Add a new CLI option / spawn options to hide the welcome screen (#6262)

### What
- Partially addresses: #6140

We still need to also tackle
#6263 since the place-holder UI
isn't great.

![image](https://github.com/rerun-io/rerun/assets/3312232/736a42fb-a29e-48e2-8316-9dc790f1e3ad)

### Details
Handling this via blueprint is awkward since the welcome screen
presentation happens without respect to any given blueprint, or in cases
when all the recordings and their blueprints have been closed.

I decided adding this as a spawn option makes the most sense, since this
is the context where someone knows how they are embedding Rerun in
another application.

### Checklist
* [x] I have read and agree to [Contributor
Guide](https://github.com/rerun-io/rerun/blob/main/CONTRIBUTING.md) and
the [Code of
Conduct](https://github.com/rerun-io/rerun/blob/main/CODE_OF_CONDUCT.md)
* [x] I've included a screenshot or gif (if applicable)
* [x] I have tested the web demo (if applicable):
* Using examples from latest `main` build:
[rerun.io/viewer](https://rerun.io/viewer/pr/6262?manifest_url=https://app.rerun.io/version/main/examples_manifest.json)
* Using full set of examples from `nightly` build:
[rerun.io/viewer](https://rerun.io/viewer/pr/6262?manifest_url=https://app.rerun.io/version/nightly/examples_manifest.json)
* [x] The PR title and labels are set such as to maximize their
usefulness for the next release's CHANGELOG
* [x] If applicable, add a new check to the [release
checklist](https://github.com/rerun-io/rerun/blob/main/tests/python/release_checklist)!

- [PR Build Summary](https://build.rerun.io/pr/6262)
- [Recent benchmark results](https://build.rerun.io/graphs/crates.html)
- [Wasm size tracking](https://build.rerun.io/graphs/sizes.html)

To run all checks from `main`, comment on the PR with `@rerun-bot
full-check`.

crates/re_sdk/src/spawn.rs

@@ -44,6 +44,9 @@ pub struct SpawnOptions {
 
     /// Extra arguments that will be passed as-is to the Rerun Viewer process.
     pub extra_args: Vec<String>,
+
+    /// Hide the welcome screen.
+    pub hide_welcome_screen: bool,
 }
 
 // NOTE: No need for .exe extension on windows.
@@ -58,6 +61,7 @@ impl Default for SpawnOptions {
             executable_name: RERUN_BINARY.into(),
             executable_path: None,
             extra_args: Vec::new(),
+            hide_welcome_screen: false,
         }
     }
 }
@@ -257,8 +261,13 @@ pub fn spawn(opts: &SpawnOptions) -> Result<(), SpawnError> {
         .stdin(std::process::Stdio::null())
         .arg(format!("--port={port}"))
         .arg(format!("--memory-limit={memory_limit}"))
-        .arg("--expect-data-soon")
-        .args(opts.extra_args.clone());
+        .arg("--expect-data-soon");
+
+    if opts.hide_welcome_screen {
+        rerun_bin.arg("--hide-welcome-screen");
+    }
+
+    rerun_bin.args(opts.extra_args.clone());
 
     // SAFETY: This code is only run in the child fork, we are not modifying any memory
     // that is shared with the parent process.

crates/re_viewer/src/app.rs

@@ -12,7 +12,10 @@ use re_viewer_context::{
     SystemCommandSender,
 };
 
-use crate::{app_blueprint::AppBlueprint, background_tasks::BackgroundTasks, AppState};
+use crate::{
+    app_blueprint::AppBlueprint, app_state::WelcomeScreenState, background_tasks::BackgroundTasks,
+    AppState,
+};
 
 // ----------------------------------------------------------------------------
 
@@ -47,6 +50,9 @@ pub struct StartupOptions {
     #[cfg(not(target_arch = "wasm32"))]
     pub screenshot_to_path_then_quit: Option<std::path::PathBuf>,
 
+    /// A user has specifically requested the welcome screen be hidden.
+    pub hide_welcome_screen: bool,
+
     /// Set the screen resolution in logical points.
     #[cfg(not(target_arch = "wasm32"))]
     pub resolution_in_points: Option<[f32; 2]>,
@@ -77,6 +83,8 @@ impl Default for StartupOptions {
             #[cfg(not(target_arch = "wasm32"))]
             screenshot_to_path_then_quit: None,
 
+            hide_welcome_screen: false,
+
             #[cfg(not(target_arch = "wasm32"))]
             resolution_in_points: None,
 
@@ -916,7 +924,10 @@ impl App {
                             &self.space_view_class_registry,
                             &self.rx,
                             &self.command_sender,
-                            self.welcome_screen_opacity(egui_ctx),
+                            &WelcomeScreenState {
+                                hide: self.startup_options.hide_welcome_screen,
+                                opacity: self.welcome_screen_opacity(egui_ctx),
+                            },
                         );
                     }
                     render_ctx.before_submit();

crates/re_viewer/src/app_state.rs

@@ -72,6 +72,14 @@ impl Default for AppState {
     }
 }
 
+pub(crate) struct WelcomeScreenState {
+    /// The normal welcome screen should be hidden. Show a fallback "no data ui" instead.
+    pub hide: bool,
+
+    /// The opacity of the welcome screen during fade-in.
+    pub opacity: f32,
+}
+
 impl AppState {
     pub fn set_examples_manifest_url(&mut self, egui_ctx: &egui::Context, url: String) {
         self.welcome_screen.set_examples_manifest_url(egui_ctx, url);
@@ -114,7 +122,7 @@ impl AppState {
         space_view_class_registry: &SpaceViewClassRegistry,
         rx: &ReceiveSet<LogMsg>,
         command_sender: &CommandSender,
-        welcome_screen_opacity: f32,
+        welcome_screen_state: &WelcomeScreenState,
     ) {
         re_tracing::profile_function!();
 
@@ -384,7 +392,7 @@ impl AppState {
                     ui.spacing_mut().item_spacing.y = 0.0;
 
                     let pre_cursor = ui.cursor();
-                    recordings_panel_ui(&ctx, rx, ui);
+                    recordings_panel_ui(&ctx, rx, ui, welcome_screen_state);
                     let any_recording_shows = pre_cursor == ui.cursor();
 
                     if any_recording_shows {
@@ -411,7 +419,7 @@ impl AppState {
             .frame(viewport_frame)
             .show_inside(ui, |ui| {
                 if show_welcome {
-                    welcome_screen.ui(ui, re_ui, command_sender, welcome_screen_opacity);
+                    welcome_screen.ui(ui, re_ui, command_sender, welcome_screen_state);
                 } else {
                     viewport.viewport_ui(ui, &ctx);
                 }

crates/re_viewer/src/ui/mod.rs

@@ -1,5 +1,6 @@
 mod blueprint_panel;
 mod mobile_warning_ui;
+mod no_data_ui;
 mod override_ui;
 mod recordings_panel;
 mod rerun_menu;
@@ -17,6 +18,6 @@ pub use recordings_panel::recordings_panel_ui;
 // ----
 
 pub(crate) use {
-    self::mobile_warning_ui::mobile_warning_ui, self::top_panel::top_panel,
-    self::welcome_screen::WelcomeScreen,
+    self::mobile_warning_ui::mobile_warning_ui, self::no_data_ui::no_data_ui,
+    self::top_panel::top_panel, self::welcome_screen::WelcomeScreen,
 };

crates/re_viewer/src/ui/no_data_ui.rs

@@ -0,0 +1,20 @@
+/// Show a minimal welcome section.
+pub fn no_data_ui(ui: &mut egui::Ui) {
+    ui.vertical(|ui| {
+        let (style, line_height) = if ui.available_width() > 400.0 {
+            (re_ui::ReUi::welcome_screen_h1(), 50.0)
+        } else {
+            (re_ui::ReUi::welcome_screen_h2(), 36.0)
+        };
+
+        ui.add(
+            egui::Label::new(
+                egui::RichText::new("No Data Loaded")
+                    .strong()
+                    .line_height(Some(line_height))
+                    .text_style(style),
+            )
+            .wrap(true),
+        );
+    });
+}

crates/re_viewer/src/ui/recordings_panel.rs

@@ -9,9 +9,16 @@ use re_viewer_context::{
     Item, StoreHub, SystemCommand, SystemCommandSender, UiVerbosity, ViewerContext,
 };
 
+use crate::app_state::WelcomeScreenState;
+
 /// Show the currently open Recordings in a selectable list.
 /// Also shows the currently loading receivers.
-pub fn recordings_panel_ui(ctx: &ViewerContext<'_>, rx: &ReceiveSet<LogMsg>, ui: &mut egui::Ui) {
+pub fn recordings_panel_ui(
+    ctx: &ViewerContext<'_>,
+    rx: &ReceiveSet<LogMsg>,
+    ui: &mut egui::Ui,
+    welcome_screen_state: &WelcomeScreenState,
+) {
     ctx.re_ui.panel_content(ui, |re_ui, ui| {
         re_ui.panel_title_bar_with_buttons(
             ui,
@@ -31,7 +38,7 @@ pub fn recordings_panel_ui(ctx: &ViewerContext<'_>, rx: &ReceiveSet<LogMsg>, ui:
         .max_height(300.)
         .show(ui, |ui| {
             ctx.re_ui.panel_content(ui, |_re_ui, ui| {
-                recording_list_ui(ctx, ui);
+                recording_list_ui(ctx, ui, welcome_screen_state);
 
                 // Show currently loading things after.
                 // They will likely end up here as recordings soon.
@@ -91,7 +98,11 @@ fn loading_receivers_ui(ctx: &ViewerContext<'_>, rx: &ReceiveSet<LogMsg>, ui: &m
 }
 
 /// Draw the recording list.
-fn recording_list_ui(ctx: &ViewerContext<'_>, ui: &mut egui::Ui) {
+fn recording_list_ui(
+    ctx: &ViewerContext<'_>,
+    ui: &mut egui::Ui,
+    welcome_screen_state: &WelcomeScreenState,
+) {
     let mut entity_dbs_map: BTreeMap<ApplicationId, Vec<&EntityDb>> = BTreeMap::new();
 
     // Always have a place for the welcome screen, even if there is no recordings or blueprints associated with it:
@@ -116,6 +127,7 @@ fn recording_list_ui(ctx: &ViewerContext<'_>, ui: &mut egui::Ui) {
         if ctx
             .app_options
             .include_welcome_screen_button_in_recordings_panel
+            && !welcome_screen_state.hide
         {
             debug_assert!(
                 entity_dbs.is_empty(),

crates/re_viewer/src/ui/welcome_screen/mod.rs

@@ -4,6 +4,10 @@ mod welcome_section;
 use example_section::{ExampleSection, MIN_COLUMN_WIDTH};
 use welcome_section::welcome_section_ui;
 
+use crate::app_state::WelcomeScreenState;
+
+use super::no_data_ui;
+
 #[derive(Default)]
 pub struct WelcomeScreen {
     example_page: ExampleSection,
@@ -20,9 +24,9 @@ impl WelcomeScreen {
         ui: &mut egui::Ui,
         re_ui: &re_ui::ReUi,
         command_sender: &re_viewer_context::CommandSender,
-        welcome_screen_opacity: f32,
+        welcome_screen_state: &WelcomeScreenState,
     ) {
-        if welcome_screen_opacity <= 0.0 {
+        if welcome_screen_state.opacity <= 0.0 {
             return;
         }
 
@@ -46,13 +50,17 @@ impl WelcomeScreen {
                     ..Default::default()
                 }
                 .show(ui, |ui| {
-                    self.example_page
-                        .ui(ui, re_ui, command_sender, &welcome_section_ui);
+                    if welcome_screen_state.hide {
+                        no_data_ui(ui);
+                    } else {
+                        self.example_page
+                            .ui(ui, re_ui, command_sender, &welcome_section_ui);
+                    }
                 });
             });
 
-        if welcome_screen_opacity < 1.0 {
-            let cover_opacity = 1.0 - welcome_screen_opacity;
+        if welcome_screen_state.opacity < 1.0 {
+            let cover_opacity = 1.0 - welcome_screen_state.opacity;
             let fill_color = ui.visuals().panel_fill.gamma_multiply(cover_opacity);
             ui.painter()
                 .rect_filled(response.inner_rect, 0.0, fill_color);

crates/re_viewer/src/web.rs

@@ -49,6 +49,7 @@ impl WebHandle {
         url: Option<String>,
         manifest_url: Option<String>,
         force_wgpu_backend: Option<String>,
+        hide_welcome_screen: Option<bool>,
     ) -> Result<(), wasm_bindgen::JsValue> {
         let web_options = eframe::WebOptions {
             follow_system_theme: false,
@@ -63,7 +64,12 @@ impl WebHandle {
                 canvas_id,
                 web_options,
                 Box::new(move |cc| {
-                    let app = create_app(cc, &url, &manifest_url);
+                    let app = create_app(
+                        cc,
+                        &url,
+                        &manifest_url,
+                        hide_welcome_screen.unwrap_or(false),
+                    );
                     Box::new(app)
                 }),
             )
@@ -213,6 +219,7 @@ fn create_app(
     cc: &eframe::CreationContext<'_>,
     url: &Option<String>,
     manifest_url: &Option<String>,
+    hide_welcome_screen: bool,
 ) -> crate::App {
     let build_info = re_build_info::build_info!();
     let app_env = crate::AppEnvironment::Web {
@@ -228,6 +235,7 @@ fn create_app(
         is_in_notebook: is_in_notebook(&cc.integration_info),
         expect_data_soon: None,
         force_wgpu_backend: None,
+        hide_welcome_screen: hide_welcome_screen,
     };
     let re_ui = crate::customize_eframe_and_setup_renderer(cc);
 

crates/rerun/src/run.rs

@@ -191,6 +191,10 @@ If no arguments are given, a server will be hosted which a Rerun SDK can connect
     #[clap(long, default_value_t = Default::default())]
     web_viewer_port: WebViewerServerPort,
 
+    /// Hide the normal Rerun welcome screen.
+    #[clap(long)]
+    hide_welcome_screen: bool,
+
     /// Set the screen resolution (in logical points), e.g. "1920x1080".
     /// Useful together with `--screenshot-to`.
     #[clap(long)]
@@ -606,6 +610,7 @@ fn run_impl(
     let startup_options = {
         re_tracing::profile_scope!("StartupOptions");
         re_viewer::StartupOptions {
+            hide_welcome_screen: args.hide_welcome_screen,
             memory_limit: re_memory::MemoryLimit::parse(&args.memory_limit)
                 .map_err(|err| anyhow::format_err!("Bad --memory-limit: {err}"))?,
             persist_state: args.persist_state,

crates/rerun_c/src/lib.rs

@@ -85,6 +85,7 @@ pub const RR_COMPONENT_TYPE_HANDLE_INVALID: CComponentTypeHandle = 0xFFFFFFFF;
 pub struct CSpawnOptions {
     pub port: u16,
     pub memory_limit: CStringView,
+    pub hide_welcome_screen: bool,
     pub executable_name: CStringView,
     pub executable_path: CStringView,
 }
@@ -104,6 +105,8 @@ impl CSpawnOptions {
             spawn_opts.memory_limit = self.memory_limit.as_str("memory_limit")?.to_owned();
         }
 
+        spawn_opts.hide_welcome_screen = self.hide_welcome_screen;
+
         if !self.executable_name.is_empty() {
             spawn_opts.executable_name = self.executable_name.as_str("executable_name")?.to_owned();
         }

crates/rerun_c/src/rerun.h

@@ -127,6 +127,9 @@ typedef struct rr_spawn_options {
     /// Defaults to `75%` if null.
     rr_string memory_limit;
 
+    /// Hide the normal Rerun welcome screen.
+    bool hide_welcome_screen;
+
     /// Specifies the name of the Rerun executable.
     ///
     /// You can omit the `.exe` suffix on Windows.

rerun_cpp/src/rerun/spawn_options.cpp

@@ -6,6 +6,7 @@ namespace rerun {
     void SpawnOptions::fill_rerun_c_struct(rr_spawn_options& spawn_opts) const {
         spawn_opts.port = port;
         spawn_opts.memory_limit = detail::to_rr_string(memory_limit);
+        spawn_opts.hide_welcome_screen = hide_welcome_screen;
         spawn_opts.executable_name = detail::to_rr_string(executable_name);
         spawn_opts.executable_path = detail::to_rr_string(executable_path);
     }

rerun_cpp/src/rerun/spawn_options.hpp

@@ -26,6 +26,11 @@ namespace rerun {
         /// Defaults to `75%` if unset.
         std::string_view memory_limit = "75%";
 
+        /// Hide the normal Rerun welcome screen.
+        ///
+        /// Defaults to `false` if unset.
+        bool hide_welcome_screen = false;
+
         /// Specifies the name of the Rerun executable.
         ///
         /// You can omit the `.exe` suffix on Windows.

rerun_js/web-viewer-react/index.js

@@ -8,6 +8,7 @@ import * as rerun from "@rerun-io/web-viewer";
  *                                   and close any URLs which are not present.
  * @property {string} [width] CSS width of the viewer's parent div
  * @property {string} [height] CSS height of the viewer's parent div
+ * @property {boolean} [hide_welcome_screen] Whether to hide the welcome screen. Default is `false`.
  */
 
 /**
@@ -27,17 +28,21 @@ export default class WebViewer extends React.Component {
   /** @type {string[]} */
   #recordings = [];
 
+  /** @type {boolean} */
+  #hide_welcome_screen = false;
+
   /** @param {Props} props */
   constructor(props) {
     super(props);
 
     this.#handle = new rerun.WebViewer();
     this.#recordings = toArray(props.rrd);
+    this.#hide_welcome_screen = props.hide_welcome_screen ?? false;
   }
 
   componentDidMount() {
     const current = /** @type {HTMLDivElement} */ (this.#parent.current);
-    this.#handle.start(this.#recordings, current);
+    this.#handle.start(this.#recordings, current, this.#hide_welcome_screen);
   }
 
   componentDidUpdate(/** @type {Props} */ prevProps) {