Support screenshots

src/window/game.rs

@@ -6,11 +6,12 @@ use crate::{
     input::{Command, ShortcutProvider},
     persistence::Persistence,
 };
+use anyhow::Context as _;
 use egui::{
     Align2, Button, CentralPanel, Color32, Context, Direction, Frame, TopBottomPanel, Ui, Vec2,
     ViewportBuilder, ViewportCommand, ViewportId, Window, menu,
 };
-use egui_toast::{Toast, Toasts};
+use egui_toast::{Toast, ToastKind, ToastOptions, Toasts};
 use serde::{Deserialize, Serialize};
 use winit::event_loop::EventLoopProxy;
 
@@ -69,7 +70,7 @@ impl GameWindow {
         }
     }
 
-    fn show_menu(&mut self, ctx: &Context, ui: &mut Ui) {
+    fn show_menu(&mut self, ctx: &Context, ui: &mut Ui, toasts: &mut Toasts) {
         let state = self.client.emulator_state();
         let is_ready = self.client.sim_state(self.sim_id) == SimState::Ready;
         let can_pause = is_ready && state == EmulatorState::Running;
@@ -113,6 +114,16 @@ impl GameWindow {
                     self.client
                         .send_command(EmulatorCommand::SetSpeed(speed as f64));
                 }
+                Command::Screenshot => {
+                    let autopause = state == EmulatorState::Running && can_pause;
+                    if autopause {
+                        self.client.send_command(EmulatorCommand::Pause);
+                    }
+                    pollster::block_on(self.take_screenshot(toasts));
+                    if autopause {
+                        self.client.send_command(EmulatorCommand::Resume);
+                    }
+                }
             }
         }
 
@@ -178,6 +189,17 @@ impl GameWindow {
                 self.client.send_command(EmulatorCommand::FrameAdvance);
                 ui.close_menu();
             }
+            ui.separator();
+            if ui
+                .add_enabled(
+                    is_ready,
+                    self.button_for(ui.ctx(), "Screenshot", Command::Screenshot),
+                )
+                .clicked()
+            {
+                pollster::block_on(self.take_screenshot(toasts));
+                ui.close_menu();
+            }
         });
         ui.menu_button("Options", |ui| self.show_options_menu(ctx, ui));
         ui.menu_button("Multiplayer", |ui| {
@@ -262,6 +284,56 @@ impl GameWindow {
         });
     }
 
+    async fn take_screenshot(&self, toasts: &mut Toasts) {
+        match self.try_take_screenshot().await {
+            Ok(Some(path)) => {
+                toasts.add(
+                    Toast::new()
+                        .kind(ToastKind::Info)
+                        .options(ToastOptions::default().duration_in_seconds(5.0))
+                        .text(format!("Saved to {path}")),
+                );
+            }
+            Ok(None) => {}
+            Err(error) => {
+                toasts.add(
+                    Toast::new()
+                        .kind(ToastKind::Error)
+                        .options(ToastOptions::default().duration_in_seconds(5.0))
+                        .text(format!("{error:#}")),
+                );
+            }
+        }
+    }
+
+    async fn try_take_screenshot(&self) -> anyhow::Result<Option<String>> {
+        let (tx, rx) = oneshot::channel();
+        self.client
+            .send_command(EmulatorCommand::Screenshot(self.sim_id, tx));
+        let bytes = rx.await.context("Could not take screenshot")?;
+        let file = rfd::AsyncFileDialog::new()
+            .add_filter("PNG images", &["png"])
+            .set_file_name("screenshot.png")
+            .save_file()
+            .await;
+        let Some(file) = file else {
+            return Ok(None);
+        };
+        if bytes.len() != 384 * 224 * 2 {
+            anyhow::bail!("Unexpected screenshot size");
+        }
+        let mut screencap = image::GrayImage::new(384 * 2, 224);
+        for (index, pixel) in bytes.into_iter().enumerate() {
+            let x = (index / 2) % 384 + ((index % 2) * 384);
+            let y = (index / 2) / 384;
+            screencap.put_pixel(x as u32, y as u32, image::Luma([pixel]));
+        }
+        screencap
+            .save(&file.path())
+            .context("Could not save screenshot")?;
+        Ok(Some(file.path().display().to_string()))
+    }
+
     fn show_options_menu(&mut self, ctx: &Context, ui: &mut Ui) {
         ui.menu_button("Video", |ui| {
             ui.menu_button("Screen Size", |ui| {
@@ -478,7 +550,7 @@ impl AppWindow for GameWindow {
             .exact_height(22.0)
             .show(ctx, |ui| {
                 menu::bar(ui, |ui| {
-                    self.show_menu(ctx, ui);
+                    self.show_menu(ctx, ui, &mut toasts);
                 });
             });
         if self.color_picker.is_some() {