Checkpoint: preserve all uncommitted rust-rewrite worktree work

Safety commit before reconciling this worktree with main, which has
diverged with its own separate fixes today. Nothing here is reviewed
or curated yet - this exists purely so none of this work can be lost
to a git operation, disk issue, or worktree cleanup while that
reconciliation happens.

1 files changed, 683 insertions, 0 deletions

diff --git a/crates/wayland/src/input/pointer.rs b/crates/wayland/src/input/pointer.rs
new file mode 100644
index 0000000..7b3bbce
--- /dev/null
+++ b/crates/wayland/src/input/pointer.rs
@@ -0,0 +1,683 @@
+//! Pointer motion, button presses, and cursor-shape resolution.
+
+use smithay::backend::input::ButtonState as BackendButtonState;
+use smithay::desktop::{layer_map_for_output, WindowSurfaceType};
+use smithay::input::pointer::{ButtonEvent, MotionEvent};
+use smithay::reexports::wayland_server::protocol::wl_surface::WlSurface;
+use smithay::utils::{Logical, Point, SERIAL_COUNTER};
+use smithay::wayland::shell::wlr_layer::KeyboardInteractivity;
+
+use srdwm_core::{TitlebarHit, WindowId};
+
+use crate::state::CompState;
+
+use super::focus::{close_dwindow, dwindow_is_visible, dwindow_wl_surface, focus_window};
+use super::keyboard::core_modifiers_from_xkb;
+use super::layers::{background_layer_surface_under, layer_surface_under};
+use super::{notify_idle_activity, DRAG_MODIFIER};
+
+/// `WindowManager::hit_test`, but substituting each window's currently
+/// *animated* rect (if it has one active in `state.window_anims`) for its
+/// final `geometry` - see `hit_test_with`'s own doc comment in
+/// `crates/core/src/manager/hittest.rs` for why plain `hit_test` alone gets
+/// this wrong during a maximize/fullscreen/snap toggle or a new window's
+/// open-slide. Every decoration hit-test call site in this module goes
+/// through this now instead of calling `hit_test` on the borrowed
+/// `WindowManager` directly.
+fn hit_test_animated(state: &CompState, x: i32, y: i32) -> Option<(WindowId, TitlebarHit)> {
+    state.wm.borrow().hit_test_with(x, y, |id, geometry| {
+        let animated = state.window_anims.get(&id).map(crate::state::WindowAnim::current_rect).unwrap_or(geometry);
+        // Also corrects for a client whose real committed size differs
+        // from what was requested (a terminal's cell-quantized size, most
+        // commonly) - see `effective_frame`'s own doc comment. Without
+        // this, the resize-margin/border hit-test zone stayed sized to the
+        // *requested* rect even after the border itself moved to match the
+        // real one, so the clickable edge and the visible edge disagreed
+        // again, just like the border and the desktop background used to.
+        state.effective_frame(id, animated)
+    })
+}
+
+/// Re-resolves and re-asserts real Wayland pointer focus at `pos` - i.e.
+/// re-runs the exact same layer-shell/decoration/content/background
+/// hit-testing `handle_pointer_position` always did, and calls
+/// `pointer.motion()` with whatever it finds, but *without* sending
+/// `wl_pointer.frame` (callers decide when their own batch of events is
+/// done) and without any of `handle_pointer_position`'s other side effects
+/// (cursor shape, focus-follows-mouse, drag/resize updates) - those only
+/// make sense on an actual motion event, not a button press.
+///
+/// Extracted so [`handle_pointer_button`] can call this immediately before
+/// delivering a click, rather than only ever trusting whatever the *last*
+/// real motion event happened to leave `PointerHandle`'s own focus at.
+/// Those can disagree: confirmed live via a temporary diagnostic (since
+/// removed) that `space.element_under(pos)` - srdwm's own, freshly
+/// computed on every click - and
+/// `PointerHandle::current_focus()` - Wayland's, last set by whichever
+/// motion event happened to run before this click - disagreed on a real
+/// user's real clicks, inconsistently, sometimes on the very same window.
+/// A click landing on stale/no Wayland focus reads exactly like "clicking
+/// doesn't work" or "the cursor isn't where clicking happens," even though
+/// srdwm's own idea of what's under the pointer was correct the whole
+/// time. Calling this right before every button event closes that gap
+/// regardless of why focus went stale, rather than chasing the exact
+/// staleness trigger (rapid clicks, a tap-to-click event with no
+/// intervening motion delta, etc.) one cause at a time.
+#[allow(clippy::type_complexity)]
+fn refresh_pointer_focus(
+    state: &mut CompState,
+    pos: Point<f64, Logical>,
+    time: u32,
+) -> (Option<(WindowId, TitlebarHit)>, bool, bool, Option<WindowId>, Option<(WlSurface, Point<f64, Logical>)>) {
+    // Checked before literally everything else, including layer-shell --
+    // see `elements::popup_surface_under`'s own doc comment for why: a
+    // popup (tooltip, dropdown, right-click menu) always renders on top of
+    // everything else, popups on their own parent's content and layer-shell
+    // bars/docks alike, and hit-testing has to match that same priority or
+    // a click/scroll over an open popup silently lands on whatever's
+    // underneath it instead.
+    let popup_hit = crate::elements::popup_surface_under(state, pos);
+    let layer_hit = layer_surface_under(state, pos);
+    // Broadened, not just layer-shell: both a layer surface and an open
+    // popup are transient client UI that should suppress WM-level
+    // decoration-cursor guessing and focus-follows-mouse the same way (see
+    // both call sites below) - hovering a dropdown menu must not refocus
+    // whatever window happens to sit underneath it.
+    let over_layer_surface = layer_hit.is_some() || popup_hit.is_some();
+    let hit = hit_test_animated(state, pos.x as i32, pos.y as i32);
+    let under = state
+        .space
+        .element_under(pos)
+        .filter(|(w, _)| dwindow_is_visible(state, w))
+        .map(|(w, loc)| (w.clone(), loc));
+    let over_content = under.is_some();
+    // Whichever core window the pointer is over right now, decoration or
+    // content - `None` while over a layer-shell surface or bare desktop.
+    // Only `handle_pointer_position` actually uses this (focus-follows-
+    // mouse), but it needs `under` before that's consumed by the match
+    // below, so it's computed here rather than recomputed by the caller.
+    let hovered_id = hit
+        .map(|(id, _)| id)
+        .or_else(|| under.as_ref().and_then(|(window, _)| dwindow_wl_surface(window)).and_then(|s| state.surface_to_id.get(&s).copied()));
+
+    let Some(pointer) = state.seat.get_pointer() else { return (hit, over_layer_surface, over_content, hovered_id, None) };
+    // Freshly resolved target from ordinary hit-testing - overridden below
+    // by `pointer_button_grab` when a button is held, per its own doc
+    // comment (the Wayland implicit-grab rule).
+    let resolved: Option<(WlSurface, Point<f64, Logical>)> = if let Some((surface, loc)) = popup_hit {
+        Some((surface, loc.to_f64()))
+    } else if let Some((surface, loc)) = layer_hit {
+        Some((surface, loc.to_f64()))
+    } else if hit.is_some() {
+        None // Over our own decoration - no client focus.
+    } else if let Some((window, loc)) = &under {
+        // `window.toplevel()` is only ever `Some` for a native xdg-shell
+        // surface - it's `None` for every XWayland window, and even for a
+        // plain xdg-shell one it's always the *root* surface regardless of
+        // which subsurface the pointer is actually over (video/GL overlays,
+        // some GTK/Electron popups). Either way that meant pointer focus
+        // landed on the wrong surface - or no surface at all, for X11
+        // clients - and the click coordinates were relative to the window
+        // root rather than whatever was actually under the cursor.
+        // `Window::surface_under` is smithay's own hit-test for this: it
+        // walks the real surface tree (subsurfaces and popups included) and
+        // unifies the xdg-shell/X11 cases the way `dwindow_wl_surface` does
+        // elsewhere in this module.
+        //
+        // `loc` (from `Space`) is the window's raw *buffer*-origin in screen
+        // space, NOT its visible top-left - see `sync_geometry`'s own doc
+        // comment (`state/geometry.rs`), which positions every window via
+        // `map_element(w, (geom.x - content_offset.x, ...))` *specifically*
+        // so that `pos - loc` alone already lands in the buffer-local
+        // coordinates `Window::surface_under` expects (confirmed against
+        // smithay 0.7.0's own source: the ordinary toplevel branch hands
+        // `point` straight through with a hardcoded `(0, 0)` offset, unlike
+        // its sibling popup branch a few lines above, which does add
+        // `self.geometry().loc` - so a toplevel's `point` has to already
+        // be buffer-local, and `map_element`'s own placement is what makes
+        // `pos - loc` be exactly that with no further adjustment needed).
+        //
+        // A previous version of this line added `content_offset` back a
+        // *second* time (`pos - loc + content_offset`), reasoning that
+        // `loc` was the visible position and needed shifting back to
+        // buffer-local - but `sync_geometry` had already done that
+        // shifting into `loc` itself, so this double-applied it: every
+        // click on a CSD window with a nonzero shadow margin (GTK4 clients
+        // - Firefox concretely, on its own titlebar/tab-strip buttons
+        // specifically, since that's real content on an undecorated
+        // window, not srdwm's own decoration) landed `content_offset`
+        // *past* whatever was actually clicked, in the opposite direction
+        // from the original (pre-any-fix) bug. Both versions were wrong in
+        // opposite directions; plain `pos - loc` is what `sync_geometry`'s
+        // own contract actually calls for.
+        let win_relative = pos - loc.to_f64();
+        window.surface_under(win_relative, WindowSurfaceType::ALL).map(|(surface, offset)| (surface, (*loc + offset).to_f64()))
+    } else {
+        // Bare desktop, no window there either - last chance for a
+        // `Bottom`/`Background` layer surface (see
+        // `layer_surface_under_layers`'s doc comment) before giving up.
+        background_layer_surface_under(state, pos).map(|(surface, loc)| (surface, loc.to_f64()))
+    };
+    // `pointer_button_grab`'s own lock is deliberately skipped whenever a
+    // real Wayland-level grab is active (`pointer.is_grabbed()`) - most
+    // concretely, a client-initiated `wl_data_device` drag-and-drop
+    // (`DnDGrab`, installed the moment a client calls `start_drag`, e.g. a
+    // browser tab being torn out into another window). smithay's own
+    // `DnDGrab::motion` ignores this call's `focus` argument for the
+    // client-facing side (it explicitly calls `handle.motion(data, None,
+    // event)`, since no client gets ordinary pointer focus mid-drag) but
+    // *does* feed the same `focus` straight into `update_focus`, which is
+    // what actually decides the current drop target as the cursor moves.
+    // Keeping the origin-surface lock active here as well meant that value
+    // stayed pinned to whichever window the drag *started* over for the
+    // entire gesture, so `update_focus` could never see a second window as
+    // the drop target no matter where the cursor actually went - reported
+    // live as not being able to drag a tab from one window onto another.
+    // The lock's own reason for existing (a GTK drag recognizer treating a
+    // mid-gesture `leave` as "abort", see this field's own doc comment)
+    // only applies to *ordinary* pointer motion, which is exactly the case
+    // `is_grabbed()` being false identifies - once a real grab has taken
+    // over, that grab's own implementation is already responsible for
+    // routing enter/leave correctly, and needs the true, freshly-resolved
+    // surface to do it, not a stale one.
+    let delivery = if pointer.is_grabbed() { resolved.clone() } else { state.pointer_button_grab.clone().or_else(|| resolved.clone()) };
+    if let Some((surface, origin)) = delivery {
+        // `MotionEvent.location` is documented on `smithay::input::pointer::
+        // MotionEvent` itself as "Location of the pointer in compositor
+        // space" - i.e. global, the same space `pos` is already in.
+        // `PointerHandle::motion`'s own `focus` parameter carries `origin`
+        // specifically so smithay can compute the surface-relative
+        // coordinate *itself* (`event.location - loc`, see `PointerInternal
+        // ::motion` in smithay's `input/pointer/mod.rs`) before handing it
+        // to the client and storing the *global* value in its own internal
+        // `self.location` (what `PointerHandle::current_location()` later
+        // returns). Subtracting `origin` here as well, before this call,
+        // fed the client `pos - origin - origin` - doubly-offset, and
+        // wrong in a way that grows with a window's distance from the
+        // screen origin - while also corrupting smithay's own idea of
+        // "where is the pointer" for anything else that reads
+        // `current_location()`. `pos` unmodified, letting smithay subtract
+        // `origin` exactly once, is what every other call site in this
+        // file (and this same function's own `None`/lock-surface branches)
+        // already does correctly.
+        pointer.motion(state, Some((surface, origin)), &MotionEvent { location: pos, serial: SERIAL_COUNTER.next_serial(), time });
+    } else {
+        pointer.motion(state, None, &MotionEvent { location: pos, serial: SERIAL_COUNTER.next_serial(), time });
+    }
+    (hit, over_layer_surface, over_content, hovered_id, resolved)
+}
+
+pub(crate) fn handle_pointer_position(state: &mut CompState, pos: Point<f64, Logical>, time: u32) {
+    notify_idle_activity(state);
+    // Locked: pointer motion goes to the lock surface only. No hit-testing
+    // against windows/decorations, so no hover, no drag, no resize.
+    if state.lock.locked {
+        let surface = state.any_lock_surface().cloned();
+        if let Some(pointer) = state.seat.get_pointer() {
+            let focus = surface.map(|s| (s, Point::from((0, 0)).to_f64()));
+            pointer.motion(state, focus, &MotionEvent { location: pos, serial: SERIAL_COUNTER.next_serial(), time });
+            pointer.frame(state);
+        }
+        return;
+    }
+
+    // Tells core which monitor the pointer is physically over right now --
+    // core has no pointer of its own to know this (see `pointer_monitor`'s
+    // own doc comment), and `add_window`'s target-monitor fallback needs
+    // it for the one case the *focused* window's monitor can't answer:
+    // nothing focused on whichever monitor the user is actually at when
+    // launching something new. `full_geometry`, not the bar-shrunk
+    // `geometry` - this is "which physical screen is this pixel on", not
+    // a work-area question. `None` if the pointer is somehow outside every
+    // known monitor (shouldn't happen given `UdevState::bounds()` already
+    // clamps to their union, but a real `None` here is honest rather than
+    // guessing).
+    {
+        let mut wm = state.wm.borrow_mut();
+        let current = wm.monitors().iter().find(|m| m.full_geometry.contains_point(pos.x as i32, pos.y as i32)).map(|m| m.id);
+        wm.set_pointer_monitor(current);
+    }
+    let (hit, over_layer_surface, over_content, hovered_id, _) = refresh_pointer_focus(state, pos, time);
+    // The only pointer-position telemetry this compositor exposes to
+    // anything outside itself - kept at `trace` (off by default, `RUST_LOG`
+    // enables it same as any other target here) rather than removed
+    // outright: a peer session building against this compositor over IPC
+    // pointed out that without *some* "where is the pointer right now" oracle,
+    // a synthetic-input tool has no way to tell whether it moved the pointer
+    // at all versus landed somewhere unexpected, short of corner-clamping (4
+    // fixed points) or hover feedback (binary, only over a reactive widget).
+    // Every earlier version of this line ran at `warn`, unconditionally on --
+    // see `docs/TODO.md`'s matching cleanup entry for why that was too loud
+    // for daily use, not for why the telemetry itself was ever the problem.
+    log::trace!("pointer motion pos={:?} hit={hit:?}", (pos.x, pos.y));
+    // Titlebar button hover highlighting (explicitly requested, see
+    // docs/TODO.md) - `Drag`/`Resize` aren't buttons, so only the three
+    // real ones count. Compared against the previous value rather than
+    // set unconditionally so an unchanged hover (the overwhelmingly common
+    // case: most motion events land on the same button, or on none at all)
+    // doesn't force a redraw every single pointer-motion event.
+    let new_hover = hit.and_then(|(id, h)| matches!(h, srdwm_core::TitlebarHit::Close | srdwm_core::TitlebarHit::Minimize | srdwm_core::TitlebarHit::Maximize).then_some((id, h)));
+    // Compared as just `(id, hit)`, ignoring the `Instant` already stored
+    // - the field itself carries a timestamp, but "is this the same hover
+    // as before" must not depend on it, or every motion event within the
+    // same button would read as a *new* hover and keep resetting the
+    // glyph-reveal animation's own start time back to zero.
+    let currently_hovering = state.hovered_titlebar_button.map(|(id, h, _)| (id, h));
+    if new_hover != currently_hovering {
+        let old = state.hovered_titlebar_button.take();
+        state.hovered_titlebar_button = new_hover.map(|(id, h)| (id, h, std::time::Instant::now()));
+        // Both windows need a fresh signature check: the newly-hovered one
+        // (to actually draw the highlight) and the previously-hovered one,
+        // if it's a *different* window, to clear its own highlight again.
+        if let Some((id, _, _)) = old {
+            state.redraw_decoration_buffer(id);
+        }
+        if let Some((id, _)) = new_hover {
+            state.redraw_decoration_buffer(id);
+        }
+    }
+    let Some(pointer) = state.seat.get_pointer() else { return };
+    // `PointerHandle::motion`/`button`/`axis` only queue the event with the
+    // active grab - nothing sends `wl_pointer.frame` on its own (confirmed
+    // reading smithay's `DefaultGrab`: its `motion`/`button` impls call
+    // straight through to the handle and never call `frame`). `frame` is
+    // what tells a client "the events since the last frame are one atomic
+    // update, process them now" - required by the protocol since
+    // `wl_pointer` version 5, and this compositor advertises v9. Without
+    // it, any client that correctly waits for `frame` before acting on
+    // motion/button state (most modern toolkits, confirmed live: neither
+    // Firefox nor wezterm registered a click or a drag-selection, in both
+    // cases with the cursor sitting squarely on the target) never actually
+    // processes what it was sent, even though every event up to this point
+    // was individually correct. This is likely the real root cause behind
+    // this whole session's "clicking/scrolling doesn't work" reports --
+    // every fix so far (subsurface routing, decoration geometry, app_id)
+    // was real and necessary, but none of them could have mattered if the
+    // client was never told to look at what it received.
+    pointer.frame(state);
+
+    update_cursor_shape(state, hit, over_layer_surface, over_content);
+
+    let mut wm = state.wm.borrow_mut();
+    let dragging_or_resizing = wm.is_dragging() || wm.is_resizing();
+    if wm.is_dragging() {
+        wm.update_drag(pos.x as i32, pos.y as i32);
+    } else if wm.is_resizing() {
+        wm.update_resize(pos.x as i32, pos.y as i32);
+    }
+    let focused = wm.focused_id();
+    // `general.focus_follows_mouse`: hovering a *different* window focuses
+    // it, no click needed - classic X11 sloppy focus. Gated on `hit`/
+    // `under` actually landing on a window (not a layer surface or bare
+    // desktop) and on not already being mid-drag/resize, where the pointer
+    // sweeps over unrelated windows constantly and none of that should
+    // steal focus from whatever's actually being dragged. `hovered_id !=
+    // focused` both skips redundant work on every one of the many motion
+    // events a stationary pointer over an already-focused window still
+    // generates, and is what makes `auto_raise` (below) only fire on an
+    // actual focus change rather than every motion tick too.
+    let focus_follow_target =
+        (wm.focus_follows_mouse && !dragging_or_resizing && !over_layer_surface).then_some(hovered_id).flatten().filter(|id| Some(*id) != focused);
+    if let Some(id) = focus_follow_target {
+        if wm.auto_raise {
+            // `raise_window` alone here, not `focus_window` - the actual
+            // core + real Wayland/X11 keyboard focus change happens once,
+            // below, through the same `focus_window` free function every
+            // click-driven focus change already goes through (sets real
+            // keyboard focus too, which `WindowManager::focus_window`
+            // alone does not).
+            wm.raise_window(id);
+        }
+    }
+    drop(wm);
+    if let Some(id) = focus_follow_target {
+        focus_window(state, id);
+    }
+    if dragging_or_resizing {
+        if let Some(id) = focused {
+            state.sync_geometry(id);
+        }
+    }
+}
+
+/// Sets the pointer to a resize-direction shape while hovering (or
+/// actively dragging) one of our own decoration's resize edges, and back
+/// to the default arrow when leaving our decoration for anything else.
+///
+/// Only ever *forces* `cursor_status` for our own decoration - never while
+/// `layer_hit`/client content has focus, since a client surface drives its
+/// own cursor via `wl_pointer.set_cursor` once it starts receiving
+/// `pointer.motion()`/`enter` (already sent above, by the time this runs),
+/// and stomping on that here would fight the client for control of its own
+/// cursor rather than just leaving it alone.
+///
+/// Without this, `cursor_status` was only ever set by client requests --
+/// nothing on the compositor's own side ever asked for a resize cursor at
+/// all, so hovering or dragging one of our own decoration's edges never
+/// looked any different from hovering plain content, regardless of what
+/// shapes `cursor.rs` can actually render.
+///
+/// `over_content` distinguishes "over a client surface that will drive its
+/// own cursor" from "over the bare desktop, where nothing ever will" --
+/// without it, dragging off one of our decoration's resize edges straight
+/// onto empty desktop left `cursor_status` stuck on that resize icon
+/// forever: there is no client there to ever call `set_cursor` and reset
+/// it, and this function's own early-return (for the "let the client drive
+/// it" case) doesn't distinguish an *absent* client from a slow one.
+///
+/// `state.decoration_cursor_active` is what makes the "leave it alone"
+/// branch below safe rather than sticky: reported live as "the resize icon
+/// stays on screen long after the pointer is nowhere near an edge." Moving
+/// from a decoration edge onto plain content sets no new `wl_pointer` focus
+/// (an undecorated/CSD window's edge and its content are the same surface,
+/// just different bands of it - see `hit_test`'s `UNDECORATED_TOP_RESIZE_
+/// MARGIN`), so the client never gets an `enter` event to react to, and most
+/// toolkits only re-call `set_cursor` when *their own* idea of which widget
+/// is hovered changes - which it hasn't, from their point of view, since
+/// they were never told the pointer was ever over a resize edge to begin
+/// with. The resize icon we forced while hovering that edge was therefore
+/// never going to be overwritten by anything, ever, without this: the very
+/// first content tick after leaving a decoration/resize hover resets to the
+/// plain arrow *once*, and only if we're the one who last set it - a
+/// client that has since claimed the cursor itself (tracked by `cursor_
+/// image` in `protocols.rs` clearing this same flag) is left alone on every
+/// following tick, so this can't fight a legitimate client cursor that
+/// isn't changing simply because the pointer kept moving.
+fn update_cursor_shape(state: &mut CompState, hit: Option<(WindowId, TitlebarHit)>, over_layer_surface: bool, over_content: bool) {
+    use smithay::input::pointer::{CursorIcon, CursorImageStatus};
+
+    if over_layer_surface {
+        return;
+    }
+    let edge = match hit {
+        Some((_, TitlebarHit::Resize(edge))) => Some(edge),
+        _ => state.wm.borrow().resize_edge(),
+    };
+    // A live "forcing the cursor here has no visible effect" report earlier
+    // this session turned out to be a real *design* gap, not a rendering
+    // bug: hovering a titlebar button used to fall into the same
+    // `CursorIcon::Default` branch as the plain drag area below it --
+    // indistinguishable from "not hovering anything special" (the desktop's
+    // own baseline cursor is also `Default`), so there was never any visible
+    // change to notice in the first place. `Pointer` (a real hand/finger
+    // cursor - see `cursor.rs`'s own `pointer_bitmap`) is what every
+    // mainstream desktop shows over a clickable titlebar button instead.
+    let icon = match edge {
+        Some(edge) => resize_cursor_icon(edge),
+        // A real button (Close/Maximize/Minimize), not the plain drag
+        // area - a hand cursor, matching every mainstream desktop's own
+        // convention for a clickable titlebar control.
+        None if matches!(hit, Some((_, TitlebarHit::Close | TitlebarHit::Maximize | TitlebarHit::Minimize))) => CursorIcon::Pointer,
+        // Hovering our own decoration but not an edge or a button (the
+        // drag area) and not actively resizing: back to the plain arrow.
+        None if hit.is_some() => CursorIcon::Default,
+        // Over a client's own content: leave `cursor_status` alone once the
+        // client has claimed it - but if we're still showing whatever we
+        // last forced (a resize icon from the edge just left), reset it
+        // back to the plain arrow this one time rather than leaving it
+        // stuck, since nothing else is ever going to.
+        None if over_content => {
+            if state.decoration_cursor_active {
+                state.cursor_status = CursorImageStatus::Named(CursorIcon::Default);
+                state.decoration_cursor_active = false;
+            }
+            return;
+        }
+        // Bare desktop: nothing else will ever reset this, so we have to.
+        None => CursorIcon::Default,
+    };
+    state.cursor_status = CursorImageStatus::Named(icon);
+    state.decoration_cursor_active = true;
+}
+
+fn resize_cursor_icon(edge: srdwm_core::ResizeEdge) -> smithay::input::pointer::CursorIcon {
+    use smithay::input::pointer::CursorIcon;
+    use srdwm_core::ResizeEdge;
+    match edge {
+        ResizeEdge::Left | ResizeEdge::Right => CursorIcon::EwResize,
+        ResizeEdge::Top | ResizeEdge::Bottom => CursorIcon::NsResize,
+        ResizeEdge::TopLeft | ResizeEdge::BottomRight => CursorIcon::NwseResize,
+        ResizeEdge::TopRight | ResizeEdge::BottomLeft => CursorIcon::NeswResize,
+    }
+}
+
+pub(crate) fn handle_pointer_button(state: &mut CompState, pos: Point<f64, Logical>, button: u32, pressed: bool, time: u32) {
+    notify_idle_activity(state);
+    const BTN_LEFT: u32 = 0x110;
+    const BTN_RIGHT: u32 = 0x111;
+    const BTN_MIDDLE: u32 = 0x112;
+    let serial = SERIAL_COUNTER.next_serial();
+
+    // Locked: forward the click to the lock surface (it may have a button or
+    // a text field) but never let it focus, raise, drag, or close a window.
+    if state.lock.locked {
+        if let Some(pointer) = state.seat.get_pointer() {
+            let button_state = if pressed { BackendButtonState::Pressed } else { BackendButtonState::Released };
+            pointer.button(state, &ButtonEvent { serial, time, button, state: button_state });
+            pointer.frame(state);
+        }
+        return;
+    }
+
+    // The context menu, if open, captures every press: a click inside
+    // resolves whichever row it landed on, a click anywhere else just
+    // dismisses it. Neither case falls through to the normal handling
+    // below - opening the menu and then clicking a window underneath it
+    // should not *also* focus/raise/drag that window on the same click,
+    // the same "one click, one action" rule every native window menu
+    // follows.
+    if pressed {
+        if let Some(menu) = state.context_menu.take() {
+            if let Some(row) = menu.row_at(pos.x as i32, pos.y as i32) {
+                let (_, action) = menu.items[row];
+                state.close_context_menu();
+                state.run_context_menu_action(menu.window, action);
+            } else {
+                state.close_context_menu();
+            }
+            return;
+        }
+        // Same "one click, one action" rule as the context menu above --
+        // a click inside the Snap-Layouts flyout applies that zone, a click
+        // anywhere else just dismisses it.
+        if let Some(flyout) = state.snap_flyout.take() {
+            if let Some(zone) = flyout.zone_at(pos.x as i32, pos.y as i32) {
+                state.close_snap_flyout();
+                state.run_snap_flyout_action(flyout.window, zone);
+            } else {
+                state.close_snap_flyout();
+            }
+            return;
+        }
+    }
+
+    // Modifier+drag: with the modifier held, dragging *anywhere* in a window
+    // moves it (left button) or resizes it from the nearest corner (right
+    // button) - the `bindm SUPER, mouse:272/273` gesture. Without this a
+    // window can only be moved by its titlebar, which is useless for
+    // windows that have none (fullscreen, CSD apps, layer surfaces).
+    //
+    // Checked before the titlebar hit-test so the modifier wins over the
+    // decoration: holding the modifier and grabbing the titlebar should
+    // still move, not press a titlebar button.
+    if pressed && (button == BTN_LEFT || button == BTN_RIGHT) {
+        let mods = state.seat.get_keyboard().map(|k| core_modifiers_from_xkb(&k.modifier_state()));
+        if mods.is_some_and(|m| m.contains(DRAG_MODIFIER)) {
+            let target = state.wm.borrow().window_at(pos.x as i32, pos.y as i32);
+            if let Some(id) = target {
+                focus_window(state, id);
+                let mut wm = state.wm.borrow_mut();
+                if button == BTN_LEFT {
+                    wm.start_drag(id, pos.x as i32, pos.y as i32);
+                } else {
+                    let edge = wm.nearest_corner(id, pos.x as i32, pos.y as i32);
+                    wm.start_resize(id, edge, pos.x as i32, pos.y as i32);
+                }
+                return;
+            }
+        }
+    }
+
+    if pressed && button == BTN_LEFT {
+        let layer_hit = layer_surface_under(state, pos);
+        if let Some((surface, _)) = &layer_hit {
+            // Look the surface up on whichever output actually holds it.
+            let on_demand = state
+                .outputs()
+                .find_map(|output| {
+                    layer_map_for_output(output)
+                        .layer_for_surface(surface, WindowSurfaceType::ALL)
+                        .map(|l| {
+                            l.can_receive_keyboard_focus()
+                                && l.cached_state().keyboard_interactivity != KeyboardInteractivity::Exclusive
+                        })
+                })
+                .unwrap_or(false);
+            // `Exclusive` layers (lock screens, exclusive launchers) already
+            // hold focus from `ensure_layer_initial_configure` and keep it
+            // regardless of where else is clicked; only `OnDemand` layers
+            // (e.g. a bar's search field) claim it on click.
+            if on_demand {
+                state.set_keyboard_focus(Some(surface.clone()));
+            }
+        }
+        let hit = if layer_hit.is_some() { None } else { hit_test_animated(state, pos.x as i32, pos.y as i32) };
+        if let Some((id, hit)) = hit {
+            focus_window(state, id);
+            match hit {
+                TitlebarHit::Drag => {
+                    // Double-click the titlebar to maximise, as every other
+                    // desktop does - one of the few window operations that
+                    // otherwise needs the keyboard or a precise button hit.
+                    if state.is_double_click(id, time) {
+                        state.wm.borrow_mut().toggle_maximize(id);
+                        state.sync_geometry(id);
+                        crate::foreign_toplevel::send_state(state, id);
+                    } else {
+                        state.wm.borrow_mut().start_drag(id, pos.x as i32, pos.y as i32)
+                    }
+                }
+                TitlebarHit::Close => {
+                    if let Some(w) = state.id_to_window.get(&id) {
+                        close_dwindow(w);
+                    }
+                }
+                TitlebarHit::Maximize => {
+                    state.wm.borrow_mut().toggle_maximize(id);
+                    state.sync_geometry(id);
+                    crate::foreign_toplevel::send_state(state, id);
+                }
+                TitlebarHit::Minimize => {
+                    state.wm.borrow_mut().minimize_window(id);
+                    crate::foreign_toplevel::send_state(state, id);
+                }
+                TitlebarHit::Resize(edge) => state.wm.borrow_mut().start_resize(id, edge, pos.x as i32, pos.y as i32),
+            }
+        } else if layer_hit.is_none() {
+            if let Some((window, _loc)) = state.space.element_under(pos).filter(|(w, _)| dwindow_is_visible(state, w)) {
+                let window = window.clone();
+                // `focus_window` itself raises both `Space` and pinned
+                // windows now - see its own doc comment. No longer done
+                // manually here first.
+                if let Some(&id) = dwindow_wl_surface(&window).and_then(|s| state.surface_to_id.get(&s)) {
+                    focus_window(state, id);
+                }
+            }
+        }
+    } else if pressed && (button == BTN_RIGHT || button == BTN_MIDDLE) {
+        // Right-click a titlebar: open the window menu (minimize/maximize/
+        // pin/close) - previously nothing at all, since the only
+        // right-button behaviour anywhere was the SUPER+right-drag resize
+        // gesture above, which needs the modifier held. Middle-click:
+        // lower the window instead, the convention several X11 WMs
+        // (twm, fvwm, IceWM) have always had. Both only fire on the
+        // titlebar's plain drag area - a resize edge or one of the three
+        // buttons keeps its own single meaning regardless of which button
+        // was pressed, so a right-click on the close button, say, doesn't
+        // do something else entirely.
+        let hit = hit_test_animated(state, pos.x as i32, pos.y as i32);
+        match (button, hit) {
+            (BTN_RIGHT, Some((id, TitlebarHit::Drag))) => state.open_context_menu(id, (pos.x as i32, pos.y as i32)),
+            (BTN_MIDDLE, Some((id, TitlebarHit::Drag))) => state.wm.borrow_mut().lower_window(id),
+            // Right-click the maximize button itself: the Snap-Layouts
+            // flyout (pick a half/quarter position for this window)
+            // instead of the window menu - a plain left-click there still
+            // just toggles maximize, unchanged.
+            (BTN_RIGHT, Some((id, TitlebarHit::Maximize))) => state.open_snap_flyout(id, (pos.x as i32, pos.y as i32)),
+            _ => {}
+        }
+    } else if !pressed {
+        let mut wm = state.wm.borrow_mut();
+        let was_dragging = wm.is_dragging();
+        let was_resizing = wm.is_resizing();
+        // `start_drag`/`start_resize` both focus the window they grab, and
+        // nothing else can change focus while a grab is active (the pointer
+        // is captured by the drag, not routed elsewhere) - so `focused_id`
+        // is reliably the window `end_drag`/`end_resize` are about to
+        // finish, without `WindowManager` needing to hand the id back
+        // itself.
+        let id = wm.focused_id();
+        if was_dragging {
+            wm.end_drag();
+        } else if was_resizing {
+            wm.end_resize();
+        }
+        drop(wm);
+        // `end_drag` can snap the geometry one more time (edge/top-of-
+        // screen snapping, `SmartPlacement::snap_zone`) *after* the last
+        // `update_drag` already moved the window - without this, that
+        // final snap only ever reached `Window.geometry`. The border and
+        // titlebar redraw fresh from live geometry every frame, so they'd
+        // jump to the snapped rect immediately, while the client's actual
+        // mapped surface (driven only by `sync_geometry`'s
+        // `space.map_element`/`xdg_toplevel.configure`) stayed wherever the
+        // drag physically stopped - decoration visibly detached from its
+        // own window's content. Click routing desynced the same way:
+        // `hit_test`/`window_at` read the now-snapped `Window.geometry`
+        // while `space.element_under` still read the stale pre-snap
+        // position, so clicks in the visually-snapped zone resolved
+        // against the wrong rect. The X11 backend already gets this right
+        // (`crates/x11/src/lib.rs`'s `ButtonRelease` handler); this was the
+        // one call site in the module doc'd as "shared by both backends"
+        // that never got the same fix.
+        if was_dragging || was_resizing {
+            if let Some(id) = id {
+                state.sync_geometry(id);
+            }
+        }
+    }
+
+    // Re-assert real Wayland pointer focus at `pos` immediately before the
+    // actual click - see `refresh_pointer_focus`'s own doc comment for why
+    // this can't just trust whatever the last motion event left focus at.
+    // A no-op from the client's perspective when focus was already correct
+    // (an idempotent motion event at the same surface-local coordinates it
+    // already has), so this costs nothing in the common case.
+    //
+    // Also where `pointer_button_grab` starts and ends - see its own doc
+    // comment. Only the 0->1 transition captures a new grab target (a
+    // second button going down mid-gesture keeps whatever the first press
+    // already locked in); only the ->0 transition releases it, and not
+    // before this press/release's own `pointer.button()` below still goes
+    // out under the (still-active) grab.
+    let (.., resolved) = refresh_pointer_focus(state, pos, time);
+    if pressed {
+        if state.pointer_buttons_held == 0 {
+            state.pointer_button_grab = resolved;
+        }
+        state.pointer_buttons_held += 1;
+    } else {
+        state.pointer_buttons_held = state.pointer_buttons_held.saturating_sub(1);
+    }
+    if let Some(pointer) = state.seat.get_pointer() {
+        let button_state = if pressed { BackendButtonState::Pressed } else { BackendButtonState::Released };
+        pointer.button(state, &ButtonEvent { serial, time, button, state: button_state });
+        // See the matching comment in `handle_pointer_position`: `button`
+        // alone never tells the client the event is ready to act on, only
+        // `frame` does.
+        pointer.frame(state);
+    }
+    if !pressed && state.pointer_buttons_held == 0 {
+        state.pointer_button_grab = None;
+    }
+}