Adress stepper review feedback

Author: scholtzan

druid/examples/switch.rs

@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-use druid::widget::{Align, Flex, Label, Padding, Parse, Stepper, Switch, TextBox};
+use druid::widget::{Flex, Label, Padding, Parse, Stepper, Switch, TextBox, WidgetExt};
 use druid::{AppLauncher, Data, Lens, LensExt, LensWrap, Widget, WindowDesc};
 
 #[derive(Clone, Data, Lens)]
@@ -31,11 +31,7 @@ fn build_widget() -> impl Widget<DemoState> {
     row.add_child(Padding::new(5.0, switch), 0.0);
 
     let stepper = LensWrap::new(
-        Stepper::new(|_ctx, _data, _env| {})
-            .max(10.0)
-            .min(0.0)
-            .step(0.5)
-            .wrap(false),
+        Stepper::new().max(10.0).min(0.0).step(0.5).wrap(false),
         DemoState::stepper_value,
     );
 
@@ -45,7 +41,7 @@ fn build_widget() -> impl Widget<DemoState> {
         DemoState::stepper_value.map(|x| Some(*x), |x, y| *x = y.unwrap_or(0.0)),
     );
     textbox_row.add_child(Padding::new(5.0, textbox), 0.0);
-    textbox_row.add_child(Padding::new(5.0, Align::centered(stepper)), 0.0);
+    textbox_row.add_child(Padding::new(5.0, stepper.center().padding(5.0)), 0.0);
 
     let mut label_row = Flex::row();
 

druid/src/widget/stepper.rs

@@ -37,49 +37,50 @@ pub struct Stepper {
     min: f64,
     step: f64,
     wrap: bool,
-    /// A closure that will be invoked when the value changed.
-    value_changed: Box<dyn Fn(&mut EventCtx, &mut f64, &Env)>,
     /// Keeps track of which button is currently triggered.
     increase_active: bool,
     decrease_active: bool,
     timer_id: TimerToken,
 }
 
 impl Stepper {
-    pub fn new(value_changed: impl Fn(&mut EventCtx, &mut f64, &Env) + 'static) -> Self {
+    pub fn new() -> Self {
         Stepper {
             max: std::f64::MAX,
             min: std::f64::MIN,
             step: 1.0,
             wrap: false,
-            value_changed: Box::new(value_changed),
             increase_active: false,
             decrease_active: false,
             timer_id: TimerToken::INVALID,
         }
     }
 
+    /// Set the stepper's maximum value.
     pub fn max(mut self, max: f64) -> Self {
         self.max = max;
         self
     }
 
+    /// Set the stepper's minimum value.
     pub fn min(mut self, min: f64) -> Self {
         self.min = min;
         self
     }
 
+    /// Set the steppers amount by which the value increases or decreases.
     pub fn step(mut self, step: f64) -> Self {
         self.step = step;
         self
     }
 
+    /// Set whether the stepper should wrap around the minimum/maximum values.
     pub fn wrap(mut self, wrap: bool) -> Self {
         self.wrap = wrap;
         self
     }
 
-    fn change_value(&mut self, ctx: &mut EventCtx, data: &mut f64, env: &Env) {
+    fn change_value(&mut self, _ctx: &mut EventCtx, data: &mut f64, _env: &Env) {
         // increase/decrease value depending on which button is currently active
         let delta = if self.increase_active {
             self.step
@@ -89,13 +90,9 @@ impl Stepper {
             0.0
         };
 
-        let old_data = *data;
         *data = (*data + delta).max(self.min).min(self.max);
 
-        if (*data - old_data).abs() > EPSILON {
-            // callback
-            (self.value_changed)(ctx, data, env);
-        } else if self.wrap {
+        if self.wrap {
             if (*data - self.min).abs() < EPSILON {
                 *data = self.max
             } else {
@@ -105,6 +102,12 @@ impl Stepper {
     }
 }
 
+impl Default for Stepper {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
 impl Widget<f64> for Stepper {
     fn paint(&mut self, paint_ctx: &mut PaintCtx, _data: &f64, env: &Env) {
         let rounded_rect =