Touch support for `PaneGrid` and `PickList` (#650)

* touch events properly parsed and converted to logical size, button working

* scrolling with a nice touch

* fixed application state level touch cursor. panel_grid is touchable now.

* format glicthes fixes

* format glitches

* tight format

* fixed pane grid

* fixing with upstream

* Remove unused `touch` module from `iced_core`

* Remove unused `crate::text` import in `iced_native`

* Remove redundant match branch in `iced_winit`

* Keep removed line break in `UserInterface::update`

* Compute `text_size` only when bounds contains cursor in `overlay::menu`

Co-authored-by: Héctor Ramón Jiménez <hector0193@gmail.com>

native/src/overlay/menu.rs

@@ -6,6 +6,7 @@ use crate::mouse;
 use crate::overlay;
 use crate::scrollable;
 use crate::text;
+use crate::touch;
 use crate::{
     Clipboard, Container, Element, Hasher, Layout, Length, Point, Rectangle,
     Scrollable, Size, Vector, Widget,
@@ -337,10 +338,11 @@ where
             }
             Event::Mouse(mouse::Event::CursorMoved { .. }) => {
                 let bounds = layout.bounds();
+
+                if bounds.contains(cursor_position) {
                     let text_size =
                         self.text_size.unwrap_or(renderer.default_size());
 
-                if bounds.contains(cursor_position) {
                     *self.hovered_option = Some(
                         ((cursor_position.y - bounds.y)
                             / f32::from(text_size + self.padding * 2))
@@ -348,6 +350,26 @@ where
                     );
                 }
             }
+            Event::Touch(touch::Event::FingerPressed { .. }) => {
+                let bounds = layout.bounds();
+
+                if bounds.contains(cursor_position) {
+                    let text_size =
+                        self.text_size.unwrap_or(renderer.default_size());
+
+                    *self.hovered_option = Some(
+                        ((cursor_position.y - bounds.y)
+                            / f32::from(text_size + self.padding * 2))
+                            as usize,
+                    );
+
+                    if let Some(index) = *self.hovered_option {
+                        if let Some(option) = self.options.get(index) {
+                            *self.last_selection = Some(option.clone());
+                        }
+                    }
+                }
+            }
             _ => {}
         }
 

native/src/widget/pane_grid.rs

@@ -33,6 +33,7 @@ use crate::layout;
 use crate::mouse;
 use crate::overlay;
 use crate::row;
+use crate::touch;
 use crate::{
     Clipboard, Element, Hasher, Layout, Length, Point, Rectangle, Size, Vector,
     Widget,
@@ -368,8 +369,8 @@ where
         let mut event_status = event::Status::Ignored;
 
         match event {
-            Event::Mouse(mouse_event) => match mouse_event {
+            Event::Mouse(mouse::Event::ButtonPressed(mouse::Button::Left))
-                mouse::Event::ButtonPressed(mouse::Button::Left) => {
+            | Event::Touch(touch::Event::FingerPressed { .. }) => {
                 let bounds = layout.bounds();
 
                 if bounds.contains(cursor_position) {
@@ -404,25 +405,22 @@ where
                             }
                         }
                         None => {
-                                self.click_pane(
+                            self.click_pane(layout, cursor_position, messages);
-                                    layout,
-                                    cursor_position,
-                                    messages,
-                                );
                         }
                     }
                 }
             }
-                mouse::Event::ButtonReleased(mouse::Button::Left) => {
+            Event::Mouse(mouse::Event::ButtonReleased(mouse::Button::Left))
+            | Event::Touch(touch::Event::FingerLifted { .. })
+            | Event::Touch(touch::Event::FingerLost { .. }) => {
                 if let Some((pane, _)) = self.state.picked_pane() {
                     if let Some(on_drag) = &self.on_drag {
-                            let mut dropped_region = self
+                        let mut dropped_region =
-                                .elements
+                            self.elements.iter().zip(layout.children()).filter(
-                                .iter()
+                                |(_, layout)| {
-                                .zip(layout.children())
-                                .filter(|(_, layout)| {
                                     layout.bounds().contains(cursor_position)
-                                });
+                                },
+                            );
 
                         let event = match dropped_region.next() {
                             Some(((target, _), _)) if pane != *target => {
@@ -446,13 +444,12 @@ where
                     event_status = event::Status::Captured;
                 }
             }
-                mouse::Event::CursorMoved { .. } => {
+            Event::Mouse(mouse::Event::CursorMoved { .. })
+            | Event::Touch(touch::Event::FingerMoved { .. }) => {
                 event_status =
                     self.trigger_resize(layout, cursor_position, messages);
             }
             _ => {}
-            },
-            _ => {}
         }
 
         if self.state.picked_pane().is_none() {

native/src/widget/pick_list.rs

@@ -6,6 +6,7 @@ use crate::overlay;
 use crate::overlay::menu::{self, Menu};
 use crate::scrollable;
 use crate::text;
+use crate::touch;
 use crate::{
     Clipboard, Element, Hasher, Layout, Length, Point, Rectangle, Size, Widget,
 };
@@ -214,7 +215,8 @@ where
         _clipboard: Option<&dyn Clipboard>,
     ) -> event::Status {
         match event {
-            Event::Mouse(mouse::Event::ButtonPressed(mouse::Button::Left)) => {
+            Event::Mouse(mouse::Event::ButtonPressed(mouse::Button::Left))
+            | Event::Touch(touch::Event::FingerPressed { .. }) => {
                 let event_status = if *self.is_open {
                     // TODO: Encode cursor availability in the type system
                     *self.is_open =

wgpu/src/text.rs

@@ -19,6 +19,7 @@ impl Pipeline {
         let default_font = default_font.map(|slice| slice.to_vec());
 
         // TODO: Font customization
+        #[cfg(not(target_os = "ios"))]
         #[cfg(feature = "default_system_font")]
         let default_font = {
             default_font.or_else(|| {