Implement stdweb backend for web platform

src/platform_impl/web/stdweb/canvas.rs

@@ -1,12 +1,51 @@
-pub struct Canvas;
+use super::event;
+use crate::dpi::{LogicalPosition, LogicalSize};
+use crate::error::OsError as RootOE;
+use crate::event::{ModifiersState, MouseButton, MouseScrollDelta, ScanCode, VirtualKeyCode};
+use crate::platform_impl::OsError;
+
+use std::rc::Rc;
+use stdweb::traits::IPointerEvent;
+use stdweb::unstable::TryInto;
+use stdweb::web::event::{
+    BlurEvent, ConcreteEvent, FocusEvent, KeyDownEvent, KeyPressEvent, KeyUpEvent, MouseWheelEvent,
+    PointerDownEvent, PointerMoveEvent, PointerOutEvent, PointerOverEvent, PointerUpEvent,
+};
+use stdweb::web::html_element::CanvasElement;
+use stdweb::web::{
+    document, window, EventListenerHandle, IChildNode, IElement, IEventTarget, IHtmlElement, INode,
+};
+
+pub struct Canvas {
+    raw: CanvasElement,
+    on_redraw: Rc<dyn Fn()>,
+    on_focus: Option<EventListenerHandle>,
+    on_blur: Option<EventListenerHandle>,
+    on_keyboard_release: Option<EventListenerHandle>,
+    on_keyboard_press: Option<EventListenerHandle>,
+    on_received_character: Option<EventListenerHandle>,
+    on_cursor_leave: Option<EventListenerHandle>,
+    on_cursor_enter: Option<EventListenerHandle>,
+    on_cursor_move: Option<EventListenerHandle>,
+    on_mouse_press: Option<EventListenerHandle>,
+    on_mouse_release: Option<EventListenerHandle>,
+    on_mouse_wheel: Option<EventListenerHandle>,
+}
+
+impl Drop for Canvas {
+    fn drop(&mut self) {
+        self.raw.remove();
+    }
+}
 
 impl Canvas {
-    pub fn new() -> Self {
-        let element = document()
+    pub fn create<F>(on_redraw: F) -> Result<Self, RootOE>
+    where
+        F: 'static + Fn(),
+    {
+        let canvas: CanvasElement = document()
             .create_element("canvas")
-            .map_err(|_| os_error!(OsError("Failed to create canvas element".to_owned())))?;
-
-        let canvas: CanvasElement = element
+            .map_err(|_| os_error!(OsError("Failed to create canvas element".to_owned())))?
             .try_into()
             .map_err(|_| os_error!(OsError("Failed to create canvas element".to_owned())))?;
 
@@ -15,6 +54,198 @@ impl Canvas {
             .ok_or_else(|| os_error!(OsError("Failed to find body node".to_owned())))?
             .append_child(&canvas);
 
-        Canvas(canvas)
+        // TODO: Set up unique ids
+        canvas
+            .set_attribute("tabindex", "0")
+            .expect("Failed to set a tabindex");
+
+        Ok(Canvas {
+            raw: canvas,
+            on_redraw: Rc::new(on_redraw),
+            on_blur: None,
+            on_focus: None,
+            on_keyboard_release: None,
+            on_keyboard_press: None,
+            on_received_character: None,
+            on_cursor_leave: None,
+            on_cursor_enter: None,
+            on_cursor_move: None,
+            on_mouse_release: None,
+            on_mouse_press: None,
+            on_mouse_wheel: None,
+        })
+    }
+
+    pub fn set_attribute(&self, attribute: &str, value: &str) {
+        self.raw
+            .set_attribute(attribute, value)
+            .expect(&format!("Set attribute: {}", attribute));
+    }
+
+    pub fn position(&self) -> (f64, f64) {
+        let bounds = self.raw.get_bounding_client_rect();
+
+        (bounds.get_x(), bounds.get_y())
+    }
+
+    pub fn width(&self) -> f64 {
+        self.raw.width() as f64
+    }
+
+    pub fn height(&self) -> f64 {
+        self.raw.height() as f64
+    }
+
+    pub fn set_size(&self, size: LogicalSize) {
+        self.raw.set_width(size.width as u32);
+        self.raw.set_height(size.height as u32);
+    }
+
+    pub fn raw(&self) -> &CanvasElement {
+        &self.raw
+    }
+
+    pub fn request_redraw(&self) {
+        let on_redraw = self.on_redraw.clone();
+        window().request_animation_frame(move |_| on_redraw());
+    }
+
+    pub fn on_blur<F>(&mut self, mut handler: F)
+    where
+        F: 'static + FnMut(),
+    {
+        self.on_blur = Some(self.add_event(move |_: BlurEvent| {
+            handler();
+        }));
+    }
+
+    pub fn on_focus<F>(&mut self, mut handler: F)
+    where
+        F: 'static + FnMut(),
+    {
+        self.on_focus = Some(self.add_event(move |_: FocusEvent| {
+            handler();
+        }));
+    }
+
+    pub fn on_keyboard_release<F>(&mut self, mut handler: F)
+    where
+        F: 'static + FnMut(ScanCode, Option<VirtualKeyCode>, ModifiersState),
+    {
+        self.on_keyboard_release = Some(self.add_event(move |event: KeyUpEvent| {
+            handler(
+                event::scan_code(&event),
+                event::virtual_key_code(&event),
+                event::keyboard_modifiers(&event),
+            );
+        }));
+    }
+
+    pub fn on_keyboard_press<F>(&mut self, mut handler: F)
+    where
+        F: 'static + FnMut(ScanCode, Option<VirtualKeyCode>, ModifiersState),
+    {
+        self.on_keyboard_press = Some(self.add_event(move |event: KeyDownEvent| {
+            handler(
+                event::scan_code(&event),
+                event::virtual_key_code(&event),
+                event::keyboard_modifiers(&event),
+            );
+        }));
+    }
+
+    pub fn on_received_character<F>(&mut self, mut handler: F)
+    where
+        F: 'static + FnMut(char),
+    {
+        // TODO: Use `beforeinput`.
+        //
+        // The `keypress` event is deprecated, but there does not seem to be a
+        // viable/compatible alternative as of now. `beforeinput` is still widely
+        // unsupported.
+        self.on_received_character = Some(self.add_event(move |event: KeyPressEvent| {
+            handler(event::codepoint(&event));
+        }));
+    }
+
+    pub fn on_cursor_leave<F>(&mut self, mut handler: F)
+    where
+        F: 'static + FnMut(i32),
+    {
+        self.on_cursor_leave = Some(self.add_event(move |event: PointerOutEvent| {
+            handler(event.pointer_id());
+        }));
+    }
+
+    pub fn on_cursor_enter<F>(&mut self, mut handler: F)
+    where
+        F: 'static + FnMut(i32),
+    {
+        self.on_cursor_enter = Some(self.add_event(move |event: PointerOverEvent| {
+            handler(event.pointer_id());
+        }));
+    }
+
+    pub fn on_mouse_release<F>(&mut self, mut handler: F)
+    where
+        F: 'static + FnMut(i32, MouseButton, ModifiersState),
+    {
+        self.on_mouse_release = Some(self.add_event(move |event: PointerUpEvent| {
+            handler(
+                event.pointer_id(),
+                event::mouse_button(&event),
+                event::mouse_modifiers(&event),
+            );
+        }));
+    }
+
+    pub fn on_mouse_press<F>(&mut self, mut handler: F)
+    where
+        F: 'static + FnMut(i32, MouseButton, ModifiersState),
+    {
+        self.on_mouse_press = Some(self.add_event(move |event: PointerDownEvent| {
+            handler(
+                event.pointer_id(),
+                event::mouse_button(&event),
+                event::mouse_modifiers(&event),
+            );
+        }));
+    }
+
+    pub fn on_cursor_move<F>(&mut self, mut handler: F)
+    where
+        F: 'static + FnMut(i32, LogicalPosition, ModifiersState),
+    {
+        self.on_cursor_move = Some(self.add_event(move |event: PointerMoveEvent| {
+            handler(
+                event.pointer_id(),
+                event::mouse_position(&event),
+                event::mouse_modifiers(&event),
+            );
+        }));
+    }
+
+    pub fn on_mouse_wheel<F>(&mut self, mut handler: F)
+    where
+        F: 'static + FnMut(i32, MouseScrollDelta, ModifiersState),
+    {
+        self.on_mouse_wheel = Some(self.add_event(move |event: MouseWheelEvent| {
+            if let Some(delta) = event::mouse_scroll_delta(&event) {
+                handler(0, delta, event::mouse_modifiers(&event));
+            }
+        }));
+    }
+
+    fn add_event<E, F>(&self, mut handler: F) -> EventListenerHandle
+    where
+        E: ConcreteEvent,
+        F: 'static + FnMut(E),
+    {
+        self.raw.add_event_listener(move |event: E| {
+            event.stop_propagation();
+            event.cancel_bubble();
+
+            handler(event);
+        })
     }
 }