Flashy typey text on one line

Cargo.lock

@@ -8,6 +8,12 @@ version = "1.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "bef38d45163c2f1dde094a7dfd33ccf595c92905c8f8f4fdc18d06fb1037718a"
 
+[[package]]
+name = "c_vec"
+version = "2.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "fdd7a427adc0135366d99db65b36dae9237130997e560ed61118041fb72be6e8"
+
 [[package]]
 name = "cfg-if"
 version = "1.0.0"
@@ -40,6 +46,7 @@ source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "f7959277b623f1fb9e04aea73686c3ca52f01b2145f8ea16f4ff30d8b7623b1a"
 dependencies = [
  "bitflags",
+ "c_vec",
  "lazy_static",
  "libc",
  "sdl2-sys",

Cargo.toml

@@ -6,4 +6,4 @@ edition = "2021"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
-sdl2 = "0.35.2"
+sdl2 = { version = "0.35.2", features = ["gfx", "ttf"] }

flake.nix

@@ -26,20 +26,21 @@
       systems = nixpkgs.lib.systems.flakeExposed;
       perSystem = { config, self', inputs', pkgs, system, ... }:
         let
-          toolchain = pkgs.rust-bin.stable.latest.default;
+          toolchain = pkgs.rust-bin.stable.latest.complete;
           naersk-lib = pkgs.callPackage naersk {
             cargo = toolchain;
             rustc = toolchain;
           };
+          deps = with pkgs; [ SDL2 SDL2_gfx SDL2_ttf ];
         in
         {
           packages.default = naersk-lib.buildPackage {
             src = ./.;
-            buildInputs = with pkgs; [ SDL2 ];
+            buildInputs = deps;
           };
           apps.default.program = "${config.packages.default}/bin/medit";
           devShells.default = pkgs.mkShell {
-            nativeBuildInputs = [ toolchain ];
+            nativeBuildInputs = [ toolchain ] ++ deps;
           };
         };
     };

src/main.rs

@@ -1,23 +1,44 @@
-use sdl2::{event::Event, init, keyboard::Keycode, pixels::Color};
+use sdl2::event::Event;
+use sdl2::keyboard::Keycode;
+use sdl2::pixels::Color;
+use sdl2::rect::Rect;
+use sdl2::render::Texture;
+use sdl2::render::TextureCreator;
+use sdl2::render::TextureQuery;
+use sdl2::ttf;
+use sdl2::ttf::Font;
+use sdl2::video::WindowContext;
 
-fn main() {
+fn string_err(e: impl ToString) -> String {
-    let ctx = init().unwrap();
+    e.to_string()
-    let vid = ctx.video().unwrap();
+}
-    let win = vid
+
-        .window("medit", 800, 600)
+const WIDTH: u32 = 800;
+const HEIGHT: u32 = 600;
+
+fn main() -> Result<(), String> {
+    let context = sdl2::init()?;
+    let video = context.video()?;
+    let ttf_context = ttf::init().map_err(string_err)?;
+
+    let window = video
+        .window("medit", WIDTH, HEIGHT)
         .position_centered()
+        .allow_highdpi()
         .build()
-        .unwrap();
+        .map_err(string_err)?;
-    let mut can = win.into_canvas().build().unwrap();
+
-    can.set_draw_color(Color::RGB(0, 255, 255));
+    let mut canvas = window.into_canvas().build().map_err(string_err)?;
-    can.clear();
+    let texture_creator = canvas.texture_creator();
-    can.present();
+
-    let mut event_pump = ctx.event_pump().unwrap();
+    let font = ttf_context.load_font("resources/fonts/ttf/FiraCode-VF.ttf", 128)?;
-    let mut i = 0;
+
+    canvas.set_draw_color(Color::WHITE);
+    canvas.clear();
+
+    let mut event_pump = context.event_pump()?;
+    let mut x = 0;
     'running: loop {
-        i = (i + 1) % 255;
-        can.set_draw_color(Color::RGB(i, 64, 255 - i));
-        can.clear();
         for event in event_pump.poll_iter() {
             match event {
                 Event::Quit { .. }
@@ -25,12 +46,46 @@ fn main() {
                     keycode: Some(Keycode::Escape),
                     ..
                 } => break 'running,
+                Event::KeyDown {
+                    keycode: Some(k), ..
+                } if is_drawable_key(k) => {
+                    canvas.clear();
+                    let texture = string_texture(&font, &texture_creator, k.name())?;
+                    let target = target_rect(x, 0, &texture);
+                    x += target.width() as i32;
+                    canvas.copy(&texture, None, Some(target))?;
+                }
                 _ => {}
             }
         }
-        // The rest of the game loop goes here...
+        canvas.present();
-
-        can.present();
         std::thread::sleep(std::time::Duration::new(0, 1_000_000_000u32 / 60));
     }
+    Ok(())
+}
+
+fn is_drawable_key(key: Keycode) -> bool {
+    let key = key as i32;
+    (key >= Keycode::A as i32 && key <= Keycode::Z as i32)
+        || (key >= Keycode::Num0 as i32 && key <= Keycode::Num9 as i32)
+}
+
+fn string_texture<'f, 't>(
+    font: &Font<'f, 'f>,
+    texture_creator: &'t TextureCreator<WindowContext>,
+    string: impl AsRef<str>,
+) -> Result<Texture<'t>, String> {
+    let surface = font
+        .render(string.as_ref())
+        .blended(Color::BLACK)
+        .map_err(string_err)?;
+    texture_creator
+        .create_texture_from_surface(surface)
+        .map_err(string_err)
+}
+
+fn target_rect(x: i32, y: i32, texture: &Texture) -> Rect {
+    let TextureQuery { width, height, .. } = texture.query();
+
+    Rect::new(x, y, width, height)
 }