ViewportId now wraps Id

crates/eframe/src/native/run.rs

@@ -2031,7 +2031,7 @@ mod wgpu_integration {
                 windows_id.insert(new_window.id(), id);
 
                 if let Err(err) = pollster::block_on(painter.set_window(id, Some(&new_window))) {
-                    log::error!("on set_window: viewport_id {id} {err}");
+                    log::error!("on set_window: viewport_id {id:?} {err}");
                 }
                 *window = Some(Rc::new(RefCell::new(new_window)));
                 *state = Some(egui_winit::State::new(event_loop));
@@ -2311,7 +2311,7 @@ mod wgpu_integration {
 
             if let Err(err) = pollster::block_on(painter.set_window(id_pair.this, Some(&win))) {
                 log::error!(
-                    "when rendering viewport_id: {}, set_window Error {err}",
+                    "when rendering viewport_id={:?}, set_window Error {err}",
                     id_pair.this
                 );
             }

crates/egui/src/context.rs

@@ -170,10 +170,9 @@ struct ContextImpl {
 
     repaint: Repaint,
 
-    viewports: HashMap<Id, Viewport>,
+    viewports: HashMap<ViewportId, Viewport>,
     viewport_commands: Vec<(ViewportId, ViewportCommand)>,
 
-    viewport_id_generator: u64,
     is_desktop: bool,
     force_embedding: bool,
 
@@ -2515,11 +2514,6 @@ impl Context {
         self.read(|ctx| ctx.parent_viewport_id())
     }
 
-    /// This will return the `ViewportIdPair` of the specified id
-    pub fn viewport_id_pair(&self, id: impl Into<Id>) -> Option<ViewportIdPair> {
-        self.read(|ctx| ctx.viewports.get(&id.into()).map(|v| v.id_pair))
-    }
-
     /// For integrations: Is used to render a sync viewport.
     ///
     /// This will only be set for the current thread.
@@ -2594,16 +2588,14 @@ impl Context {
                     window.used = true;
                     window.viewport_ui_cb = Some(Arc::new(Box::new(viewport_ui_cb)));
                 } else {
-                    ctx.viewport_id_generator += 1;
-                    let id = ViewportId(ctx.viewport_id_generator);
                     ctx.viewports.insert(
                         viewport_builder.id,
                         Viewport {
-                            builder: viewport_builder,
                             id_pair: ViewportIdPair {
-                                this: id,
+                                this: viewport_builder.id,
                                 parent: viewport_id,
                             },
+                            builder: viewport_builder,
                             used: true,
                             viewport_ui_cb: Some(Arc::new(Box::new(viewport_ui_cb))),
                         },
@@ -2661,9 +2653,8 @@ impl Context {
                     window.id_pair
                 } else {
                     // New
-                    ctx.viewport_id_generator += 1;
                     let id_pair = ViewportIdPair {
-                        this: ViewportId(ctx.viewport_id_generator),
+                        this: viewport_builder.id,
                         parent,
                     };
                     ctx.viewports.insert(

crates/egui/src/id.rs

@@ -35,11 +35,11 @@ impl Id {
     ///
     /// The null [`Id`] is still a valid id to use in all circumstances,
     /// though obviously it will lead to a lot of collisions if you do use it!
-    pub fn null() -> Self {
+    pub const fn null() -> Self {
         Self(0)
     }
 
-    pub(crate) fn background() -> Self {
+    pub(crate) const fn background() -> Self {
         Self(1)
     }
 

crates/egui/src/viewport.rs

@@ -5,7 +5,7 @@
 //! * Sync viewports are executed immediately.
 //! * Async viewports are executed later.
 
-use std::{fmt::Display, sync::Arc};
+use std::sync::Arc;
 
 use epaint::{ColorImage, Pos2, Vec2};
 
@@ -16,27 +16,42 @@ use crate::{Context, Id};
 /// Generated by [`Context`].
 ///
 /// This is returned by [`Context::viewport_id`] and [`Context::parent_viewport_id`].
-#[derive(Default, Debug, Hash, Clone, Copy, PartialEq, Eq)]
+#[derive(Hash, Clone, Copy, PartialEq, Eq)]
-pub struct ViewportId(pub(crate) u64);
+pub struct ViewportId(pub Id);
 
-impl Display for ViewportId {
+impl Default for ViewportId {
+    fn default() -> Self {
+        Self::MAIN
+    }
+}
+
+impl std::fmt::Debug for ViewportId {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
-        self.0.fmt(f)
+        self.0.short_debug_format().fmt(f)
     }
 }
 
 impl ViewportId {
     /// This will return the `ViewportId` of the main viewport
-    pub const MAIN: Self = Self(0);
+    pub const MAIN: Self = Self(Id::null());
 }
 
 /// This will deref to [`Self::this`].
-#[derive(Default, Debug, Hash, Clone, Copy, PartialEq, Eq)]
+#[derive(Debug, Hash, Clone, Copy, PartialEq, Eq)]
 pub struct ViewportIdPair {
     pub this: ViewportId,
     pub parent: ViewportId,
 }
 
+impl Default for ViewportIdPair {
+    fn default() -> Self {
+        Self {
+            this: ViewportId::MAIN,
+            parent: ViewportId::MAIN,
+        }
+    }
+}
+
 impl ViewportIdPair {
     /// This will return the `ViewportIdPair` of the main viewport
     pub const MAIN: Self = Self {
@@ -61,7 +76,7 @@ pub type ViewportRenderSyncCallback =
 #[derive(PartialEq, Eq, Clone)]
 #[allow(clippy::option_option)]
 pub struct ViewportBuilder {
-    pub id: Id,
+    pub id: ViewportId,
 
     /// The title of the vieweport.
     /// `eframe` will use this as the title of the native window.
@@ -97,7 +112,7 @@ pub struct ViewportBuilder {
 impl ViewportBuilder {
     pub fn new(id: impl Into<Id>) -> Self {
         Self {
-            id: id.into(),
+            id: ViewportId(id.into()),
             title: "egui".into(),
             name: None,
             position: None,
@@ -125,7 +140,7 @@ impl ViewportBuilder {
 
     pub fn empty(id: impl Into<Id>) -> Self {
         Self {
-            id: id.into(),
+            id: ViewportId(id.into()),
             title: "egui".into(),
             name: None,
             position: None,

examples/viewports/src/main.rs

@@ -331,8 +331,11 @@ fn generic_ui(ui: &mut egui::Ui, container_id: impl Into<Id>) {
 
     ui.add_space(8.0);
 
-    ui.label(format!("Viewport Id: {}", ctx.viewport_id()));
+    ui.label(format!("Viewport Id: {:?}", ctx.viewport_id()));
-    ui.label(format!("Parent Viewport Id: {}", ctx.parent_viewport_id()));
+    ui.label(format!(
+        "Parent Viewport Id: {:?}",
+        ctx.parent_viewport_id()
+    ));
 
     ui.add_space(8.0);