From cc0e2769d9496b601be3cd502f73f3340ce6873c Mon Sep 17 00:00:00 2001
From: Consolatis <35009135+Consolatis@users.noreply.github.com>
Date: Tue, 24 May 2022 13:02:51 +0200
Subject: [PATCH] src/cursor.c: Fix branch condition for out-of-view
 selecting/dragging

Instead of using the stored view for comparison use the actual surface.

Before this patch, there were situations where the branch intended for
out-of-window text selection / scrollbar dragging was used even though
the cursor never left the surface.

Partly fixes #340
Fixes #347

Backport of 6dd290afc9fd009a6631df4a057f385d1c01a403
---
 include/labwc.h | 11 +++++++----
 src/cursor.c    | 26 +++++++++++++++++---------
 src/xdg.c       |  5 +++--
 src/xwayland.c  |  5 +++--
 4 files changed, 30 insertions(+), 17 deletions(-)

diff --git a/include/labwc.h b/include/labwc.h
index ff74ef72..2a081a89 100644
--- a/include/labwc.h
+++ b/include/labwc.h
@@ -80,16 +80,19 @@ struct seat {
 	struct wlr_layer_surface_v1 *focused_layer;
 
 	/**
-	 * active_view will usually be NULL and is only set on button press
-	 * while the mouse is over a view surface and reset to NULL on button
-	 * release.
+	 * pressed view/surface will usually be NULL and is only set on button
+	 * press while the mouse is over a view surface and reset to NULL on
+	 * button release.
 	 * It is used to send cursor motion events to a surface even though
 	 * the cursor has left the surface in the meantime.
 	 *
 	 * This allows to keep dragging a scrollbar or selecting text even
 	 * when moving outside of the window.
 	 */
-	struct view *active_view;
+	struct {
+		struct view *view;
+		struct wlr_surface *surface;
+	} pressed;
 
 	struct wl_client *active_client_while_inhibited;
 	struct wl_list inputs;
diff --git a/src/cursor.c b/src/cursor.c
index 94c79f0d..0c946c52 100644
--- a/src/cursor.c
+++ b/src/cursor.c
@@ -296,22 +296,27 @@ process_cursor_motion(struct server *server, uint32_t time)
 		last_button_hover = LAB_SSD_NONE;
 	}
 
-	if (server->seat.active_view && !server->seat.drag_icon) {
+	if (server->seat.pressed.surface &&
+			server->seat.pressed.surface != surface &&
+			!server->seat.drag_icon) {
 		/*
 		 * Button has been pressed while over a view surface
 		 * and is still held down. Just send the adjusted motion
 		 * events to the focused surface so we can keep scrolling
 		 * or selecting text even if the cursor moves outside of
 		 * the surface.
+		 *
+		 * TODO: This seems to miss calculations for invisible CSD borders.
+		 *       Tracked at https://github.com/labwc/labwc/issues/340
 		 */
-		view = server->seat.active_view;
-		double sx = server->seat.cursor->x - view->x;
-		double sy = server->seat.cursor->y - view->y;
+		view = server->seat.pressed.view;
+		sx = server->seat.cursor->x - view->x;
+		sy = server->seat.cursor->y - view->y;
 		sx = sx < 0 ? 0 : (sx > view->w ? view->w : sx);
 		sy = sy < 0 ? 0 : (sy > view->h ? view->h : sy);
 		wlr_seat_pointer_notify_motion(server->seat.seat, time, sx, sy);
-	} else if (surface &&
-	    !input_inhibit_blocks_surface(&server->seat, surface->resource)) {
+	} else if (surface && !input_inhibit_blocks_surface(
+			&server->seat, surface->resource)) {
 		bool focus_changed =
 			wlr_seat->pointer_state.focused_surface != surface;
 		/*
@@ -362,7 +367,8 @@ start_drag(struct wl_listener *listener, void *data)
 {
 	struct seat *seat = wl_container_of(listener, seat, start_drag);
 	struct wlr_drag *wlr_drag = data;
-	seat->active_view = NULL;
+	seat->pressed.view = NULL;
+	seat->pressed.surface = NULL;
 	seat->drag_icon = wlr_drag->icon;
 	wl_signal_add(&seat->drag_icon->events.destroy, &seat->destroy_drag);
 }
@@ -669,7 +675,8 @@ cursor_button(struct wl_listener *listener, void *data)
 
 	/* handle _release_ */
 	if (event->state == WLR_BUTTON_RELEASED) {
-		server->seat.active_view = NULL;
+		server->seat.pressed.view = NULL;
+		server->seat.pressed.surface = NULL;
 
 		if (server->input_mode == LAB_INPUT_STATE_MENU) {
 			return;
@@ -705,7 +712,8 @@ cursor_button(struct wl_listener *listener, void *data)
 
 	/* Handle _press */
 	if (view_area == LAB_SSD_CLIENT) {
-		server->seat.active_view = view;
+		server->seat.pressed.view = view;
+		server->seat.pressed.surface = surface;
 	}
 
 	if (server->input_mode == LAB_INPUT_STATE_MENU) {
diff --git a/src/xdg.c b/src/xdg.c
index 412e799b..9de3dbea 100644
--- a/src/xdg.c
+++ b/src/xdg.c
@@ -96,8 +96,9 @@ handle_destroy(struct wl_listener *listener, void *data)
 		wlr_foreign_toplevel_handle_v1_destroy(view->toplevel_handle);
 	}
 	interactive_end(view);
-	if (view->server->seat.active_view == view) {
-		view->server->seat.active_view = NULL;
+	if (view->server->seat.pressed.view == view) {
+		view->server->seat.pressed.view = NULL;
+		view->server->seat.pressed.surface = NULL;
 	}
 	wl_list_remove(&view->link);
 	wl_list_remove(&view->destroy.link);
diff --git a/src/xwayland.c b/src/xwayland.c
index 3ad89a42..c9e897fe 100644
--- a/src/xwayland.c
+++ b/src/xwayland.c
@@ -88,8 +88,9 @@ handle_destroy(struct wl_listener *listener, void *data)
 		wlr_foreign_toplevel_handle_v1_destroy(view->toplevel_handle);
 	}
 	interactive_end(view);
-	if (view->server->seat.active_view == view) {
-		view->server->seat.active_view = NULL;
+	if (view->server->seat.pressed.view == view) {
+		view->server->seat.pressed.view = NULL;
+		view->server->seat.pressed.surface = NULL;
 	}
 	view->xwayland_surface = NULL;
 	wl_list_remove(&view->link);