Introduce FingerId (#3783)

src/platform/web.rs

@@ -56,6 +56,7 @@ use web_sys::HtmlCanvasElement;
 use crate::application::ApplicationHandler;
 use crate::cursor::CustomCursorSource;
 use crate::error::NotSupportedError;
+use crate::event::FingerId;
 use crate::event_loop::{ActiveEventLoop, EventLoop};
 use crate::monitor::MonitorHandle;
 use crate::platform_impl::PlatformCustomCursorSource;
@@ -763,3 +764,16 @@ impl Display for OrientationLockError {
 }
 
 impl Error for OrientationLockError {}
+
+/// Additional methods on [`FingerId`] that are specific to Web.
+pub trait FingerIdExtWeb {
+    /// Indicates if the finger represents the first contact in a multi-touch interaction.
+    #[allow(clippy::wrong_self_convention)]
+    fn is_primary(self) -> bool;
+}
+
+impl FingerIdExtWeb for FingerId {
+    fn is_primary(self) -> bool {
+        self.0.is_primary()
+    }
+}