Set modifiers on baseview mouse events

Using the changes from RustAudio/baseview#117.

Until baseview implements proper keyboard focus handling this helps when
dragging a knob or slider outside of the window. Otherwise the modifier
state may get stuck on an incorrect value.

baseview/Cargo.toml

@@ -10,7 +10,7 @@ description = "Baseview backend for vizia"
 
 [dependencies]
 vizia_core = { path = "../core" }
-baseview = { git = "https://github.com/RustAudio/baseview.git", rev = "b3712638bacb3fdf2883cb5aa3f6caed0e91ac8c", features = ["opengl"] }
+baseview = { git = "https://github.com/robbert-vdh/baseview.git", branch = "feature/mouse-event-modifiers", features = ["opengl"] }
 keyboard-types = { version = "0.6.2", default-features = false }
 raw-window-handle = "0.4"
 femtovg = { git = "https://github.com/femtovg/femtovg", rev = "87fe627794f3f793d8e3a338c838a2f8e8a8aa9d", default-features = false }

baseview/src/application.rs

@@ -318,23 +318,31 @@ impl ApplicationRunner {
 
         match event {
             baseview::Event::Mouse(event) => match event {
-                baseview::MouseEvent::CursorMoved { position } => {
+                baseview::MouseEvent::CursorMoved { position, modifiers } => {
+                    self.update_modifiers(modifiers);
+
                     let physical_posx = position.x * self.context.style.dpi_factor;
                     let physical_posy = position.y * self.context.style.dpi_factor;
                     let cursorx = (physical_posx) as f32;
                     let cursory = (physical_posy) as f32;
                     self.context.dispatch_system_event(WindowEvent::MouseMove(cursorx, cursory));
                 }
-                baseview::MouseEvent::ButtonPressed(button) => {
+                baseview::MouseEvent::ButtonPressed { button, modifiers } => {
+                    self.update_modifiers(modifiers);
+
                     let b = translate_mouse_button(button);
                     self.context.dispatch_system_event(WindowEvent::MouseDown(b));
                 }
-                baseview::MouseEvent::ButtonReleased(button) => {
+                baseview::MouseEvent::ButtonReleased { button, modifiers } => {
+                    self.update_modifiers(modifiers);
+
                     let b = translate_mouse_button(button);
                     self.context.dispatch_system_event(WindowEvent::MouseUp(b));
                 }
-                baseview::MouseEvent::WheelScrolled(scroll_delta) => {
-                    let (lines_x, lines_y) = match scroll_delta {
+                baseview::MouseEvent::WheelScrolled { delta, modifiers } => {
+                    self.update_modifiers(modifiers);
+
+                    let (lines_x, lines_y) = match delta {
                         baseview::ScrollDelta::Lines { x, y } => (x, y),
                         baseview::ScrollDelta::Pixels { x, y } => (
                             if x < 0.0 {
@@ -476,6 +484,21 @@ impl ApplicationRunner {
             (idle_callback)(&mut self.context);
         }
     }
+
+    fn update_modifiers(&mut self, modifiers: keyboard_types::Modifiers) {
+        self.context
+            .modifiers
+            .set(Modifiers::SHIFT, modifiers.contains(keyboard_types::Modifiers::SHIFT));
+        self.context
+            .modifiers
+            .set(Modifiers::CTRL, modifiers.contains(keyboard_types::Modifiers::CONTROL));
+        self.context
+            .modifiers
+            .set(Modifiers::LOGO, modifiers.contains(keyboard_types::Modifiers::META));
+        self.context
+            .modifiers
+            .set(Modifiers::ALT, modifiers.contains(keyboard_types::Modifiers::ALT));
+    }
 }
 
 /// Returns true if the provided event should cause an [`Application`] to