Add opt-in `puffin` feature to `egui-extras` (#3307)

* Add opt-in `puffin` feature to `egui-extras`

Image loading can be slow.

Related to https://github.com/emilk/egui/pull/3297

* Silence warning

Cargo.lock

@@ -1265,6 +1265,7 @@ dependencies = [
  "egui",
  "image",
  "log",
+ "puffin",
  "resvg",
  "serde",
  "tiny-skia",

crates/egui_extras/Cargo.toml

@@ -29,12 +29,17 @@ default = []
 ## Enable [`DatePickerButton`] widget.
 datepicker = ["chrono"]
 
-## Support loading svg images.
-svg = ["resvg", "tiny-skia", "usvg"]
-
 ## Log warnings using [`log`](https://docs.rs/log) crate.
 log = ["dep:log", "egui/log"]
 
+## Enable profiling with the [`puffin`](https://docs.rs/puffin) crate.
+##
+## Only enabled on native, because of the low resolution (1ms) of clocks in browsers.
+puffin = ["dep:puffin", "egui/puffin"]
+
+## Support loading svg images.
+svg = ["resvg", "tiny-skia", "usvg"]
+
 
 [dependencies]
 egui = { version = "0.22.0", path = "../egui", default-features = false }
@@ -65,6 +70,8 @@ image = { version = "0.24", optional = true, default-features = false }
 # feature "log"
 log = { version = "0.4", optional = true, features = ["std"] }
 
+puffin = { version = "0.16", optional = true }
+
 # svg feature
 resvg = { version = "0.28", optional = true, default-features = false }
 tiny-skia = { version = "0.8", optional = true, default-features = false } # must be updated in lock-step with resvg

crates/egui_extras/src/image.rs

@@ -203,6 +203,7 @@ use egui::ColorImage;
 /// On invalid image or unsupported image format.
 #[cfg(feature = "image")]
 pub fn load_image_bytes(image_bytes: &[u8]) -> Result<egui::ColorImage, String> {
+    crate::profile_function!();
     let image = image::load_from_memory(image_bytes).map_err(|err| err.to_string())?;
     let size = [image.width() as _, image.height() as _];
     let image_buffer = image.to_rgba8();
@@ -235,6 +236,7 @@ pub fn load_svg_bytes_with_size(
     svg_bytes: &[u8],
     fit_to: FitTo,
 ) -> Result<egui::ColorImage, String> {
+    crate::profile_function!();
     let opt = usvg::Options::default();
 
     let rtree = usvg::Tree::from_data(svg_bytes, &opt).map_err(|err| err.to_string())?;

crates/egui_extras/src/lib.rs

@@ -28,6 +28,38 @@ pub use crate::sizing::Size;
 pub use crate::strip::*;
 pub use crate::table::*;
 
+// ---------------------------------------------------------------------------
+
+mod profiling_scopes {
+    #![allow(unused_macros)]
+    #![allow(unused_imports)]
+
+    /// Profiling macro for feature "puffin"
+    macro_rules! profile_function {
+        ($($arg: tt)*) => {
+            #[cfg(not(target_arch = "wasm32"))] // Disabled on web because of the coarse 1ms clock resolution there.
+            #[cfg(feature = "puffin")]
+            puffin::profile_function!($($arg)*);
+        };
+    }
+    pub(crate) use profile_function;
+
+    /// Profiling macro for feature "puffin"
+    macro_rules! profile_scope {
+        ($($arg: tt)*) => {
+            #[cfg(not(target_arch = "wasm32"))] // Disabled on web because of the coarse 1ms clock resolution there.
+            #[cfg(feature = "puffin")]
+            puffin::profile_scope!($($arg)*);
+        };
+    }
+    pub(crate) use profile_scope;
+}
+
+#[allow(unused_imports)]
+pub(crate) use profiling_scopes::*;
+
+// ---------------------------------------------------------------------------
+
 /// Log an error with either `log` or `eprintln`
 macro_rules! log_err {
     ($fmt: literal, $($arg: tt)*) => {{