Unify scroll and hscroll

linebender · Apr 24, 2019 · 2cf48ec · 2cf48ec
1 parent 9fbcda0
commit 2cf48ec
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Showing 5 changed files with 40 additions and 32 deletions.
diff --git a/druid-shell/src/mac/mod.rs b/druid-shell/src/mac/mod.rs
@@ -309,8 +309,15 @@ extern "C" fn scroll_wheel(this: &mut Object, _: Sel, nsevent: id) {
     unsafe {
         let view_state: *mut c_void = *this.get_ivar("viewState");
         let view_state = &mut *(view_state as *mut ViewState);
-        let dx = nsevent.scrollingDeltaX() as i32;
-        let dy = nsevent.scrollingDeltaY() as i32;
+        let (dx, dy) = {
+            let dx = nsevent.scrollingDeltaX() as i32;
+            let dy = nsevent.scrollingDeltaY() as i32;
+            if nsevent.hasPreciseScrollingDeltas() == cocoa::base::YES {
+                (dx, dy)
+            } else {
+                (dx * 32, dy * 32)
+            }
+        };
         let mods = 0; // TODO:
         if dx != 0 {
             (*view_state)

diff --git a/druid-shell/src/window.rs b/druid-shell/src/window.rs
@@ -165,3 +165,14 @@ pub enum Cursor {
     Arrow,
     IBeam,
 }
+
+/// A scroll wheel event.
+#[derive(Debug)]
+pub struct ScrollEvent {
+    /// The scroll wheel’s horizontal delta.
+    pub dx: f32,
+    /// The scroll wheel’s vertical delta.
+    pub dy: f32,
+    /// Modifiers, as in raw WM message
+    pub mods: u32,
+}
diff --git a/examples/mouse.rs b/examples/mouse.rs
@@ -28,7 +28,7 @@ use druid_shell::win_main;
 
 use druid::{Ui, UiMain, UiState};
 
-use druid::widget::Widget;
+use druid::widget::{Widget, ScrollEvent};
 use druid::HandlerCtx;
 use druid::{BoxConstraints, Geometry, LayoutResult};
 use druid::{Id, LayoutCtx, PaintCtx};
@@ -69,13 +69,9 @@ impl Widget for FooWidget {
         LayoutResult::Size(bc.constrain((100.0, 100.0)))
     }
 
-    fn scroll(&mut self, dy: f32, ctx: &mut HandlerCtx) {
-        self.size.1 += dy as f64;
-        ctx.invalidate();
-    }
-
-    fn hscroll(&mut self, dx: f32, ctx: &mut HandlerCtx) {
-        self.size.0 += dx as f64;
+    fn scroll(&mut self, event: &ScrollEvent, ctx: &mut HandlerCtx) {
+        self.size.0 += event.dx as f64;
+        self.size.1 += event.dy as f64;
         ctx.invalidate();
     }
 

diff --git a/src/lib.rs b/src/lib.rs
@@ -417,24 +417,13 @@ impl UiState {
         }
     }
 
-    fn handle_scroll(&mut self, dy: f32) {
+    fn handle_scroll(&mut self, event: &window::ScrollEvent) {
         if let Some(id) = self.layout_ctx.hot {
             let mut ctx = HandlerCtx {
                 id,
                 layout_ctx: &mut self.inner.layout_ctx,
             };
-            self.inner.widgets[id].scroll(dy, &mut ctx);
-            self.dispatch_events();
-        }
-    }
-
-    fn handle_hscroll(&mut self, dx: f32) {
-        if let Some(id) = self.layout_ctx.hot {
-            let mut ctx = HandlerCtx {
-                id,
-                layout_ctx: &mut self.inner.layout_ctx,
-            };
-            self.inner.widgets[id].hscroll(dx, &mut ctx);
+            self.inner.widgets[id].scroll(event, &mut ctx);
             self.dispatch_events();
         }
     }
@@ -948,14 +937,22 @@ impl WinHandler for UiMain {
         state.handle_key_event(&key_event)
     }
 
-    fn mouse_wheel(&self, delta: i32, _mods: u32) {
+    fn mouse_wheel(&self, dy: i32, mods: u32) {
         let mut state = self.state.borrow_mut();
-        state.handle_scroll(delta as f32);
+        state.handle_scroll(&window::ScrollEvent{
+            dx: 0.0,
+            dy: dy as f32,
+            mods,
+        });
     }
 
-    fn mouse_hwheel(&self, delta: i32, _mods: u32) {
+    fn mouse_hwheel(&self, dx: i32, mods: u32) {
         let mut state = self.state.borrow_mut();
-        state.handle_hscroll(delta as f32);
+        state.handle_scroll(&window::ScrollEvent{
+            dx: dx as f32,
+            dy: 0.0,
+            mods,
+        });
     }
 
     fn mouse_move(&self, x: i32, y: i32, _mods: u32) {

diff --git a/src/widget/mod.rs b/src/widget/mod.rs
@@ -16,7 +16,7 @@
 
 use std::any::Any;
 
-pub use druid_shell::window::MouseButton;
+pub use druid_shell::window::{MouseButton, ScrollEvent};
 
 use crate::{BoxConstraints, Geometry, LayoutResult};
 use crate::{HandlerCtx, Id, LayoutCtx, PaintCtx};
@@ -112,10 +112,7 @@ pub trait Widget {
     }
 
     #[allow(unused)]
-    fn scroll(&mut self, dy: f32, ctx: &mut HandlerCtx) {}
-
-    #[allow(unused)]
-    fn hscroll(&mut self, dx: f32, ctx: &mut HandlerCtx) {}
+    fn scroll(&mut self, event: &ScrollEvent, ctx: &mut HandlerCtx) {}
 
     /// Called at the beginning of a new animation frame.
     ///