Add layer shell support and fix floating windows

Now, I actually save the river-layer-shell-v1 and keep track of the
non-exclusive area. The layout calculation uses the usable area instead
of the entire output's geometry.

I removed boundary clamping for the floating windows because it was a
bit janky when hitting the edges. I'll probably add it back at some
point. I also made windows default to 75% of the usable area instead of
keeping their tiled size so that maximized windows look decent when
floating for the first time. Finally, since I removed the clamping, I
added a center_float keybind to center a floating window. If you're
cycling through focused windows and one isn't on the screen, you can use
the center_float bind to get the window visible again.

Replaced all divTrunc with divFloor to be consistent. I think they
should all be positive, anyways, so they'd be the same, but I like just
having one.

docs/CONFIGURATION.md

@@ -146,6 +146,7 @@ Full command reference:
 | `move_right`             | pixels           | Move floating window right                        |
 | `resize_width`           | pixels           | Resize floating window width (negative to shrink) |
 | `resize_height`          | pixels           | Resize floating window height (negative to shrink)|
+| `center_float`           |                  | Center the focused floating window on its output  |
 | `set_output_tags`        | tags (u32 bitmask) | Set the tags on the focused output              |
 | `set_window_tags`        | tags (u32 bitmask) | Set the tags on the focused window              |
 | `toggle_output_tags`     | tags (u32 bitmask) | Toggle a tag on the focused output              |

docs/TODO.md

@@ -4,6 +4,7 @@ These are in rough order of my priority, though no promises I do them in this or
 
 - [ ] Implement a river-tag-overlay clone
 - [ ] Implement an optional clock bar
+- [ ] Make a Rect struct to combine x, y, width, and height
 - [ ] Support window rules (float/tags/SSD by app-id/title)
 - [ ] Support overriding config location
 - [ ] Support configuring primary vs secondary stack side

src/Config.zig

@@ -506,6 +506,7 @@ fn loadKeybindsChildBlock(config: *Config, parser: *kdl.Parser, hostname: ?[]con
                         .decrement_primary_count,
                         .swap_next,
                         .swap_prev,
+                        .center_float,
                         => |cmd| {
                             // None of these have arguments, just create the union and give it back
                             break :sw @unionInit(XkbBindings.Command, @tagName(cmd), {});

src/Context.zig

@@ -14,6 +14,7 @@ wl_registry: *wl.Registry,
 wl_shm: *wl.Shm,
 wl_outputs: *std.AutoHashMapUnmanaged(u32, *wl.Output),
 
+river_layer_shell_v1: *river.LayerShellV1,
 zwlr_layer_shell_v1: *zwlr.LayerShellV1,
 
 // Wayland globals that we have special structs for
@@ -68,6 +69,7 @@ pub fn create(options: Options) !*Context {
         .wl_registry = options.wl_registry,
         .wl_shm = options.wl_shm,
         .wl_outputs = options.wl_outputs,
+        .river_layer_shell_v1 = options.river_layer_shell_v1,
         .zwlr_layer_shell_v1 = options.zwlr_layer_shell_v1,
         .wallpaper_image = loadWallpaperImage(options.config),
         .im = try InputManager.create(context, options.river_input_manager_v1, options.river_libinput_config_v1),

src/Output.zig

@@ -7,6 +7,7 @@ const Output = @This();
 context: *Context,
 
 river_output_v1: *river.OutputV1,
+river_layer_shell_output_v1: *river.LayerShellOutputV1,
 
 // We have to wait for the rwm.wl_output event to get this
 wl_output: ?*wl.Output = null,
@@ -16,10 +17,16 @@ name: ?[]const u8 = null,
 
 // Output geometry
 scale: u31 = 1,
-width: u31 = 0,
-height: u31 = 0,
 x: i32 = 0,
 y: i32 = 0,
+width: u31 = 0,
+height: u31 = 0,
+
+// Area left after layer shell surfaces take exclusive area
+usable_x: i32 = 0,
+usable_y: i32 = 0,
+usable_width: u31 = 0,
+usable_height: u31 = 0,
 
 // Information for this Output's wallpaper
 wallpaper_render_width: u31 = 0,
@@ -62,10 +69,15 @@ pub const TagLayoutOverride = struct {
 };
 
 pub const PendingManage = struct {
-    width: ?u31 = null,
-    height: ?u31 = null,
     x: ?i32 = null,
     y: ?i32 = null,
+    width: ?u31 = null,
+    height: ?u31 = null,
+
+    usable_x: ?i32 = null,
+    usable_y: ?i32 = null,
+    usable_width: ?u31 = null,
+    usable_height: ?u31 = null,
 
     tags: ?u32 = null,
     primary_ratio: ?f32 = null,
@@ -84,6 +96,7 @@ pub fn create(context: *Context, river_output_v1: *river.OutputV1) !*Output {
     output.* = .{
         .context = context,
         .river_output_v1 = river_output_v1,
+        .river_layer_shell_output_v1 = try context.river_layer_shell_v1.getOutput(river_output_v1),
         .bar = bar,
         .primary_count = context.config.primary_count,
         .primary_ratio = context.config.primary_ratio,
@@ -94,6 +107,7 @@ pub fn create(context: *Context, river_output_v1: *river.OutputV1) !*Output {
     output.windows.init();
 
     output.river_output_v1.setListener(*Output, riverOutputListener, output);
+    output.river_layer_shell_output_v1.setListener(*Output, riverLayerShellOutputListener, output);
 
     return output;
 }
@@ -268,6 +282,24 @@ fn wlOutputListener(_: *wl.Output, event: wl.Output.Event, output: *Output) void
     }
 }
 
+// Used for the river_layer_shell_output_v1 interface
+fn riverLayerShellOutputListener(
+    river_layer_shell_output_v1: *river.LayerShellOutputV1,
+    event: river.LayerShellOutputV1.Event,
+    output: *Output,
+) void {
+    assert(output.river_layer_shell_output_v1 == river_layer_shell_output_v1);
+    switch (event) {
+        .non_exclusive_area => |ev| {
+            output.pending_manage.usable_x = ev.x;
+            output.pending_manage.usable_y = ev.y;
+            output.pending_manage.usable_width = @intCast(ev.width);
+            output.pending_manage.usable_height = @intCast(ev.height);
+            output.context.wm.river_window_manager_v1.manageDirty();
+        },
+    }
+}
+
 pub fn initWallpaperLayerSurface(output: *Output) !void {
     if (output.context.wallpaper_image == null) {
         // No wallpaper image, so we don't need any surfaces
@@ -446,17 +478,30 @@ pub fn renderWallpaper(output: *Output) !void {
 pub fn manage(output: *Output) void {
     defer output.pending_manage = .{};
 
+    if (output.pending_manage.x) |x| {
+        output.x = x;
+    }
+    if (output.pending_manage.y) |y| {
+        output.y = y;
+    }
     if (output.pending_manage.width) |width| {
         output.width = width;
     }
     if (output.pending_manage.height) |height| {
         output.height = height;
     }
-    if (output.pending_manage.x) |x| {
-        output.x = x;
+
+    if (output.pending_manage.usable_x) |usable_x| {
+        output.usable_x = usable_x;
     }
-    if (output.pending_manage.y) |y| {
-        output.y = y;
+    if (output.pending_manage.usable_y) |usable_y| {
+        output.usable_y = usable_y;
+    }
+    if (output.pending_manage.usable_width) |usable_width| {
+        output.usable_width = usable_width;
+    }
+    if (output.pending_manage.usable_height) |usable_height| {
+        output.usable_height = usable_height;
     }
 
     if (output.pending_manage.primary_ratio) |primary_ratio| {
@@ -542,12 +587,11 @@ fn calculatePrimaryStackLayout(output: *Output) void {
 
     if (active_count == 0) return;
 
-    // Output dimensions come as i32 from the protocol, convert to u31 for window dimensions
-    // since they can't be negative.
-    const output_width: u31 = @intCast(output.width);
-    const output_height: u31 = @intCast(output.height);
-    const output_x = output.x;
-    const output_y = output.y;
+    // We have to use the usable area for the layout so windows don't overlap with widgets
+    const output_x = output.usable_x;
+    const output_y = output.usable_y;
+    const output_width = output.usable_width;
+    const output_height = output.usable_height;
     const border_width = output.context.config.border_width;
 
     // Single window: maximize and return early
@@ -621,6 +665,15 @@ fn calculatePrimaryStackLayout(output: *Output) void {
     assert(active_list.first == null);
 }
 
+pub fn occupiedTags(output: *Output) u32 {
+    var occupied_tags: u32 = 0x0000;
+    var it = output.windows.iterator(.forward);
+    while (it.next()) |window| {
+        occupied_tags |= window.tags;
+    }
+    return occupied_tags;
+}
+
 const std = @import("std");
 const assert = std.debug.assert;
 const mem = std.mem;

src/Seat.zig

@@ -159,8 +159,8 @@ pub fn manage(seat: *Seat) void {
             // Warp pointer to center of focused window;
             // because the x and y coords are set during render, we need to check if
             // there are new coordinates in window.pending_render.
-            const pointer_x: i32 = (window.pending_render.x orelse window.x) + @divTrunc(window.width, 2);
-            const pointer_y: i32 = (window.pending_render.y orelse window.y) + @divTrunc(window.height, 2);
+            const pointer_x: i32 = (window.pending_render.x orelse window.x) + @divFloor(window.width, 2);
+            const pointer_y: i32 = (window.pending_render.y orelse window.y) + @divFloor(window.height, 2);
             seat.river_seat_v1.pointerWarp(pointer_x, pointer_y);
         }
     }
@@ -204,17 +204,8 @@ pub fn manage(seat: *Seat) void {
         switch (seat.pointer_op) {
             .none => {},
             .move => |op| {
-                const output = op.window.output orelse {
-                    log.err("window has no output during move operation", .{});
-                    return;
-                };
-                const min_x = output.x;
-                const max_x = output.x + output.width - @as(i32, op.window.float_width);
-                const min_y = output.y;
-                const max_y = output.y + output.height - @as(i32, op.window.float_height);
-
-                op.window.float_x = std.math.clamp(op.start_x + delta.dx, min_x, @max(min_x, max_x));
-                op.window.float_y = std.math.clamp(op.start_y + delta.dy, min_y, @max(min_y, max_y));
+                op.window.float_x = op.start_x + delta.dx;
+                op.window.float_y = op.start_y + delta.dy;
                 op.window.pending_render.x = op.window.float_x;
                 op.window.pending_render.y = op.window.float_y;
             },
@@ -238,22 +229,10 @@ pub fn manage(seat: *Seat) void {
 
                 // Clamp to minimum size
                 const min_size: i32 = 50;
-                if (new_width < min_size) {
-                    if (op.edges.left) new_x -= min_size - new_width;
-                    new_width = min_size;
-                }
-                if (new_height < min_size) {
-                    if (op.edges.top) new_y -= min_size - new_height;
-                    new_height = min_size;
-                }
-
-                // Clamp position to output bounds
-                const output = op.window.output orelse {
-                    log.err("window has no output during resize operation", .{});
-                    return;
-                };
-                new_x = std.math.clamp(new_x, output.x, @max(output.x, output.x + output.width - new_width));
-                new_y = std.math.clamp(new_y, output.y, @max(output.y, output.y + output.height - new_height));
+                if (op.edges.left) new_x = @min(new_x, op.start_x + @as(i32, op.start_width) - min_size);
+                if (op.edges.top) new_y = @min(new_y, op.start_y + @as(i32, op.start_height) - min_size);
+                new_width = @max(new_width, min_size);
+                new_height = @max(new_height, min_size);
 
                 op.window.float_width = @intCast(new_width);
                 op.window.float_height = @intCast(new_height);

src/Window.zig

@@ -184,14 +184,17 @@ pub fn manage(window: *Window) void {
             river_window_v1.setTiled(.{});
 
             if (window.float_width == 0) {
-                // Never floated before; use current dimensions but centered on output
+                // Never floated before; use 75% of usable area, centered on output
+                if (window.output) |output| {
+                    window.float_width = @divFloor(output.usable_width * 3, 4);
+                    window.float_height = @divFloor(output.usable_height * 3, 4);
+                    window.float_x = output.usable_x + @divFloor(output.usable_width, 2) - @divFloor(window.float_width, 2);
+                    window.float_y = output.usable_y + @divFloor(output.usable_height, 2) - @divFloor(window.float_height, 2);
+                } else {
                     window.float_width = window.width;
                     window.float_height = window.height;
-                if (window.output) |output| {
-                    // Need to find center and then subtract half of the window's width/height
-                    window.float_x = output.x + @divTrunc(output.width, 2) - @divTrunc(window.width, 2);
-                    window.float_y = output.y + @divTrunc(output.height, 2) - @divTrunc(window.height, 2);
                 }
+                river_window_v1.proposeDimensions(window.float_width, window.float_height);
             } else {
                 // Window has floated before; re-use its old dimensions
                 river_window_v1.proposeDimensions(window.float_width, window.float_height);

src/XkbBindings.zig

@@ -41,6 +41,9 @@ pub const Command = union(enum) {
     resize_width: i32,
     resize_height: i32,
 
+    // Center floating window on its output
+    center_float,
+
     // Swap window position in stack
     swap_next,
     swap_prev,
@@ -237,6 +240,7 @@ const XkbBinding = struct {
             .move_right => |pixels| moveFloatingWindow(context, pixels, 0),
             .resize_width => |delta| resizeFloatingWindow(context, delta, 0),
             .resize_height => |delta| resizeFloatingWindow(context, 0, delta),
+            .center_float => centerFloatingWindow(context),
             .swap_next => swapWindow(context, .next),
             .swap_prev => swapWindow(context, .prev),
         }
@@ -336,18 +340,9 @@ const XkbBinding = struct {
         const seat = context.wm.seats.first() orelse return;
         const window = seat.focused_window orelse return;
         if (!window.floating) return;
-        const output = window.output orelse {
-            log.err("focused floating window has no output during move", .{});
-            return;
-        };
 
-        const min_x = output.x;
-        const max_x = output.x + output.width - @as(i32, window.float_width);
-        const min_y = output.y;
-        const max_y = output.y + output.height - @as(i32, window.float_height);
-
-        window.float_x = std.math.clamp(window.float_x + dx, min_x, @max(min_x, max_x));
-        window.float_y = std.math.clamp(window.float_y + dy, min_y, @max(min_y, max_y));
+        window.float_x += dx;
+        window.float_y += dy;
         window.pending_render.x = window.float_x;
         window.pending_render.y = window.float_y;
         context.wm.river_window_manager_v1.manageDirty();
@@ -357,25 +352,27 @@ const XkbBinding = struct {
         const seat = context.wm.seats.first() orelse return;
         const window = seat.focused_window orelse return;
         if (!window.floating) return;
-        const output = window.output orelse {
-            log.err("focused floating window has no output during resize", .{});
-            return;
-        };
 
         const new_width: i32 = @as(i32, window.float_width) + dw;
         const new_height: i32 = @as(i32, window.float_height) + dh;
         window.float_width = @intCast(@max(50, new_width));
         window.float_height = @intCast(@max(50, new_height));
 
-        // Clamp position to keep window on screen after resize
-        const max_x = output.x + output.width - @as(i32, window.float_width);
-        const max_y = output.y + output.height - @as(i32, window.float_height);
-        window.float_x = std.math.clamp(window.float_x, output.x, @max(output.x, max_x));
-        window.float_y = std.math.clamp(window.float_y, output.y, @max(output.y, max_y));
+        window.pending_manage.width = window.float_width;
+        window.pending_manage.height = window.float_height;
+        context.wm.river_window_manager_v1.manageDirty();
+    }
 
+    fn centerFloatingWindow(context: *Context) void {
+        const seat = context.wm.seats.first() orelse return;
+        const window = seat.focused_window orelse return;
+        if (!window.floating) return;
+        const output = window.output orelse return;
+
+        window.float_x = output.usable_x + @divFloor(output.usable_width, 2) - @divFloor(window.float_width, 2);
+        window.float_y = output.usable_y + @divFloor(output.usable_height, 2) - @divFloor(window.float_height, 2);
         window.pending_render.x = window.float_x;
         window.pending_render.y = window.float_y;
-        window.river_window_v1.proposeDimensions(window.float_width, window.float_height);
         context.wm.river_window_manager_v1.manageDirty();
     }
 

src/main.zig

@@ -145,7 +145,7 @@ fn run(wl_display: *wl.Display, context: *Context) !void {
             log.err("Got a negative time ({d})", .{time});
             return error.InvalidTime;
         }
-        const timeout: i32 = @intCast((@divTrunc(time, 60) * 60 + 60 - time) * 1000);
+        const timeout: i32 = @intCast((@divFloor(time, 60) * 60 + 60 - time) * 1000);
 
         const poll_rc = posix.poll(&pollfds, timeout) catch |err| {
             fatal("Failed to poll {s}", .{@errorName(err)});