From c89f30827ce5947fe7697bcffd9b11061fb5b16d Mon Sep 17 00:00:00 2001
From: werapi <sokneip@tuta.io>
Date: Sun, 5 Apr 2026 14:04:27 +0200
Subject: [PATCH] fix: correct touch motion surface-local coordinate
 calculation

---
 src/mango.c | 38 +++++++++++++++-----------------------
 1 file changed, 15 insertions(+), 23 deletions(-)

diff --git a/src/mango.c b/src/mango.c
index 1e0ead3f..dae07d78 100644
--- a/src/mango.c
+++ b/src/mango.c
@@ -455,6 +455,7 @@ typedef struct {
 typedef struct {
 	struct wl_list link;
 	int32_t touch_id;
+	double start_x, start_y, start_surface_x, start_surface_y;
 } TouchPoint;
 
 typedef struct TouchGroup {
@@ -5910,6 +5911,8 @@ void touchdown(struct wl_listener *listener, void *data) {
 	Monitor *m;
 
 	t->touch_id = event->touch_id;
+	t->start_x = lx;
+	t->start_y = ly;
 	wl_list_insert(&tg->touch_points, &t->link);
 
 	wlr_idle_notifier_v1_notify_activity(idle_notifier, seat);
@@ -5938,6 +5941,8 @@ void touchdown(struct wl_listener *listener, void *data) {
 
 	/* Find the client under the pointer and send the event along. */
 	xytonode(lx, ly, &surface, &c, NULL, &sx, &sy);
+	t->start_surface_x = sx;
+	t->start_surface_y = sy;
 	if (surface != NULL && wlr_surface_accepts_touch(surface, seat)) {
 		if (c)
 			focusclient(c, 0);
@@ -6023,10 +6028,8 @@ void touchmotion(struct wl_listener *listener, void *data) {
 	double lx, ly;
 	double sx, sy;
 	double dx, dy;
-	int32_t node_x, node_y;
 	struct wlr_surface *surface;
 	Client *c = NULL;
-	struct wlr_scene_tree *tree;
 	struct wlr_touch_point *p = NULL;
 
 	wl_list_for_each(t_iter, &tg->touch_points, link) {
@@ -6038,10 +6041,11 @@ void touchmotion(struct wl_listener *listener, void *data) {
 	if (!t) // invalid or cancelled
 		return;
 
+	wlr_cursor_absolute_to_layout_coords(cursor, &event->touch->base, event->x,
+										 event->y, &lx, &ly);
+
 	if (emulating_pointer_from_touch) {
 		if (emulated_pointer_touch_id == event->touch_id) {
-			wlr_cursor_absolute_to_layout_coords(cursor, &event->touch->base,
-												 event->x, event->y, &lx, &ly);
 			dx = lx - cursor->x;
 			dy = ly - cursor->y;
 			motionnotify(event->time_msec, &event->touch->base, dx, dy, dx, dy);
@@ -6055,31 +6059,19 @@ void touchmotion(struct wl_listener *listener, void *data) {
 		return;
 	}
 
-	wlr_cursor_absolute_to_layout_coords(cursor, &event->touch->base, event->x,
-										 event->y, &lx, &ly);
+	sx = t->start_surface_x + (lx - t->start_x);
+	sy = t->start_surface_y + (ly - t->start_y);
+
 	surface = p->surface;
 	if (surface && surface->data) {
-		tree = surface->data;
-		wlr_scene_node_coords(&tree->node, &node_x, &node_y);
-		sx = lx - node_x;
-		sy = ly - node_y;
-
 		toplevel_from_wlr_surface(surface, &c, NULL);
 		if (c)
 			focusclient(c, 0);
-
-		wlr_seat_touch_point_focus(seat, surface, event->time_msec,
-								   event->touch_id, sx, sy);
-		wlr_seat_touch_notify_motion(seat, event->time_msec, event->touch_id,
-									 sx, sy);
-
-		wlr_idle_notifier_v1_notify_activity(idle_notifier, seat);
-	} else {
-		focusclient(NULL, 0);
-		wlr_seat_touch_point_clear_focus(seat, event->time_msec,
-										 event->touch_id);
-		wlr_idle_notifier_v1_notify_activity(idle_notifier, seat);
 	}
+	wlr_seat_touch_notify_motion(seat, event->time_msec, event->touch_id, sx,
+								 sy);
+
+	wlr_idle_notifier_v1_notify_activity(idle_notifier, seat);
 }
 
 void touchcancel(struct wl_listener *listener, void *data) {