Add example for connecting stepper widget with textbox

Author: scholtzan

druid/examples/switch.rs

@@ -12,8 +12,8 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-use druid::widget::{Flex, Switch, DynLabel, Label, Padding, Row, Stepper, Switch};
-use druid::{AppLauncher, Data, Lens, LensWrap, Widget, WindowDesc};
+use druid::widget::{Flex, Label, Padding, Parse, Stepper, Switch, TextBox};
+use druid::{AppLauncher, Data, Lens, LensExt, LensWrap, Widget, WindowDesc};
 
 #[derive(Clone, Data, Lens)]
 struct DemoState {
@@ -30,22 +30,30 @@ fn build_widget() -> impl Widget<DemoState> {
     row.add_child(Padding::new(5.0, switch_label), 0.0);
     row.add_child(Padding::new(5.0, switch), 0.0);
 
-    let label_stepper = LensWrap::new(
+    let stepper = LensWrap::new(
         Stepper::new(0.0, 10.0, 0.25, true, |_ctx, _data, _env| {}),
-        lenses::demo_state::stepper_value,
+        DemoState::stepper_value,
     );
 
-    let mut stepper_row = Row::new();
+    let mut textbox_row = Flex::row();
+    let textbox = LensWrap::new(
+        Parse::new(TextBox::new()),
+        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, stepper), 0.0);
+
+    let mut label_row = Flex::row();
 
-    let label = DynLabel::new(|data: &DemoState, _env| {
+    let label = Label::new(|data: &DemoState, _env: &_| {
         format!("Stepper value: {0:.2}", data.stepper_value)
     });
 
-    stepper_row.add_child(Padding::new(5.0, label), 0.0);
-    stepper_row.add_child(Padding::new(5.0, label_stepper), 0.0);
+    label_row.add_child(Padding::new(5.0, label), 0.0);
 
     col.add_child(Padding::new(5.0, row), 1.0);
-    col.add_child(Padding::new(5.0, stepper_row), 1.0);
+    col.add_child(Padding::new(5.0, textbox_row), 1.0);
+    col.add_child(Padding::new(5.0, label_row), 1.0);
     col
 }
 

druid/src/widget/mod.rs

@@ -31,6 +31,7 @@ mod scroll;
 mod sized_box;
 mod slider;
 mod split;
+mod stepper;
 #[cfg(feature = "svg")]
 #[cfg_attr(docsrs, doc(cfg(feature = "svg")))]
 mod svg;
@@ -55,6 +56,7 @@ pub use scroll::Scroll;
 pub use sized_box::SizedBox;
 pub use slider::Slider;
 pub use split::Split;
+pub use stepper::Stepper;
 #[cfg(feature = "svg")]
 #[cfg_attr(docsrs, doc(cfg(feature = "svg")))]
 pub use svg::{Svg, SvgData};

druid/src/widget/stepper.rs

@@ -15,9 +15,9 @@
 //! A stepper widget.
 
 use crate::{
-    BaseState, BoxConstraints, Env, Event, EventCtx, LayoutCtx, PaintCtx, Size, TimerToken,
-    UpdateCtx, Widget,
+    BoxConstraints, Env, Event, EventCtx, LayoutCtx, PaintCtx, Size, TimerToken, UpdateCtx, Widget,
 };
+use std::f64::EPSILON;
 use std::time::{Duration, Instant};
 
 use crate::kurbo::{BezPath, Rect, RoundedRect};
@@ -77,11 +77,11 @@ impl Stepper {
         let old_data = *data;
         *data = (*data + delta).min(self.min).max(self.max);
 
-        if old_data != *data {
+        if (*data - old_data).abs() > EPSILON {
             // callback
             (self.value_changed)(ctx, data, env);
         } else if self.wrap {
-            if *data == self.min {
+            if (*data - self.min).abs() < EPSILON {
                 *data = self.max
             } else {
                 *data = self.min
@@ -91,11 +91,11 @@ impl Stepper {
 }
 
 impl Widget<f64> for Stepper {
-    fn paint(&mut self, paint_ctx: &mut PaintCtx, base_state: &BaseState, _data: &f64, env: &Env) {
+    fn paint(&mut self, paint_ctx: &mut PaintCtx, _data: &f64, env: &Env) {
         let rounded_rect =
-            RoundedRect::from_origin_size(Point::ORIGIN, base_state.size().to_vec2(), 4.);
+            RoundedRect::from_origin_size(Point::ORIGIN, paint_ctx.size().to_vec2(), 4.);
 
-        let height = base_state.size().height;
+        let height = paint_ctx.size().height;
         let width = env.get(theme::BASIC_WIDGET_HEIGHT);
         let button_size = Size::new(width, height / 2.);
 
@@ -164,7 +164,7 @@ impl Widget<f64> for Stepper {
         ))
     }
 
-    fn event(&mut self, event: &Event, ctx: &mut EventCtx, data: &mut f64, env: &Env) {
+    fn event(&mut self, ctx: &mut EventCtx, event: &Event, data: &mut f64, env: &Env) {
         let height = env.get(theme::BORDERED_WIDGET_HEIGHT);
 
         match event {