Work in progress xilem prototype

This is a snapshot of the current state of the xilem prototype built on new infrastructure: glazier for window creation, piet-gpu for drawing, and parley for text.

As of this snapshot, only the text widget has been ported, and there are a number of rough edges. It should be considered a proof of concept. That said, it should be possible to build more from here.

Cargo.toml

@@ -1,16 +1,25 @@
 [package]
 name = "xilem"
 version = "0.1.0"
-license = "Apache-2.0"
-authors = ["Raph Levien <raph@google.com>"]
 edition = "2021"
 
+# This is just a bin for now but will be a lib + examples soon
+
 [dependencies]
-"druid-shell" = "0.7"
-bitflags = "1.3.2"
+glazier = { git = "https://github.com/linebender/glazier" }
+piet-gpu-hal = { git = "https://github.com/linebender/piet-gpu" }
+piet-gpu = { git = "https://github.com/linebender/piet-gpu" }
+piet-scene = { git = "https://github.com/linebender/piet-gpu" }
+raw-window-handle = "0.5"
+png = "0.16.2"
+rand = "0.7.3"
+roxmltree = "0.13"
+swash = "0.1.4"
+bytemuck = { version = "1.7.2", features = ["derive"] }
+parley = { git = "https://github.com/dfrg/parley" }
+tokio = { version = "1.21", features = ["full"] }
 futures-task = "0.3"
-tokio = { version = "1", features = ["full"] }
+bitflags = "1.3.2"
 
-[dev-dependencies]
-sha2 = "0.10"
-hex = "0.4.3"
+[patch."https://github.com/dfrg/fount"]
+fount = { git = "https://github.com/jneem/fount" }

src/app.rs

@@ -16,14 +16,14 @@ use std::collections::HashSet;
 use std::sync::{Arc, Mutex};
 use std::time::Duration;
 
-use druid_shell::kurbo::Size;
-use druid_shell::piet::{Color, Piet, RenderContext};
-use druid_shell::{IdleHandle, IdleToken, WindowHandle};
+use glazier::kurbo::Size;
+use glazier::{IdleHandle, IdleToken, WindowHandle};
+use parley::FontContext;
 use tokio::runtime::Runtime;
 
 use crate::event::{AsyncWake, EventResult};
 use crate::id::IdPath;
-use crate::widget::{CxState, EventCx, LayoutCx, PaintCx, Pod, UpdateCx, WidgetState};
+use crate::widget::{CxState, EventCx, LayoutCx, PaintCx, Pod, Rendered, UpdateCx, WidgetState};
 use crate::{
     event::Event,
     id::Id,
@@ -42,6 +42,7 @@ pub struct App<T, V: View<T>> {
     root_pod: Option<Pod>,
     size: Size,
     cx: Cx,
+    font_cx: FontContext,
     pub(crate) rt: Runtime,
 }
 
@@ -92,8 +93,6 @@ enum UiState {
 #[derive(Clone, Default)]
 pub struct WakeQueue(Arc<Mutex<Vec<IdPath>>>);
 
-const BG_COLOR: Color = Color::rgb8(0x27, 0x28, 0x22);
-
 impl<T: Send + 'static, V: View<T> + 'static> App<T, V>
 where
     V::Element: Widget + 'static,
@@ -153,6 +152,7 @@ where
             root_state: Default::default(),
             size: Default::default(),
             cx,
+            font_cx: FontContext::new(),
             rt,
         }
     }
@@ -170,15 +170,13 @@ where
         self.size = size;
     }
 
-    pub fn paint(&mut self, piet: &mut Piet) {
-        let rect = self.size.to_rect();
-        piet.fill(rect, &BG_COLOR);
-
+    pub fn paint(&mut self) -> Rendered {
         loop {
             self.send_events();
             self.render();
             let root_pod = self.root_pod.as_mut().unwrap();
-            let mut cx_state = CxState::new(&self.window_handle, &mut self.events);
+            let mut cx_state =
+                CxState::new(&self.window_handle, &mut self.font_cx, &mut self.events);
             let mut update_cx = UpdateCx::new(&mut cx_state, &mut self.root_state);
             root_pod.update(&mut update_cx);
             let mut layout_cx = LayoutCx::new(&mut cx_state, &mut self.root_state);
@@ -198,15 +196,14 @@ where
                 // Rerun app logic, primarily for virtualized scrolling
                 continue;
             }
-            let mut paint_cx = PaintCx::new(&mut cx_state, &mut self.root_state, piet);
-            root_pod.paint(&mut paint_cx);
-            break;
+            let mut paint_cx = PaintCx::new(&mut cx_state, &mut self.root_state);
+            return root_pod.paint(&mut paint_cx);
         }
     }
 
     pub fn window_event(&mut self, event: RawEvent) {
         let root_pod = self.root_pod.as_mut().unwrap();
-        let mut cx_state = CxState::new(&self.window_handle, &mut self.events);
+        let mut cx_state = CxState::new(&self.window_handle, &mut self.font_cx, &mut self.events);
         let mut event_cx = EventCx::new(&mut cx_state, &mut self.root_state);
         root_pod.event(&mut event_cx, &event);
         self.send_events();
@@ -325,7 +322,7 @@ where
                             self.ui_state = UiState::Delayed;
                         }
                     }
-                }
+                },
                 Ok(None) => break,
                 Err(_) => {
                     self.render().await;

src/app_main.rs

@@ -14,10 +14,12 @@
 
 use std::any::Any;
 
-use druid_shell::{
-    kurbo::Size, Application, Cursor, HotKey, IdleToken, Menu, MouseEvent, Region, SysMods,
-    WinHandler, WindowBuilder, WindowHandle,
+use glazier::{
+    kurbo::Size, Application, Cursor, HotKey, IdleToken, Menu, MouseEvent, Region, Scalable,
+    SysMods, WinHandler, WindowBuilder, WindowHandle,
 };
+use parley::FontContext;
+use piet_scene::{Scene, SceneBuilder, SceneFragment};
 
 use crate::{app::App, widget::RawEvent, View, Widget};
 
@@ -35,6 +37,10 @@ where
 {
     handle: WindowHandle,
     app: App<T, V>,
+    pgpu_state: Option<crate::render::PgpuState>,
+    font_context: FontContext,
+    scene: Scene,
+    counter: u64,
 }
 
 const QUIT_MENU_ID: u32 = 0x100;
@@ -58,7 +64,7 @@ impl<T: Send + 'static, V: View<T> + 'static> AppLauncher<T, V> {
             QUIT_MENU_ID,
             "E&xit",
             Some(&HotKey::new(SysMods::Cmd, "q")),
-            true,
+            Some(true),
             false,
         );
         let mut menubar = Menu::new();
@@ -71,6 +77,7 @@ impl<T: Send + 'static, V: View<T> + 'static> AppLauncher<T, V> {
         builder.set_handler(Box::new(main_state));
         builder.set_title(self.title);
         builder.set_menu(menubar);
+        builder.set_size(Size::new(1024., 768.));
         let window = builder.build().unwrap();
         window.show();
         druid_app.run(None);
@@ -88,8 +95,17 @@ where
 
     fn prepare_paint(&mut self) {}
 
-    fn paint(&mut self, piet: &mut druid_shell::piet::Piet, _: &Region) {
-        self.app.paint(piet);
+    fn paint(&mut self, _: &Region) {
+        let rendered = self.app.paint();
+        self.render(rendered.0);
+        self.schedule_render();
+    }
+
+    // TODO: temporary hack
+    fn idle(&mut self, _: IdleToken) {
+        let rendered = self.app.paint();
+        self.render(rendered.0);
+        self.schedule_render();
     }
 
     fn command(&mut self, id: u32) {
@@ -135,11 +151,6 @@ where
         Application::global().quit()
     }
 
-    fn idle(&mut self, _token: IdleToken) {
-        // TODO: wire up invalidation through widget hierarchy
-        self.handle.invalidate();
-    }
-
     fn as_any(&mut self) -> &mut dyn Any {
         self
     }
@@ -153,7 +164,53 @@ where
         let state = MainState {
             handle: Default::default(),
             app,
+            font_context: FontContext::new(),
+            pgpu_state: None,
+            scene: Scene::default(),
+            counter: 0,
         };
         state
     }
+
+    #[cfg(target_os = "macos")]
+    fn schedule_render(&self) {
+        self.handle
+            .get_idle_handle()
+            .unwrap()
+            .schedule_idle(IdleToken::new(0));
+    }
+
+    #[cfg(not(target_os = "macos"))]
+    fn schedule_render(&self) {
+        self.handle.invalidate();
+    }
+
+    fn render(&mut self, fragment: SceneFragment) {
+        if self.pgpu_state.is_none() {
+            let handle = &self.handle;
+            let scale = handle.get_scale().unwrap();
+            let insets = handle.content_insets().to_px(scale);
+            let mut size = handle.get_size().to_px(scale);
+            size.width -= insets.x_value();
+            size.height -= insets.y_value();
+            println!("render size: {:?}", size);
+            self.pgpu_state = Some(
+                crate::render::PgpuState::new(
+                    handle,
+                    handle,
+                    size.width as usize,
+                    size.height as usize,
+                )
+                .unwrap(),
+            );
+        }
+        if let Some(pgpu_state) = self.pgpu_state.as_mut() {
+            if let Some(_timestamps) = pgpu_state.pre_render() {}
+            let mut builder = SceneBuilder::for_scene(&mut self.scene);
+            builder.append(&fragment, None);
+            //crate::test_scenes::render(&mut self.font_context, &mut self.scene, 0, self.counter);
+            self.counter += 1;
+            pgpu_state.render(&self.scene);
+        }
+    }
 }

src/id.rs

@@ -23,7 +23,7 @@ pub type IdPath = Vec<Id>;
 impl Id {
     /// Allocate a new, unique `Id`.
     pub fn next() -> Id {
-        use druid_shell::Counter;
+        use glazier::Counter;
         static WIDGET_ID_COUNTER: Counter = Counter::new();
         Id(WIDGET_ID_COUNTER.next_nonzero())
     }