[button] add ability to disable Button

egui/src/containers/collapsing_header.rs

@@ -154,7 +154,7 @@ impl CollapsingHeader {
                 .text_style(TextStyle::Button)
                 .multiline(false),
             default_open: false,
-            id_source : None,
+            id_source: None,
         }
     }
 

egui/src/context.rs

@@ -321,6 +321,7 @@ impl Context {
         if interaction_id.is_none() || sense == Sense::nothing() {
             // Not interested in input:
             return InteractInfo {
+                sense,
                 rect,
                 hovered,
                 clicked: false,
@@ -341,6 +342,7 @@ impl Context {
         if self.input.mouse.pressed {
             if hovered {
                 let mut info = InteractInfo {
+                    sense,
                     rect,
                     hovered: true,
                     clicked: false,
@@ -368,6 +370,7 @@ impl Context {
             } else {
                 // miss
                 InteractInfo {
+                    sense,
                     rect,
                     hovered,
                     clicked: false,
@@ -378,6 +381,7 @@ impl Context {
         } else if self.input.mouse.released {
             let clicked = hovered && active;
             InteractInfo {
+                sense,
                 rect,
                 hovered,
                 clicked,
@@ -386,6 +390,7 @@ impl Context {
             }
         } else if self.input.mouse.down {
             InteractInfo {
+                sense,
                 rect,
                 hovered: hovered && active,
                 clicked: false,
@@ -394,6 +399,7 @@ impl Context {
             }
         } else {
             InteractInfo {
+                sense,
                 rect,
                 hovered,
                 clicked: false,

egui/src/examples/app.rs

@@ -274,7 +274,7 @@ impl ExampleWindow {
 #[cfg_attr(feature = "with_serde", derive(serde::Deserialize, serde::Serialize))]
 #[cfg_attr(feature = "with_serde", serde(default))]
 struct Widgets {
-    checked: bool,
+    button_enabled: bool,
     count: usize,
     radio: usize,
     slider_value: f32,
@@ -285,7 +285,7 @@ struct Widgets {
 impl Default for Widgets {
     fn default() -> Self {
         Self {
-            checked: true,
+            button_enabled: true,
             radio: 0,
             count: 0,
             slider_value: 3.14,
@@ -305,8 +305,6 @@ impl Widgets {
                 );
             });
 
-        ui.add(Checkbox::new(&mut self.checked, "checkbox"));
-
         ui.horizontal(|ui| {
             if ui.add(radio(self.radio == 0, "First")).clicked {
                 self.radio = 0;
@@ -319,9 +317,11 @@ impl Widgets {
             }
         });
 
+        ui.add(Checkbox::new(&mut self.button_enabled, "Button enabled"));
+
         ui.inner_layout(Layout::horizontal(Align::Center), |ui| {
             if ui
-                .add(Button::new("Click me"))
+                .add(Button::new("Click me").enabled(self.button_enabled))
                 .tooltip_text("This will just increase a counter.")
                 .clicked
             {

egui/src/style.rs

@@ -104,6 +104,7 @@ pub struct Interact {
     pub active: WidgetStyle,
     pub hovered: WidgetStyle,
     pub inactive: WidgetStyle,
+    pub disabled: WidgetStyle,
 }
 
 impl Default for Interact {
@@ -133,13 +134,23 @@ impl Default for Interact {
                 rect_outline: Some(LineStyle::new(1.0, white(128))),
                 corner_radius: 4.0,
             },
+            disabled: WidgetStyle {
+                bg_fill: None,
+                fill: srgba(50, 50, 50, 255),
+                stroke_color: gray(128, 255), // Should look grayed out
+                stroke_width: 0.5,
+                rect_outline: Some(LineStyle::new(0.5, white(128))),
+                corner_radius: 4.0,
+            },
         }
     }
 }
 
 impl Interact {
     pub fn style(&self, interact: &InteractInfo) -> &WidgetStyle {
-        if interact.active {
+        if interact.sense == Sense::nothing() {
+            &self.disabled
+        } else if interact.active {
             &self.active
         } else if interact.hovered {
             &self.hovered

egui/src/types.rs

@@ -41,6 +41,9 @@ impl Default for CursorIcon {
 #[derive(Clone, Copy, Debug)]
 #[cfg_attr(feature = "with_serde", derive(serde::Serialize))]
 pub struct InteractInfo {
+    /// The senses (click or drag) that the widget is interested in (if any).
+    pub sense: Sense,
+
     /// The mouse is hovering above this thing
     pub hovered: bool,
 
@@ -59,6 +62,7 @@ pub struct InteractInfo {
 impl InteractInfo {
     pub fn nothing() -> Self {
         Self {
+            sense: Sense::nothing(),
             hovered: false,
             clicked: false,
             double_clicked: false,
@@ -69,6 +73,7 @@ impl InteractInfo {
 
     pub fn union(self, other: Self) -> Self {
         Self {
+            sense: self.sense.union(other.sense),
             hovered: self.hovered || other.hovered,
             clicked: self.clicked || other.clicked,
             double_clicked: self.double_clicked || other.double_clicked,
@@ -82,6 +87,9 @@ impl InteractInfo {
 
 // TODO: rename GuiResponse
 pub struct GuiResponse {
+    /// The senses (click or drag) that the widget is interested in (if any).
+    pub sense: Sense,
+
     /// The mouse is hovering above this
     pub hovered: bool,
 
@@ -120,6 +128,7 @@ impl GuiResponse {
 impl Into<InteractInfo> for GuiResponse {
     fn into(self) -> InteractInfo {
         InteractInfo {
+            sense: self.sense,
             hovered: self.hovered,
             clicked: self.clicked,
             double_clicked: self.double_clicked,
@@ -133,6 +142,7 @@ impl Into<InteractInfo> for GuiResponse {
 
 /// What sort of interaction is a widget sensitive to?
 #[derive(Clone, Copy, Debug, Eq, PartialEq)]
+#[cfg_attr(feature = "with_serde", derive(serde::Serialize))]
 pub struct Sense {
     /// buttons, sliders, windows ...
     pub click: bool,
@@ -170,4 +180,12 @@ impl Sense {
             drag: true,
         }
     }
+
+    #[must_use]
+    pub fn union(self, other: Self) -> Self {
+        Self {
+            click: self.click | other.click,
+            drag: self.drag | other.drag,
+        }
+    }
 }

egui/src/ui.rs

@@ -303,8 +303,7 @@ impl Ui {
         &mut self,
         explicit_id_source: Option<Id>,
         default_id_source: Option<&str>,
-    ) -> Id
-    {
+    ) -> Id {
         let id = if let Some(explicit_id_source) = explicit_id_source {
             self.id.with(&explicit_id_source)
         } else {
@@ -315,7 +314,8 @@ impl Ui {
                 self.make_position_id()
             }
         };
-        self.ctx.register_unique_id(id, default_id_source.unwrap_or_default(), self.cursor)
+        self.ctx
+            .register_unique_id(id, default_id_source.unwrap_or_default(), self.cursor)
     }
 
     /// Make an Id that is unique to this positon.
@@ -349,12 +349,21 @@ impl Ui {
     #[must_use]
     pub fn response(&mut self, interact: InteractInfo) -> GuiResponse {
         // TODO: unify GuiResponse and InteractInfo. They are the same thing!
+        let InteractInfo {
+            sense,
+            hovered,
+            clicked,
+            double_clicked,
+            active,
+            rect,
+        } = interact;
         GuiResponse {
-            hovered: interact.hovered,
-            clicked: interact.clicked,
-            double_clicked: interact.double_clicked,
-            active: interact.active,
-            rect: interact.rect,
+            sense,
+            hovered,
+            clicked,
+            double_clicked,
+            active,
+            rect,
             ctx: self.ctx.clone(),
         }
     }

egui/src/widgets.rs

@@ -232,6 +232,15 @@ impl Button {
         self.sense = sense;
         self
     }
+
+    /// If you set this to `false`, the button will be grayed out and un-clickable.
+    /// `enabled(false)` has the same effect as calling `sense(Sense::nothing())`.
+    pub fn enabled(mut self, enabled: bool) -> Self {
+        if !enabled {
+            self.sense = Sense::nothing();
+        }
+        self
+    }
 }
 
 impl Widget for Button {