text: #define _POSIX_C_SOURCE 200809L
  #include <assert.h>
  #include <stdlib.h>
  #include <string.h>
  #include <tgmath.h>
  #include <time.h>
  #include <wayland-server.h>
  #include <wlr/interfaces/wlr_output.h>
  #include <wlr/render/wlr_renderer.h>
  #include <wlr/types/wlr_box.h>
  #include <wlr/types/wlr_matrix.h>
  #include <wlr/types/wlr_output.h>
  #include <wlr/types/wlr_seat.h>
  #include <wlr/types/wlr_surface.h>
  #include <wlr/util/log.h>
  #include <wlr/util/region.h>
  #include "util/signal.h"
  
  #define OUTPUT_VERSION 3
  
  static void output_send_to_resource(struct wl_resource *resource) {
  	struct wlr_output *output = wlr_output_from_resource(resource);
  	const uint32_t version = wl_resource_get_version(resource);
  	if (version >= WL_OUTPUT_GEOMETRY_SINCE_VERSION) {
  		wl_output_send_geometry(resource, output->lx, output->ly,
  			output->phys_width, output->phys_height, output->subpixel,
  			output->make, output->model, output->transform);
  	}
  	if (version >= WL_OUTPUT_MODE_SINCE_VERSION) {
  		struct wlr_output_mode *mode;
  		wl_list_for_each(mode, &output->modes, link) {
  			uint32_t flags = mode->flags & WL_OUTPUT_MODE_PREFERRED;
  			if (output->current_mode == mode) {
  				flags |= WL_OUTPUT_MODE_CURRENT;
  			}
  			wl_output_send_mode(resource, flags, mode->width, mode->height,
  				mode->refresh);
  		}
  
  		if (wl_list_length(&output->modes) == 0) {
  			// Output has no mode, send the current width/height
  			wl_output_send_mode(resource, WL_OUTPUT_MODE_CURRENT,
  				output->width, output->height, output->refresh);
  		}
  	}
  	if (version >= WL_OUTPUT_SCALE_SINCE_VERSION) {
  		wl_output_send_scale(resource, (uint32_t)ceil(output->scale));
  	}
  	if (version >= WL_OUTPUT_DONE_SINCE_VERSION) {
  		wl_output_send_done(resource);
  	}
  }
  
  static void output_send_current_mode_to_resource(
  		struct wl_resource *resource) {
  	struct wlr_output *output = wlr_output_from_resource(resource);
  	const uint32_t version = wl_resource_get_version(resource);
  	if (version < WL_OUTPUT_MODE_SINCE_VERSION) {
  		return;
  	}
  	if (output->current_mode != NULL) {
  		struct wlr_output_mode *mode = output->current_mode;
  		uint32_t flags = mode->flags & WL_OUTPUT_MODE_PREFERRED;
  		wl_output_send_mode(resource, flags | WL_OUTPUT_MODE_CURRENT,
  			mode->width, mode->height, mode->refresh);
  	} else {
  		// Output has no mode
  		wl_output_send_mode(resource, WL_OUTPUT_MODE_CURRENT, output->width,
  			output->height, output->refresh);
  	}
  	if (version >= WL_OUTPUT_DONE_SINCE_VERSION) {
  		wl_output_send_done(resource);
  	}
  }
  
  static void output_handle_resource_destroy(struct wl_resource *resource) {
  	wl_list_remove(wl_resource_get_link(resource));
  }
  
  static void output_handle_release(struct wl_client *client,
  		struct wl_resource *resource) {
  	wl_resource_destroy(resource);
  }
  
  static const struct wl_output_interface output_impl = {
  	.release = output_handle_release,
  };
  
  static void output_bind(struct wl_client *wl_client, void *data,
  		uint32_t version, uint32_t id) {
  	struct wlr_output *output = data;
  
  	struct wl_resource *resource = wl_resource_create(wl_client,
  		&wl_output_interface, version, id);
  	if (resource == NULL) {
  		wl_client_post_no_memory(wl_client);
  		return;
  	}
  	wl_resource_set_implementation(resource, &output_impl, output,
  		output_handle_resource_destroy);
  	wl_list_insert(&output->resources, wl_resource_get_link(resource));
  	output_send_to_resource(resource);
  }
  
  void wlr_output_create_global(struct wlr_output *output) {
  	if (output->global != NULL) {
  		return;
  	}
  	output->global = wl_global_create(output->display,
  		&wl_output_interface, OUTPUT_VERSION, output, output_bind);
  	if (output->global == NULL) {
  		wlr_log(WLR_ERROR, "Failed to allocate wl_output global");
  	}
  }
  
  void wlr_output_destroy_global(struct wlr_output *output) {
  	if (output->global == NULL) {
  		return;
  	}
  	// Make all output resources inert
  	struct wl_resource *resource, *tmp;
  	wl_resource_for_each_safe(resource, tmp, &output->resources) {
  		wl_resource_set_user_data(resource, NULL);
  		wl_list_remove(wl_resource_get_link(resource));
  		wl_list_init(wl_resource_get_link(resource));
  	}
  	wl_global_destroy(output->global);
  	output->global = NULL;
  }
  
  void wlr_output_update_enabled(struct wlr_output *output, bool enabled) {
  	if (output->enabled == enabled) {
  		return;
  	}
  
  	output->enabled = enabled;
  	wlr_signal_emit_safe(&output->events.enable, output);
  }
  
  static void output_update_matrix(struct wlr_output *output) {
  	wlr_matrix_projection(output->transform_matrix, output->width,
  		output->height, output->transform);
  }
  
  void wlr_output_enable(struct wlr_output *output, bool enable) {
  	if (output->enabled == enable) {
  		return;
  	}
  
  	if (output->impl->enable) {
  		output->impl->enable(output, enable);
  	}
  }
  
  bool wlr_output_set_mode(struct wlr_output *output,
  		struct wlr_output_mode *mode) {
  	if (!output->impl || !output->impl->set_mode) {
  		return false;
  	}
  	return output->impl->set_mode(output, mode);
  }
  
  bool wlr_output_set_custom_mode(struct wlr_output *output, int32_t width,
  		int32_t height, int32_t refresh) {
  	if (!output->impl || !output->impl->set_custom_mode) {
  		return false;
  	}
  	return output->impl->set_custom_mode(output, width, height, refresh);
  }
  
  void wlr_output_update_mode(struct wlr_output *output,
  		struct wlr_output_mode *mode) {
  	output->current_mode = mode;
  	wlr_output_update_custom_mode(output, mode->width, mode->height,
  		mode->refresh);
  }
  
  void wlr_output_update_custom_mode(struct wlr_output *output, int32_t width,
  		int32_t height, int32_t refresh) {
  	if (output->width == width && output->height == height &&
  			output->refresh == refresh) {
  		return;
  	}
  
  	output->width = width;
  	output->height = height;
  	output_update_matrix(output);
  
  	output->refresh = refresh;
  
  	struct wl_resource *resource;
  	wl_resource_for_each(resource, &output->resources) {
  		output_send_current_mode_to_resource(resource);
  	}
  
  	wlr_signal_emit_safe(&output->events.mode, output);
  }
  
  void wlr_output_set_transform(struct wlr_output *output,
  		enum wl_output_transform transform) {
  	output->impl->transform(output, transform);
  	output_update_matrix(output);
  
  	// TODO: only send geometry and done
  	struct wl_resource *resource;
  	wl_resource_for_each(resource, &output->resources) {
  		output_send_to_resource(resource);
  	}
  
  	wlr_signal_emit_safe(&output->events.transform, output);
  }
  
  void wlr_output_set_position(struct wlr_output *output, int32_t lx,
  		int32_t ly) {
  	if (lx == output->lx && ly == output->ly) {
  		return;
  	}
  
  	output->lx = lx;
  	output->ly = ly;
  
  	// TODO: only send geometry and done
  	struct wl_resource *resource;
  	wl_resource_for_each(resource, &output->resources) {
  		output_send_to_resource(resource);
  	}
  }
  
  void wlr_output_set_scale(struct wlr_output *output, float scale) {
  	if (output->scale == scale) {
  		return;
  	}
  
  	output->scale = scale;
  
  	// TODO: only send mode and done
  	struct wl_resource *resource;
  	wl_resource_for_each(resource, &output->resources) {
  		output_send_to_resource(resource);
  	}
  
  	wlr_signal_emit_safe(&output->events.scale, output);
  }
  
  static void handle_display_destroy(struct wl_listener *listener, void *data) {
  	struct wlr_output *output =
  		wl_container_of(listener, output, display_destroy);
  	wlr_output_destroy_global(output);
  }
  
  void wlr_output_init(struct wlr_output *output, struct wlr_backend *backend,
  		const struct wlr_output_impl *impl, struct wl_display *display) {
  	assert(impl->make_current && impl->swap_buffers && impl->transform);
  	if (impl->set_cursor || impl->move_cursor) {
  		assert(impl->set_cursor && impl->move_cursor);
  	}
  	output->backend = backend;
  	output->impl = impl;
  	output->display = display;
  	wl_list_init(&output->modes);
  	output->transform = WL_OUTPUT_TRANSFORM_NORMAL;
  	output->scale = 1;
  	wl_list_init(&output->cursors);
  	wl_list_init(&output->resources);
  	wl_signal_init(&output->events.frame);
  	wl_signal_init(&output->events.needs_swap);
  	wl_signal_init(&output->events.swap_buffers);
  	wl_signal_init(&output->events.enable);
  	wl_signal_init(&output->events.mode);
  	wl_signal_init(&output->events.scale);
  	wl_signal_init(&output->events.transform);
  	wl_signal_init(&output->events.destroy);
  	pixman_region32_init(&output->damage);
  
  	output->display_destroy.notify = handle_display_destroy;
  	wl_display_add_destroy_listener(display, &output->display_destroy);
  
  	output->frame_pending = true;
  }
  
  void wlr_output_destroy(struct wlr_output *output) {
  	if (!output) {
  		return;
  	}
  
  	wl_list_remove(&output->display_destroy.link);
  	wlr_output_destroy_global(output);
  	wlr_output_set_fullscreen_surface(output, NULL);
  
  	wlr_signal_emit_safe(&output->events.destroy, output);
  
  	struct wlr_output_mode *mode, *tmp_mode;
  	wl_list_for_each_safe(mode, tmp_mode, &output->modes, link) {
  		wl_list_remove(&mode->link);
  		free(mode);
  	}
  
  	struct wlr_output_cursor *cursor, *tmp_cursor;
  	wl_list_for_each_safe(cursor, tmp_cursor, &output->cursors, link) {
  		wlr_output_cursor_destroy(cursor);
  	}
  
  	pixman_region32_fini(&output->damage);
  
  	if (output->impl && output->impl->destroy) {
  		output->impl->destroy(output);
  	} else {
  		free(output);
  	}
  }
  
  void wlr_output_transformed_resolution(struct wlr_output *output,
  		int *width, int *height) {
  	if (output->transform % 2 == 0) {
  		*width = output->width;
  		*height = output->height;
  	} else {
  		*width = output->height;
  		*height = output->width;
  	}
  }
  
  void wlr_output_effective_resolution(struct wlr_output *output,
  		int *width, int *height) {
  	wlr_output_transformed_resolution(output, width, height);
  	*width /= output->scale;
  	*height /= output->scale;
  }
  
  bool wlr_output_make_current(struct wlr_output *output, int *buffer_age) {
  	return output->impl->make_current(output, buffer_age);
  }
  
  static void output_scissor(struct wlr_output *output, pixman_box32_t *rect) {
  	struct wlr_renderer *renderer = wlr_backend_get_renderer(output->backend);
  	assert(renderer);
  
  	struct wlr_box box = {
  		.x = rect->x1,
  		.y = rect->y1,
  		.width = rect->x2 - rect->x1,
  		.height = rect->y2 - rect->y1,
  	};
  
  	int ow, oh;
  	wlr_output_transformed_resolution(output, &ow, &oh);
  
  	// Scissor is in renderer coordinates, ie. upside down
  	enum wl_output_transform transform =
  		wlr_output_transform_invert(output->transform);
  	wlr_box_transform(&box, transform, ow, oh, &box);
  
  	wlr_renderer_scissor(renderer, &box);
  }
  
  static void output_fullscreen_surface_get_box(struct wlr_output *output,
  		struct wlr_surface *surface, struct wlr_box *box) {
  	int width, height;
  	wlr_output_effective_resolution(output, &width, &height);
  
  	int x = (width - surface->current.width) / 2;
  	int y = (height - surface->current.height) / 2;
  
  	box->x = x * output->scale;
  	box->y = y * output->scale;
  	box->width = surface->current.width * output->scale;
  	box->height = surface->current.height * output->scale;
  }
  
  static void output_fullscreen_surface_render(struct wlr_output *output,
  		struct wlr_surface *surface, const struct timespec *when,
  		pixman_region32_t *damage) {
  	struct wlr_renderer *renderer = wlr_backend_get_renderer(output->backend);
  	assert(renderer);
  
  	struct wlr_texture *texture = wlr_surface_get_texture(surface);
  	if (texture == NULL) {
  		wlr_renderer_clear(renderer, (float[]){0, 0, 0, 1});
  		return;
  	}
  
  	struct wlr_box box;
  	output_fullscreen_surface_get_box(output, surface, &box);
  
  	float matrix[9];
  	enum wl_output_transform transform =
  		wlr_output_transform_invert(surface->current.transform);
  	wlr_matrix_project_box(matrix, &box, transform, 0,
  		output->transform_matrix);
  
  	int nrects;
  	pixman_box32_t *rects = pixman_region32_rectangles(damage, &nrects);
  	for (int i = 0; i < nrects; ++i) {
  		output_scissor(output, &rects[i]);
  		wlr_renderer_clear(renderer, (float[]){0, 0, 0, 1});
  		wlr_render_texture_with_matrix(surface->renderer, texture, matrix, 1.0f);
  	}
  	wlr_renderer_scissor(renderer, NULL);
  
  	wlr_surface_send_frame_done(surface, when);
  }
  
  /**
   * Returns the cursor box, scaled for its output.
   */
  static void output_cursor_get_box(struct wlr_output_cursor *cursor,
  		struct wlr_box *box) {
  	box->x = cursor->x - cursor->hotspot_x;
  	box->y = cursor->y - cursor->hotspot_y;
  	box->width = cursor->width;
  	box->height = cursor->height;
  }
  
  static void output_cursor_render(struct wlr_output_cursor *cursor,
  		const struct timespec *when, pixman_region32_t *damage) {
  	struct wlr_renderer *renderer =
  		wlr_backend_get_renderer(cursor->output->backend);
  	assert(renderer);
  
  	struct wlr_texture *texture = cursor->texture;
  	if (cursor->surface != NULL) {
  		texture = wlr_surface_get_texture(cursor->surface);
  	}
  	if (texture == NULL) {
  		return;
  	}
  
  	struct wlr_box box;
  	output_cursor_get_box(cursor, &box);
  
  	pixman_region32_t surface_damage;
  	pixman_region32_init(&surface_damage);
  	pixman_region32_union_rect(&surface_damage, &surface_damage, box.x, box.y,
  		box.width, box.height);
  	pixman_region32_intersect(&surface_damage, &surface_damage, damage);
  	if (!pixman_region32_not_empty(&surface_damage)) {
  		goto surface_damage_finish;
  	}
  
  	float matrix[9];
  	wlr_matrix_project_box(matrix, &box, WL_OUTPUT_TRANSFORM_NORMAL, 0,
  		cursor->output->transform_matrix);
  
  	int nrects;
  	pixman_box32_t *rects = pixman_region32_rectangles(&surface_damage, &nrects);
  	for (int i = 0; i < nrects; ++i) {
  		output_scissor(cursor->output, &rects[i]);
  		wlr_render_texture_with_matrix(renderer, texture, matrix, 1.0f);
  	}
  	wlr_renderer_scissor(renderer, NULL);
  
  	if (cursor->surface != NULL) {
  		wlr_surface_send_frame_done(cursor->surface, when);
  	}
  
  surface_damage_finish:
  	pixman_region32_fini(&surface_damage);
  }
  
  bool wlr_output_swap_buffers(struct wlr_output *output, struct timespec *when,
  		pixman_region32_t *damage) {
  	if (output->frame_pending) {
  		wlr_log(WLR_ERROR, "Tried to swap buffers when a frame is pending");
  		return false;
  	}
  	if (output->idle_frame != NULL) {
  		wl_event_source_remove(output->idle_frame);
  		output->idle_frame = NULL;
  	}
  
  	struct wlr_output_event_swap_buffers event = {
  		.output = output,
  		.when = when,
  		.damage = damage,
  	};
  	wlr_signal_emit_safe(&output->events.swap_buffers, &event);
  
  	int width, height;
  	wlr_output_transformed_resolution(output, &width, &height);
  
  	pixman_region32_t render_damage;
  	pixman_region32_init(&render_damage);
  	pixman_region32_union_rect(&render_damage, &render_damage, 0, 0,
  		width, height);
  	if (damage != NULL) {
  		// Damage tracking supported
  		pixman_region32_intersect(&render_damage, &render_damage, damage);
  	}
  
  	struct timespec now;
  	if (when == NULL) {
  		clock_gettime(CLOCK_MONOTONIC, &now);
  		when = &now;
  	}
  
  	if (pixman_region32_not_empty(&render_damage)) {
  		if (output->fullscreen_surface != NULL) {
  			output_fullscreen_surface_render(output, output->fullscreen_surface,
  				when, &render_damage);
  		}
  
  		struct wlr_output_cursor *cursor;
  		wl_list_for_each(cursor, &output->cursors, link) {
  			if (!cursor->enabled || !cursor->visible ||
  					output->hardware_cursor == cursor) {
  				continue;
  			}
  			output_cursor_render(cursor, when, &render_damage);
  		}
  	}
  
  	// Transform damage into renderer coordinates, ie. upside down
  	enum wl_output_transform transform = wlr_output_transform_compose(
  		wlr_output_transform_invert(output->transform),
  		WL_OUTPUT_TRANSFORM_FLIPPED_180);
  	wlr_region_transform(&render_damage, &render_damage, transform, width,
  		height);
  
  	if (!output->impl->swap_buffers(output, damage ? &render_damage : NULL)) {
  		return false;
  	}
  
  	output->frame_pending = true;
  	output->needs_swap = false;
  	pixman_region32_clear(&output->damage);
  
  	pixman_region32_fini(&render_damage);
  	return true;
  }
  
  void wlr_output_send_frame(struct wlr_output *output) {
  	output->frame_pending = false;
  	wlr_signal_emit_safe(&output->events.frame, output);
  }
  
  static void schedule_frame_handle_idle_timer(void *data) {
  	struct wlr_output *output = data;
  	output->idle_frame = NULL;
  	if (!output->frame_pending) {
  		wlr_output_send_frame(output);
  	}
  }
  
  void wlr_output_schedule_frame(struct wlr_output *output) {
  	if (output->frame_pending || output->idle_frame != NULL) {
  		return;
  	}
  
  	// TODO: ask the backend to send a frame event when appropriate instead
  	struct wl_event_loop *ev = wl_display_get_event_loop(output->display);
  	output->idle_frame =
  		wl_event_loop_add_idle(ev, schedule_frame_handle_idle_timer, output);
  }
  
  void wlr_output_set_gamma(struct wlr_output *output,
  	uint32_t size, uint16_t *r, uint16_t *g, uint16_t *b) {
  	if (output->impl->set_gamma) {
  		output->impl->set_gamma(output, size, r, g, b);
  	}
  }
  
  uint32_t wlr_output_get_gamma_size(struct wlr_output *output) {
  	if (!output->impl->get_gamma_size) {
  		return 0;
  	}
  	return output->impl->get_gamma_size(output);
  }
  
  bool wlr_output_export_dmabuf(struct wlr_output *output,
  		struct wlr_dmabuf_attributes *attribs) {
  	if (!output->impl->export_dmabuf) {
  		return false;
  	}
  	return output->impl->export_dmabuf(output, attribs);
  }
  
  void wlr_output_update_needs_swap(struct wlr_output *output) {
  	output->needs_swap = true;
  	wlr_signal_emit_safe(&output->events.needs_swap, output);
  }
  
  void wlr_output_damage_whole(struct wlr_output *output) {
  	int width, height;
  	wlr_output_transformed_resolution(output, &width, &height);
  
  	pixman_region32_union_rect(&output->damage, &output->damage, 0, 0,
  		width, height);
  	wlr_output_update_needs_swap(output);
  }
  
  static void output_fullscreen_surface_reset(struct wlr_output *output) {
  	if (output->fullscreen_surface != NULL) {
  		wl_list_remove(&output->fullscreen_surface_commit.link);
  		wl_list_remove(&output->fullscreen_surface_destroy.link);
  		output->fullscreen_surface = NULL;
  		wlr_output_damage_whole(output);
  	}
  }
  
  static void output_fullscreen_surface_handle_commit(
  		struct wl_listener *listener, void *data) {
  	struct wlr_output *output = wl_container_of(listener, output,
  		fullscreen_surface_commit);
  	struct wlr_surface *surface = output->fullscreen_surface;
  
  	if (output->fullscreen_width != surface->current.width ||
  			output->fullscreen_height != surface->current.height) {
  		output->fullscreen_width = surface->current.width;
  		output->fullscreen_height = surface->current.height;
  		wlr_output_damage_whole(output);
  		return;
  	}
  
  	struct wlr_box box;
  	output_fullscreen_surface_get_box(output, surface, &box);
  
  	pixman_region32_t damage;
  	pixman_region32_init(&damage);
  	pixman_region32_copy(&damage, &surface->current.surface_damage);
  	wlr_region_scale(&damage, &damage, output->scale);
  	pixman_region32_translate(&damage, box.x, box.y);
  	pixman_region32_union(&output->damage, &output->damage, &damage);
  	pixman_region32_fini(&damage);
  
  	wlr_output_update_needs_swap(output);
  }
  
  static void output_fullscreen_surface_handle_destroy(
  		struct wl_listener *listener, void *data) {
  	struct wlr_output *output = wl_container_of(listener, output,
  		fullscreen_surface_destroy);
  	output_fullscreen_surface_reset(output);
  }
  
  void wlr_output_set_fullscreen_surface(struct wlr_output *output,
  		struct wlr_surface *surface) {
  	// TODO: hardware fullscreen
  
  	if (output->fullscreen_surface == surface) {
  		return;
  	}
  
  	output_fullscreen_surface_reset(output);
  
  	output->fullscreen_surface = surface;
  	wlr_output_damage_whole(output);
  
  	if (surface == NULL) {
  		return;
  	}
  
  	output->fullscreen_surface_commit.notify =
  		output_fullscreen_surface_handle_commit;
  	wl_signal_add(&surface->events.commit, &output->fullscreen_surface_commit);
  	output->fullscreen_surface_destroy.notify =
  		output_fullscreen_surface_handle_destroy;
  	wl_signal_add(&surface->events.destroy,
  		&output->fullscreen_surface_destroy);
  }
  
  struct wlr_output *wlr_output_from_resource(struct wl_resource *resource) {
  	assert(wl_resource_instance_of(resource, &wl_output_interface,
  		&output_impl));
  	return wl_resource_get_user_data(resource);
  }
  
  
  static void output_cursor_damage_whole(struct wlr_output_cursor *cursor) {
  	struct wlr_box box;
  	output_cursor_get_box(cursor, &box);
  	pixman_region32_union_rect(&cursor->output->damage, &cursor->output->damage,
  		box.x, box.y, box.width, box.height);
  	wlr_output_update_needs_swap(cursor->output);
  }
  
  static void output_cursor_reset(struct wlr_output_cursor *cursor) {
  	if (cursor->output->hardware_cursor != cursor) {
  		output_cursor_damage_whole(cursor);
  	}
  	if (cursor->surface != NULL) {
  		wl_list_remove(&cursor->surface_commit.link);
  		wl_list_remove(&cursor->surface_destroy.link);
  		cursor->surface = NULL;
  	}
  }
  
  static void output_cursor_update_visible(struct wlr_output_cursor *cursor) {
  	struct wlr_box output_box;
  	output_box.x = output_box.y = 0;
  	wlr_output_transformed_resolution(cursor->output, &output_box.width,
  		&output_box.height);
  
  	struct wlr_box cursor_box;
  	output_cursor_get_box(cursor, &cursor_box);
  
  	struct wlr_box intersection;
  	bool visible =
  		wlr_box_intersection(&output_box, &cursor_box, &intersection);
  
  	if (cursor->surface != NULL) {
  		if (cursor->visible && !visible) {
  			wlr_surface_send_leave(cursor->surface, cursor->output);
  		}
  		if (!cursor->visible && visible) {
  			wlr_surface_send_enter(cursor->surface, cursor->output);
  		}
  	}
  
  	cursor->visible = visible;
  }
  
  static bool output_cursor_attempt_hardware(struct wlr_output_cursor *cursor) {
  	int32_t scale = cursor->output->scale;
  	enum wl_output_transform transform = WL_OUTPUT_TRANSFORM_NORMAL;
  	struct wlr_texture *texture = cursor->texture;
  	if (cursor->surface != NULL) {
  		texture = wlr_surface_get_texture(cursor->surface);
  		scale = cursor->surface->current.scale;
  		transform = cursor->surface->current.transform;
  	}
  
  	struct wlr_output_cursor *hwcur = cursor->output->hardware_cursor;
  	if (cursor->output->impl->set_cursor && (hwcur == NULL || hwcur == cursor)) {
  		// If the cursor was hidden or was a software cursor, the hardware
  		// cursor position is outdated
  		assert(cursor->output->impl->move_cursor);
  		cursor->output->impl->move_cursor(cursor->output,
  			(int)cursor->x, (int)cursor->y);
  		if (cursor->output->impl->set_cursor(cursor->output, texture,
  				scale, transform, cursor->hotspot_x, cursor->hotspot_y, true)) {
  			cursor->output->hardware_cursor = cursor;
  			return true;
  		}
  	}
  	return false;
  }
  
  bool wlr_output_cursor_set_image(struct wlr_output_cursor *cursor,
  		const uint8_t *pixels, int32_t stride, uint32_t width, uint32_t height,
  		int32_t hotspot_x, int32_t hotspot_y) {
  	struct wlr_renderer *renderer =
  		wlr_backend_get_renderer(cursor->output->backend);
  	assert(renderer);
  
  	output_cursor_reset(cursor);
  
  	cursor->width = width;
  	cursor->height = height;
  	cursor->hotspot_x = hotspot_x;
  	cursor->hotspot_y = hotspot_y;
  	output_cursor_update_visible(cursor);
  
  	wlr_texture_destroy(cursor->texture);
  	cursor->texture = NULL;
  
  	cursor->enabled = false;
  	if (pixels != NULL) {
  		cursor->texture = wlr_texture_from_pixels(renderer,
  			WL_SHM_FORMAT_ARGB8888, stride, width, height, pixels);
  		if (cursor->texture == NULL) {
  			return false;
  		}
  		cursor->enabled = true;
  	}
  
  	if (output_cursor_attempt_hardware(cursor)) {
  		return true;
  	}
  
  	wlr_log(WLR_DEBUG, "Falling back to software cursor");
  	output_cursor_damage_whole(cursor);
  	return true;
  }
  
  static void output_cursor_commit(struct wlr_output_cursor *cursor,
  		bool update_hotspot) {
  	if (cursor->output->hardware_cursor != cursor) {
  		output_cursor_damage_whole(cursor);
  	}
  
  	struct wlr_surface *surface = cursor->surface;
  	assert(surface != NULL);
  
  	// Some clients commit a cursor surface with a NULL buffer to hide it.
  	cursor->enabled = wlr_surface_has_buffer(surface);
  	cursor->width = surface->current.width * cursor->output->scale;
  	cursor->height = surface->current.height * cursor->output->scale;
  	if (update_hotspot) {
  		cursor->hotspot_x -= surface->current.dx * cursor->output->scale;
  		cursor->hotspot_y -= surface->current.dy * cursor->output->scale;
  	}
  
  	if (output_cursor_attempt_hardware(cursor)) {
  		struct timespec now;
  		clock_gettime(CLOCK_MONOTONIC, &now);
  		wlr_surface_send_frame_done(surface, &now);
  		return;
  	}
  
  	// Fallback to software cursor
  	output_cursor_damage_whole(cursor);
  }
  
  static void output_cursor_handle_commit(struct wl_listener *listener,
  		void *data) {
  	struct wlr_output_cursor *cursor =
  		wl_container_of(listener, cursor, surface_commit);
  	output_cursor_commit(cursor, true);
  }
  
  static void output_cursor_handle_destroy(struct wl_listener *listener,
  		void *data) {
  	struct wlr_output_cursor *cursor = wl_container_of(listener, cursor,
  		surface_destroy);
  	output_cursor_reset(cursor);
  }
  
  void wlr_output_cursor_set_surface(struct wlr_output_cursor *cursor,
  		struct wlr_surface *surface, int32_t hotspot_x, int32_t hotspot_y) {
  	if (surface && !wlr_surface_is_pointer_cursor(surface)) {
  		wlr_log(WLR_ERROR, "Tried to set a cursor surface with invalid role");
  		return;
  	}
  
  	hotspot_x *= cursor->output->scale;
  	hotspot_y *= cursor->output->scale;
  
  	if (surface && surface == cursor->surface) {
  		// Only update the hotspot: surface hasn't changed
  
  		if (cursor->output->hardware_cursor != cursor) {
  			output_cursor_damage_whole(cursor);
  		}
  		cursor->hotspot_x = hotspot_x;
  		cursor->hotspot_y = hotspot_y;
  		if (cursor->output->hardware_cursor != cursor) {
  			output_cursor_damage_whole(cursor);
  		} else {
  			assert(cursor->output->impl->set_cursor);
  			cursor->output->impl->set_cursor(cursor->output, NULL,
  				1, WL_OUTPUT_TRANSFORM_NORMAL, hotspot_x, hotspot_y, false);
  		}
  		return;
  	}
  
  	output_cursor_reset(cursor);
  
  	cursor->surface = surface;
  	cursor->hotspot_x = hotspot_x;
  	cursor->hotspot_y = hotspot_y;
  
  	if (surface != NULL) {
  		wl_signal_add(&surface->events.commit, &cursor->surface_commit);
  		wl_signal_add(&surface->events.destroy, &cursor->surface_destroy);
  		output_cursor_commit(cursor, false);
  
  		cursor->visible = false;
  		output_cursor_update_visible(cursor);
  	} else {
  		cursor->enabled = false;
  		cursor->width = 0;
  		cursor->height = 0;
  
  		if (cursor->output->hardware_cursor == cursor) {
  			assert(cursor->output->impl->set_cursor);
  			cursor->output->impl->set_cursor(cursor->output, NULL, 1,
  				WL_OUTPUT_TRANSFORM_NORMAL, 0, 0, true);
  		}
  	}
  }
  
  bool wlr_output_cursor_move(struct wlr_output_cursor *cursor,
  		double x, double y) {
  	if (cursor->x == x && cursor->y == y) {
  		return true;
  	}
  
  	if (cursor->output->hardware_cursor != cursor) {
  		output_cursor_damage_whole(cursor);
  	}
  
  	bool was_visible = cursor->visible;
  	x *= cursor->output->scale;
  	y *= cursor->output->scale;
  	cursor->x = x;
  	cursor->y = y;
  	output_cursor_update_visible(cursor);
  
  	if (!was_visible && !cursor->visible) {
  		// Cursor is still hidden, do nothing
  		return true;
  	}
  
  	if (cursor->output->hardware_cursor != cursor) {
  		output_cursor_damage_whole(cursor);
  		return true;
  	}
  
  	assert(cursor->output->impl->move_cursor);
  	return cursor->output->impl->move_cursor(cursor->output, (int)x, (int)y);
  }
  
  struct wlr_output_cursor *wlr_output_cursor_create(struct wlr_output *output) {
  	struct wlr_output_cursor *cursor =
  		calloc(1, sizeof(struct wlr_output_cursor));
  	if (cursor == NULL) {
  		return NULL;
  	}
  	cursor->output = output;
  	wl_signal_init(&cursor->events.destroy);
  	wl_list_init(&cursor->surface_commit.link);
  	cursor->surface_commit.notify = output_cursor_handle_commit;
  	wl_list_init(&cursor->surface_destroy.link);
  	cursor->surface_destroy.notify = output_cursor_handle_destroy;
  	wl_list_insert(&output->cursors, &cursor->link);
  	cursor->visible = true; // default position is at (0, 0)
  	return cursor;
  }
  
  void wlr_output_cursor_destroy(struct wlr_output_cursor *cursor) {
  	if (cursor == NULL) {
  		return;
  	}
  	output_cursor_reset(cursor);
  	wlr_signal_emit_safe(&cursor->events.destroy, cursor);
  	if (cursor->output->hardware_cursor == cursor) {
  		// If this cursor was the hardware cursor, disable it
  		if (cursor->output->impl->set_cursor) {
  			cursor->output->impl->set_cursor(cursor->output, NULL, 1,
  				WL_OUTPUT_TRANSFORM_NORMAL, 0, 0, true);
  		}
  		cursor->output->hardware_cursor = NULL;
  	}
  	wlr_texture_destroy(cursor->texture);
  	wl_list_remove(&cursor->link);
  	free(cursor);
  }
  
  
  enum wl_output_transform wlr_output_transform_invert(
  		enum wl_output_transform tr) {
  	if ((tr & WL_OUTPUT_TRANSFORM_90) && !(tr & WL_OUTPUT_TRANSFORM_FLIPPED)) {
  		tr ^= WL_OUTPUT_TRANSFORM_180;
  	}
  	return tr;
  }
  
  enum wl_output_transform wlr_output_transform_compose(
  		enum wl_output_transform tr_a, enum wl_output_transform tr_b) {
  	uint32_t flipped = (tr_a ^ tr_b) & WL_OUTPUT_TRANSFORM_FLIPPED;
  	uint32_t rotated =
  		(tr_a + tr_b) & (WL_OUTPUT_TRANSFORM_90 | WL_OUTPUT_TRANSFORM_180);
  	return flipped | rotated;
  }
  