input: Add InputBackend::set_mouse_cursor. Change cursor on buttons

It doesn't feel like Flash without having the hand cursor display
when hovering over buttons. First pass at implementing this;
core communicates which mouse cursor to use via
`InputBackend::set_mouse_cursor`.

TODO: Hand cursor only displayed for Button display objects
currently. Movie clips should also display this when they are in
"button mode" (when a button mouse event is set on them in AVM1,
or `buttonMode` property in AVM2).

core/src/backend/input.rs

@@ -11,6 +11,9 @@ pub trait InputBackend: Downcast {
     fn hide_mouse(&mut self);
 
     fn show_mouse(&mut self);
+
+    /// Changes the mouse cursor image.
+    fn set_mouse_cursor(&mut self, cursor: MouseCursor);
 }
 impl_downcast!(InputBackend);
 
@@ -39,6 +42,8 @@ impl InputBackend for NullInputBackend {
     fn hide_mouse(&mut self) {}
 
     fn show_mouse(&mut self) {}
+
+    fn set_mouse_cursor(&mut self, _cursor: MouseCursor) {}
 }
 
 impl Default for NullInputBackend {
@@ -46,3 +51,24 @@ impl Default for NullInputBackend {
         NullInputBackend::new()
     }
 }
+
+/// A mouse cursor icon displayed by the Flash Player.
+/// Communicated from the core to the input backend via `InputBackend::set_mouse_cursor`.
+#[derive(Clone, Copy, Debug, PartialEq, Eq)]
+pub enum MouseCursor {
+    /// The default arrow icon.
+    /// Equivalent to AS3 `MouseCursor.ARROW`.
+    Arrow,
+
+    /// The hand icon incdicating a button or link.
+    /// Equivalent to AS3 `MouseCursor.BUTTON`.
+    Hand,
+
+    /// The text I-beam.
+    /// Equivalent to AS3 `MouseCursor.IBEAM`.
+    IBeam,
+
+    /// The grabby-dragging hand icon.
+    /// Equivalent to AS3 `MouseCursor.HAND`.
+    Grab,
+}

core/src/player.rs

@@ -1,6 +1,6 @@
 use crate::avm1::listeners::SystemListener;
 use crate::avm1::Avm1;
-use crate::backend::input::InputBackend;
+use crate::backend::input::{InputBackend, MouseCursor};
 use crate::backend::{
     audio::AudioBackend, navigator::NavigatorBackend, render::Letterbox, render::RenderBackend,
 };
@@ -130,6 +130,9 @@ pub struct Player {
     mouse_pos: (Twips, Twips),
     is_mouse_down: bool,
 
+    /// The current mouse cursor icon.
+    mouse_cursor: MouseCursor,
+
     /// Self-reference to ourselves.
     ///
     /// This is a weak reference that is upgraded and handed out in various
@@ -224,6 +227,7 @@ impl Player {
 
             mouse_pos: (Twips::new(0), Twips::new(0)),
             is_mouse_down: false,
+            mouse_cursor: MouseCursor::Arrow,
 
             renderer,
             audio,
@@ -485,7 +489,8 @@ impl Player {
         }
         let mouse_pos = self.mouse_pos;
 
-        self.mutate_with_update_context(|avm, context| {
+        let mut new_cursor = self.mouse_cursor;
+        let hover_changed = self.mutate_with_update_context(|avm, context| {
             // Check hovered object.
             let mut new_hovered = None;
             for (_depth, level) in context.levels.iter().rev() {
@@ -507,9 +512,11 @@ impl Player {
                 }
 
                 // RollOver on new node.
+                new_cursor = MouseCursor::Arrow;
                 if let Some(node) = new_hovered {
                     if let Some(mut button) = node.as_button() {
                         button.handle_button_event(context, ButtonEvent::RollOver);
+                        new_cursor = MouseCursor::Hand;
                     }
                 }
 
@@ -520,7 +527,15 @@ impl Player {
             } else {
                 false
             }
-        })
+        });
+
+        // Update mouse cursor if it has changed.
+        if new_cursor != self.mouse_cursor {
+            self.mouse_cursor = new_cursor;
+            self.input.set_mouse_cursor(new_cursor)
+        }
+
+        hover_changed
     }
 
     /// Preload the first movie in the player.

desktop/src/input.rs

@@ -1,5 +1,5 @@
 use glium::Display;
-use ruffle_core::backend::input::InputBackend;
+use ruffle_core::backend::input::{InputBackend, MouseCursor};
 use ruffle_core::events::{KeyCode, PlayerEvent};
 use std::collections::HashSet;
 use winit::event::{ElementState, VirtualKeyCode, WindowEvent};
@@ -178,6 +178,17 @@ impl InputBackend for WinitInputBackend {
         self.display.gl_window().window().set_cursor_visible(true);
         self.cursor_visible = true;
     }
+
+    fn set_mouse_cursor(&mut self, cursor: MouseCursor) {
+        use winit::window::CursorIcon;
+        let icon = match cursor {
+            MouseCursor::Arrow => CursorIcon::Arrow,
+            MouseCursor::Hand => CursorIcon::Hand,
+            MouseCursor::IBeam => CursorIcon::Text,
+            MouseCursor::Grab => CursorIcon::Grab,
+        };
+        self.display.gl_window().window().set_cursor_icon(icon);
+    }
 }
 
 /// Converts a winit `VirtualKeyCode` into a Ruffle `KeyCode`.

web/src/input.rs

@@ -1,5 +1,5 @@
 use crate::utils::JsResult;
-use ruffle_core::backend::input::InputBackend;
+use ruffle_core::backend::input::{InputBackend, MouseCursor};
 use ruffle_core::events::KeyCode;
 use std::collections::HashSet;
 use web_sys::HtmlCanvasElement;
@@ -10,6 +10,7 @@ pub struct WebInputBackend {
     keys_down: HashSet<String>,
     canvas: HtmlCanvasElement,
     cursor_visible: bool,
+    cursor: MouseCursor,
     last_key: KeyCode,
 }
 
@@ -19,6 +20,7 @@ impl WebInputBackend {
             keys_down: HashSet::new(),
             canvas: canvas.clone(),
             cursor_visible: true,
+            cursor: MouseCursor::Arrow,
             last_key: KeyCode::Unknown,
         }
     }
@@ -33,6 +35,23 @@ impl WebInputBackend {
     pub fn keyup(&mut self, code: String) {
         self.keys_down.remove(&code);
     }
+
+    fn update_mouse_cursor(&self) {
+        let cursor = if self.cursor_visible {
+            "none"
+        } else {
+            match self.cursor {
+                MouseCursor::Arrow => "auto",
+                MouseCursor::Hand => "pointer",
+                MouseCursor::IBeam => "text",
+                MouseCursor::Grab => "grab",
+            }
+        };
+        self.canvas
+            .style()
+            .set_property("cursor", cursor)
+            .warn_on_error();
+    }
 }
 
 impl InputBackend for WebInputBackend {
@@ -151,19 +170,18 @@ impl InputBackend for WebInputBackend {
     }
 
     fn hide_mouse(&mut self) {
-        self.canvas
-            .style()
-            .set_property("cursor", "none")
-            .warn_on_error();
         self.cursor_visible = false;
+        self.update_mouse_cursor();
     }
 
     fn show_mouse(&mut self) {
-        self.canvas
-            .style()
-            .set_property("cursor", "auto")
-            .warn_on_error();
         self.cursor_visible = true;
+        self.update_mouse_cursor();
+    }
+
+    fn set_mouse_cursor(&mut self, cursor: MouseCursor) {
+        self.cursor = cursor;
+        self.update_mouse_cursor();
     }
 }