Desktop: Add the transparent viewport hole punch and hook up window button plumbing (#2949)

editor/src/messages/app_window/app_window_message.rs

@@ -0,0 +1,9 @@
+use crate::messages::prelude::*;
+
+#[impl_message(Message, AppWindow)]
+#[derive(PartialEq, Clone, Debug, serde::Serialize, serde::Deserialize)]
+pub enum AppWindowMessage {
+	AppWindowMinimize,
+	AppWindowMaximize,
+	AppWindowClose,
+}

editor/src/messages/app_window/app_window_message_handler.rs

@@ -0,0 +1,52 @@
+use crate::messages::app_window::AppWindowMessage;
+use crate::messages::prelude::*;
+use graphite_proc_macros::{ExtractField, message_handler_data};
+
+#[derive(Debug, Clone, Default, ExtractField)]
+pub struct AppWindowMessageHandler {
+	platform: AppWindowPlatform,
+	maximized: bool,
+	viewport_hole_punch_active: bool,
+}
+
+#[message_handler_data]
+impl MessageHandler<AppWindowMessage, ()> for AppWindowMessageHandler {
+	fn process_message(&mut self, message: AppWindowMessage, responses: &mut std::collections::VecDeque<Message>, _: ()) {
+		match message {
+			AppWindowMessage::AppWindowMinimize => {
+				self.platform = if self.platform == AppWindowPlatform::Mac {
+					AppWindowPlatform::Windows
+				} else {
+					AppWindowPlatform::Mac
+				};
+				responses.add(FrontendMessage::UpdatePlatform { platform: self.platform });
+			}
+			AppWindowMessage::AppWindowMaximize => {
+				self.maximized = !self.maximized;
+				responses.add(FrontendMessage::UpdateMaximized { maximized: self.maximized });
+
+				self.viewport_hole_punch_active = !self.viewport_hole_punch_active;
+				responses.add(FrontendMessage::UpdateViewportHolePunch {
+					active: self.viewport_hole_punch_active,
+				});
+			}
+			AppWindowMessage::AppWindowClose => {
+				self.platform = AppWindowPlatform::Web;
+				responses.add(FrontendMessage::UpdatePlatform { platform: self.platform });
+			}
+		}
+	}
+
+	fn actions(&self) -> ActionList {
+		actions!(AppWindowMessageDiscriminant;)
+	}
+}
+
+#[derive(PartialEq, Eq, Clone, Copy, Default, Debug, serde::Serialize, serde::Deserialize, specta::Type)]
+pub enum AppWindowPlatform {
+	#[default]
+	Web,
+	Windows,
+	Mac,
+	Linux,
+}

editor/src/messages/app_window/mod.rs

@@ -0,0 +1,7 @@
+mod app_window_message;
+pub mod app_window_message_handler;
+
+#[doc(inline)]
+pub use app_window_message::{AppWindowMessage, AppWindowMessageDiscriminant};
+#[doc(inline)]
+pub use app_window_message_handler::AppWindowMessageHandler;