground: &[u8; 3], background: &[u8; 3]) -> bool {
+	return check_contrast(foreground, background) >= 5.0 &&
+		   get_saturation(background) < 0.65 &&
+		   get_saturation(foreground) < 0.65
+}

web/src/main.rs

@@ -1,4 +1,5 @@
 pub mod ogp_images;
+pub mod contrast;
 
 use std::collections::HashMap;
 use std::fmt::{self, Display};

web/src/ogp_images.rs

@@ -1,8 +1,10 @@
 #![cfg(feature = "ogp_images")]
 
+use crate::contrast::generate_color_pair_rgba;
+
 use image::{DynamicImage, ImageBuffer, Pixel, Rgb, Rgba};
 use lazy_static::lazy_static;
-use pronouns_today::Pronoun;
+use pronouns_today::{Pronoun, util::{self, pcg64_seed, seed_with_today}};
 use rusttype::{Font, Scale, point};
 
 const SCALE: u32 = 400;
@@ -13,9 +15,16 @@ lazy_static! {
 		.expect("Invalid font data in build.  This build and binary is invalid, and cannot be used.");
 }
 
-pub fn render(pronouns: &Pronoun) -> ImageBuffer<Rgb<u8>, Vec<u8>> {
-	// TODO:  Use a real seed here
-	let (color1, color2) = generate_color_pair(&[13, 12]);
+pub fn render_today(pronouns: &Pronoun, name: &str) -> ImageBuffer<Rgb<u8>, Vec<u8>> {
+	let mut state = util::INITIAL_STATE;
+
+	seed_with_today(&mut state);
+	pcg64_seed(&mut state, name.as_bytes());
+
+	render(pronouns, &mut state)
+}
+pub fn render(pronouns: &Pronoun, pcg64: &mut u128) -> ImageBuffer<Rgb<u8>, Vec<u8>> {
+	let (color1, color2) = generate_color_pair_rgba(pcg64);
 
 	render_with_colors(pronouns, color1, color2)
 }
@@ -74,7 +83,3 @@ pub fn render_with_colors(pronouns: &Pronoun, color1: Rgba<u8>, color2: Rgba<u8>
 
 	image::DynamicImage::ImageRgba8(output_image).into_rgb8()
 }
-
-pub fn generate_color_pair(seed: &[u8]) -> (Rgba<u8>, Rgba<u8>) {
-	todo!();
-}