input/tablet: add seatop_down entry for tablet input

Currently, when tablet input exits a window during an implicit grab, it
passes focus to another window.

For instance, this is problematic when trying to drag a scrollbar, and
exiting the window — the scrollbar motion stops. Additionally,
without `focus_follows_mouse no`, the tablet passes focus to whatever
surface it goes over regardless of if there is an active implicit.

If the tablet is over a surface that does not bind tablet handlers, sway
will fall back to pointer emulation, and all of this works fine. It
probably should have consistent behavior between emulated and
not-emulated input, though.

This commit adds a condition for entering seatop_down when a tablet's
tool tip goes down, and exiting when it goes up. Since events won't be
routed through seatop_default, this prevents windows losing focus during
implicit grabs.

Closes #5302.

1 files changed, 24 insertions, 0 deletions

diff --git a/sway/input/seatop_down.c b/sway/input/seatop_down.c
index 358d5c59..dd8be6bf 100644
--- a/sway/input/seatop_down.c
+++ b/sway/input/seatop_down.c
@@ -1,6 +1,7 @@
 #define _POSIX_C_SOURCE 200809L
 #include <float.h>
 #include <wlr/types/wlr_cursor.h>
+#include <wlr/types/wlr_tablet_v2.h>
 #include "sway/input/cursor.h"
 #include "sway/input/seat.h"
 #include "sway/tree/view.h"
@@ -49,6 +50,27 @@ static void handle_pointer_motion(struct sway_seat *seat, uint32_t time_msec,
 	}
 }
 
+static void handle_tablet_tool_tip(struct sway_seat *seat,
+		struct sway_tablet_tool *tool, uint32_t time_msec,
+		enum wlr_tablet_tool_tip_state state) {
+	if (state == WLR_TABLET_TOOL_TIP_UP) {
+		seatop_begin_default(seat);
+	}
+}
+
+static void handle_tablet_tool_motion(struct sway_seat *seat,
+		struct sway_tablet_tool *tool, uint32_t time_msec, double dx, double dy) {
+	struct seatop_down_event *e = seat->seatop_data;
+	struct sway_container *con = e->con;
+	if (seat_is_input_allowed(seat, con->view->surface)) {
+		double moved_x = seat->cursor->cursor->x - e->ref_lx;
+		double moved_y = seat->cursor->cursor->y - e->ref_ly;
+		double sx = e->ref_con_lx + moved_x;
+		double sy = e->ref_con_ly + moved_y;
+		wlr_tablet_v2_tablet_tool_notify_motion(tool->tablet_v2_tool, sx, sy);
+	}
+}
+
 static void handle_unref(struct sway_seat *seat, struct sway_container *con) {
 	struct seatop_down_event *e = seat->seatop_data;
 	if (e->con == con) {
@@ -60,6 +82,8 @@ static const struct sway_seatop_impl seatop_impl = {
 	.button = handle_button,
 	.pointer_motion = handle_pointer_motion,
 	.pointer_axis = handle_pointer_axis,
+	.tablet_tool_tip = handle_tablet_tool_tip,
+	.tablet_tool_motion = handle_tablet_tool_motion,
 	.unref = handle_unref,
 	.allow_set_cursor = true,
 };