tree: move container scroll logic to separate util

src/tree/container.rs

@@ -4,9 +4,8 @@ use {
         cursor::KnownCursor,
         fixed::Fixed,
         ifs::wl_seat::{
-            collect_kb_foci, collect_kb_foci2,
-            wl_pointer::{PendingScroll, VERTICAL_SCROLL},
-            NodeSeatState, SeatId, WlSeatGlobal, BTN_LEFT, PX_PER_SCROLL,
+            collect_kb_foci, collect_kb_foci2, wl_pointer::PendingScroll, NodeSeatState, SeatId,
+            WlSeatGlobal, BTN_LEFT,
         },
         rect::Rect,
         render::{Renderer, Texture},
@@ -23,6 +22,7 @@ use {
             linkedlist::{LinkedList, LinkedNode, NodeRef},
             numcell::NumCell,
             rc_eq::rc_eq,
+            scroller::Scroller,
         },
     },
     ahash::AHashMap,
@@ -113,7 +113,7 @@ pub struct ContainerNode {
     seats: RefCell<AHashMap<SeatId, SeatState>>,
     state: Rc<State>,
     pub render_data: RefCell<ContainerRenderData>,
-    scroll: Cell<f64>,
+    scroller: Scroller,
     toplevel_data: ToplevelData,
 }
 
@@ -209,7 +209,7 @@ impl ContainerNode {
             seats: RefCell::new(Default::default()),
             state: state.clone(),
             render_data: Default::default(),
-            scroll: Cell::new(0.0),
+            scroller: Default::default(),
             toplevel_data: ToplevelData::new(state, Default::default(), None),
         });
         slf.tl_set_parent(parent);
@@ -1154,17 +1154,9 @@ impl Node for ContainerNode {
             Some(mc) => mc,
             _ => return,
         };
-        let discrete = if let Some(d) = event.discrete[VERTICAL_SCROLL as usize].get() {
-            self.scroll.set(0.0);
-            d
-        } else if let Some(scroll) = event.axis[VERTICAL_SCROLL as usize].get() {
-            let mut scroll = self.scroll.get() + scroll.to_f64();
-            let discrete = (scroll / PX_PER_SCROLL).trunc();
-            scroll -= discrete * PX_PER_SCROLL;
-            self.scroll.set(scroll);
-            discrete as i32
-        } else {
-            return;
+        let discrete = match self.scroller.handle(event) {
+            Some(d) => d,
+            _ => return,
         };
         let mut new_mc = cur_mc.clone();
         for _ in 0..discrete.abs() {

src/utils.rs

@@ -21,6 +21,7 @@ pub mod ptr_ext;
 pub mod queue;
 pub mod rc_eq;
 pub mod run_toplevel;
+pub mod scroller;
 pub mod smallmap;
 pub mod stack;
 pub mod syncqueue;

src/utils/scroller.rs

@@ -0,0 +1,29 @@
+use {
+    crate::ifs::wl_seat::{
+        wl_pointer::{PendingScroll, VERTICAL_SCROLL},
+        PX_PER_SCROLL,
+    },
+    std::cell::Cell,
+};
+
+#[derive(Default)]
+pub struct Scroller {
+    scroll: Cell<f64>,
+}
+
+impl Scroller {
+    pub fn handle(&self, scroll: &PendingScroll) -> Option<i32> {
+        if let Some(d) = scroll.discrete[VERTICAL_SCROLL as usize].get() {
+            self.scroll.set(0.0);
+            Some(d)
+        } else if let Some(scroll) = scroll.axis[VERTICAL_SCROLL as usize].get() {
+            let mut scroll = self.scroll.get() + scroll.to_f64();
+            let discrete = (scroll / PX_PER_SCROLL).trunc();
+            scroll -= discrete * PX_PER_SCROLL;
+            self.scroll.set(scroll);
+            Some(discrete as i32)
+        } else {
+            None
+        }
+    }
+}