Restructured everything to make profiling a feature of iced_winit.

.gitignore

@@ -4,3 +4,4 @@ pkg/
 Cargo.lock
 .cargo/
 dist/
+traces/

Cargo.toml

@@ -39,13 +39,12 @@ smol = ["iced_futures/smol"]
 palette = ["iced_core/palette"]
 # Enables querying system information
 system = ["iced_winit/system"]
-# Enables tracing with Chrome
-trace_chrome = [
-    "iced_winit/trace",
-    "iced_wgpu?/trace",
-    "iced_glow?/trace",
+# Enables chrome traces
+chrome-trace = [
+    "iced_winit/chrome-trace",
     "iced_glutin?/trace",
-    "iced_profiling/tracing-chrome"
+    "iced_wgpu?/tracing",
+    "iced_glow?/tracing",
 ]
 
 [badges]
@@ -59,7 +58,6 @@ members = [
     "glow",
     "glutin",
     "lazy",
-    "profiling",
     "native",
     "style",
     "wgpu",
@@ -75,7 +73,6 @@ iced_graphics = { version = "0.5", path = "graphics" }
 iced_winit = { version = "0.6", path = "winit", features = ["application"] }
 iced_glutin = { version = "0.5", path = "glutin", optional = true }
 iced_glow = { version = "0.5", path = "glow", optional = true }
-iced_profiling = { version = "0.1.0", path = "profiling", optional = true }
 thiserror = "1.0"
 
 [dependencies.image_rs]

examples/integration_wgpu/Cargo.toml

@@ -8,7 +8,6 @@ publish = false
 [dependencies]
 iced_winit = { path = "../../winit" }
 iced_wgpu = { path = "../../wgpu", features = ["webgl"] }
-iced_profiling = { path = "../../profiling", features = ["tracing-chrome"]}
 env_logger = "0.8"
 
 [target.'cfg(target_arch = "wasm32")'.dependencies]

examples/integration_wgpu/src/main.rs

@@ -16,8 +16,6 @@ use winit::{
     event_loop::{ControlFlow, EventLoop},
 };
 
-use iced_profiling::info_span;
-
 #[cfg(target_arch = "wasm32")]
 use wasm_bindgen::JsCast;
 #[cfg(target_arch = "wasm32")]
@@ -41,9 +39,6 @@ pub fn main() {
     #[cfg(not(target_arch = "wasm32"))]
     env_logger::init();
 
-    // Initialize tracing
-    let _guard = iced_profiling::init();
-
     // Initialize winit
     let event_loop = EventLoop::new();
 
@@ -203,8 +198,6 @@ pub fn main() {
                 }
             }
             Event::RedrawRequested(_) => {
-                let _ = info_span!("Integration_WGPU", "DRAW").entered();
-
                 if resized {
                     let size = window.inner_size();
 

glow/Cargo.toml

@@ -8,7 +8,6 @@ license = "MIT AND OFL-1.1"
 repository = "https://github.com/iced-rs/iced"
 
 [features]
-trace = ["iced_profiling"]
 svg = ["iced_graphics/svg"]
 image = ["iced_graphics/image"]
 png = ["iced_graphics/png"]
@@ -43,9 +42,8 @@ version = "0.5"
 path = "../graphics"
 features = ["font-fallback", "font-icons", "opengl"]
 
-[dependencies.iced_profiling]
-version = "0.1.0"
-path = "../profiling"
+[dependencies.tracing]
+version = "0.1.6"
 optional = true
 
 [package.metadata.docs.rs]

glow/src/image.rs

@@ -21,8 +21,8 @@ use glow::HasContext;
 
 use std::cell::RefCell;
 
-#[cfg(feature = "trace")]
-use iced_profiling::info_span;
+#[cfg(feature = "tracing")]
+use tracing::info_span;
 
 #[derive(Debug)]
 pub(crate) struct Pipeline {
@@ -151,7 +151,7 @@ impl Pipeline {
         images: &[layer::Image],
         layer_bounds: Rectangle<u32>,
     ) {
-        #[cfg(feature = "trace")]
+        #[cfg(feature = "tracing")]
         let _ = info_span!("Glow::Image", "DRAW").entered();
 
         unsafe {

glow/src/quad.rs

@@ -7,8 +7,8 @@ use glow::HasContext;
 use iced_graphics::layer;
 use iced_native::Rectangle;
 
-#[cfg(feature = "trace")]
-use iced_profiling::info_span;
+#[cfg(feature = "tracing")]
+use tracing::info_span;
 
 #[derive(Debug)]
 pub enum Pipeline {
@@ -45,7 +45,7 @@ impl Pipeline {
         scale: f32,
         bounds: Rectangle<u32>,
     ) {
-        #[cfg(feature = "trace")]
+        #[cfg(feature = "tracing")]
         let _ = info_span!("Glow::Quad", "DRAW").enter();
 
         match self {

glow/src/triangle.rs

@@ -9,8 +9,8 @@ use iced_graphics::triangle::{ColoredVertex2D, Vertex2D};
 use glow::HasContext;
 use std::marker::PhantomData;
 
-#[cfg(feature = "trace")]
-use iced_profiling::info_span;
+#[cfg(feature = "tracing")]
+use tracing::info_span;
 
 const DEFAULT_VERTICES: usize = 1_000;
 const DEFAULT_INDICES: usize = 1_000;
@@ -61,7 +61,7 @@ impl Pipeline {
         transformation: Transformation,
         scale_factor: f32,
     ) {
-        #[cfg(feature = "trace")]
+        #[cfg(feature = "tracing")]
         let _ = info_span!("Glow::Triangle", "DRAW").enter();
 
         unsafe {

glutin/Cargo.toml

@@ -11,7 +11,7 @@ keywords = ["gui", "ui", "graphics", "interface", "widgets"]
 categories = ["gui"]
 
 [features]
-trace = ["iced_profiling/tracing-chrome"]
+trace = ["iced_winit/trace"]
 debug = ["iced_winit/debug"]
 system = ["iced_winit/system"]
 
@@ -37,7 +37,6 @@ version = "0.5"
 path = "../graphics"
 features = ["opengl"]
 
-[dependencies.iced_profiling]
-version = "0.1.0"
-path = "../profiling"
-optional = true
+[dependencies.tracing]
+version = "0.1.6"
+optional = true

glutin/src/application.rs

@@ -17,8 +17,8 @@ use iced_winit::{Clipboard, Command, Debug, Proxy, Settings};
 use glutin::window::Window;
 use std::mem::ManuallyDrop;
 
-#[cfg(feature = "trace")]
-use iced_profiling::{info_span, instrument::Instrument};
+#[cfg(feature = "tracing")]
+use tracing::{info_span, instrument::Instrument};
 
 /// Runs an [`Application`] with an executor, compositor, and the provided
 /// settings.
@@ -39,12 +39,12 @@ where
     use glutin::ContextBuilder;
 
     #[cfg(feature = "trace")]
-    let _guard = iced_profiling::init();
+    let _guard = iced_winit::Profiler::init();
 
     let mut debug = Debug::new();
     debug.startup_started();
 
-    #[cfg(feature = "trace")]
+    #[cfg(feature = "tracing")]
     let _ = info_span!("Application::Glutin", "RUN").entered();
 
     let mut event_loop = EventLoopBuilder::with_user_event().build();
@@ -147,7 +147,7 @@ where
             settings.exit_on_close_request,
         );
 
-        #[cfg(feature = "trace")]
+        #[cfg(feature = "tracing")]
         let run_instance =
             run_instance.instrument(info_span!("Application", "LOOP"));
 
@@ -350,7 +350,7 @@ async fn run_instance<A, E, C>(
                 messages.push(message);
             }
             event::Event::RedrawRequested(_) => {
-                #[cfg(feature = "trace")]
+                #[cfg(feature = "tracing")]
                 let _ = info_span!("Application", "FRAME").entered();
 
                 debug.render_started();

profiling/Cargo.toml

@@ -1,15 +0,0 @@
-[package]
-name = "iced_profiling"
-authors = ["Bingus <shankern@protonmail.com>"]
-version = "0.1.0"
-edition = "2021"
-description = "Profiling backend implementations for Iced"
-
-[dependencies]
-tracing = { version = "0.1.37", default-features = false, features = ["std"] }
-tracing-core = "0.1.30"
-tracing-subscriber = { version = "0.3.16", features = ["registry", "env-filter"] }
-
-[dependencies.tracing-chrome]
-version = "0.7.0"
-optional = true

profiling/README.md

@@ -1,61 +0,0 @@
-# `iced_profiling`
-[![Documentation](https://docs.rs/iced_profiling/badge.svg)]
-[![Crates.io](https://img.shields.io/crates/v/iced_profiling.svg)](https://crates.io/crates/iced_profiling)
-[![License](https://img.shields.io/crates/l/iced_profiling.svg)](https://github.com/iced-rs/iced/blob/master/LICENSE)
-[![Discord Server](https://img.shields.io/discord/628993209984614400?label=&labelColor=6A7EC2&logo=discord&logoColor=ffffff&color=7389D8)](https://discord.gg/3xZJ65GAhd)
-
-`iced_profiling` is a crate which implements various tracing backends for Iced.
-
-It relies on the [tracing](https://crates.io/crates/tracing) crate to collect diagnostics. We currently only support 
-tracing with `tracing`'s `info_span!` macro, but will consider different logging levels in the future. PRs welcome!
-
-## Trace backends
-
-We currently support only Chrome JSON traces using the [tracing-chrome](https://crates.io/crates/tracing-chrome) crate.
-
-There are plans to add support for [Tracy](https://github.com/wolfpld/tracy) in the near future!
-
-## Generating a trace file
-
-### Using Iced's `Application`
-
-Simply enable your tracing backend of choice (e.g. `trace_chrome`) feature in Iced & run your project.
-
-```shell
-cargo run --features iced/trace_chrome
-```
-### Standalone dependency
-
-You can enable tracing by enabling your tracing backend of choice as a feature of `iced_profiling`.
-
-```toml
-iced_profiling = { version = "0.1.0", features = ["tracing-chrome"]}
-```
-
-Doing so will require you to initialize the profiler manually like so:
-
-```rust
-let _guard = iced_profiling::init();
-```
-
-This reference must be kept alive for the entire duration of your application that you wish to profile.
-
-## Chrome
-
-By default, Chrome trace files will be generated in the current working directory:
-```shell
-path/to/your/project/project_trace_{timestamp}.json
-```
-
-You also set a specific path by setting the `CHROME_TRACE_FILE` env variable:
-```shell
-CHROME_TRACE_FILE = ~/Desktop/trace.json cargo run
-```
-
-If you cannot find your trace file, there may have been a permission issue when trying to generate your file. Be sure to check your cargo manifest directory!
-
-Once your file is generated, you can view it in Google Chrome at either [ui.perfetto.dev](ui.perfetto.dev) (new) or [chrome://trace](chrome://trace) (old).
-
-<p align="center">
-  <img alt="The native target" src="../docs/images/perfetto.png" width="80%">
-</p>

profiling/src/lib.rs

@@ -1,100 +0,0 @@
-use std::time::Duration;
-use tracing_subscriber::prelude::*;
-use tracing_subscriber::Registry;
-
-#[cfg(feature = "tracing-chrome")]
-use {
-    tracing_chrome::FlushGuard,
-    tracing_subscriber::fmt::{format::DefaultFields, FormattedFields},
-};
-
-pub use tracing::{info_span, instrument};
-
-/// Profiler state. This will likely need to be updated or reworked when adding new tracing backends.
-pub struct Profiler {
-    #[cfg(feature = "tracing-chrome")]
-    /// [`FlushGuard`] must not be dropped until the application scope is dropped for accurate tracing.
-    _guard: FlushGuard,
-}
-
-pub fn init() -> Profiler {
-    // Registry stores the spans & generates unique span IDs
-    let subscriber = Registry::default();
-
-    #[cfg(feature = "tracing-chrome")]
-    let (chrome_layer, guard) = {
-        let mut layer = tracing_chrome::ChromeLayerBuilder::new();
-
-        // Optional configurable env var: CHROME_TRACE_FILE=/path/to/trace_file/file.json,
-        // for uploading to chrome://tracing (old) or ui.perfetto.dev (new).
-        if let Ok(path) = std::env::var("CHROME_TRACE_FILE") {
-            layer = layer.file(path);
-        } else if let Ok(current_dir) = std::env::current_dir() {
-            let time = std::time::SystemTime::now()
-                .duration_since(std::time::UNIX_EPOCH)
-                .unwrap_or(Duration::from_millis(0))
-                .as_millis();
-
-            let trace_file_name = current_dir
-                .file_name()
-                .map(|file_dir| {
-                    format!(
-                        "{}_trace_{}.json",
-                        file_dir.to_str().unwrap_or("trace"),
-                        time
-                    )
-                })
-                .unwrap_or_else(|| "trace.json".to_string());
-
-            let path = format!(
-                "{}/{}",
-                current_dir.to_str().expect("Invalid path"),
-                trace_file_name
-            );
-
-            layer = layer.file(path);
-        } else {
-            layer = layer.file(env!("CARGO_MANIFEST_DIR"))
-        }
-
-        let (chrome_layer, guard) = layer
-            .name_fn(Box::new(|event_or_span| match event_or_span {
-                tracing_chrome::EventOrSpan::Event(event) => {
-                    event.metadata().name().into()
-                }
-                tracing_chrome::EventOrSpan::Span(span) => {
-                    if let Some(fields) = span
-                        .extensions()
-                        .get::<FormattedFields<DefaultFields>>()
-                    {
-                        format!(
-                            "{}: {}",
-                            span.metadata().name(),
-                            fields.fields.as_str()
-                        )
-                    } else {
-                        span.metadata().name().into()
-                    }
-                }
-            }))
-            .build();
-
-        (chrome_layer, guard)
-    };
-
-    let fmt_layer = tracing_subscriber::fmt::Layer::default();
-    let subscriber = subscriber.with(fmt_layer);
-
-    #[cfg(feature = "tracing-chrome")]
-    let subscriber = subscriber.with(chrome_layer);
-
-    // create dispatcher which will forward span events to the subscriber
-    // this can only be set once or will panic
-    tracing::subscriber::set_global_default(subscriber)
-        .expect("Profiler could not set the global default subscriber.");
-
-    Profiler {
-        #[cfg(feature = "tracing-chrome")]
-        _guard: guard,
-    }
-}

wgpu/Cargo.toml

@@ -8,25 +8,24 @@ license = "MIT AND OFL-1.1"
 repository = "https://github.com/iced-rs/iced"
 
 [features]
-bmp = ["iced_graphics/bmp"]
-canvas = ["iced_graphics/canvas"]
-dds = ["iced_graphics/dds"]
-default_system_font = ["iced_graphics/font-source"]
-farbfeld = ["iced_graphics/farbfeld"]
-gif = ["iced_graphics/gif"]
-hdr = ["iced_graphics/hdr"]
-ico = ["iced_graphics/ico"]
+svg = ["iced_graphics/svg"]
 image = ["iced_graphics/image"]
+png = ["iced_graphics/png"]
 jpeg = ["iced_graphics/jpeg"]
 jpeg_rayon = ["iced_graphics/jpeg_rayon"]
-png = ["iced_graphics/png"]
-pnm = ["iced_graphics/pnm"]
-qr_code = ["iced_graphics/qr_code"]
-spirv = ["wgpu/spirv"]
-svg = ["iced_graphics/svg"]
-trace = ["iced_profiling"]
-webgl = ["wgpu/webgl"]
+gif = ["iced_graphics/gif"]
 webp = ["iced_graphics/webp"]
+pnm = ["iced_graphics/pnm"]
+ico = ["iced_graphics/ico"]
+bmp = ["iced_graphics/bmp"]
+hdr = ["iced_graphics/hdr"]
+dds = ["iced_graphics/dds"]
+farbfeld = ["iced_graphics/farbfeld"]
+canvas = ["iced_graphics/canvas"]
+qr_code = ["iced_graphics/qr_code"]
+default_system_font = ["iced_graphics/font-source"]
+spirv = ["wgpu/spirv"]
+webgl = ["wgpu/webgl"]
 
 [dependencies]
 wgpu = "0.14"
@@ -51,9 +50,8 @@ version = "0.5"
 path = "../graphics"
 features = ["font-fallback", "font-icons"]
 
-[dependencies.iced_profiling]
-version = "0.1.0"
-path = "../profiling"
+[dependencies.tracing]
+version = "0.1.6"
 optional = true
 
 [dependencies.encase]

wgpu/src/backend.rs

@@ -10,8 +10,8 @@ use iced_graphics::{Primitive, Viewport};
 use iced_native::alignment;
 use iced_native::{Font, Size};
 
-#[cfg(feature = "trace")]
-use iced_profiling::info_span;
+#[cfg(feature = "tracing")]
+use tracing::info_span;
 
 #[cfg(any(feature = "image", feature = "svg"))]
 use crate::image;
@@ -80,7 +80,7 @@ impl Backend {
         overlay_text: &[T],
     ) {
         log::debug!("Drawing");
-        #[cfg(feature = "trace")]
+        #[cfg(feature = "tracing")]
         let _ = info_span!("Wgpu::Backend", "PRESENT").entered();
 
         let target_size = viewport.physical_size();

wgpu/src/image.rs

@@ -23,8 +23,8 @@ use iced_native::image;
 #[cfg(feature = "svg")]
 use iced_native::svg;
 
-#[cfg(feature = "trace")]
-use iced_profiling::info_span;
+#[cfg(feature = "tracing")]
+use tracing::info_span;
 
 #[derive(Debug)]
 pub struct Pipeline {
@@ -292,7 +292,7 @@ impl Pipeline {
         target: &wgpu::TextureView,
         _scale: f32,
     ) {
-        #[cfg(feature = "trace")]
+        #[cfg(feature = "tracing")]
         let _ = info_span!("Wgpu::Image", "DRAW").entered();
 
         let instances: &mut Vec<Instance> = &mut Vec::new();

wgpu/src/quad.rs

@@ -6,8 +6,8 @@ use bytemuck::{Pod, Zeroable};
 use std::mem;
 use wgpu::util::DeviceExt;
 
-#[cfg(feature = "trace")]
-use iced_profiling::info_span;
+#[cfg(feature = "tracing")]
+use tracing::info_span;
 
 #[derive(Debug)]
 pub struct Pipeline {
@@ -176,7 +176,7 @@ impl Pipeline {
         bounds: Rectangle<u32>,
         target: &wgpu::TextureView,
     ) {
-        #[cfg(feature = "trace")]
+        #[cfg(feature = "tracing")]
         let _ = info_span!("Wgpu::Quad", "DRAW").entered();
 
         let uniforms = Uniforms::new(transformation, scale);
@@ -213,7 +213,7 @@ impl Pipeline {
 
             instance_buffer.copy_from_slice(instance_bytes);
 
-            #[cfg(feature = "trace")]
+            #[cfg(feature = "tracing")]
             let _ = info_span!("Wgpu::Quad", "BEGIN_RENDER_PASS").enter();
 
             {

wgpu/src/triangle.rs

@@ -8,8 +8,8 @@ use crate::Transformation;
 use iced_graphics::layer::mesh::{self, Mesh};
 use iced_graphics::triangle::ColoredVertex2D;
 use iced_graphics::Size;
-#[cfg(feature = "trace")]
-use iced_profiling::info_span;
+#[cfg(feature = "tracing")]
+use tracing::info_span;
 
 #[derive(Debug)]
 pub struct Pipeline {
@@ -55,7 +55,7 @@ impl Pipeline {
         scale_factor: f32,
         meshes: &[Mesh<'_>],
     ) {
-        #[cfg(feature = "trace")]
+        #[cfg(feature = "tracing")]
         let _ = info_span!("Wgpu::Triangle", "DRAW").entered();
 
         // Count the total amount of vertices & indices we need to handle
@@ -252,7 +252,7 @@ impl Pipeline {
                 (target, None, wgpu::LoadOp::Load)
             };
 
-            #[cfg(feature = "trace")]
+            #[cfg(feature = "tracing")]
             let _ = info_span!("Wgpu::Triangle", "BEGIN_RENDER_PASS").enter();
 
             let mut render_pass =

winit/Cargo.toml

@@ -11,7 +11,8 @@ keywords = ["gui", "ui", "graphics", "interface", "widgets"]
 categories = ["gui"]
 
 [features]
-trace = ["iced_profiling"]
+trace = ["tracing", "tracing-core", "tracing-subscriber"]
+chrome-trace = ["trace", "tracing-chrome"]
 debug = ["iced_native/debug"]
 system = ["sysinfo"]
 application = []
@@ -38,9 +39,22 @@ path = "../graphics"
 version = "0.5"
 path = "../futures"
 
-[dependencies.iced_profiling]
-version = "0.1.0"
-path = "../profiling"
+[dependencies.tracing]
+version = "0.1.37"
+optional = true
+features = ["std"]
+
+[dependencies.tracing-core]
+version = "0.1.30"
+optional = true
+
+[dependencies.tracing-subscriber]
+version = "0.3.16"
+optional = true
+features = ["registry"]
+
+[dependencies.tracing-chrome]
+version = "0.7.0"
 optional = true
 
 [target.'cfg(target_os = "windows")'.dependencies.winapi]

winit/src/application.rs

@@ -1,4 +1,6 @@
 //! Create interactive, native cross-platform applications.
+#[cfg(feature = "trace")]
+mod profiler;
 mod state;
 
 pub use state::State;
@@ -25,7 +27,9 @@ pub use iced_native::application::{Appearance, StyleSheet};
 use std::mem::ManuallyDrop;
 
 #[cfg(feature = "trace")]
-use iced_profiling::{info_span, instrument::Instrument};
+pub use profiler::Profiler;
+#[cfg(feature = "trace")]
+use tracing::{info_span, instrument::Instrument};
 
 /// An interactive, native cross-platform application.
 ///
@@ -115,7 +119,7 @@ where
     use winit::event_loop::EventLoopBuilder;
 
     #[cfg(feature = "trace")]
-    let _guard = iced_profiling::init();
+    let _guard = Profiler::init();
 
     let mut debug = Debug::new();
     debug.startup_started();

winit/src/application/profiler.rs

@@ -0,0 +1,101 @@
+//! A simple profiler for Iced.
+use std::ffi::OsStr;
+use std::path::Path;
+use std::time::Duration;
+use tracing_subscriber::prelude::*;
+use tracing_subscriber::Registry;
+#[cfg(feature = "chrome-trace")]
+use {
+    tracing_chrome::FlushGuard,
+    tracing_subscriber::fmt::{format::DefaultFields, FormattedFields},
+};
+
+/// Profiler state. This will likely need to be updated or reworked when adding new tracing backends.
+#[allow(missing_debug_implementations)]
+pub struct Profiler {
+    #[cfg(feature = "chrome-trace")]
+    /// [`FlushGuard`] must not be dropped until the application scope is dropped for accurate tracing.
+    _guard: FlushGuard,
+}
+
+impl Profiler {
+    /// Initializes the [`Profiler`].
+    pub fn init() -> Self {
+        // Registry stores the spans & generates unique span IDs
+        let subscriber = Registry::default();
+
+        let default_path = Path::new(env!("CARGO_MANIFEST_DIR"));
+        let curr_exe = std::env::current_exe()
+            .unwrap_or_else(|_| default_path.to_path_buf());
+        let out_dir = curr_exe.parent().unwrap_or(default_path).join("traces");
+
+        #[cfg(feature = "chrome-trace")]
+        let (chrome_layer, guard) = {
+            let mut layer = tracing_chrome::ChromeLayerBuilder::new();
+
+            // Optional configurable env var: CHROME_TRACE_FILE=/path/to/trace_file/file.json,
+            // for uploading to chrome://tracing (old) or ui.perfetto.dev (new).
+            if let Ok(path) = std::env::var("CHROME_TRACE_FILE") {
+                layer = layer.file(path);
+            } else if std::fs::create_dir_all(&out_dir).is_ok() {
+                let time = std::time::SystemTime::now()
+                    .duration_since(std::time::UNIX_EPOCH)
+                    .unwrap_or(Duration::from_millis(0))
+                    .as_millis();
+
+                let curr_exe_name = curr_exe
+                    .file_name()
+                    .unwrap_or_else(|| OsStr::new("trace"))
+                    .to_str()
+                    .unwrap_or("trace");
+
+                let path = out_dir
+                    .join(format!("{}_trace_{}.json", curr_exe_name, time));
+
+                layer = layer.file(path);
+            } else {
+                layer = layer.file(env!("CARGO_MANIFEST_DIR"))
+            }
+
+            let (chrome_layer, guard) = layer
+                .name_fn(Box::new(|event_or_span| match event_or_span {
+                    tracing_chrome::EventOrSpan::Event(event) => {
+                        event.metadata().name().into()
+                    }
+                    tracing_chrome::EventOrSpan::Span(span) => {
+                        if let Some(fields) = span
+                            .extensions()
+                            .get::<FormattedFields<DefaultFields>>()
+                        {
+                            format!(
+                                "{}: {}",
+                                span.metadata().name(),
+                                fields.fields.as_str()
+                            )
+                        } else {
+                            span.metadata().name().into()
+                        }
+                    }
+                }))
+                .build();
+
+            (chrome_layer, guard)
+        };
+
+        let fmt_layer = tracing_subscriber::fmt::Layer::default();
+        let subscriber = subscriber.with(fmt_layer);
+
+        #[cfg(feature = "chrome-trace")]
+        let subscriber = subscriber.with(chrome_layer);
+
+        // create dispatcher which will forward span events to the subscriber
+        // this can only be set once or will panic
+        tracing::subscriber::set_global_default(subscriber)
+            .expect("Tracer could not set the global default subscriber.");
+
+        Profiler {
+            #[cfg(feature = "chrome-trace")]
+            _guard: guard,
+        }
+    }
+}

winit/src/lib.rs

@@ -51,6 +51,8 @@ mod proxy;
 
 #[cfg(feature = "application")]
 pub use application::Application;
+#[cfg(feature = "trace")]
+pub use application::Profiler;
 pub use clipboard::Clipboard;
 pub use error::Error;
 pub use position::Position;