Add support for disabled menu items on gtk. (#897)

Author: jneem

CHANGELOG.md

@@ -68,6 +68,7 @@ While some features like the clipboard, menus or file dialogs are not yet availa
 - Windows: Termiate app when all windows have closed. ([#763] by [@xStrom])
 - macOS: `Application::quit` now quits the run loop instead of killing the process. ([#763] by [@xStrom])
 - macOS/GTK/web: `MouseButton::X1` and `MouseButton::X2` clicks are now recognized. ([#843] by [@xStrom])
+- GTK: Support disabled menu items ([#897] by [@jneem])
 
 ### Visual
 
@@ -139,8 +140,9 @@ While some features like the clipboard, menus or file dialogs are not yet availa
 [#861]: https://github.com/xi-editor/druid/pull/861
 [#869]: https://github.com/xi-editor/druid/pull/869
 [#878]: https://github.com/xi-editor/druid/pull/878
-[#889]: https://github.com/xi-editor/druid/pull/899
+[#889]: https://github.com/xi-editor/druid/pull/889
 [#894]: https://github.com/xi-editor/druid/pull/894
+[#897]: https://github.com/xi-editor/druid/pull/897
 [#898]: https://github.com/xi-editor/druid/pull/898
 
 ## [0.5.0] - 2020-04-01

druid-shell/src/platform/gtk/menu.rs

@@ -32,7 +32,12 @@ pub struct Menu {
 
 #[derive(Debug)]
 enum MenuItem {
-    Entry(String, u32, Option<HotKey>),
+    Entry {
+        name: String,
+        id: u32,
+        key: Option<HotKey>,
+        enabled: bool,
+    },
     SubMenu(String, Menu),
     Separator,
 }
@@ -57,12 +62,16 @@ impl Menu {
         id: u32,
         text: &str,
         key: Option<&HotKey>,
-        _enabled: bool,
+        enabled: bool,
         _selected: bool,
     ) {
-        // TODO: implement enabled, selected item
-        self.items
-            .push(MenuItem::Entry(strip_access_key(text), id, key.cloned()));
+        // TODO: implement selected items
+        self.items.push(MenuItem::Entry {
+            name: strip_access_key(text),
+            id,
+            key: key.cloned(),
+            enabled,
+        });
     }
 
     pub fn add_separator(&mut self) {
@@ -77,8 +86,14 @@ impl Menu {
     ) {
         for item in self.items {
             match item {
-                MenuItem::Entry(name, id, key) => {
+                MenuItem::Entry {
+                    name,
+                    id,
+                    key,
+                    enabled,
+                } => {
                     let item = GtkMenuItem::new_with_label(&name);
+                    item.set_sensitive(enabled);
 
                     if let Some(k) = key {
                         register_accelerator(&item, accel_group, k);