From 934183ef003714f4d8dedeba55396c76ec8d5e4c Mon Sep 17 00:00:00 2001
From: Ivan Molodetskikh <yalterz@gmail.com>
Date: Tue, 5 Sep 2023 18:02:05 +0400
Subject: input: Clip pointer movement smarter

---
 src/input.rs | 77 ++++++++++++++++++++++++++++++++++++++++++++----------------
 1 file changed, 57 insertions(+), 20 deletions(-)

diff --git a/src/input.rs b/src/input.rs
index 3dc589c0..ec3f9afd 100644
--- a/src/input.rs
+++ b/src/input.rs
@@ -294,36 +294,73 @@ impl State {
                 }
             }
             InputEvent::PointerMotion { event, .. } => {
+                // We need an output to be able to move the pointer.
+                if self.niri.global_space.outputs().next().is_none() {
+                    return;
+                }
+
                 let serial = SERIAL_COUNTER.next_serial();
 
                 let pointer = self.niri.seat.get_pointer().unwrap();
-                let mut pos = pointer.current_location();
-
-                pos += event.delta();
-
-                let mut min_x = i32::MAX;
-                let mut min_y = i32::MAX;
-                let mut max_x = 0;
-                let mut max_y = 0;
-                for output in self.niri.global_space.outputs() {
-                    // FIXME: smarter clamping.
-                    let geom = self.niri.global_space.output_geometry(output).unwrap();
-                    min_x = min_x.min(geom.loc.x);
-                    min_y = min_y.min(geom.loc.y);
-                    max_x = max_x.max(geom.loc.x + geom.size.w);
-                    max_y = max_y.max(geom.loc.y + geom.size.h);
-                }
 
-                pos.x = pos.x.clamp(min_x as f64, max_x as f64);
-                pos.y = pos.y.clamp(min_y as f64, max_y as f64);
+                let pos = pointer.current_location();
+
+                // We have an output, so we can compute the new location and focus.
+                let mut new_pos = pos + event.delta();
+
+                if self
+                    .niri
+                    .global_space
+                    .output_under(new_pos)
+                    .next()
+                    .is_none()
+                {
+                    // We ended up outside the outputs and need to clip the movement.
+                    if let Some(output) = self.niri.global_space.output_under(pos).next() {
+                        // The pointer was previously on some output. Clip the movement against its
+                        // boundaries.
+                        let geom = self.niri.global_space.output_geometry(output).unwrap();
+                        new_pos.x = new_pos
+                            .x
+                            .clamp(geom.loc.x as f64, (geom.loc.x + geom.size.w - 1) as f64);
+                        new_pos.y = new_pos
+                            .y
+                            .clamp(geom.loc.y as f64, (geom.loc.y + geom.size.h - 1) as f64);
+                    } else {
+                        // The pointer was not on any output in the first place. Find one for it.
+                        // Start by clamping the X coordinate.
+                        let mut min_x = i32::MAX;
+                        let mut max_x = 0;
+                        for output in self.niri.global_space.outputs() {
+                            let geom = self.niri.global_space.output_geometry(output).unwrap();
+                            min_x = min_x.min(geom.loc.x);
+                            max_x = max_x.max(geom.loc.x + geom.size.w);
+                        }
+
+                        new_pos.x = new_pos.x.clamp(min_x as f64, (max_x - 1) as f64);
+
+                        // Now clamp the Y coordinate. Assume every X from min to max has some
+                        // output.
+                        let geom = self
+                            .niri
+                            .global_space
+                            .outputs()
+                            .map(|output| self.niri.global_space.output_geometry(output).unwrap())
+                            .find(|geom| geom.contains((new_pos.x as i32, geom.loc.y)))
+                            .unwrap();
+                        new_pos.y = new_pos
+                            .y
+                            .clamp(geom.loc.y as f64, (geom.loc.y + geom.size.h - 1) as f64);
+                    }
+                }
 
-                let under = self.niri.surface_under_and_global_space(pos);
+                let under = self.niri.surface_under_and_global_space(new_pos);
 
                 pointer.motion(
                     self,
                     under.clone(),
                     &MotionEvent {
-                        location: pos,
+                        location: new_pos,
                         serial,
                         time: event.time_msec(),
                     },
-- 
cgit