Allow floating views to appear at the mouse

doc/riverctl.1.scd

@@ -298,9 +298,11 @@ matches everything while _\*\*_ and the empty string are invalid.
 	  with make: _HP Inc._, model: _HP 22w_, and serial: _CNC93720WF_, the
 	  identifier would be: _HP Inc. HP 22w CNC93720WF_. If the make, model, or
 	  serial is unknown, the word "Unknown" is used instead.
-	- *position*: Set the initial position of the view, clamping to the
-	  bounds of the output. Requires x and y coordinates of the view as
-	  arguments, both of which must be non-negative. Applies only to new views.
+	- *position*: Set the initial position of the view, clamping to the bounds
+	  of the output. Requires x and y coordinates of the view as arguments, both
+	  of which must be non-negative. Optionally, the string "mouse" can appear
+	  as the only argument. In this case, the view will appear at the mouse's
+	  position. Applies only to new views.
 	- *dimensions*: Set the initial dimensions of the view, clamping to the
 	  constraints of the view. Requires width and height of the view as
 	  arguments, both of which must be non-negative. Applies only to new views.

river/Config.zig

@@ -58,11 +58,21 @@ pub const HideCursorWhenTypingMode = enum {
     enabled,
 };
 
+pub const PositionType = enum {
+    absolute,
+    at_mouse,
+};
+
 pub const Position = struct {
     x: u31,
     y: u31,
 };
 
+pub const FloatPosition = union(PositionType) {
+    absolute: Position,
+    at_mouse,
+};
+
 pub const Dimensions = struct {
     width: u31,
     height: u31,
@@ -98,7 +108,7 @@ rules: struct {
     ssd: RuleList(bool) = .{},
     tags: RuleList(u32) = .{},
     output: RuleList([]const u8) = .{},
-    position: RuleList(Position) = .{},
+    position: RuleList(FloatPosition) = .{},
     dimensions: RuleList(Dimensions) = .{},
     fullscreen: RuleList(bool) = .{},
     tearing: RuleList(bool) = .{},

river/View.zig

@@ -678,8 +678,17 @@ pub fn map(view: *View) !void {
         server.input_manager.defaultSeat().focused_output;
 
     if (server.config.rules.position.match(view)) |position| {
-        view.pending.box.x = position.x;
-        view.pending.box.y = position.y;
+        switch (position) {
+            .absolute => |pos| {
+                view.pending.box.x = pos.x;
+                view.pending.box.y = pos.y;
+            },
+            .at_mouse => {
+                const cursor = server.input_manager.defaultSeat().cursor.wlr_cursor;
+                view.pending.box.x = @as(c_int, @intFromFloat(cursor.x));
+                view.pending.box.y = @as(c_int, @intFromFloat(cursor.y));
+            },
+        }
     } else if (output) |o| {
         // Center the initial pending box on the output
         view.pending.box.x = @divTrunc(@max(0, o.usable_box.width - view.pending.box.width), 2);

river/command/rule.zig

@@ -54,10 +54,17 @@ pub fn ruleAdd(_: *Seat, args: []const [:0]const u8, _: *?[]const u8) Error!void
 
     const action = std.meta.stringToEnum(Action, result.args[0]) orelse return Error.UnknownOption;
 
+    var pos_is_mouse = false;
     const positional_arguments_count: u8 = switch (action) {
         .float, .@"no-float", .ssd, .csd, .fullscreen, .@"no-fullscreen", .tearing, .@"no-tearing" => 1,
         .tags, .output => 2,
-        .position, .dimensions => 3,
+        .dimensions => 3,
+        .position => blk: {
+            if (result.args.len >= 2 and std.mem.eql(u8, result.args[1], "mouse")) {
+                pos_is_mouse = true;
+                break :blk 2;
+            } else break :blk 3;
+        },
     };
     if (result.args.len > positional_arguments_count) return Error.TooManyArguments;
     if (result.args.len < positional_arguments_count) return Error.NotEnoughArguments;
@@ -111,16 +118,24 @@ pub fn ruleAdd(_: *Seat, args: []const [:0]const u8, _: *?[]const u8) Error!void
             });
         },
         .position => {
+            if (pos_is_mouse) {
+                try server.config.rules.position.add(.{
+                    .app_id_glob = app_id_glob,
+                    .title_glob = title_glob,
+                    .value = .at_mouse,
+                });
+            } else {
                 const x = try fmt.parseInt(u31, result.args[1], 10);
                 const y = try fmt.parseInt(u31, result.args[2], 10);
                 try server.config.rules.position.add(.{
                     .app_id_glob = app_id_glob,
                     .title_glob = title_glob,
-                .value = .{
+                    .value = .{ .absolute = .{
                         .x = x,
                         .y = y,
-                },
+                    } },
                 });
+            }
         },
         .dimensions => {
             const width = try fmt.parseInt(u31, result.args[1], 10);
@@ -277,7 +292,10 @@ pub fn listRules(_: *Seat, args: []const [:0]const u8, out: *?[]const u8) Error!
             for (server.config.rules.position.rules.items) |rule| {
                 try fmt.formatBuf(rule.title_glob, .{ .width = title_column_max, .alignment = .left }, writer);
                 try fmt.formatBuf(rule.app_id_glob, .{ .width = app_id_column_max, .alignment = .left }, writer);
-                try writer.print("{d},{d}\n", .{ rule.value.x, rule.value.y });
+                switch (rule.value) {
+                    .absolute => |pos| try writer.print("{d},{d}\n", .{ pos.x, pos.y }),
+                    .at_mouse => try writer.print("mouse\n", .{}),
+                }
             }
         },
         .dimensions => {