Allow mouse movements to trigger SnapToEdge

docs/rc.xml.all

@@ -29,6 +29,14 @@
     <raiseOnFocus>no</raiseOnFocus>
   </focus>
 
+  <!--
+    Set range to 0 to disable window snapping completely
+  -->
+  <snapping>
+    <range>1</range>
+    <topMaximize>yes</topMaximize>
+  </snapping>
+
   <!--
     Keybind actions are specified in labwc-actions(5)
     The following keybind modifiers are supported:

include/config/rcxml.h

@@ -44,6 +44,10 @@ struct rcxml {
 
 	/* resistance */
 	int screen_edge_strength;
+
+	/* window snapping */
+	int snap_edge_range;
+	bool snap_top_maximize;
 };
 
 extern struct rcxml rc;

src/config/rcxml.c

@@ -374,6 +374,10 @@ entry(xmlNode *node, char *nodename, char *content)
 		rc.repeat_delay = atoi(content);
 	} else if (!strcasecmp(nodename, "screenEdgeStrength.resistance")) {
 		rc.screen_edge_strength = atoi(content);
+	} else if (!strcasecmp(nodename, "range.snapping")) {
+		rc.snap_edge_range = atoi(content);
+	} else if (!strcasecmp(nodename, "topMaximize.snapping")) {
+		rc.snap_top_maximize = get_bool(content);
 	}
 }
 
@@ -470,6 +474,8 @@ rcxml_init()
 	rc.repeat_rate = 25;
 	rc.repeat_delay = 600;
 	rc.screen_edge_strength = 20;
+	rc.snap_edge_range = 1;
+	rc.snap_top_maximize = true;
 }
 
 static struct {

src/cursor.c

@@ -607,8 +607,12 @@ cursor_button(struct wl_listener *listener, void *data)
 		damage_all_outputs(server);
 		if (server->input_mode != LAB_INPUT_STATE_PASSTHROUGH) {
 			/* Exit interactive move/resize/menu mode. */
-			server->input_mode = LAB_INPUT_STATE_PASSTHROUGH;
+			if (server->grabbed_view == view) {
-			server->grabbed_view = NULL;
+				interactive_end(view);
+			} else {
+				server->input_mode = LAB_INPUT_STATE_PASSTHROUGH;
+				server->grabbed_view = NULL;
+			}
 			cursor_rebase(&server->seat, event->time_msec);
 		}
 

src/interactive.c

@@ -76,7 +76,36 @@ void
 interactive_end(struct view *view)
 {
 	if (view->server->grabbed_view == view) {
+		bool should_snap = view->server->input_mode == LAB_INPUT_STATE_MOVE
+			 && rc.snap_edge_range;
 		view->server->input_mode = LAB_INPUT_STATE_PASSTHROUGH;
 		view->server->grabbed_view = NULL;
+		if (should_snap) {
+			int snap_range = rc.snap_edge_range;
+			struct wlr_box *area = &view->output->usable_area;
+
+			/* Translate into output local coordinates */
+			double cursor_x = view->server->seat.cursor->x;
+			double cursor_y = view->server->seat.cursor->y;
+			wlr_output_layout_output_coords(view->server->output_layout,
+				view->output->wlr_output, &cursor_x, &cursor_y);
+
+			if (cursor_x <= area->x + snap_range) {
+				view_snap_to_edge(view, "left");
+			} else if (cursor_x >= area->x + area->width - snap_range) {
+				view_snap_to_edge(view, "right");
+			} else if (cursor_y <= area->y + snap_range) {
+				if (rc.snap_top_maximize) {
+					view_maximize(view, true);
+					/* When unmaximizing later on restore original position */
+					view->unmaximized_geometry.x = view->server->grab_box.x;
+					view->unmaximized_geometry.y = view->server->grab_box.y;
+				} else {
+					view_snap_to_edge(view, "up");
+				}
+			} else if (cursor_y >= area->y + area->height - snap_range) {
+				view_snap_to_edge(view, "down");
+			}
+		}
 	}
 }