[proof-of-concept] add swipe mousebinds

Use like
```xml
<mousebind direction="Down" fingers="4" action="swipe">
	<action name="GoToDesktop" to="right" wrap="false" />
</mousebind>
<mousebind direction="Up" fingers="4" action="swipe">
	<action name="GoToDesktop" to="left" wrap="false" />
</mousebind>
```

include/config/mousebind.h

@@ -14,6 +14,7 @@ enum mouse_event {
 	MOUSE_ACTION_RELEASE,
 	MOUSE_ACTION_DRAG,
 	MOUSE_ACTION_SCROLL,
+	MOUSE_ACTION_SWIPE,
 };
 
 enum direction {
@@ -30,6 +31,9 @@ struct mousebind {
 	/* ex: BTN_LEFT, BTN_RIGHT from linux/input_event_codes.h */
 	uint32_t button;
 
+	/* used for MOUSE_ACTION_SWIPE */
+	uint32_t fingers;
+
 	/* scroll direction; considered instead of button for scroll events */
 	enum direction direction;
 

src/config/mousebind.c

@@ -98,6 +98,8 @@ mousebind_event_from_str(const char *str)
 		return MOUSE_ACTION_DRAG;
 	} else if (!strcasecmp(str, "scroll")) {
 		return MOUSE_ACTION_SCROLL;
+	} else if (!strcasecmp(str, "swipe")) {
+		return MOUSE_ACTION_SWIPE;
 	}
 	wlr_log(WLR_ERROR, "unknown mouse action (%s)", str);
 	return MOUSE_ACTION_NONE;
@@ -111,7 +113,8 @@ mousebind_the_same(struct mousebind *a, struct mousebind *b)
 		&& a->button == b->button
 		&& a->direction == b->direction
 		&& a->mouse_event == b->mouse_event
-		&& a->modifiers == b->modifiers;
+		&& a->modifiers == b->modifiers
+		&& a->fingers == b->fingers;
 }
 
 struct mousebind *

src/config/rcxml.c

@@ -591,6 +591,9 @@ fill_mousebind(xmlNode *node, const char *context)
 		mousebind->direction = mousebind_direction_from_str(
 			buf, &mousebind->modifiers);
 	}
+	if (lab_xml_get_string(node, "fingers", buf, sizeof(buf))) {
+		mousebind->fingers = atoi(buf);
+	}
 	if (lab_xml_get_string(node, "action", buf, sizeof(buf))) {
 		/* <mousebind button="" action="EVENT"> */
 		mousebind->mouse_event = mousebind_event_from_str(buf);

src/input/gestures.c

@@ -2,10 +2,20 @@
 #include "input/gestures.h"
 #include <wlr/types/wlr_cursor.h>
 #include <wlr/types/wlr_pointer_gestures_v1.h>
+#include "action.h"
 #include "common/macros.h"
+#include "config/mousebind.h"
+#include "config/rcxml.h"
+#include "input/gestures.h"
 #include "labwc.h"
 #include "idle.h"
 
+static struct {
+	double dx;
+	double dy;
+	uint32_t fingers;
+} swipe_state;
+
 static void
 handle_pinch_begin(struct wl_listener *listener, void *data)
 {
@@ -57,6 +67,10 @@ handle_swipe_begin(struct wl_listener *listener, void *data)
 
 	wlr_pointer_gestures_v1_send_swipe_begin(seat->pointer_gestures,
 		seat->seat, event->time_msec, event->fingers);
+
+	swipe_state.dx = 0;
+	swipe_state.dy = 0;
+	swipe_state.fingers = event->fingers;
 }
 
 static void
@@ -70,6 +84,14 @@ handle_swipe_update(struct wl_listener *listener, void *data)
 
 	wlr_pointer_gestures_v1_send_swipe_update(seat->pointer_gestures,
 		seat->seat, event->time_msec, event->dx, event->dy);
+
+	if (swipe_state.fingers == event->fingers) {
+		swipe_state.dx += event->dx;
+		swipe_state.dy += event->dy;
+	} else {
+		swipe_state.dx = 0;
+		swipe_state.dy = 0;
+	}
 }
 
 static void
@@ -83,6 +105,37 @@ handle_swipe_end(struct wl_listener *listener, void *data)
 
 	wlr_pointer_gestures_v1_send_swipe_end(seat->pointer_gestures,
 		seat->seat, event->time_msec, event->cancelled);
+
+	// TODO: check for !event->cancelled ?
+	if (swipe_state.dx || swipe_state.dy) {
+		enum direction direction;
+		if (swipe_state.dx * swipe_state.dx > swipe_state.dy * swipe_state.dy) {
+			direction = swipe_state.dx > 0
+				? LAB_DIRECTION_RIGHT
+				: LAB_DIRECTION_LEFT;
+		} else {
+			direction = swipe_state.dy > 0
+				? LAB_DIRECTION_DOWN
+				: LAB_DIRECTION_UP;
+		}
+		struct mousebind *mousebind;
+		wl_list_for_each(mousebind, &rc.mousebinds, link) {
+			if (mousebind->mouse_event != MOUSE_ACTION_SWIPE) {
+				continue;
+			}
+			if (mousebind->fingers != swipe_state.fingers) {
+				continue;
+			}
+			if (mousebind->direction != direction) {
+				continue;
+			}
+			actions_run(/*view*/ NULL, seat->server,
+				&mousebind->actions, /*cursor_ctx*/ NULL);
+		}
+	}
+	swipe_state.dx = 0;
+	swipe_state.dy = 0;
+	swipe_state.fingers = 0;
 }
 
 static void