Make hot corners configurable, including per-output (#2108)

* Add corner selection in config

* Add hot corner docs

* Working per-monitor hot corners

Handle defaults

* run cargo fmt --all

* Fix hot corners in is_sticky_obscured_under

* Change default to fall back to gesture hot corners if output hot corners are unset

* Add hot corner output config docs

* Support fractional scaling

* Trigger hot corners over widgets

* Improve float handling
Fixed YaLTeR/niri/pull/2108

* Refactor

* Bug Fixes

* Amend docs

Fix styling

Co-authored-by: Ivan Molodetskikh <yalterz@gmail.com>

* Integrate code review

Move is_inside_hot_corner

* fixes

---------

Co-authored-by: Aadniz <8147434+Aadniz@users.noreply.github.com>
Co-authored-by: Ivan Molodetskikh <yalterz@gmail.com>

docs/wiki/Configuration:-Gestures.md

@@ -23,6 +23,10 @@ gestures {
 
     hot-corners {
         // off
+        top-left
+        // top-right
+        // bottom-left
+        // bottom-right
     }
 }
 ```
@@ -94,3 +98,18 @@ gestures {
     }
 }
 ```
+
+<sup>Since: next release</sup> You can choose specific hot corners by name: `top-left`, `top-right`, `bottom-left`, `bottom-right`.
+If no corners are explicitly set, the top-left corner will be active by default.
+
+```kdl
+// Enable the top-right and bottom-right hot corners.
+gestures {
+    hot-corners {
+        top-right
+        bottom-right
+    }
+}
+```
+
+You can also customize hot corners per-output [in the output config](./Configuration:-Outputs.md#hot-corners).

docs/wiki/Configuration:-Outputs.md

@@ -16,6 +16,14 @@ output "eDP-1" {
     focus-at-startup
     background-color "#003300"
     backdrop-color "#001100"
+
+    hot-corners {
+        // off
+        top-left
+        // top-right
+        // bottom-left
+        // bottom-right
+    }
 }
 
 output "HDMI-A-1" {
@@ -217,3 +225,31 @@ output "HDMI-A-1" {
     backdrop-color "#001100"
 }
 ```
+
+### `hot-corners`
+
+<sup>Since: next release</sup>
+
+Customize the hot corners for this output.
+By default, hot corners [in the gestures settings](./Configuration:-Gestures.md#hot-corners) are used for all outputs.
+
+Hot corners toggle the overview when you put your mouse at the very corner of a monitor.
+
+`off` will disable the hot corners on this output, and writing specific corners will enable only those hot corners on this output.
+
+```kdl
+// Enable the bottom-left and bottom-right hot corners on HDMI-A-1.
+output "HDMI-A-1" {
+    hot-corners {
+        bottom-left
+        bottom-right
+    }
+}
+
+// Disable the hot corners on DP-2.
+output "DP-2" {
+    hot-corners {
+        off
+    }
+}
+```

niri-config/src/gestures.rs

@@ -54,4 +54,12 @@ impl Default for DndEdgeWorkspaceSwitch {
 pub struct HotCorners {
     #[knuffel(child)]
     pub off: bool,
+    #[knuffel(child)]
+    pub top_left: bool,
+    #[knuffel(child)]
+    pub top_right: bool,
+    #[knuffel(child)]
+    pub bottom_left: bool,
+    #[knuffel(child)]
+    pub bottom_right: bool,
 }

niri-config/src/lib.rs

@@ -348,6 +348,13 @@ mod tests {
                 mode "1920x1080@144"
                 variable-refresh-rate on-demand=true
                 background-color "rgba(25, 25, 102, 1.0)"
+                hot-corners {
+                    off
+                    top-left
+                    top-right
+                    bottom-left
+                    bottom-right
+                }
             }
 
             layout {
@@ -742,6 +749,15 @@ mod tests {
                             },
                         ),
                         backdrop_color: None,
+                        hot_corners: Some(
+                            HotCorners {
+                                off: true,
+                                top_left: true,
+                                top_right: true,
+                                bottom_left: true,
+                                bottom_right: true,
+                            },
+                        ),
                     },
                 ],
             ),
@@ -1158,6 +1174,10 @@ mod tests {
                 },
                 hot_corners: HotCorners {
                     off: false,
+                    top_left: false,
+                    top_right: false,
+                    bottom_left: false,
+                    bottom_right: false,
                 },
             },
             overview: Overview {

niri-config/src/output.rs

@@ -1,5 +1,6 @@
 use niri_ipc::{ConfiguredMode, Transform};
 
+use crate::gestures::HotCorners;
 use crate::{Color, FloatOrInt};
 
 #[derive(Debug, Default, Clone, PartialEq)]
@@ -27,6 +28,8 @@ pub struct Output {
     pub background_color: Option<Color>,
     #[knuffel(child)]
     pub backdrop_color: Option<Color>,
+    #[knuffel(child)]
+    pub hot_corners: Option<HotCorners>,
 }
 
 impl Output {
@@ -56,6 +59,7 @@ impl Default for Output {
             variable_refresh_rate: None,
             background_color: None,
             backdrop_color: None,
+            hot_corners: None,
         }
     }
 }

src/niri.rs

@@ -3118,6 +3118,49 @@ impl Niri {
         Some((output, pos_within_output))
     }
 
+    fn is_inside_hot_corner(&self, output: &Output, pos: Point<f64, Logical>) -> bool {
+        let config = self.config.borrow();
+        let hot_corners = output
+            .user_data()
+            .get::<OutputName>()
+            .and_then(|name| config.outputs.find(name))
+            .and_then(|c| c.hot_corners)
+            .unwrap_or(config.gestures.hot_corners);
+
+        if hot_corners.off {
+            return false;
+        }
+
+        // Use size from the ceiled output geometry, since that's what we currently use for pointer
+        // motion clamping.
+        let geom = self.global_space.output_geometry(output).unwrap();
+        let size = geom.size.to_f64();
+
+        let contains = move |corner: Point<f64, Logical>| {
+            Rectangle::new(corner, Size::new(1., 1.)).contains(pos)
+        };
+
+        if hot_corners.top_right && contains(Point::new(size.w - 1., 0.)) {
+            return true;
+        }
+        if hot_corners.bottom_left && contains(Point::new(0., size.h - 1.)) {
+            return true;
+        }
+        if hot_corners.bottom_right && contains(Point::new(size.w - 1., size.h - 1.)) {
+            return true;
+        }
+
+        // If the user didn't explicitly set any corners, we default to top-left.
+        if (hot_corners.top_left
+            || !(hot_corners.top_right || hot_corners.bottom_right || hot_corners.bottom_left))
+            && contains(Point::new(0., 0.))
+        {
+            return true;
+        }
+
+        false
+    }
+
     pub fn is_sticky_obscured_under(
         &self,
         output: &Output,
@@ -3161,12 +3204,8 @@ impl Niri {
             return false;
         }
 
-        let hot_corners = self.config.borrow().gestures.hot_corners;
-        if !hot_corners.off {
-            let hot_corner = Rectangle::from_size(Size::from((1., 1.)));
-            if hot_corner.contains(pos_within_output) {
-                return true;
-            }
+        if self.is_inside_hot_corner(output, pos_within_output) {
+            return true;
         }
 
         if layer_popup_under(Layer::Top) || layer_toplevel_under(Layer::Top) {
@@ -3438,13 +3477,9 @@ impl Niri {
                 .or_else(|| layer_toplevel_under(Layer::Bottom))
                 .or_else(|| layer_toplevel_under(Layer::Background));
         } else {
-            let hot_corners = self.config.borrow().gestures.hot_corners;
-            if !hot_corners.off {
-                let hot_corner = Rectangle::from_size(Size::from((1., 1.)));
-                if hot_corner.contains(pos_within_output) {
-                    rv.hot_corner = true;
-                    return rv;
-                }
+            if self.is_inside_hot_corner(output, pos_within_output) {
+                rv.hot_corner = true;
+                return rv;
             }
 
             under = under