From 50814e0ffe3a89126e1b163dc24b09a004fc499d Mon Sep 17 00:00:00 2001
From: Isaac Freund <mail@isaacfreund.com>
Date: Mon, 11 Oct 2021 15:01:57 +0200
Subject: [PATCH] pointer-constraints: fix coordinates

Currently the implementation treats the x/y coordinates of
View.State.box as layout coordinates instead of output-relative. This
causes issues when using an output not at 0,0.
---
 deps/zig-pixman             |  2 +-
 river/PointerConstraint.zig | 41 ++++++++++++++++++++++++++-----------
 2 files changed, 30 insertions(+), 13 deletions(-)

diff --git a/deps/zig-pixman b/deps/zig-pixman
index 135f223..88520f2 160000
--- a/deps/zig-pixman
+++ b/deps/zig-pixman
@@ -1 +1 @@
-Subproject commit 135f22345671e0ae2d1bc4b27cfdee9e97b97dfc
+Subproject commit 88520f264cd65153fe77ad2e5a17d22eee5e1af4
diff --git a/river/PointerConstraint.zig b/river/PointerConstraint.zig
index 7ab8ad5..5e632e6 100644
--- a/river/PointerConstraint.zig
+++ b/river/PointerConstraint.zig
@@ -24,6 +24,7 @@ const wl = @import("wayland").server.wl;
 const pixman = @import("pixman");
 
 const log = @import("log.zig");
+const server = &@import("main.zig").server;
 const util = @import("util.zig");
 
 const Cursor = @import("Cursor.zig");
@@ -62,11 +63,16 @@ pub fn setAsActive(self: *Self) void {
 
     self.cursor.constraint = self.constraint;
 
+    // TODO: This is the same hack sway uses to deal with the fact that this
+    // function may be called in response to a surface commit but before the
+    // the wlroots pointer constraints implementation's commit handler has been called.
+    // This logic is duplicated from that commit handler.
     if (self.constraint.current.region.notEmpty()) {
         _ = self.constraint.region.intersect(&self.constraint.surface.input_region, &self.constraint.current.region);
     } else {
         _ = self.constraint.region.copy(&self.constraint.surface.input_region);
     }
+
     self.constrainToRegion();
 
     self.constraint.sendActivated();
@@ -75,19 +81,23 @@ pub fn setAsActive(self: *Self) void {
 fn constrainToRegion(self: *Self) void {
     if (self.cursor.constraint != self.constraint) return;
     if (View.fromWlrSurface(self.constraint.surface)) |view| {
-        const cx = @floatToInt(c_int, self.cursor.wlr_cursor.x) - @intCast(c_int, view.current.box.x);
-        const cy = @floatToInt(c_int, self.cursor.wlr_cursor.y) - @intCast(c_int, view.current.box.y);
+        const output = view.output;
+        const output_box = server.root.output_layout.getBox(output.wlr_output).?;
 
-        var box: pixman.Box32 = undefined;
+        const surface_lx = @intToFloat(f64, output_box.x + view.current.box.x - view.surface_box.x);
+        const surface_ly = @intToFloat(f64, output_box.y + view.current.box.y - view.surface_box.y);
 
-        if (!self.constraint.region.containsPoint(cx, cy, &box)) {
+        const sx = @floatToInt(c_int, self.cursor.wlr_cursor.x - surface_lx);
+        const sy = @floatToInt(c_int, self.cursor.wlr_cursor.y - surface_ly);
+
+        // If the cursor is not already inside the constraint region, warp
+        // it to an arbitrary point inside the constraint region.
+        if (!self.constraint.region.containsPoint(sx, sy, null)) {
             const rects = self.constraint.region.rectangles();
-
             if (rects.len > 0) {
-                const new_cx = @intToFloat(f64, view.current.box.x + rects[0].x1 + @divFloor(rects[0].x2, 2));
-                const new_cy = @intToFloat(f64, view.current.box.y + rects[0].y1 + @divFloor(rects[0].y2, 2));
-
-                self.cursor.wlr_cursor.warpClosest(null, new_cx, new_cy);
+                const new_lx = surface_lx + @intToFloat(f64, rects[0].x1 + rects[0].x2) / 2;
+                const new_ly = surface_ly + @intToFloat(f64, rects[0].y1 + rects[0].y2) / 2;
+                self.cursor.wlr_cursor.warpClosest(null, new_lx, new_ly);
             }
         }
     }
@@ -117,10 +127,17 @@ pub fn warpToHint(cursor: *Cursor) void {
     if (cursor.constraint) |constraint| {
         if (constraint.current.committed.cursor_hint) {
             if (View.fromWlrSurface(constraint.surface)) |view| {
-                const cx = constraint.current.cursor_hint.x + @intToFloat(f64, view.current.box.x);
-                const cy = constraint.current.cursor_hint.y + @intToFloat(f64, view.current.box.y);
+                const output = view.output;
+                const output_box = server.root.output_layout.getBox(output.wlr_output).?;
 
-                _ = cursor.wlr_cursor.warp(null, cx, cy);
+                const surface_lx = @intToFloat(f64, output_box.x + view.current.box.x - view.surface_box.x);
+                const surface_ly = @intToFloat(f64, output_box.y + view.current.box.y - view.surface_box.y);
+
+                _ = cursor.wlr_cursor.warp(
+                    null,
+                    surface_lx + constraint.current.cursor_hint.x,
+                    surface_ly + constraint.current.cursor_hint.y,
+                );
             }
         }
     }