Add ui.set_enabled(false) to disable all widgets in a Ui

Closes https://github.com/emilk/egui/issues/50

egui_demo_lib/src/apps/demo/drag_and_drop.rs

@@ -51,20 +51,24 @@ pub fn drop_target<R>(
 
     let style = if is_being_dragged && can_accept_what_is_being_dragged && response.hovered() {
         ui.visuals().widgets.active
-    } else if is_being_dragged && can_accept_what_is_being_dragged {
-        ui.visuals().widgets.inactive
-    } else if is_being_dragged && !can_accept_what_is_being_dragged {
-        ui.visuals().widgets.disabled
     } else {
         ui.visuals().widgets.inactive
     };
 
+    let mut fill = style.bg_fill;
+    let mut stroke = style.bg_stroke;
+    if is_being_dragged && !can_accept_what_is_being_dragged {
+        // gray out:
+        fill = color::tint_color_towards(fill, ui.visuals().window_fill());
+        stroke.color = color::tint_color_towards(stroke.color, ui.visuals().window_fill());
+    }
+
     ui.painter().set(
         where_to_put_background,
         Shape::Rect {
             corner_radius: style.corner_radius,
-            fill: style.bg_fill,
-            stroke: style.bg_stroke,
+            fill,
+            stroke,
             rect,
         },
     );

egui_demo_lib/src/apps/demo/toggle_switch.rs

@@ -83,9 +83,12 @@ fn toggle_compact(ui: &mut egui::Ui, on: &mut bool) -> egui::Response {
 
 pub fn demo(ui: &mut egui::Ui, on: &mut bool) {
     ui.horizontal_wrapped_for_text(egui::TextStyle::Button, |ui| {
-        ui.label("It's easy to create your own widgets!");
-        ui.label("This toggle switch is just one function and 15 lines of code:");
         toggle(ui, on).on_hover_text("Click to toggle");
         ui.add(crate::__egui_github_link_file!());
-    });
+    })
+    .1
+    .on_hover_text(
+        "It's easy to create your own widgets!\n\
+        This toggle switch is just one function and 20 lines of code.",
+    );
 }

egui_demo_lib/src/apps/demo/widget_gallery.rs

@@ -8,6 +8,7 @@ enum Enum {
 
 #[cfg_attr(feature = "persistence", derive(serde::Deserialize, serde::Serialize))]
 pub struct WidgetGallery {
+    enabled: bool,
     boolean: bool,
     radio: Enum,
     scalar: f32,
@@ -18,6 +19,7 @@ pub struct WidgetGallery {
 impl Default for WidgetGallery {
     fn default() -> Self {
         Self {
+            enabled: true,
             boolean: false,
             radio: Enum::First,
             scalar: 42.0,
@@ -46,6 +48,7 @@ impl super::Demo for WidgetGallery {
 impl super::View for WidgetGallery {
     fn ui(&mut self, ui: &mut egui::Ui) {
         let Self {
+            enabled,
             boolean,
             radio,
             scalar,
@@ -53,6 +56,12 @@ impl super::View for WidgetGallery {
             color,
         } = self;
 
+        ui.horizontal(|ui| {
+            ui.radio_value(enabled, true, "Enabled");
+            ui.radio_value(enabled, false, "Disabled");
+        });
+        ui.set_enabled(*enabled);
+
         let grid = egui::Grid::new("my_grid")
             .striped(true)
             .spacing([40.0, 4.0]);
@@ -65,7 +74,7 @@ impl super::View for WidgetGallery {
             ui.add(egui::Hyperlink::new("https://github.com/emilk/egui").text(" egui home page"));
             ui.end_row();
 
-            ui.label("Text Input:");
+            ui.label("TextEdit:");
             ui.add(egui::TextEdit::singleline(string).hint_text("Write something here"));
             ui.end_row();
 
@@ -73,7 +82,7 @@ impl super::View for WidgetGallery {
             ui.checkbox(boolean, "Checkbox");
             ui.end_row();
 
-            ui.label("Radio buttons:");
+            ui.label("RadioButton:");
             ui.horizontal(|ui| {
                 ui.radio_value(radio, Enum::First, "First");
                 ui.radio_value(radio, Enum::Second, "Second");
@@ -143,6 +152,10 @@ impl super::View for WidgetGallery {
                 });
             });
             ui.end_row();
+
+            ui.label("Custom widget");
+            super::toggle_switch::demo(ui, boolean);
+            ui.end_row();
         });
 
         ui.separator();

egui_demo_lib/src/apps/demo/widgets.rs

@@ -134,8 +134,5 @@ impl Widgets {
 
         ui.label("Multiline text input:");
         ui.text_edit_multiline(&mut self.multiline_text_input);
-
-        ui.separator();
-        super::toggle_switch::demo(ui, &mut self.toggle_switch);
     }
 }

egui_demo_lib/src/apps/demo/window_options.rs

@@ -7,6 +7,7 @@ pub struct WindowOptions {
     collapsible: bool,
     resizable: bool,
     scroll: bool,
+    disabled_time: f64,
 }
 
 impl Default for WindowOptions {
@@ -18,6 +19,7 @@ impl Default for WindowOptions {
             collapsible: true,
             resizable: true,
             scroll: false,
+            disabled_time: f64::NEG_INFINITY,
         }
     }
 }
@@ -36,15 +38,22 @@ impl super::Demo for WindowOptions {
             collapsible,
             resizable,
             scroll,
+            disabled_time,
         } = self.clone();
 
+        let enabled = ctx.input().time - disabled_time > 2.0;
+        if !enabled {
+            ctx.request_repaint();
+        }
+
         use super::View;
         let mut window = egui::Window::new(title)
             .id(egui::Id::new("demo_window_options")) // required since we change the title
             .resizable(resizable)
             .collapsible(collapsible)
             .title_bar(title_bar)
-            .scroll(scroll);
+            .scroll(scroll)
+            .enabled(enabled);
         if closable {
             window = window.open(open);
         }
@@ -63,6 +72,7 @@ impl super::View for WindowOptions {
             collapsible,
             resizable,
             scroll,
+            disabled_time,
         } = self;
 
         ui.horizontal(|ui| {
@@ -77,5 +87,9 @@ impl super::View for WindowOptions {
         ui.vertical_centered(|ui| {
             ui.add(crate::__egui_github_link_file!());
         });
+
+        if ui.button("Disable for 2 seconds").clicked() {
+            *disabled_time = ui.input().time;
+        }
     }
 }