Implement some floating move commands

This implements the following for floating containers:

* move <direction> <amount>
* move [absolute] position <x> <y>
* move [absolute] position mouse

include/sway/desktop.h

@@ -1,4 +1,8 @@
 #include <wlr/types/wlr_surface.h>
 
+struct sway_container;
+
 void desktop_damage_surface(struct wlr_surface *surface, double lx, double ly,
 	bool whole);
+
+void desktop_damage_whole_container(struct sway_container *con);

include/sway/output.h

@@ -97,4 +97,6 @@ void output_drag_icons_for_each_surface(struct wl_list *drag_icons,
 	struct sway_output *output, struct root_geometry *geo,
 	wlr_surface_iterator_func_t iterator, void *user_data);
 
+struct sway_container *output_get_active_workspace(struct sway_output *output);
+
 #endif

include/sway/tree/container.h

@@ -297,4 +297,10 @@ bool container_is_floating(struct sway_container *container);
  */
 void container_get_box(struct sway_container *container, struct wlr_box *box);
 
+/**
+ * Move a floating container to a new layout-local position.
+ */
+void container_floating_move_to(struct sway_container *con,
+		double lx, double ly);
+
 #endif

sway/commands/move.c

@@ -1,11 +1,13 @@
 #define _XOPEN_SOURCE 500
 #include <string.h>
 #include <strings.h>
+#include <wlr/types/wlr_cursor.h>
 #include <wlr/types/wlr_output.h>
 #include <wlr/types/wlr_output_layout.h>
 #include <wlr/util/log.h>
 #include "sway/commands.h"
 #include "sway/desktop/transaction.h"
+#include "sway/input/cursor.h"
 #include "sway/input/seat.h"
 #include "sway/output.h"
 #include "sway/tree/arrange.h"
@@ -184,11 +186,49 @@ static struct cmd_results *cmd_move_workspace(struct sway_container *current,
 }
 
 static struct cmd_results *move_in_direction(struct sway_container *container,
-		enum movement_direction direction, int move_amt) {
+		enum movement_direction direction, int argc, char **argv) {
+	int move_amt = 10;
+	if (argc > 1) {
+		char *inv;
+		move_amt = (int)strtol(argv[1], &inv, 10);
+		if (*inv != '\0' && strcasecmp(inv, "px") != 0) {
+			return cmd_results_new(CMD_FAILURE, "move",
+					"Invalid distance specified");
+		}
+	}
+
 	if (container->type == C_WORKSPACE) {
 		return cmd_results_new(CMD_FAILURE, "move",
 				"Cannot move workspaces in a direction");
 	}
+	if (container_is_floating(container)) {
+		if (container->type == C_VIEW && container->sway_view->is_fullscreen) {
+			return cmd_results_new(CMD_FAILURE, "move",
+					"Cannot move fullscreen floating container");
+		}
+		double lx = container->x;
+		double ly = container->y;
+		switch (direction) {
+		case MOVE_LEFT:
+			lx -= move_amt;
+			break;
+		case MOVE_RIGHT:
+			lx += move_amt;
+			break;
+		case MOVE_UP:
+			ly -= move_amt;
+			break;
+		case MOVE_DOWN:
+			ly += move_amt;
+			break;
+		case MOVE_PARENT:
+		case MOVE_CHILD:
+			return cmd_results_new(CMD_FAILURE, "move",
+					"Cannot move floating container to parent or child");
+		}
+		container_floating_move_to(container, lx, ly);
+		return cmd_results_new(CMD_SUCCESS, NULL, NULL);
+	}
 	// For simplicity, we'll arrange the entire workspace. The reason for this
 	// is moving the container might reap the old parent, and container_move
 	// does not return a surviving parent.
@@ -208,31 +248,78 @@ static struct cmd_results *move_in_direction(struct sway_container *container,
 	return cmd_results_new(CMD_SUCCESS, NULL, NULL);
 }
 
+static const char* expected_position_syntax =
+	"Expected 'move [absolute] position <x> <y>' or "
+	"'move [absolute] position mouse'";
+
+static struct cmd_results *move_to_position(struct sway_container *container,
+		int argc, char **argv) {
+	if (!container_is_floating(container)) {
+		return cmd_results_new(CMD_FAILURE, "move",
+				"Only floating containers "
+				"can be moved to an absolute position");
+	}
+	if (!argc) {
+		return cmd_results_new(CMD_FAILURE, "move", expected_position_syntax);
+	}
+	if (strcmp(argv[0], "absolute") == 0) {
+		--argc;
+		++argv;
+	}
+	if (!argc) {
+		return cmd_results_new(CMD_FAILURE, "move", expected_position_syntax);
+	}
+	if (strcmp(argv[0], "position") == 0) {
+		--argc;
+		++argv;
+	}
+	if (!argc) {
+		return cmd_results_new(CMD_FAILURE, "move", expected_position_syntax);
+	}
+	if (strcmp(argv[0], "mouse") == 0) {
+		struct sway_seat *seat = config->handler_context.seat;
+		if (!seat->cursor) {
+			return cmd_results_new(CMD_FAILURE, "move", "No cursor device");
+		}
+		double lx = seat->cursor->cursor->x - container->width / 2;
+		double ly = seat->cursor->cursor->y - container->height / 2;
+		container_floating_move_to(container, lx, ly);
+		return cmd_results_new(CMD_SUCCESS, NULL, NULL);
+	}
+	if (argc != 2) {
+		return cmd_results_new(CMD_FAILURE, "move", expected_position_syntax);
+	}
+	double lx, ly;
+	char *inv;
+	lx = (double)strtol(argv[0], &inv, 10);
+	if (*inv != '\0' && strcasecmp(inv, "px") != 0) {
+		return cmd_results_new(CMD_FAILURE, "move",
+				"Invalid position specified");
+	}
+	ly = (double)strtol(argv[1], &inv, 10);
+	if (*inv != '\0' && strcasecmp(inv, "px") != 0) {
+		return cmd_results_new(CMD_FAILURE, "move",
+				"Invalid position specified");
+	}
+	container_floating_move_to(container, lx, ly);
+	return cmd_results_new(CMD_SUCCESS, NULL, NULL);
+}
+
 struct cmd_results *cmd_move(int argc, char **argv) {
 	struct cmd_results *error = NULL;
-	int move_amt = 10;
 	if ((error = checkarg(argc, "move", EXPECTED_AT_LEAST, 1))) {
 		return error;
 	}
 	struct sway_container *current = config->handler_context.current_container;
 
-	if (argc == 2 || (argc == 3 && strcasecmp(argv[2], "px") == 0)) {
-		char *inv;
-		move_amt = (int)strtol(argv[1], &inv, 10);
-		if (*inv != '\0' && strcasecmp(inv, "px") != 0) {
-			return cmd_results_new(CMD_FAILURE, "move",
-					"Invalid distance specified");
-		}
-	}
-
 	if (strcasecmp(argv[0], "left") == 0) {
-		return move_in_direction(current, MOVE_LEFT, move_amt);
+		return move_in_direction(current, MOVE_LEFT, argc, argv);
 	} else if (strcasecmp(argv[0], "right") == 0) {
-		return move_in_direction(current, MOVE_RIGHT, move_amt);
+		return move_in_direction(current, MOVE_RIGHT, argc, argv);
 	} else if (strcasecmp(argv[0], "up") == 0) {
-		return move_in_direction(current, MOVE_UP, move_amt);
+		return move_in_direction(current, MOVE_UP, argc, argv);
 	} else if (strcasecmp(argv[0], "down") == 0) {
-		return move_in_direction(current, MOVE_DOWN, move_amt);
+		return move_in_direction(current, MOVE_DOWN, argc, argv);
 	} else if (strcasecmp(argv[0], "container") == 0
 			|| strcasecmp(argv[0], "window") == 0) {
 		return cmd_move_container(current, argc, argv);
@@ -244,8 +331,9 @@ struct cmd_results *cmd_move(int argc, char **argv) {
 		// TODO: scratchpad
 		return cmd_results_new(CMD_FAILURE, "move", "Unimplemented");
 	} else if (strcasecmp(argv[0], "position") == 0) {
-		// TODO: floating
-		return cmd_results_new(CMD_FAILURE, "move", "Unimplemented");
+		return move_to_position(current, argc, argv);
+	} else if (strcasecmp(argv[0], "absolute") == 0) {
+		return move_to_position(current, argc, argv);
 	} else {
 		return cmd_results_new(CMD_INVALID, "move", expected_syntax);
 	}

sway/desktop/desktop.c

@@ -13,3 +13,12 @@ void desktop_damage_surface(struct wlr_surface *surface, double lx, double ly,
 		}
 	}
 }
+
+void desktop_damage_whole_container(struct sway_container *con) {
+	for (int i = 0; i < root_container.children->length; ++i) {
+		struct sway_container *cont = root_container.children->items[i];
+		if (cont->type == C_OUTPUT) {
+			output_damage_whole_container(cont->sway_output, con);
+		}
+	}
+}

sway/tree/container.c

@@ -11,11 +11,14 @@
 #include "cairo.h"
 #include "pango.h"
 #include "sway/config.h"
+#include "sway/desktop.h"
+#include "sway/desktop/transaction.h"
 #include "sway/input/input-manager.h"
 #include "sway/input/seat.h"
 #include "sway/ipc-server.h"
 #include "sway/output.h"
 #include "sway/server.h"
+#include "sway/tree/arrange.h"
 #include "sway/tree/layout.h"
 #include "sway/tree/view.h"
 #include "sway/tree/workspace.h"
@@ -989,3 +992,82 @@ void container_get_box(struct sway_container *container, struct wlr_box *box) {
 	box->width = container->width;
 	box->height = container->height;
 }
+
+/**
+ * Translate the container's position as well as all children.
+ */
+static void container_floating_translate(struct sway_container *con,
+		double x_amount, double y_amount) {
+	con->x += x_amount;
+	con->y += y_amount;
+	con->current.swayc_x += x_amount;
+	con->current.swayc_y += y_amount;
+	if (con->type == C_VIEW) {
+		con->sway_view->x += x_amount;
+		con->sway_view->y += y_amount;
+		con->current.view_x += x_amount;
+		con->current.view_y += y_amount;
+	} else {
+		for (int i = 0; i < con->children->length; ++i) {
+			struct sway_container *child = con->children->items[i];
+			container_floating_translate(child, x_amount, y_amount);
+		}
+	}
+}
+
+/**
+ * Choose an output for the floating container's new position.
+ *
+ * If the center of the container intersects an output then we'll choose that
+ * one, otherwise we'll choose whichever output is closest to the container's
+ * center.
+ */
+static struct sway_container *container_floating_find_output(
+		struct sway_container *con) {
+	double center_x = con->x + con->width / 2;
+	double center_y = con->y + con->height / 2;
+	struct sway_container *closest_output = NULL;
+	double closest_distance = DBL_MAX;
+	for (int i = 0; i < root_container.children->length; ++i) {
+		struct sway_container *output = root_container.children->items[i];
+		struct wlr_box output_box;
+		double closest_x, closest_y;
+		container_get_box(output, &output_box);
+		wlr_box_closest_point(&output_box, center_x, center_y,
+				&closest_x, &closest_y);
+		if (center_x == closest_x && center_y == closest_y) {
+			// The center of the floating container is on this output
+			return output;
+		}
+		double x_dist = closest_x - center_x;
+		double y_dist = closest_y - center_y;
+		double distance = x_dist * x_dist + y_dist * y_dist;
+		if (distance < closest_distance) {
+			closest_output = output;
+			closest_distance = distance;
+		}
+	}
+	return closest_output;
+}
+
+void container_floating_move_to(struct sway_container *con,
+		double lx, double ly) {
+	desktop_damage_whole_container(con);
+	container_floating_translate(con, lx - con->x, ly - con->y);
+	desktop_damage_whole_container(con);
+	struct sway_container *old_workspace = container_parent(con, C_WORKSPACE);
+	struct sway_container *new_output = container_floating_find_output(con);
+	if (!sway_assert(new_output, "Unable to find any output")) {
+		return;
+	}
+	struct sway_container *new_workspace =
+		output_get_active_workspace(new_output->sway_output);
+	if (old_workspace != new_workspace) {
+		container_remove_child(con);
+		container_add_child(new_workspace->sway_workspace->floating, con);
+		struct sway_transaction *transaction = transaction_create();
+		arrange_windows(old_workspace, transaction);
+		arrange_windows(new_workspace, transaction);
+		transaction_commit(transaction);
+	}
+}