overview: Add two-finger touchpad scroll

1 files changed, 69 insertions, 0 deletions

diff --git a/src/input/scroll_swipe_gesture.rs b/src/input/scroll_swipe_gesture.rs
new file mode 100644
index 00000000..c15ace23
--- /dev/null
+++ b/src/input/scroll_swipe_gesture.rs
@@ -0,0 +1,69 @@
+//! Swipe gesture from scroll events.
+//!
+//! Tracks when to begin, update, and end a swipe gesture from pointer axis events, also whether
+//! the gesture is vertical or horizontal. Necessary because libinput only provides touchpad swipe
+//! gesture events for 3+ fingers.
+
+#[derive(Debug)]
+pub struct ScrollSwipeGesture {
+    ongoing: bool,
+    vertical: bool,
+}
+
+#[derive(Debug, Clone, Copy, PartialEq, Eq)]
+pub enum Action {
+    BeginUpdate,
+    Update,
+    End,
+}
+
+impl ScrollSwipeGesture {
+    pub const fn new() -> Self {
+        Self {
+            ongoing: false,
+            vertical: false,
+        }
+    }
+
+    pub fn update(&mut self, dx: f64, dy: f64) -> Action {
+        if dx == 0. && dy == 0. {
+            self.ongoing = false;
+            Action::End
+        } else if !self.ongoing {
+            self.ongoing = true;
+            self.vertical = dy != 0.;
+            Action::BeginUpdate
+        } else {
+            Action::Update
+        }
+    }
+
+    pub fn reset(&mut self) -> bool {
+        if self.ongoing {
+            self.ongoing = false;
+            true
+        } else {
+            false
+        }
+    }
+
+    pub fn is_vertical(&self) -> bool {
+        self.vertical
+    }
+}
+
+impl Default for ScrollSwipeGesture {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+impl Action {
+    pub fn begin(self) -> bool {
+        self == Action::BeginUpdate
+    }
+
+    pub fn end(self) -> bool {
+        self == Action::End
+    }
+}