Refactor seat operations to use an interface

This splits each seat operation (drag/move tiling/floating etc) into a
separate file and introduces a struct sway_seatop_impl to abstract the
operation.

The move_tiling_threshold operation has been merged into move_tiling.

The main logic for each operation is untouched aside from variable
renames.

The following previously-static functions have been made public:
* node_at_coords
* container_raise_floating
* render_rect
* premultiply_alpha
* scale_box

1 files changed, 77 insertions, 0 deletions

diff --git a/sway/input/seatop_down.c b/sway/input/seatop_down.c
new file mode 100644
index 00000000..ad11c5ca
--- /dev/null
+++ b/sway/input/seatop_down.c
@@ -0,0 +1,77 @@
+#define _POSIX_C_SOURCE 200809L
+#include <wlr/types/wlr_cursor.h>
+#include "sway/input/cursor.h"
+#include "sway/input/seat.h"
+#include "sway/tree/view.h"
+
+struct seatop_down_event {
+	struct sway_container *con;
+	double ref_lx, ref_ly;         // cursor's x/y at start of op
+	double ref_con_lx, ref_con_ly; // container's x/y at start of op
+	bool moved;
+};
+
+static void handle_motion(struct sway_seat *seat, uint32_t time_msec) {
+	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_seat_pointer_notify_motion(seat->wlr_seat, time_msec, sx, sy);
+	}
+	e->moved = true;
+}
+
+static void handle_finish(struct sway_seat *seat) {
+	struct seatop_down_event *e = seat->seatop_data;
+	// Set the cursor's previous coords to the x/y at the start of the
+	// operation, so the container change will be detected if using
+	// focus_follows_mouse and the cursor moved off the original container
+	// during the operation.
+	seat->cursor->previous.x = e->ref_lx;
+	seat->cursor->previous.y = e->ref_ly;
+	if (e->moved) {
+		cursor_send_pointer_motion(seat->cursor, 0);
+	}
+}
+
+static void handle_abort(struct sway_seat *seat) {
+	cursor_set_image(seat->cursor, "left_ptr", NULL);
+}
+
+static void handle_unref(struct sway_seat *seat, struct sway_container *con) {
+	struct seatop_down_event *e = seat->seatop_data;
+	if (e->con == con) {
+		seatop_abort(seat);
+	}
+}
+
+static const struct sway_seatop_impl seatop_impl = {
+	.motion = handle_motion,
+	.finish = handle_finish,
+	.abort = handle_abort,
+	.unref = handle_unref,
+};
+
+void seatop_begin_down(struct sway_seat *seat,
+		struct sway_container *con, uint32_t button, int sx, int sy) {
+	seatop_abort(seat);
+
+	struct seatop_down_event *e =
+		calloc(1, sizeof(struct seatop_down_event));
+	if (!e) {
+		return;
+	}
+	e->con = con;
+	e->ref_lx = seat->cursor->cursor->x;
+	e->ref_ly = seat->cursor->cursor->y;
+	e->ref_con_lx = sx;
+	e->ref_con_ly = sy;
+	e->moved = false;
+
+	seat->seatop_impl = &seatop_impl;
+	seat->seatop_data = e;
+	seat->seatop_button = button;
+}