Add menu with an image button (#2488)

crates/egui/src/menu.rs

@@ -100,6 +100,20 @@ pub fn menu_button<R>(
     stationary_menu_impl(ui, title, Box::new(add_contents))
 }
 
+/// Construct a top level menu with an image in a menu bar. This would be e.g. "File", "Edit" etc.
+///
+/// Responds to primary clicks.
+///
+/// Returns `None` if the menu is not open.
+pub fn menu_image_button<R>(
+    ui: &mut Ui,
+    texture_id: TextureId,
+    image_size: impl Into<Vec2>,
+    add_contents: impl FnOnce(&mut Ui) -> R,
+) -> InnerResponse<Option<R>> {
+    stationary_menu_image_impl(ui, texture_id, image_size, Box::new(add_contents))
+}
+
 /// Construct a nested sub menu in another menu.
 ///
 /// Opens on hover.
@@ -177,6 +191,25 @@ fn stationary_menu_impl<'c, R>(
     InnerResponse::new(inner.map(|r| r.inner), button_response)
 }
 
+/// Build a top level menu with an image button.
+///
+/// Responds to primary clicks.
+fn stationary_menu_image_impl<'c, R>(
+    ui: &mut Ui,
+    texture_id: TextureId,
+    image_size: impl Into<Vec2>,
+    add_contents: Box<dyn FnOnce(&mut Ui) -> R + 'c>,
+) -> InnerResponse<Option<R>> {
+    let bar_id = ui.id();
+
+    let mut bar_state = BarState::load(ui.ctx(), bar_id);
+    let button_response = ui.add(ImageButton::new(texture_id, image_size));
+    let inner = bar_state.bar_menu(&button_response, add_contents);
+
+    bar_state.store(ui.ctx(), bar_id);
+    InnerResponse::new(inner.map(|r| r.inner), button_response)
+}
+
 /// Response to secondary clicks (right-clicks) by showing the given menu.
 pub(crate) fn context_menu(
     response: &Response,

crates/egui/src/ui.rs

@@ -2157,6 +2157,43 @@ impl Ui {
             menu::menu_button(self, title, add_contents)
         }
     }
+
+    #[inline]
+    /// Create a menu button with an image that when clicked will show the given menu.
+    ///
+    /// If called from within a menu this will instead create a button for a sub-menu.
+    ///
+    /// ```
+    /// use egui_extras;
+    ///
+    /// let img = egui_extrasRetainedImage::from_svg_bytes_with_size(
+    ///     "rss",
+    ///     include_bytes!("rss.svg"),
+    ///     egui_extras::image::FitTo::Size(24, 24),
+    /// );
+    ///
+    /// ui.menu_image_button(img.texture_id(ctx), img.size_vec2(), |ui| {
+    ///     ui.menu_button("My sub-menu", |ui| {
+    ///         if ui.button("Close the menu").clicked() {
+    ///             ui.close_menu();
+    ///         }
+    ///     });
+    /// });
+    /// ```
+    ///
+    /// See also: [`Self::close_menu`] and [`Response::context_menu`].
+    pub fn menu_image_button<R>(
+        &mut self,
+        texture_id: TextureId,
+        image_size: impl Into<Vec2>,
+        add_contents: impl FnOnce(&mut Ui) -> R,
+    ) -> InnerResponse<Option<R>> {
+        if let Some(menu_state) = self.menu_state.clone() {
+            menu::submenu_button(self, menu_state, String::new(), add_contents)
+        } else {
+            menu::menu_image_button(self, texture_id, image_size, add_contents)
+        }
+    }
 }
 
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