Add some documentation.

src/color.rs

@@ -56,6 +56,7 @@ pub fn set_style_alpha_in_place(style: &mut Style, factor: f32) {
     //style.visuals.widgets.noninteractive.bg_fill = Color32::TRANSPARENT;
 }
 
+/// Render some children with the specified alpha from 0 to 1.
 pub fn with_alpha<R>(
     ui: &mut Ui,
     alpha: f32,

src/component.rs

+/// See component directory.
 pub mod code;
 pub mod grid;

src/component/code.rs

@@ -29,7 +29,7 @@ impl Default for Code {
             size_pixels: 400.0,
             background: Color32::from_rgb(230, 230, 230),
             alpha: 1.0,
-            code: String::from(r#"println!("Hello world!");"#),
+            code: String::from(r#"println("Hello world!");"#),
         }
     }
 }
@@ -83,5 +83,6 @@ pub fn pseudocode(code: &str) -> String {
         .replace("mut ", "")
         .replace(": f32", "")
         .replace(" -> bool", "")
+        .replace("println!", "println")
         .replace(";\n", "\n")
 }

src/fade_in.rs

@@ -3,6 +3,7 @@ use crate::egui::{InnerResponse, Ui};
 
 const FADE_DURATION: f64 = 0.6;
 
+/// Fade in some children, assuming the fading in started at [`fade_start`].
 pub fn fade_in<R>(
     ui: &mut Ui,
     fade_start: f64,

src/governor.rs

+/// Good for rate-limiting certain things.
 #[derive(Default)]
 pub struct Governor {
     last: f64,
 }
 
 impl Governor {
+    /// Is the rate limit ready to allow another action?
     pub fn ready(&mut self, time: f64, limit: f64) -> bool {
         if time > self.last + limit {
             self.last = time;

src/image.rs

+/// Embed an image in the binary and load it at runtime.
 #[macro_export]
 macro_rules! img {
     ($name: literal) => {{
@@ -10,6 +11,7 @@ macro_rules! img {
     }};
 }
 
+/// Embed an image in the binary and load it into the [`Context`] at runtime.
 #[macro_export]
 macro_rules! ctx_img {
     ($ctx: expr, $name: literal) => {{
@@ -17,6 +19,7 @@ macro_rules! ctx_img {
     }};
 }
 
+/// Decodes image data.
 pub fn load_image_from_memory(
     image_data: &[u8],
 ) -> Result<eframe::egui::ColorImage, image::ImageError> {

src/main.rs

@@ -23,9 +23,11 @@ use eframe::egui::{Key, Style, TextStyle, Visuals};
 use eframe::epi::{Frame, Storage};
 use eframe::{egui, epi};
 
+// Entry point.
 fn main() {
     let app = Cartoon::default();
 
+    // 16:9 aspect ratio.
     let size = egui::Vec2::new(1280f32, 720f32);
 
     let native_options = eframe::NativeOptions {
@@ -45,9 +47,13 @@ fn main() {
     eframe::run_native(Box::new(app), native_options);
 }
 
+/// Top-level state.
 pub struct Cartoon {
+    /// All slides (including their state).
     slides: Vec<Box<dyn Slide>>,
+    /// Current index into [`slides`].
     slide_index: usize,
+    /// When we started fading in the current slide, in seconds (with respect to `ctx.input().time`).
     transition_time: f64,
 }
 
@@ -61,6 +67,10 @@ impl Default for Cartoon {
     }
 }
 
+/// Creates all the slides from default values. This will reset any and all animations and
+/// transitions built into the slides.
+///
+/// This is also how the chronology of the slideshow is determined.
 fn create_slides() -> Vec<Box<dyn Slide>> {
     vec![
         Box::new(Title::default()) as Box<dyn Slide>,
@@ -75,15 +85,20 @@ fn create_slides() -> Vec<Box<dyn Slide>> {
 }
 
 impl epi::App for Cartoon {
+    /// The title of the window, which is mostly irrelevant.
     fn name(&self) -> &str {
         "Generative Art Cartoon"
     }
 
+    /// Called once at window initialization.
     fn setup(&mut self, ctx: &egui::Context, _frame: &Frame, _storage: Option<&dyn Storage>) {
+        // Top level style overrides.
         let mut style = Style::default();
         style.animation_time = 0.5;
         style.visuals = Visuals::light();
         style.spacing.window_margin = Margin::same(24.0);
+
+        // Increase font sizes a lot.
         {
             let header_style = style.text_styles.get_mut(&TextStyle::Heading).unwrap();
             header_style.size = 48.0;
@@ -96,6 +111,7 @@ impl epi::App for Cartoon {
             let small_style = style.text_styles.get_mut(&TextStyle::Small).unwrap();
             small_style.size = 22.0;
         }
+        // TODO(finnb): This doesn't work. May have to fork syntax coloring code to fix it.
         /*
         {
             let monospaced_style = style.text_styles.get_mut(&TextStyle::Monospace).unwrap();
@@ -104,6 +120,7 @@ impl epi::App for Cartoon {
          */
         ctx.set_style(style);
 
+        // Start fading in title slide now.
         self.transition_time = ctx.input().time;
     }
 
@@ -123,9 +140,20 @@ impl epi::App for Cartoon {
         });
          */
 
+        // Go forward one slide (don't wait for intra-slide transitions).
+        //
+        // This will wrap around to the beginning.
         let force_advance =
             ctx.input().key_pressed(Key::ArrowRight) || ctx.input().key_pressed(Key::D);
+
+        // Play the next intra-slide transition or, if there isn't one, then go forward one slide.
+        //
+        // This will wrap around to the beginning.
         let advance = force_advance || ctx.input().key_pressed(Key::Space);
+
+        // Go backward one slide (don't wait for intra-slide transitions).
+        //
+        // This will wrap around to the end.
         let retreat = ctx.input().key_pressed(Key::ArrowLeft) || ctx.input().key_pressed(Key::A);
 
         if advance || retreat {
@@ -133,6 +161,7 @@ impl epi::App for Cartoon {
                 if force_advance || self.slides[self.slide_index].transition(ctx) {
                     let new = (self.slide_index + 1) % self.slides.len();
                     if new == 0 {
+                        // We wrapped around to the beginning, so create slides to reset transitions.
                         self.slides = create_slides();
                     }
                     self.transition_time = ctx.input().time;
@@ -151,7 +180,9 @@ impl epi::App for Cartoon {
         }
 
         egui::CentralPanel::default().show(ctx, |ui| {
+            // The current slide may be fading in.
             fade_in(ui, self.transition_time, |ui| {
+                // Render the current slide.
                 self.slides[self.slide_index].show(ui);
             });
         });

src/slide.rs

@@ -9,6 +9,7 @@ pub mod s6_computation;
 pub mod s7_mosaic;
 pub mod s8_conclusion;
 
+/// An interface for all slides.
 pub trait Slide {
     /// Returns whether "done."
     /// Repaint automatically requested.