Hide DragValue tooltips unless user set Style::explanation_tooltips (#708)

* Hide DragValue tooltips unless user set Style::explanation_tooltips

Closes https://github.com/emilk/egui/issues/548
Closes https://github.com/emilk/egui/pull/704

* Silence drag_angle_tau tooltip too

CHANGELOG.md

@@ -19,6 +19,7 @@ NOTE: [`eframe`](eframe/CHANGELOG.md), [`egui_web`](egui_web/CHANGELOG.md) and [
   * Deprecated: `max_rect_finite`, `available_size_before_wrap_finite` and `available_rect_before_wrap_finite`.
 * `Painter`/`Fonts`: text layout now expect color when creating a `Galley`. You may override that color with `Painter::galley_with_color`.
 * MSRV (Minimum Supported Rust Version) is now `1.54.0`.
+* By default, `DragValue`:s no longer show a tooltip when hovered. Change with `Style::explanation_tooltips`.
 
 ### Fixed 🐛
 * Fix wrongly sized multiline `TextEdit` in justified layouts.

egui/src/style.rs

@@ -47,6 +47,11 @@ pub struct Style {
 
     /// Options to help debug why egui behaves strangely.
     pub debug: DebugOptions,
+
+    /// Show tooltips explaining `DragValue`:s etc when hovered.
+    ///
+    /// This only affects a few egui widgets.
+    pub explanation_tooltips: bool,
 }
 
 impl Style {
@@ -361,6 +366,7 @@ impl Default for Style {
             visuals: Visuals::default(),
             animation_time: 1.0 / 12.0,
             debug: Default::default(),
+            explanation_tooltips: false,
         }
     }
 }
@@ -566,6 +572,7 @@ impl Style {
             visuals,
             animation_time,
             debug,
+            explanation_tooltips,
         } = self;
 
         visuals.light_dark_radio_buttons(ui);
@@ -625,6 +632,11 @@ impl Style {
         ui.collapsing("🎨 Visuals", |ui| visuals.ui(ui));
         ui.collapsing("🐛 Debug", |ui| debug.ui(ui));
 
+        ui.checkbox(explanation_tooltips, "Explanation tooltips")
+            .on_hover_text(
+                "Show explanatory text when hovering DragValue:s and other egui widgets",
+            );
+
         ui.vertical_centered(|ui| reset_button(ui, self));
     }
 }

egui/src/ui.rs

@@ -1144,9 +1144,12 @@ impl Ui {
         use std::f32::consts::TAU;
 
         let mut taus = *radians / TAU;
-        let mut response = self
-            .add(DragValue::new(&mut taus).speed(0.01).suffix("τ"))
-            .on_hover_text("1τ = one turn, 0.5τ = half a turn, etc. 0.25τ = 90°");
+        let mut response = self.add(DragValue::new(&mut taus).speed(0.01).suffix("τ"));
+
+        if self.style().explanation_tooltips {
+            response =
+                response.on_hover_text("1τ = one turn, 0.5τ = half a turn, etc. 0.25τ = 90°");
+        }
 
         // only touch `*radians` if we actually changed the value
         if taus != *radians / TAU {

egui/src/widgets/color_picker.rs

@@ -337,8 +337,10 @@ fn color_picker_hsva_2d(ui: &mut Ui, hsva: &mut Hsva, alpha: Alpha) -> bool {
 pub fn color_edit_button_hsva(ui: &mut Ui, hsva: &mut Hsva, alpha: Alpha) -> Response {
     let pupup_id = ui.auto_id_with("popup");
     let open = ui.memory().is_popup_open(pupup_id);
-    let mut button_response =
-        color_button(ui, (*hsva).into(), open).on_hover_text("Click to edit color");
+    let mut button_response = color_button(ui, (*hsva).into(), open);
+    if ui.style().explanation_tooltips {
+        button_response = button_response.on_hover_text("Click to edit color");
+    }
 
     if button_response.clicked() {
         ui.memory().toggle_popup(pupup_id);

egui/src/widgets/drag_value.rs

@@ -215,14 +215,16 @@ impl<'a> Widget for DragValue<'a> {
                 .min_size(ui.spacing().interact_size); // TODO: find some more generic solution to this
 
             let response = ui.add(button);
-            let response = response
-                .on_hover_cursor(CursorIcon::ResizeHorizontal)
-                .on_hover_text(format!(
+            let mut response = response.on_hover_cursor(CursorIcon::ResizeHorizontal);
+
+            if ui.style().explanation_tooltips {
+                response = response .on_hover_text(format!(
                     "{}{}{}\nDrag to edit or click to enter a value.\nPress 'Shift' while dragging for better control.",
                     prefix,
                     value as f32, // Show full precision value on-hover. TODO: figure out f64 vs f32
                     suffix
                 ));
+            }
 
             if response.clicked() {
                 ui.memory().request_focus(kb_edit_id);