Fix `InputState::any_touches` and add `InputState::has_touch_screen` (#4247)

Add `InputState::has_touch_screen` to query if there ever has been any
touches (which is what `any_touches` used to return).

crates/egui/src/input_state.rs

@@ -485,6 +485,11 @@ impl InputState {
 
     /// True if there currently are any fingers touching egui.
     pub fn any_touches(&self) -> bool {
+        self.touch_states.values().any(|t| t.any_touches())
+    }
+
+    /// True if we have ever received a touch event.
+    pub fn has_touch_screen(&self) -> bool {
         !self.touch_states.is_empty()
     }
 

crates/egui/src/input_state/touch_state.rs

@@ -177,6 +177,11 @@ impl TouchState {
         }
     }
 
+    /// Are there currently any fingers touching the surface?
+    pub fn any_touches(&self) -> bool {
+        !self.active_touches.is_empty()
+    }
+
     pub fn info(&self) -> Option<MultiTouchInfo> {
         self.gesture_state.as_ref().map(|state| {
             // state.previous can be `None` when the number of simultaneous touches has just

crates/egui/src/widgets/label.rs

@@ -128,7 +128,7 @@ impl Label {
             // dragging select text, or scroll the enclosing [`ScrollArea`] (if any)?
             // Since currently copying selected text in not supported on `eframe` web,
             // we prioritize touch-scrolling:
-            let allow_drag_to_select = ui.input(|i| !i.any_touches());
+            let allow_drag_to_select = ui.input(|i| !i.has_touch_screen());
 
             let mut select_sense = if allow_drag_to_select {
                 Sense::click_and_drag()

crates/egui/src/widgets/text_edit/builder.rs

@@ -527,7 +527,7 @@ impl<'t> TextEdit<'t> {
         // Since currently copying selected text in not supported on `eframe` web,
         // we prioritize touch-scrolling:
         let allow_drag_to_select =
-            ui.input(|i| !i.any_touches()) || ui.memory(|mem| mem.has_focus(id));
+            ui.input(|i| !i.has_touch_screen()) || ui.memory(|mem| mem.has_focus(id));
 
         let sense = if interactive {
             if allow_drag_to_select {