libweston/compositor.c

/*
 * Copyright © 2010-2011 Intel Corporation
 * Copyright © 2008-2011 Kristian Høgsberg
 * Copyright © 2012-2018 Collabora, Ltd.
 * Copyright © 2017, 2018 General Electric Company
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice (including the
 * next paragraph) shall be included in all copies or substantial
 * portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT.  IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#include "config.h"

#include <fcntl.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <stdint.h>
#include <limits.h>
#include <stdarg.h>
#include <assert.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <sys/wait.h>
#include <sys/socket.h>
#include <sys/utsname.h>
#include <sys/stat.h>
#include <unistd.h>
#include <math.h>
#include <linux/input.h>
#include <dlfcn.h>
#include <signal.h>
#include <setjmp.h>
#include <sys/time.h>
#include <time.h>
#include <errno.h>

#include "timeline.h"

#include "compositor.h"
#include "alpha-compositing-unstable-v1-server-protocol.h"
#include "viewporter-server-protocol.h"
#include "presentation-time-server-protocol.h"
#include "shared/helpers.h"
#include "shared/os-compatibility.h"
#include "shared/string-helpers.h"
#include "shared/timespec-util.h"
#include "git-version.h"
#include "version.h"
#include "plugin-registry.h"

#define DEFAULT_REPAINT_WINDOW 16 /* milliseconds */

static void
weston_output_update_matrix(struct weston_output *output);

static void
weston_output_transform_scale_init(struct weston_output *output,
				   uint32_t transform, uint32_t scale);

static void
weston_compositor_build_view_list(struct weston_compositor *compositor);

static char *
weston_output_create_heads_string(struct weston_output *output);

/** Send wl_output events for mode and scale changes
 *
 * \param head Send on all resources bound to this head.
 * \param mode_changed If true, send the current mode.
 * \param scale_changed If true, send the current scale.
 */
static void
weston_mode_switch_send_events(struct weston_head *head,
			       bool mode_changed, bool scale_changed)
{
	struct weston_output *output = head->output;
	struct wl_resource *resource;
	int version;

	wl_resource_for_each(resource, &head->resource_list) {
		if (mode_changed) {
			wl_output_send_mode(resource,
					    output->current_mode->flags,
					    output->current_mode->width,
					    output->current_mode->height,
					    output->current_mode->refresh);
		}

		version = wl_resource_get_version(resource);
		if (version >= WL_OUTPUT_SCALE_SINCE_VERSION && scale_changed)
			wl_output_send_scale(resource, output->current_scale);

		if (version >= WL_OUTPUT_DONE_SINCE_VERSION)
			wl_output_send_done(resource);
	}
}

static void
weston_mode_switch_finish(struct weston_output *output,
			  int mode_changed, int scale_changed)
{
	struct weston_seat *seat;
	struct weston_head *head;
	pixman_region32_t old_output_region;

	pixman_region32_init(&old_output_region);
	pixman_region32_copy(&old_output_region, &output->region);

	/* Update output region and transformation matrix */
	weston_output_transform_scale_init(output, output->transform, output->current_scale);

	pixman_region32_init(&output->previous_damage);
	pixman_region32_init_rect(&output->region, output->x, output->y,
				  output->width, output->height);

	weston_output_update_matrix(output);

	/* If a pointer falls outside the outputs new geometry, move it to its
	 * lower-right corner */
	wl_list_for_each(seat, &output->compositor->seat_list, link) {
		struct weston_pointer *pointer = weston_seat_get_pointer(seat);
		int32_t x, y;

		if (!pointer)
			continue;

		x = wl_fixed_to_int(pointer->x);
		y = wl_fixed_to_int(pointer->y);

		if (!pixman_region32_contains_point(&old_output_region,
						    x, y, NULL) ||
		    pixman_region32_contains_point(&output->region,
						   x, y, NULL))
			continue;

		if (x >= output->x + output->width)
			x = output->x + output->width - 1;
		if (y >= output->y + output->height)
			y = output->y + output->height - 1;

		pointer->x = wl_fixed_from_int(x);
		pointer->y = wl_fixed_from_int(y);
	}

	pixman_region32_fini(&old_output_region);

	if (!mode_changed && !scale_changed)
		return;

	/* notify clients of the changes */
	wl_list_for_each(head, &output->head_list, output_link)
		weston_mode_switch_send_events(head,
					       mode_changed, scale_changed);
}

static void
weston_compositor_reflow_outputs(struct weston_compositor *compositor,
				struct weston_output *resized_output, int delta_width);

WL_EXPORT int
weston_output_mode_set_native(struct weston_output *output,
			      struct weston_mode *mode,
			      int32_t scale)
{
	int ret;
	int mode_changed = 0, scale_changed = 0;
	int32_t old_width;

	if (!output->switch_mode)
		return -1;

	if (!output->original_mode) {
		mode_changed = 1;
		ret = output->switch_mode(output, mode);
		if (ret < 0)
			return ret;
		if (output->current_scale != scale) {
			scale_changed = 1;
			output->current_scale = scale;
		}
	}

	old_width = output->width;
	output->native_mode = mode;
	output->native_scale = scale;

	weston_mode_switch_finish(output, mode_changed, scale_changed);

	if (mode_changed || scale_changed) {
		weston_compositor_reflow_outputs(output->compositor, output, output->width - old_width);

		wl_signal_emit(&output->compositor->output_resized_signal, output);
	}
	return 0;
}

WL_EXPORT int
weston_output_mode_switch_to_native(struct weston_output *output)
{
	int ret;
	int mode_changed = 0, scale_changed = 0;

	if (!output->switch_mode)
		return -1;

	if (!output->original_mode) {
		weston_log("already in the native mode\n");
		return -1;
	}
	/* the non fullscreen clients haven't seen a mode set since we
	 * switched into a temporary, so we need to notify them if the
	 * mode at that time is different from the native mode now.
	 */
	mode_changed = (output->original_mode != output->native_mode);
	scale_changed = (output->original_scale != output->native_scale);

	ret = output->switch_mode(output, output->native_mode);
	if (ret < 0)
		return ret;

	output->current_scale = output->native_scale;

	output->original_mode = NULL;
	output->original_scale = 0;

	weston_mode_switch_finish(output, mode_changed, scale_changed);

	return 0;
}

WL_EXPORT int
weston_output_mode_switch_to_temporary(struct weston_output *output,
				       struct weston_mode *mode,
				       int32_t scale)
{
	int ret;

	if (!output->switch_mode)
		return -1;

	/* original_mode is the last mode non full screen clients have seen,
	 * so we shouldn't change it if we already have one set.
	 */
	if (!output->original_mode) {
		output->original_mode = output->native_mode;
		output->original_scale = output->native_scale;
	}
	ret = output->switch_mode(output, mode);
	if (ret < 0)
		return ret;

	output->current_scale = scale;

	weston_mode_switch_finish(output, 0, 0);

	return 0;
}

static void
region_init_infinite(pixman_region32_t *region)
{
	pixman_region32_init_rect(region, INT32_MIN, INT32_MIN,
				  UINT32_MAX, UINT32_MAX);
}

static struct weston_subsurface *
weston_surface_to_subsurface(struct weston_surface *surface);

WL_EXPORT struct weston_view *
weston_view_create(struct weston_surface *surface)
{
	struct weston_view *view;

	view = zalloc(sizeof *view);
	if (view == NULL)
		return NULL;

	view->surface = surface;
	view->plane = &surface->compositor->primary_plane;

	/* Assign to surface */
	wl_list_insert(&surface->views, &view->surface_link);

	wl_signal_init(&view->destroy_signal);
	wl_list_init(&view->link);
	wl_list_init(&view->layer_link.link);

	pixman_region32_init(&view->clip);

	view->alpha = 1.0;
	view->blending_alpha = 1.0;
	view->blending_equation = ZWP_BLENDING_V1_BLENDING_EQUATION_NONE;
	pixman_region32_init(&view->transform.opaque);

	wl_list_init(&view->geometry.transformation_list);
	wl_list_insert(&view->geometry.transformation_list,
		       &view->transform.position.link);
	weston_matrix_init(&view->transform.position.matrix);
	wl_list_init(&view->geometry.child_list);
	pixman_region32_init(&view->geometry.scissor);
	pixman_region32_init(&view->transform.boundingbox);
	view->transform.dirty = 1;

	return view;
}

struct weston_frame_callback {
	struct wl_resource *resource;
	struct wl_list link;
};

struct weston_presentation_feedback {
	struct wl_resource *resource;

	/* XXX: could use just wl_resource_get_link() instead */
	struct wl_list link;

	/* The per-surface feedback flags */
	uint32_t psf_flags;
};

static void
weston_presentation_feedback_discard(
		struct weston_presentation_feedback *feedback)
{
	wp_presentation_feedback_send_discarded(feedback->resource);
	wl_resource_destroy(feedback->resource);
}

static void
weston_presentation_feedback_discard_list(struct wl_list *list)
{
	struct weston_presentation_feedback *feedback, *tmp;

	wl_list_for_each_safe(feedback, tmp, list, link)
		weston_presentation_feedback_discard(feedback);
}

static void
weston_presentation_feedback_present(
		struct weston_presentation_feedback *feedback,
		struct weston_output *output,
		uint32_t refresh_nsec,
		const struct timespec *ts,
		uint64_t seq,
		uint32_t flags)
{
	struct wl_client *client = wl_resource_get_client(feedback->resource);
	struct weston_head *head;
	struct wl_resource *o;
	uint32_t tv_sec_hi;
	uint32_t tv_sec_lo;
	uint32_t tv_nsec;
	bool done = false;

	wl_list_for_each(head, &output->head_list, output_link) {
		wl_resource_for_each(o, &head->resource_list) {
			if (wl_resource_get_client(o) != client)
				continue;

			wp_presentation_feedback_send_sync_output(feedback->resource, o);
			done = true;
		}

		/* For clone mode, send it for just one wl_output global,
		 * they are all equivalent anyway.
		 */
		if (done)
			break;
	}

	timespec_to_proto(ts, &tv_sec_hi, &tv_sec_lo, &tv_nsec);
	wp_presentation_feedback_send_presented(feedback->resource,
						tv_sec_hi, tv_sec_lo, tv_nsec,
						refresh_nsec,
						seq >> 32, seq & 0xffffffff,
						flags | feedback->psf_flags);
	wl_resource_destroy(feedback->resource);
}

static void
weston_presentation_feedback_present_list(struct wl_list *list,
					  struct weston_output *output,
					  uint32_t refresh_nsec,
					  const struct timespec *ts,
					  uint64_t seq,
					  uint32_t flags)
{
	struct weston_presentation_feedback *feedback, *tmp;

	assert(!(flags & WP_PRESENTATION_FEEDBACK_INVALID) ||
	       wl_list_empty(list));

	wl_list_for_each_safe(feedback, tmp, list, link)
		weston_presentation_feedback_present(feedback, output,
						     refresh_nsec, ts, seq,
						     flags);
}

static void
surface_state_handle_buffer_destroy(struct wl_listener *listener, void *data)
{
	struct weston_surface_state *state =
		container_of(listener, struct weston_surface_state,
			     buffer_destroy_listener);

	state->buffer = NULL;
}

static void
weston_surface_state_init(struct weston_surface_state *state)
{
	state->newly_attached = 0;
	state->buffer = NULL;
	state->buffer_destroy_listener.notify =
		surface_state_handle_buffer_destroy;
	state->sx = 0;
	state->sy = 0;

	pixman_region32_init(&state->damage_surface);
	pixman_region32_init(&state->damage_buffer);
	pixman_region32_init(&state->opaque);
	region_init_infinite(&state->input);

	wl_list_init(&state->frame_callback_list);
	wl_list_init(&state->feedback_list);

	state->buffer_viewport.buffer.transform = WL_OUTPUT_TRANSFORM_NORMAL;
	state->buffer_viewport.buffer.scale = 1;
	state->buffer_viewport.buffer.src_width = wl_fixed_from_int(-1);
	state->buffer_viewport.surface.width = -1;
	state->buffer_viewport.changed = 0;

	state->blending_equation = ZWP_BLENDING_V1_BLENDING_EQUATION_NONE;
	state->blending_alpha = 1.0;
}

static void
weston_surface_state_fini(struct weston_surface_state *state)
{
	struct weston_frame_callback *cb, *next;

	wl_list_for_each_safe(cb, next,
			      &state->frame_callback_list, link)
		wl_resource_destroy(cb->resource);

	weston_presentation_feedback_discard_list(&state->feedback_list);

	pixman_region32_fini(&state->input);
	pixman_region32_fini(&state->opaque);
	pixman_region32_fini(&state->damage_surface);
	pixman_region32_fini(&state->damage_buffer);

	if (state->buffer)
		wl_list_remove(&state->buffer_destroy_listener.link);
	state->buffer = NULL;
}

static void
weston_surface_state_set_buffer(struct weston_surface_state *state,
				struct weston_buffer *buffer)
{
	if (state->buffer == buffer)
		return;

	if (state->buffer)
		wl_list_remove(&state->buffer_destroy_listener.link);
	state->buffer = buffer;
	if (state->buffer)
		wl_signal_add(&state->buffer->destroy_signal,
			      &state->buffer_destroy_listener);
}

WL_EXPORT struct weston_surface *
weston_surface_create(struct weston_compositor *compositor)
{
	struct weston_surface *surface;

	surface = zalloc(sizeof *surface);
	if (surface == NULL)
		return NULL;

	wl_signal_init(&surface->destroy_signal);
	wl_signal_init(&surface->commit_signal);

	surface->compositor = compositor;
	surface->ref_count = 1;

	surface->buffer_viewport.buffer.transform = WL_OUTPUT_TRANSFORM_NORMAL;
	surface->buffer_viewport.buffer.scale = 1;
	surface->buffer_viewport.buffer.src_width = wl_fixed_from_int(-1);
	surface->buffer_viewport.surface.width = -1;

	weston_surface_state_init(&surface->pending);

	pixman_region32_init(&surface->damage);
	pixman_region32_init(&surface->opaque);
	region_init_infinite(&surface->input);

	wl_list_init(&surface->views);

	wl_list_init(&surface->frame_callback_list);
	wl_list_init(&surface->feedback_list);

	wl_list_init(&surface->subsurface_list);
	wl_list_init(&surface->subsurface_list_pending);

	weston_matrix_init(&surface->buffer_to_surface_matrix);
	weston_matrix_init(&surface->surface_to_buffer_matrix);

	wl_list_init(&surface->pointer_constraints);

	return surface;
}

WL_EXPORT void
weston_surface_set_color(struct weston_surface *surface,
		 float red, float green, float blue, float alpha)
{
	surface->compositor->renderer->surface_set_color(surface, red, green, blue, alpha);
}

WL_EXPORT void
weston_view_to_global_float(struct weston_view *view,
			    float sx, float sy, float *x, float *y)
{
	if (view->transform.enabled) {
		struct weston_vector v = { { sx, sy, 0.0f, 1.0f } };

		weston_matrix_transform(&view->transform.matrix, &v);

		if (fabsf(v.f[3]) < 1e-6) {
			weston_log("warning: numerical instability in "
				"%s(), divisor = %g\n", __func__,
				v.f[3]);
			*x = 0;
			*y = 0;
			return;
		}

		*x = v.f[0] / v.f[3];
		*y = v.f[1] / v.f[3];
	} else {
		*x = sx + view->geometry.x;
		*y = sy + view->geometry.y;
	}
}

WL_EXPORT void
weston_transformed_coord(int width, int height,
			 enum wl_output_transform transform,
			 int32_t scale,
			 float sx, float sy, float *bx, float *by)
{
	switch (transform) {
	case WL_OUTPUT_TRANSFORM_NORMAL:
	default:
		*bx = sx;
		*by = sy;
		break;
	case WL_OUTPUT_TRANSFORM_FLIPPED:
		*bx = width - sx;
		*by = sy;
		break;
	case WL_OUTPUT_TRANSFORM_90:
		*bx = height - sy;
		*by = sx;
		break;
	case WL_OUTPUT_TRANSFORM_FLIPPED_90:
		*bx = height - sy;
		*by = width - sx;
		break;
	case WL_OUTPUT_TRANSFORM_180:
		*bx = width - sx;
		*by = height - sy;
		break;
	case WL_OUTPUT_TRANSFORM_FLIPPED_180:
		*bx = sx;
		*by = height - sy;
		break;
	case WL_OUTPUT_TRANSFORM_270:
		*bx = sy;
		*by = width - sx;
		break;
	case WL_OUTPUT_TRANSFORM_FLIPPED_270:
		*bx = sy;
		*by = sx;
		break;
	}

	*bx *= scale;
	*by *= scale;
}

WL_EXPORT pixman_box32_t
weston_transformed_rect(int width, int height,
			enum wl_output_transform transform,
			int32_t scale,
			pixman_box32_t rect)
{
	float x1, x2, y1, y2;

	pixman_box32_t ret;

	weston_transformed_coord(width, height, transform, scale,
				 rect.x1, rect.y1, &x1, &y1);
	weston_transformed_coord(width, height, transform, scale,
				 rect.x2, rect.y2, &x2, &y2);

	if (x1 <= x2) {
		ret.x1 = x1;
		ret.x2 = x2;
	} else {
		ret.x1 = x2;
		ret.x2 = x1;
	}

	if (y1 <= y2) {
		ret.y1 = y1;
		ret.y2 = y2;
	} else {
		ret.y1 = y2;
		ret.y2 = y1;
	}

	return ret;
}

/** Transform a region by a matrix, restricted to axis-aligned transformations
 *
 * Warning: This function does not work for projective, affine, or matrices
 * that encode arbitrary rotations. Only 90-degree step rotations are
 * supported.
 */
WL_EXPORT void
weston_matrix_transform_region(pixman_region32_t *dest,
			       struct weston_matrix *matrix,
			       pixman_region32_t *src)
{
	pixman_box32_t *src_rects, *dest_rects;
	int nrects, i;

	src_rects = pixman_region32_rectangles(src, &nrects);
	dest_rects = malloc(nrects * sizeof(*dest_rects));
	if (!dest_rects)
		return;

	for (i = 0; i < nrects; i++) {
		struct weston_vector vec1 = {{
			src_rects[i].x1, src_rects[i].y1, 0, 1
		}};
		weston_matrix_transform(matrix, &vec1);
		vec1.f[0] /= vec1.f[3];
		vec1.f[1] /= vec1.f[3];

		struct weston_vector vec2 = {{
			src_rects[i].x2, src_rects[i].y2, 0, 1
		}};
		weston_matrix_transform(matrix, &vec2);
		vec2.f[0] /= vec2.f[3];
		vec2.f[1] /= vec2.f[3];

		if (vec1.f[0] < vec2.f[0]) {
			dest_rects[i].x1 = floor(vec1.f[0]);
			dest_rects[i].x2 = ceil(vec2.f[0]);
		} else {
			dest_rects[i].x1 = floor(vec2.f[0]);
			dest_rects[i].x2 = ceil(vec1.f[0]);
		}

		if (vec1.f[1] < vec2.f[1]) {
			dest_rects[i].y1 = floor(vec1.f[1]);
			dest_rects[i].y2 = ceil(vec2.f[1]);
		} else {
			dest_rects[i].y1 = floor(vec2.f[1]);
			dest_rects[i].y2 = ceil(vec1.f[1]);
		}
	}

	pixman_region32_clear(dest);
	pixman_region32_init_rects(dest, dest_rects, nrects);
	free(dest_rects);
}

WL_EXPORT void
weston_transformed_region(int width, int height,
			  enum wl_output_transform transform,
			  int32_t scale,
			  pixman_region32_t *src, pixman_region32_t *dest)
{
	pixman_box32_t *src_rects, *dest_rects;
	int nrects, i;

	if (transform == WL_OUTPUT_TRANSFORM_NORMAL && scale == 1) {
		if (src != dest)
			pixman_region32_copy(dest, src);
		return;
	}

	src_rects = pixman_region32_rectangles(src, &nrects);
	dest_rects = malloc(nrects * sizeof(*dest_rects));
	if (!dest_rects)
		return;

	if (transform == WL_OUTPUT_TRANSFORM_NORMAL) {
		memcpy(dest_rects, src_rects, nrects * sizeof(*dest_rects));
	} else {
		for (i = 0; i < nrects; i++) {
			switch (transform) {
			default:
			case WL_OUTPUT_TRANSFORM_NORMAL:
				dest_rects[i].x1 = src_rects[i].x1;
				dest_rects[i].y1 = src_rects[i].y1;
				dest_rects[i].x2 = src_rects[i].x2;
				dest_rects[i].y2 = src_rects[i].y2;
				break;
			case WL_OUTPUT_TRANSFORM_90:
				dest_rects[i].x1 = height - src_rects[i].y2;
				dest_rects[i].y1 = src_rects[i].x1;
				dest_rects[i].x2 = height - src_rects[i].y1;
				dest_rects[i].y2 = src_rects[i].x2;
				break;
			case WL_OUTPUT_TRANSFORM_180:
				dest_rects[i].x1 = width - src_rects[i].x2;
				dest_rects[i].y1 = height - src_rects[i].y2;
				dest_rects[i].x2 = width - src_rects[i].x1;
				dest_rects[i].y2 = height - src_rects[i].y1;
				break;
			case WL_OUTPUT_TRANSFORM_270:
				dest_rects[i].x1 = src_rects[i].y1;
				dest_rects[i].y1 = width - src_rects[i].x2;
				dest_rects[i].x2 = src_rects[i].y2;
				dest_rects[i].y2 = width - src_rects[i].x1;
				break;
			case WL_OUTPUT_TRANSFORM_FLIPPED:
				dest_rects[i].x1 = width - src_rects[i].x2;
				dest_rects[i].y1 = src_rects[i].y1;
				dest_rects[i].x2 = width - src_rects[i].x1;
				dest_rects[i].y2 = src_rects[i].y2;
				break;
			case WL_OUTPUT_TRANSFORM_FLIPPED_90:
				dest_rects[i].x1 = height - src_rects[i].y2;
				dest_rects[i].y1 = width - src_rects[i].x2;
				dest_rects[i].x2 = height - src_rects[i].y1;
				dest_rects[i].y2 = width - src_rects[i].x1;
				break;
			case WL_OUTPUT_TRANSFORM_FLIPPED_180:
				dest_rects[i].x1 = src_rects[i].x1;
				dest_rects[i].y1 = height - src_rects[i].y2;
				dest_rects[i].x2 = src_rects[i].x2;
				dest_rects[i].y2 = height - src_rects[i].y1;
				break;
			case WL_OUTPUT_TRANSFORM_FLIPPED_270:
				dest_rects[i].x1 = src_rects[i].y1;
				dest_rects[i].y1 = src_rects[i].x1;
				dest_rects[i].x2 = src_rects[i].y2;
				dest_rects[i].y2 = src_rects[i].x2;
				break;
			}
		}
	}

	if (scale != 1) {
		for (i = 0; i < nrects; i++) {
			dest_rects[i].x1 *= scale;
			dest_rects[i].x2 *= scale;
			dest_rects[i].y1 *= scale;
			dest_rects[i].y2 *= scale;
		}
	}

	pixman_region32_clear(dest);
	pixman_region32_init_rects(dest, dest_rects, nrects);
	free(dest_rects);
}

static void
viewport_surface_to_buffer(struct weston_surface *surface,
			   float sx, float sy, float *bx, float *by)
{
	struct weston_buffer_viewport *vp = &surface->buffer_viewport;
	double src_width, src_height;
	double src_x, src_y;

	if (vp->buffer.src_width == wl_fixed_from_int(-1)) {
		if (vp->surface.width == -1) {
			*bx = sx;
			*by = sy;
			return;
		}

		src_x = 0.0;
		src_y = 0.0;
		src_width = surface->width_from_buffer;
		src_height = surface->height_from_buffer;
	} else {
		src_x = wl_fixed_to_double(vp->buffer.src_x);
		src_y = wl_fixed_to_double(vp->buffer.src_y);
		src_width = wl_fixed_to_double(vp->buffer.src_width);
		src_height = wl_fixed_to_double(vp->buffer.src_height);
	}

	*bx = sx * src_width / surface->width + src_x;
	*by = sy * src_height / surface->height + src_y;
}

WL_EXPORT void
weston_surface_to_buffer_float(struct weston_surface *surface,
			       float sx, float sy, float *bx, float *by)
{
	struct weston_buffer_viewport *vp = &surface->buffer_viewport;

	/* first transform coordinates if the viewport is set */
	viewport_surface_to_buffer(surface, sx, sy, bx, by);

	weston_transformed_coord(surface->width_from_buffer,
				 surface->height_from_buffer,
				 vp->buffer.transform, vp->buffer.scale,
				 *bx, *by, bx, by);
}

/** Transform a rectangle from surface coordinates to buffer coordinates
 *
 * \param surface The surface to fetch wp_viewport and buffer transformation
 * from.
 * \param rect The rectangle to transform.
 * \return The transformed rectangle.
 *
 * Viewport and buffer transformations can only do translation, scaling,
 * and rotations in 90-degree steps. Therefore the only loss in the
 * conversion is coordinate rounding.
 *
 * However, some coordinate rounding takes place as an intermediate
 * step before the buffer scale factor is applied, so the rectangle
 * boundary may not be exactly as expected.
 *
 * This is OK for damage tracking since a little extra coverage is
 * not a problem.
 */
WL_EXPORT pixman_box32_t
weston_surface_to_buffer_rect(struct weston_surface *surface,
			      pixman_box32_t rect)
{
	struct weston_buffer_viewport *vp = &surface->buffer_viewport;
	float xf, yf;

	/* first transform box coordinates if the viewport is set */
	viewport_surface_to_buffer(surface, rect.x1, rect.y1, &xf, &yf);
	rect.x1 = floorf(xf);
	rect.y1 = floorf(yf);

	viewport_surface_to_buffer(surface, rect.x2, rect.y2, &xf, &yf);
	rect.x2 = ceilf(xf);
	rect.y2 = ceilf(yf);

	return weston_transformed_rect(surface->width_from_buffer,
				       surface->height_from_buffer,
				       vp->buffer.transform, vp->buffer.scale,
				       rect);
}

/** Transform a region from surface coordinates to buffer coordinates
 *
 * \param surface The surface to fetch wp_viewport and buffer transformation
 * from.
 * \param surface_region[in] The region in surface coordinates.
 * \param buffer_region[out] The region converted to buffer coordinates.
 *
 * Buffer_region must be init'd, but will be completely overwritten.
 *
 * Viewport and buffer transformations can only do translation, scaling,
 * and rotations in 90-degree steps. Therefore the only loss in the
 * conversion is from the coordinate rounding that takes place in
 * \ref weston_surface_to_buffer_rect.
 */
WL_EXPORT void
weston_surface_to_buffer_region(struct weston_surface *surface,
				pixman_region32_t *surface_region,
				pixman_region32_t *buffer_region)
{
	pixman_box32_t *src_rects, *dest_rects;
	int nrects, i;

	src_rects = pixman_region32_rectangles(surface_region, &nrects);
	dest_rects = malloc(nrects * sizeof(*dest_rects));
	if (!dest_rects)
		return;

	for (i = 0; i < nrects; i++) {
		dest_rects[i] = weston_surface_to_buffer_rect(surface,
							      src_rects[i]);
	}

	pixman_region32_fini(buffer_region);
	pixman_region32_init_rects(buffer_region, dest_rects, nrects);
	free(dest_rects);
}

WL_EXPORT void
weston_view_move_to_plane(struct weston_view *view,
			     struct weston_plane *plane)
{
	if (view->plane == plane)
		return;

	weston_view_damage_below(view);
	view->plane = plane;
	weston_surface_damage(view->surface);
}

/** Inflict damage on the plane where the view is visible.
 *
 * \param view The view that causes the damage.
 *
 * If the view is currently on a plane (including the primary plane),
 * take the view's boundingbox, subtract all the opaque views that cover it,
 * and add the remaining region as damage to the plane. This corresponds
 * to the damage inflicted to the plane if this view disappeared.
 *
 * A repaint is scheduled for this view.
 *
 * The region of all opaque views covering this view is stored in
 * weston_view::clip and updated by view_accumulate_damage() during
 * weston_output_repaint(). Specifically, that region matches the
 * scenegraph as it was last painted.
 */
WL_EXPORT void
weston_view_damage_below(struct weston_view *view)
{
	pixman_region32_t damage;

	pixman_region32_init(&damage);
	pixman_region32_subtract(&damage, &view->transform.boundingbox,
				 &view->clip);
	if (view->plane)
		pixman_region32_union(&view->plane->damage,
				      &view->plane->damage, &damage);
	pixman_region32_fini(&damage);
	weston_view_schedule_repaint(view);
}

/** Send wl_surface.enter/leave events
 *
 * \param surface The surface.
 * \param head A head of the entered/left output.
 * \param enter True if entered.
 * \param left True if left.
 *
 * Send the enter/leave events for all protocol objects bound to the given
 * output by the client owning the surface.
 */
static void
weston_surface_send_enter_leave(struct weston_surface *surface,
				struct weston_head *head,
				bool enter,
				bool leave)
{
	struct wl_resource *wloutput;
	struct wl_client *client;

	assert(enter != leave);

	client = wl_resource_get_client(surface->resource);
	wl_resource_for_each(wloutput, &head->resource_list) {
		if (wl_resource_get_client(wloutput) != client)
			continue;

		if (enter)
			wl_surface_send_enter(surface->resource, wloutput);
		if (leave)
			wl_surface_send_leave(surface->resource, wloutput);
	}
}

/**
 * \param es    The surface
 * \param mask  The new set of outputs for the surface
 *
 * Sets the surface's set of outputs to the ones specified by
 * the new output mask provided.  Identifies the outputs that
 * have changed, the posts enter and leave events for these
 * outputs as appropriate.
 */
static void
weston_surface_update_output_mask(struct weston_surface *es, uint32_t mask)
{
	uint32_t different = es->output_mask ^ mask;
	uint32_t entered = mask & different;
	uint32_t left = es->output_mask & different;
	uint32_t output_bit;
	struct weston_output *output;
	struct weston_head *head;

	es->output_mask = mask;
	if (es->resource == NULL)
		return;
	if (different == 0)
		return;

	wl_list_for_each(output, &es->compositor->output_list, link) {
		output_bit = 1u << output->id;
		if (!(output_bit & different))
			continue;

		wl_list_for_each(head, &output->head_list, output_link) {
			weston_surface_send_enter_leave(es, head,
							output_bit & entered,
							output_bit & left);
		}
	}
}

static void
notify_view_output_destroy(struct wl_listener *listener, void *data)
{
	struct weston_view *view =
		container_of(listener,
		     struct weston_view, output_destroy_listener);

	view->output = NULL;
	view->output_destroy_listener.notify = NULL;
}

/** Set the primary output of the view
 *
 * \param view The view whose primary output to set
 * \param output The new primary output for the view
 *
 * Set \a output to be the primary output of the \a view.
 *
 * Notice that the assignment may be temporary; the primary output could be
 * automatically changed. Hence, one cannot rely on the value persisting.
 *
 * Passing NULL as /a output will set the primary output to NULL.
 */
WL_EXPORT void
weston_view_set_output(struct weston_view *view, struct weston_output *output)
{
	if (view->output_destroy_listener.notify) {
		wl_list_remove(&view->output_destroy_listener.link);
		view->output_destroy_listener.notify = NULL;
	}
	view->output = output;
	if (output) {
		view->output_destroy_listener.notify =
			notify_view_output_destroy;
		wl_signal_add(&output->destroy_signal,
			      &view->output_destroy_listener);
	}
}

/** Recalculate which output(s) the surface has views displayed on
 *
 * \param es  The surface to remap to outputs
 *
 * Finds the output that is showing the largest amount of one
 * of the surface's various views.  This output becomes the
 * surface's primary output for vsync and frame callback purposes.
 *
 * Also notes all outputs of all of the surface's views
 * in the output_mask for the surface.
 */
static void
weston_surface_assign_output(struct weston_surface *es)
{
	struct weston_output *new_output;
	struct weston_view *view;
	pixman_region32_t region;
	uint32_t max, area, mask;
	pixman_box32_t *e;

	new_output = NULL;
	max = 0;
	mask = 0;
	pixman_region32_init(&region);
	wl_list_for_each(view, &es->views, surface_link) {
		if (!view->output)
			continue;

		pixman_region32_intersect(&region, &view->transform.boundingbox,
					  &view->output->region);

		e = pixman_region32_extents(&region);
		area = (e->x2 - e->x1) * (e->y2 - e->y1);

		mask |= view->output_mask;

		if (area >= max) {
			new_output = view->output;
			max = area;
		}
	}
	pixman_region32_fini(&region);

	es->output = new_output;
	weston_surface_update_output_mask(es, mask);
}

/** Recalculate which output(s) the view is displayed on
 *
 * \param ev  The view to remap to outputs
 *
 * Identifies the set of outputs that the view is visible on,
 * noting them into the output_mask.  The output that the view
 * is most visible on is set as the view's primary output.
 *
 * Also does the same for the view's surface.  See
 * weston_surface_assign_output().
 */
static void
weston_view_assign_output(struct weston_view *ev)
{
	struct weston_compositor *ec = ev->surface->compositor;
	struct weston_output *output, *new_output;
	pixman_region32_t region;
	uint32_t max, area, mask;
	pixman_box32_t *e;

	new_output = NULL;
	max = 0;
	mask = 0;
	pixman_region32_init(&region);
	wl_list_for_each(output, &ec->output_list, link) {
		if (output->destroying)
			continue;

		pixman_region32_intersect(&region, &ev->transform.boundingbox,
					  &output->region);

		e = pixman_region32_extents(&region);
		area = (e->x2 - e->x1) * (e->y2 - e->y1);

		if (area > 0)
			mask |= 1u << output->id;

		if (area >= max) {
			new_output = output;
			max = area;
		}
	}
	pixman_region32_fini(&region);

	weston_view_set_output(ev, new_output);
	ev->output_mask = mask;

	weston_surface_assign_output(ev->surface);
}

static void
weston_view_to_view_map(struct weston_view *from, struct weston_view *to,
			int from_x, int from_y, int *to_x, int *to_y)
{
	float x, y;

	weston_view_to_global_float(from, from_x, from_y, &x, &y);
	weston_view_from_global_float(to, x, y, &x, &y);

	*to_x = round(x);
	*to_y = round(y);
}

static void
weston_view_transfer_scissor(struct weston_view *from, struct weston_view *to)
{
	pixman_box32_t *a;
	pixman_box32_t b;

	a = pixman_region32_extents(&from->geometry.scissor);

	weston_view_to_view_map(from, to, a->x1, a->y1, &b.x1, &b.y1);
	weston_view_to_view_map(from, to, a->x2, a->y2, &b.x2, &b.y2);

	pixman_region32_fini(&to->geometry.scissor);
	pixman_region32_init_with_extents(&to->geometry.scissor, &b);
}

static void
view_compute_bbox(struct weston_view *view, const pixman_box32_t *inbox,
		  pixman_region32_t *bbox)
{
	float min_x = HUGE_VALF,  min_y = HUGE_VALF;
	float max_x = -HUGE_VALF, max_y = -HUGE_VALF;
	int32_t s[4][2] = {
		{ inbox->x1, inbox->y1 },
		{ inbox->x1, inbox->y2 },
		{ inbox->x2, inbox->y1 },
		{ inbox->x2, inbox->y2 },
	};
	float int_x, int_y;
	int i;

	if (inbox->x1 == inbox->x2 || inbox->y1 == inbox->y2) {
		/* avoid rounding empty bbox to 1x1 */
		pixman_region32_init(bbox);
		return;
	}

	for (i = 0; i < 4; ++i) {
		float x, y;
		weston_view_to_global_float(view, s[i][0], s[i][1], &x, &y);
		if (x < min_x)
			min_x = x;
		if (x > max_x)
			max_x = x;
		if (y < min_y)
			min_y = y;
		if (y > max_y)
			max_y = y;
	}

	int_x = floorf(min_x);
	int_y = floorf(min_y);
	pixman_region32_init_rect(bbox, int_x, int_y,
				  ceilf(max_x) - int_x, ceilf(max_y) - int_y);
}

static void
weston_view_update_transform_disable(struct weston_view *view)
{
	view->transform.enabled = 0;

	/* round off fractions when not transformed */
	view->geometry.x = roundf(view->geometry.x);
	view->geometry.y = roundf(view->geometry.y);

	/* Otherwise identity matrix, but with x and y translation. */
	view->transform.position.matrix.type = WESTON_MATRIX_TRANSFORM_TRANSLATE;
	view->transform.position.matrix.d[12] = view->geometry.x;
	view->transform.position.matrix.d[13] = view->geometry.y;

	view->transform.matrix = view->transform.position.matrix;

	view->transform.inverse = view->transform.position.matrix;
	view->transform.inverse.d[12] = -view->geometry.x;
	view->transform.inverse.d[13] = -view->geometry.y;

	pixman_region32_init_rect(&view->transform.boundingbox,
				  0, 0,
				  view->surface->width,
				  view->surface->height);
	if (view->geometry.scissor_enabled)
		pixman_region32_intersect(&view->transform.boundingbox,
					  &view->transform.boundingbox,
					  &view->geometry.scissor);

	pixman_region32_translate(&view->transform.boundingbox,
				  view->geometry.x, view->geometry.y);

	if (view->alpha == 1.0) {
		pixman_region32_copy(&view->transform.opaque,
				     &view->surface->opaque);
		pixman_region32_translate(&view->transform.opaque,
					  view->geometry.x,
					  view->geometry.y);
	}
}

static int
weston_view_update_transform_enable(struct weston_view *view)
{
	struct weston_view *parent = view->geometry.parent;
	struct weston_matrix *matrix = &view->transform.matrix;
	struct weston_matrix *inverse = &view->transform.inverse;
	struct weston_transform *tform;
	pixman_region32_t surfregion;
	const pixman_box32_t *surfbox;

	view->transform.enabled = 1;

	/* Otherwise identity matrix, but with x and y translation. */
	view->transform.position.matrix.type = WESTON_MATRIX_TRANSFORM_TRANSLATE;
	view->transform.position.matrix.d[12] = view->geometry.x;
	view->transform.position.matrix.d[13] = view->geometry.y;

	weston_matrix_init(matrix);
	wl_list_for_each(tform, &view->geometry.transformation_list, link)
		weston_matrix_multiply(matrix, &tform->matrix);

	if (parent)
		weston_matrix_multiply(matrix, &parent->transform.matrix);

	if (weston_matrix_invert(inverse, matrix) < 0) {
		/* Oops, bad total transformation, not invertible */
		weston_log("error: weston_view %p"
			" transformation not invertible.\n", view);
		return -1;
	}

	if (view->alpha == 1.0 &&
	    matrix->type == WESTON_MATRIX_TRANSFORM_TRANSLATE) {
		pixman_region32_copy(&view->transform.opaque,
				     &view->surface->opaque);
		pixman_region32_translate(&view->transform.opaque,
					  matrix->d[12],
					  matrix->d[13]);
	}

	pixman_region32_init_rect(&surfregion, 0, 0,
				  view->surface->width, view->surface->height);
	if (view->geometry.scissor_enabled)
		pixman_region32_intersect(&surfregion, &surfregion,
					  &view->geometry.scissor);
	surfbox = pixman_region32_extents(&surfregion);

	view_compute_bbox(view, surfbox, &view->transform.boundingbox);
	pixman_region32_fini(&surfregion);

	return 0;
}

static struct weston_layer *
get_view_layer(struct weston_view *view)
{
	if (view->parent_view)
		return get_view_layer(view->parent_view);
	return view->layer_link.layer;
}

WL_EXPORT void
weston_view_update_transform(struct weston_view *view)
{
	struct weston_view *parent = view->geometry.parent;
	struct weston_layer *layer;
	pixman_region32_t mask;

	if (!view->transform.dirty)
		return;

	if (parent)
		weston_view_update_transform(parent);

	view->transform.dirty = 0;

	weston_view_damage_below(view);

	pixman_region32_fini(&view->transform.boundingbox);
	pixman_region32_fini(&view->transform.opaque);
	pixman_region32_init(&view->transform.opaque);

	/* transform.position is always in transformation_list */
	if (view->geometry.transformation_list.next ==
	    &view->transform.position.link &&
	    view->geometry.transformation_list.prev ==
	    &view->transform.position.link &&
	    !parent) {
		weston_view_update_transform_disable(view);
	} else {
		if (weston_view_update_transform_enable(view) < 0)
			weston_view_update_transform_disable(view);
	}

	layer = get_view_layer(view);
	if (layer) {
		pixman_region32_init_with_extents(&mask, &layer->mask);
		pixman_region32_intersect(&view->transform.boundingbox,
					  &view->transform.boundingbox, &mask);
		pixman_region32_intersect(&view->transform.opaque,
					  &view->transform.opaque, &mask);
		pixman_region32_fini(&mask);
	}

	if (parent) {
		if (parent->geometry.scissor_enabled) {
			view->geometry.scissor_enabled = true;
			weston_view_transfer_scissor(parent, view);
		} else {
			view->geometry.scissor_enabled = false;
		}
	}

	weston_view_damage_below(view);

	weston_view_assign_output(view);

	wl_signal_emit(&view->surface->compositor->transform_signal,
		       view->surface);
}

WL_EXPORT void
weston_view_geometry_dirty(struct weston_view *view)
{
	struct weston_view *child;

	/*
	 * The invariant: if view->geometry.dirty, then all views
	 * in view->geometry.child_list have geometry.dirty too.
	 * Corollary: if not parent->geometry.dirty, then all ancestors
	 * are not dirty.
	 */

	if (view->transform.dirty)
		return;

	view->transform.dirty = 1;

	wl_list_for_each(child, &view->geometry.child_list,
			 geometry.parent_link)
		weston_view_geometry_dirty(child);
}

WL_EXPORT void
weston_view_to_global_fixed(struct weston_view *view,
			    wl_fixed_t vx, wl_fixed_t vy,
			    wl_fixed_t *x, wl_fixed_t *y)
{
	float xf, yf;

	weston_view_to_global_float(view,
				    wl_fixed_to_double(vx),
				    wl_fixed_to_double(vy),
				    &xf, &yf);
	*x = wl_fixed_from_double(xf);
	*y = wl_fixed_from_double(yf);
}

WL_EXPORT void
weston_view_from_global_float(struct weston_view *view,
			      float x, float y, float *vx, float *vy)
{
	if (view->transform.enabled) {
		struct weston_vector v = { { x, y, 0.0f, 1.0f } };

		weston_matrix_transform(&view->transform.inverse, &v);

		if (fabsf(v.f[3]) < 1e-6) {
			weston_log("warning: numerical instability in "
				"weston_view_from_global(), divisor = %g\n",
				v.f[3]);
			*vx = 0;
			*vy = 0;
			return;
		}

		*vx = v.f[0] / v.f[3];
		*vy = v.f[1] / v.f[3];
	} else {
		*vx = x - view->geometry.x;
		*vy = y - view->geometry.y;
	}
}

WL_EXPORT void
weston_view_from_global_fixed(struct weston_view *view,
			      wl_fixed_t x, wl_fixed_t y,
			      wl_fixed_t *vx, wl_fixed_t *vy)
{
	float vxf, vyf;

	weston_view_from_global_float(view,
				      wl_fixed_to_double(x),
				      wl_fixed_to_double(y),
				      &vxf, &vyf);
	*vx = wl_fixed_from_double(vxf);
	*vy = wl_fixed_from_double(vyf);
}

WL_EXPORT void
weston_view_from_global(struct weston_view *view,
			int32_t x, int32_t y, int32_t *vx, int32_t *vy)
{
	float vxf, vyf;

	weston_view_from_global_float(view, x, y, &vxf, &vyf);
	*vx = floorf(vxf);
	*vy = floorf(vyf);
}

/**
 * \param surface  The surface to be repainted
 *
 * Marks the output(s) that the surface is shown on as needing to be
 * repainted.  See weston_output_schedule_repaint().
 */
WL_EXPORT void
weston_surface_schedule_repaint(struct weston_surface *surface)
{
	struct weston_output *output;

	wl_list_for_each(output, &surface->compositor->output_list, link)
		if (surface->output_mask & (1u << output->id))
			weston_output_schedule_repaint(output);
}

/**
 * \param view  The view to be repainted
 *
 * Marks the output(s) that the view is shown on as needing to be
 * repainted.  See weston_output_schedule_repaint().
 */
WL_EXPORT void
weston_view_schedule_repaint(struct weston_view *view)
{
	struct weston_output *output;

	wl_list_for_each(output, &view->surface->compositor->output_list, link)
		if (view->output_mask & (1u << output->id))
			weston_output_schedule_repaint(output);
}

/**
 * XXX: This function does it the wrong way.
 * surface->damage is the damage from the client, and causes
 * surface_flush_damage() to copy pixels. No window management action can
 * cause damage to the client-provided content, warranting re-upload!
 *
 * Instead of surface->damage, this function should record the damage
 * with all the views for this surface to avoid extraneous texture
 * uploads.
 */
WL_EXPORT void
weston_surface_damage(struct weston_surface *surface)
{
	pixman_region32_union_rect(&surface->damage, &surface->damage,
				   0, 0, surface->width,
				   surface->height);

	weston_surface_schedule_repaint(surface);
}

WL_EXPORT void
weston_view_set_position(struct weston_view *view, float x, float y)
{
	if (view->geometry.x == x && view->geometry.y == y)
		return;

	view->geometry.x = x;
	view->geometry.y = y;
	weston_view_geometry_dirty(view);
}

static void
transform_parent_handle_parent_destroy(struct wl_listener *listener,
				       void *data)
{
	struct weston_view *view =
		container_of(listener, struct weston_view,
			     geometry.parent_destroy_listener);

	weston_view_set_transform_parent(view, NULL);
}

WL_EXPORT void
weston_view_set_transform_parent(struct weston_view *view,
				 struct weston_view *parent)
{
	if (view->geometry.parent) {
		wl_list_remove(&view->geometry.parent_destroy_listener.link);
		wl_list_remove(&view->geometry.parent_link);

		if (!parent)
			view->geometry.scissor_enabled = false;
	}

	view->geometry.parent = parent;

	view->geometry.parent_destroy_listener.notify =
		transform_parent_handle_parent_destroy;
	if (parent) {
		wl_signal_add(&parent->destroy_signal,
			      &view->geometry.parent_destroy_listener);
		wl_list_insert(&parent->geometry.child_list,
			       &view->geometry.parent_link);
	}

	weston_view_geometry_dirty(view);
}

/** Set a clip mask rectangle on a view
 *
 * \param view The view to set the clip mask on.
 * \param x Top-left corner X coordinate of the clip rectangle.
 * \param y Top-left corner Y coordinate of the clip rectangle.
 * \param width Width of the clip rectangle, non-negative.
 * \param height Height of the clip rectangle, non-negative.
 *
 * A shell may set a clip mask rectangle on a view. Everything outside
 * the rectangle is cut away for input and output purposes: it is
 * not drawn and cannot be hit by hit-test based input like pointer
 * motion or touch-downs. Everything inside the rectangle will behave
 * normally. Clients are unaware of clipping.
 *
 * The rectangle is set in surface-local coordinates. Setting a clip
 * mask rectangle does not affect the view position, the view is positioned
 * as it would be without a clip. The clip also does not change
 * weston_surface::width,height.
 *
 * The clip mask rectangle is part of transformation inheritance
 * (weston_view_set_transform_parent()). A clip set in the root of the
 * transformation inheritance tree will affect all views in the tree.
 * A clip can be set only on the root view. Attempting to set a clip
 * on view that has a transformation parent will fail. Assigning a parent
 * to a view that has a clip set will cause the clip to be forgotten.
 *
 * Because the clip mask is an axis-aligned rectangle, it poses restrictions
 * on the additional transformations in the child views. These transformations
 * may not rotate the coordinate axes, i.e., only translation and scaling
 * are allowed. Violating this restriction causes the clipping to malfunction.
 * Furthermore, using scaling may cause rounding errors in child clipping.
 *
 * The clip mask rectangle is not automatically adjusted based on
 * wl_surface.attach dx and dy arguments.
 *
 * A clip mask rectangle can be set only if the compositor capability
 * WESTON_CAP_VIEW_CLIP_MASK is present.
 *
 * This function sets the clip mask rectangle and schedules a repaint for
 * the view.
 */
WL_EXPORT void
weston_view_set_mask(struct weston_view *view,
		     int x, int y, int width, int height)
{
	struct weston_compositor *compositor = view->surface->compositor;

	if (!(compositor->capabilities & WESTON_CAP_VIEW_CLIP_MASK)) {
		weston_log("%s not allowed without capability!\n", __func__);
		return;
	}

	if (view->geometry.parent) {
		weston_log("view %p has a parent, clip forbidden!\n", view);
		return;
	}

	if (width < 0 || height < 0) {
		weston_log("%s: illegal args %d, %d, %d, %d\n", __func__,
			   x, y, width, height);
		return;
	}

	pixman_region32_fini(&view->geometry.scissor);
	pixman_region32_init_rect(&view->geometry.scissor, x, y, width, height);
	view->geometry.scissor_enabled = true;
	weston_view_geometry_dirty(view);
	weston_view_schedule_repaint(view);
}

/** Remove the clip mask from a view
 *
 * \param view The view to remove the clip mask from.
 *
 * Removed the clip mask rectangle and schedules a repaint.
 *
 * \sa weston_view_set_mask
 */
WL_EXPORT void
weston_view_set_mask_infinite(struct weston_view *view)
{
	view->geometry.scissor_enabled = false;
	weston_view_geometry_dirty(view);
	weston_view_schedule_repaint(view);
}

/* Check if view should be displayed
 *
 * The indicator is set manually when assigning
 * a view to a surface.
 *
 * This needs reworking. See the thread starting at:
 *
 * https://lists.freedesktop.org/archives/wayland-devel/2016-June/029656.html
 */
WL_EXPORT bool
weston_view_is_mapped(struct weston_view *view)
{
	return view->is_mapped;
}

/* Check if a surface has a view assigned to it
 *
 * The indicator is set manually when mapping
 * a surface and creating a view for it.
 *
 * This needs to go. See the thread starting at:
 *
 * https://lists.freedesktop.org/archives/wayland-devel/2016-June/029656.html
 *
 */
WL_EXPORT bool
weston_surface_is_mapped(struct weston_surface *surface)
{
	return surface->is_mapped;
}

static void
surface_set_size(struct weston_surface *surface, int32_t width, int32_t height)
{
	struct weston_view *view;

	if (surface->width == width && surface->height == height)
		return;

	surface->width = width;
	surface->height = height;

	wl_list_for_each(view, &surface->views, surface_link)
		weston_view_geometry_dirty(view);
}

WL_EXPORT void
weston_surface_set_size(struct weston_surface *surface,
			int32_t width, int32_t height)
{
	assert(!surface->resource);
	surface_set_size(surface, width, height);
}

static int
fixed_round_up_to_int(wl_fixed_t f)
{
	return wl_fixed_to_int(wl_fixed_from_int(1) - 1 + f);
}

static void
convert_size_by_transform_scale(int32_t *width_out, int32_t *height_out,
				int32_t width, int32_t height,
				uint32_t transform,
				int32_t scale)
{
	assert(scale > 0);

	switch (transform) {
	case WL_OUTPUT_TRANSFORM_NORMAL:
	case WL_OUTPUT_TRANSFORM_180:
	case WL_OUTPUT_TRANSFORM_FLIPPED:
	case WL_OUTPUT_TRANSFORM_FLIPPED_180:
		*width_out = width / scale;
		*height_out = height / scale;
		break;
	case WL_OUTPUT_TRANSFORM_90:
	case WL_OUTPUT_TRANSFORM_270:
	case WL_OUTPUT_TRANSFORM_FLIPPED_90:
	case WL_OUTPUT_TRANSFORM_FLIPPED_270:
		*width_out = height / scale;
		*height_out = width / scale;
		break;
	default:
		assert(0 && "invalid transform");
	}
}

static void
weston_surface_calculate_size_from_buffer(struct weston_surface *surface)
{
	struct weston_buffer_viewport *vp = &surface->buffer_viewport;

	if (!surface->buffer_ref.buffer) {
		surface->width_from_buffer = 0;
		surface->height_from_buffer = 0;
		return;
	}

	convert_size_by_transform_scale(&surface->width_from_buffer,
					&surface->height_from_buffer,
					surface->buffer_ref.buffer->width,
					surface->buffer_ref.buffer->height,
					vp->buffer.transform,
					vp->buffer.scale);
}

static void
weston_surface_update_size(struct weston_surface *surface)
{
	struct weston_buffer_viewport *vp = &surface->buffer_viewport;
	int32_t width, height;

	width = surface->width_from_buffer;
	height = surface->height_from_buffer;

	if (width != 0 && vp->surface.width != -1) {
		surface_set_size(surface,
				 vp->surface.width, vp->surface.height);
		return;
	}

	if (width != 0 && vp->buffer.src_width != wl_fixed_from_int(-1)) {
		int32_t w = fixed_round_up_to_int(vp->buffer.src_width);
		int32_t h = fixed_round_up_to_int(vp->buffer.src_height);

		surface_set_size(surface, w ?: 1, h ?: 1);
		return;
	}

	surface_set_size(surface, width, height);
}

WL_EXPORT void
weston_compositor_get_time(struct timespec *time)
{
	clock_gettime(CLOCK_REALTIME, time);
}

WL_EXPORT struct weston_view *
weston_compositor_pick_view(struct weston_compositor *compositor,
			    wl_fixed_t x, wl_fixed_t y,
			    wl_fixed_t *vx, wl_fixed_t *vy)
{
	struct weston_view *view;
	wl_fixed_t view_x, view_y;
	int view_ix, view_iy;
	int ix = wl_fixed_to_int(x);
	int iy = wl_fixed_to_int(y);

	wl_list_for_each(view, &compositor->view_list, link) {
		if (!pixman_region32_contains_point(
				&view->transform.boundingbox, ix, iy, NULL))
			continue;

		weston_view_from_global_fixed(view, x, y, &view_x, &view_y);
		view_ix = wl_fixed_to_int(view_x);
		view_iy = wl_fixed_to_int(view_y);

		if (!pixman_region32_contains_point(&view->surface->input,
						    view_ix, view_iy, NULL))
			continue;

		if (view->geometry.scissor_enabled &&
		    !pixman_region32_contains_point(&view->geometry.scissor,
						    view_ix, view_iy, NULL))
			continue;

		*vx = view_x;
		*vy = view_y;
		return view;
	}

	*vx = wl_fixed_from_int(-1000000);
	*vy = wl_fixed_from_int(-1000000);
	return NULL;
}

static void
weston_compositor_repick(struct weston_compositor *compositor)
{
	struct weston_seat *seat;

	if (!compositor->session_active)
		return;

	wl_list_for_each(seat, &compositor->seat_list, link)
		weston_seat_repick(seat);
}

WL_EXPORT void
weston_view_unmap(struct weston_view *view)
{
	struct weston_seat *seat;

	if (!weston_view_is_mapped(view))
		return;

	weston_view_damage_below(view);
	weston_view_set_output(view, NULL);
	view->plane = NULL;
	view->is_mapped = false;
	weston_layer_entry_remove(&view->layer_link);
	wl_list_remove(&view->link);
	wl_list_init(&view->link);
	view->output_mask = 0;
	weston_surface_assign_output(view->surface);

	if (weston_surface_is_mapped(view->surface))
		return;

	wl_list_for_each(seat, &view->surface->compositor->seat_list, link) {
		struct weston_touch *touch = weston_seat_get_touch(seat);
		struct weston_pointer *pointer = weston_seat_get_pointer(seat);
		struct weston_keyboard *keyboard =
			weston_seat_get_keyboard(seat);

		if (keyboard && keyboard->focus == view->surface)
			weston_keyboard_set_focus(keyboard, NULL);
		if (pointer && pointer->focus == view)
			weston_pointer_clear_focus(pointer);
		if (touch && touch->focus == view)
			weston_touch_set_focus(touch, NULL);
	}
}

WL_EXPORT void
weston_surface_unmap(struct weston_surface *surface)
{
	struct weston_view *view;

	surface->is_mapped = false;
	wl_list_for_each(view, &surface->views, surface_link)
		weston_view_unmap(view);
	surface->output = NULL;
}

static void
weston_surface_reset_pending_buffer(struct weston_surface *surface)
{
	weston_surface_state_set_buffer(&surface->pending, NULL);
	surface->pending.sx = 0;
	surface->pending.sy = 0;
	surface->pending.newly_attached = 0;
	surface->pending.buffer_viewport.changed = 0;
}

WL_EXPORT void
weston_view_destroy(struct weston_view *view)
{
	wl_signal_emit(&view->destroy_signal, view);

	assert(wl_list_empty(&view->geometry.child_list));

	if (weston_view_is_mapped(view)) {
		weston_view_unmap(view);
		weston_compositor_build_view_list(view->surface->compositor);
	}

	wl_list_remove(&view->link);
	weston_layer_entry_remove(&view->layer_link);

	pixman_region32_fini(&view->clip);
	pixman_region32_fini(&view->geometry.scissor);
	pixman_region32_fini(&view->transform.boundingbox);
	pixman_region32_fini(&view->transform.opaque);

	weston_view_set_transform_parent(view, NULL);
	weston_view_set_output(view, NULL);

	wl_list_remove(&view->surface_link);

	free(view);
}

WL_EXPORT void
weston_surface_destroy(struct weston_surface *surface)
{
	struct weston_frame_callback *cb, *next;
	struct weston_view *ev, *nv;
	struct weston_pointer_constraint *constraint, *next_constraint;

	if (--surface->ref_count > 0)
		return;

	assert(surface->resource == NULL);

	wl_signal_emit(&surface->destroy_signal, surface);

	assert(wl_list_empty(&surface->subsurface_list_pending));
	assert(wl_list_empty(&surface->subsurface_list));

	wl_list_for_each_safe(ev, nv, &surface->views, surface_link)
		weston_view_destroy(ev);

	weston_surface_state_fini(&surface->pending);

	weston_buffer_reference(&surface->buffer_ref, NULL);

	pixman_region32_fini(&surface->damage);
	pixman_region32_fini(&surface->opaque);
	pixman_region32_fini(&surface->input);

	wl_list_for_each_safe(cb, next, &surface->frame_callback_list, link)
		wl_resource_destroy(cb->resource);

	weston_presentation_feedback_discard_list(&surface->feedback_list);

	wl_list_for_each_safe(constraint, next_constraint,
			      &surface->pointer_constraints,
			      link)
		weston_pointer_constraint_destroy(constraint);

	free(surface);
}

static void
destroy_surface(struct wl_resource *resource)
{
	struct weston_surface *surface = wl_resource_get_user_data(resource);

	assert(surface);

	/* Set the resource to NULL, since we don't want to leave a
	 * dangling pointer if the surface was refcounted and survives
	 * the weston_surface_destroy() call. */
	surface->resource = NULL;

	if (surface->viewport_resource)
		wl_resource_set_user_data(surface->viewport_resource, NULL);

	if (surface->blending_resource)
		wl_resource_set_user_data(surface->blending_resource, NULL);

	weston_surface_destroy(surface);
}

static void
weston_buffer_destroy_handler(struct wl_listener *listener, void *data)
{
	struct weston_buffer *buffer =
		container_of(listener, struct weston_buffer, destroy_listener);

	wl_signal_emit(&buffer->destroy_signal, buffer);
	free(buffer);
}

WL_EXPORT struct weston_buffer *
weston_buffer_from_resource(struct wl_resource *resource)
{
	struct weston_buffer *buffer;
	struct wl_listener *listener;

	listener = wl_resource_get_destroy_listener(resource,
						    weston_buffer_destroy_handler);

	if (listener)
		return container_of(listener, struct weston_buffer,
				    destroy_listener);

	buffer = zalloc(sizeof *buffer);
	if (buffer == NULL)
		return NULL;

	buffer->resource = resource;
	wl_signal_init(&buffer->destroy_signal);
	buffer->destroy_listener.notify = weston_buffer_destroy_handler;
	buffer->y_inverted = 1;
	wl_resource_add_destroy_listener(resource, &buffer->destroy_listener);

	return buffer;
}

static void
weston_buffer_reference_handle_destroy(struct wl_listener *listener,
				       void *data)
{
	struct weston_buffer_reference *ref =
		container_of(listener, struct weston_buffer_reference,
			     destroy_listener);

	assert((struct weston_buffer *)data == ref->buffer);
	ref->buffer = NULL;
}

WL_EXPORT void
weston_buffer_reference(struct weston_buffer_reference *ref,
			struct weston_buffer *buffer)
{
	if (ref->buffer && buffer != ref->buffer) {
		ref->buffer->busy_count--;
		if (ref->buffer->busy_count == 0) {
			assert(wl_resource_get_client(ref->buffer->resource));
			wl_buffer_send_release(ref->buffer->resource);
		}
		wl_list_remove(&ref->destroy_listener.link);
	}

	if (buffer && buffer != ref->buffer) {
		buffer->busy_count++;
		wl_signal_add(&buffer->destroy_signal,
			      &ref->destroy_listener);
	}

	ref->buffer = buffer;
	ref->destroy_listener.notify = weston_buffer_reference_handle_destroy;
}

static void
weston_surface_attach(struct weston_surface *surface,
		      struct weston_buffer *buffer)
{
	weston_buffer_reference(&surface->buffer_ref, buffer);

	if (!buffer) {
		if (weston_surface_is_mapped(surface))
			weston_surface_unmap(surface);
	}

	surface->compositor->renderer->attach(surface, buffer);

	weston_surface_calculate_size_from_buffer(surface);
	weston_presentation_feedback_discard_list(&surface->feedback_list);
}

WL_EXPORT void
weston_compositor_damage_all(struct weston_compositor *compositor)
{
	struct weston_output *output;

	wl_list_for_each(output, &compositor->output_list, link)
		weston_output_damage(output);
}

WL_EXPORT void
weston_output_damage(struct weston_output *output)
{
	struct weston_compositor *compositor = output->compositor;

	pixman_region32_union(&compositor->primary_plane.damage,
			      &compositor->primary_plane.damage,
			      &output->region);
	weston_output_schedule_repaint(output);
}

static void
surface_flush_damage(struct weston_surface *surface)
{
	if (surface->buffer_ref.buffer &&
	    wl_shm_buffer_get(surface->buffer_ref.buffer->resource))
		surface->compositor->renderer->flush_damage(surface);

	if (weston_timeline_enabled_ &&
	    pixman_region32_not_empty(&surface->damage))
		TL_POINT("core_flush_damage", TLP_SURFACE(surface),
			 TLP_OUTPUT(surface->output), TLP_END);

	pixman_region32_clear(&surface->damage);
}

static void
view_accumulate_damage(struct weston_view *view,
		       pixman_region32_t *opaque)
{
	pixman_region32_t damage;

	pixman_region32_init(&damage);
	if (view->transform.enabled) {
		pixman_box32_t *extents;

		extents = pixman_region32_extents(&view->surface->damage);
		view_compute_bbox(view, extents, &damage);
	} else {
		pixman_region32_copy(&damage, &view->surface->damage);
		pixman_region32_translate(&damage,
					  view->geometry.x, view->geometry.y);
	}

	pixman_region32_intersect(&damage, &damage,
				  &view->transform.boundingbox);
	pixman_region32_subtract(&damage, &damage, opaque);
	pixman_region32_union(&view->plane->damage,
			      &view->plane->damage, &damage);
	pixman_region32_fini(&damage);
	pixman_region32_copy(&view->clip, opaque);
	pixman_region32_union(opaque, opaque, &view->transform.opaque);
}

static void
compositor_accumulate_damage(struct weston_compositor *ec)
{
	struct weston_plane *plane;
	struct weston_view *ev;
	pixman_region32_t opaque, clip;

	pixman_region32_init(&clip);

	wl_list_for_each(plane, &ec->plane_list, link) {
		pixman_region32_copy(&plane->clip, &clip);

		pixman_region32_init(&opaque);

		wl_list_for_each(ev, &ec->view_list, link) {
			if (ev->plane != plane)
				continue;

			view_accumulate_damage(ev, &opaque);
		}

		pixman_region32_union(&clip, &clip, &opaque);
		pixman_region32_fini(&opaque);
	}

	pixman_region32_fini(&clip);

	wl_list_for_each(ev, &ec->view_list, link)
		ev->surface->touched = false;

	wl_list_for_each(ev, &ec->view_list, link) {
		if (ev->surface->touched)
			continue;
		ev->surface->touched = true;

		surface_flush_damage(ev->surface);

		/* Both the renderer and the backend have seen the buffer
		 * by now. If renderer needs the buffer, it has its own
		 * reference set. If the backend wants to keep the buffer
		 * around for migrating the surface into a non-primary plane
		 * later, keep_buffer is true. Otherwise, drop the core
		 * reference now, and allow early buffer release. This enables
		 * clients to use single-buffering.
		 */
		if (!ev->surface->keep_buffer)
			weston_buffer_reference(&ev->surface->buffer_ref, NULL);
	}
}

static void
surface_stash_subsurface_views(struct weston_surface *surface)
{
	struct weston_subsurface *sub;

	wl_list_for_each(sub, &surface->subsurface_list, parent_link) {
		if (sub->surface == surface)
			continue;

		wl_list_insert_list(&sub->unused_views, &sub->surface->views);
		wl_list_init(&sub->surface->views);

		surface_stash_subsurface_views(sub->surface);
	}
}

static void
surface_free_unused_subsurface_views(struct weston_surface *surface)
{
	struct weston_subsurface *sub;
	struct weston_view *view, *nv;

	wl_list_for_each(sub, &surface->subsurface_list, parent_link) {
		if (sub->surface == surface)
			continue;

		wl_list_for_each_safe(view, nv, &sub->unused_views, surface_link) {
			weston_view_unmap (view);
			weston_view_destroy(view);
		}

		surface_free_unused_subsurface_views(sub->surface);
	}
}

static void
view_list_add_subsurface_view(struct weston_compositor *compositor,
			      struct weston_subsurface *sub,
			      struct weston_view *parent)
{
	struct weston_subsurface *child;
	struct weston_view *view = NULL, *iv;

	if (!weston_surface_is_mapped(sub->surface))
		return;

	wl_list_for_each(iv, &sub->unused_views, surface_link) {
		if (iv->geometry.parent == parent) {
			view = iv;
			break;
		}
	}

	if (view) {
		/* Put it back in the surface's list of views */
		wl_list_remove(&view->surface_link);
		wl_list_insert(&sub->surface->views, &view->surface_link);
	} else {
		view = weston_view_create(sub->surface);
		weston_view_set_position(view,
					 sub->position.x,
					 sub->position.y);
		weston_view_set_transform_parent(view, parent);
	}

	view->parent_view = parent;
	weston_view_update_transform(view);
	view->is_mapped = true;

	if (wl_list_empty(&sub->surface->subsurface_list)) {
		wl_list_insert(compositor->view_list.prev, &view->link);
		return;
	}

	wl_list_for_each(child, &sub->surface->subsurface_list, parent_link) {
		if (child->surface == sub->surface)
			wl_list_insert(compositor->view_list.prev, &view->link);
		else
			view_list_add_subsurface_view(compositor, child, view);
	}
}

/* This recursively adds the sub-surfaces for a view, relying on the
 * sub-surface order. Thus, if a client restacks the sub-surfaces, that
 * change first happens to the sub-surface list, and then automatically
 * propagates here. See weston_surface_damage_subsurfaces() for how the
 * sub-surfaces receive damage when the client changes the state.
 */
static void
view_list_add(struct weston_compositor *compositor,
	      struct weston_view *view)
{
	struct weston_subsurface *sub;

	weston_view_update_transform(view);

	if (wl_list_empty(&view->surface->subsurface_list)) {
		wl_list_insert(compositor->view_list.prev, &view->link);
		return;
	}

	wl_list_for_each(sub, &view->surface->subsurface_list, parent_link) {
		if (sub->surface == view->surface)
			wl_list_insert(compositor->view_list.prev, &view->link);
		else
			view_list_add_subsurface_view(compositor, sub, view);
	}
}

static void
weston_compositor_build_view_list(struct weston_compositor *compositor)
{
	struct weston_view *view;
	struct weston_layer *layer;

	wl_list_for_each(layer, &compositor->layer_list, link)
		wl_list_for_each(view, &layer->view_list.link, layer_link.link)
			surface_stash_subsurface_views(view->surface);

	wl_list_init(&compositor->view_list);
	wl_list_for_each(layer, &compositor->layer_list, link) {
		wl_list_for_each(view, &layer->view_list.link, layer_link.link) {
			view_list_add(compositor, view);
		}
	}

	wl_list_for_each(layer, &compositor->layer_list, link)
		wl_list_for_each(view, &layer->view_list.link, layer_link.link)
			surface_free_unused_subsurface_views(view->surface);
}

static void
weston_output_take_feedback_list(struct weston_output *output,
				 struct weston_surface *surface)
{
	struct weston_view *view;
	struct weston_presentation_feedback *feedback;
	uint32_t flags = 0xffffffff;

	if (wl_list_empty(&surface->feedback_list))
		return;

	/* All views must have the flag for the flag to survive. */
	wl_list_for_each(view, &surface->views, surface_link) {
		/* ignore views that are not on this output at all */
		if (view->output_mask & (1u << output->id))
			flags &= view->psf_flags;
	}

	wl_list_for_each(feedback, &surface->feedback_list, link)
		feedback->psf_flags = flags;

	wl_list_insert_list(&output->feedback_list, &surface->feedback_list);
	wl_list_init(&surface->feedback_list);
}

static int
weston_output_repaint(struct weston_output *output, void *repaint_data)
{
	struct weston_compositor *ec = output->compositor;
	struct weston_view *ev;
	struct weston_animation *animation, *next;
	struct weston_frame_callback *cb, *cnext;
	struct wl_list frame_callback_list;
	pixman_region32_t output_damage;
	int r;
	uint32_t frame_time_msec;

	if (output->destroying)
		return 0;

	TL_POINT("core_repaint_begin", TLP_OUTPUT(output), TLP_END);

	/* Rebuild the surface list and update surface transforms up front. */
	weston_compositor_build_view_list(ec);

	if (output->assign_planes && !output->disable_planes) {
		output->assign_planes(output, repaint_data);
	} else {
		wl_list_for_each(ev, &ec->view_list, link) {
			weston_view_move_to_plane(ev, &ec->primary_plane);
			ev->psf_flags = 0;
		}
	}

	wl_list_init(&frame_callback_list);
	wl_list_for_each(ev, &ec->view_list, link) {
		/* Note: This operation is safe to do multiple times on the
		 * same surface.
		 */
		if (ev->surface->output == output) {
			wl_list_insert_list(&frame_callback_list,
					    &ev->surface->frame_callback_list);
			wl_list_init(&ev->surface->frame_callback_list);

			weston_output_take_feedback_list(output, ev->surface);
		}
	}

	compositor_accumulate_damage(ec);

	pixman_region32_init(&output_damage);
	pixman_region32_intersect(&output_damage,
				  &ec->primary_plane.damage, &output->region);
	pixman_region32_subtract(&output_damage,
				 &output_damage, &ec->primary_plane.clip);

	if (output->dirty)
		weston_output_update_matrix(output);

	r = output->repaint(output, &output_damage, repaint_data);

	pixman_region32_fini(&output_damage);

	output->repaint_needed = false;
	if (r == 0)
		output->repaint_status = REPAINT_AWAITING_COMPLETION;

	weston_compositor_repick(ec);

	frame_time_msec = timespec_to_msec(&output->frame_time);

	wl_list_for_each_safe(cb, cnext, &frame_callback_list, link) {
		wl_callback_send_done(cb->resource, frame_time_msec);
		wl_resource_destroy(cb->resource);
	}

	wl_list_for_each_safe(animation, next, &output->animation_list, link) {
		animation->frame_counter++;
		animation->frame(animation, output, &output->frame_time);
	}

	TL_POINT("core_repaint_posted", TLP_OUTPUT(output), TLP_END);

	return r;
}

static void
weston_output_schedule_repaint_reset(struct weston_output *output)
{
	output->repaint_status = REPAINT_NOT_SCHEDULED;
	TL_POINT("core_repaint_exit_loop", TLP_OUTPUT(output), TLP_END);
}

static int
weston_output_maybe_repaint(struct weston_output *output, struct timespec *now,
			    void *repaint_data)
{
	struct weston_compositor *compositor = output->compositor;
	int ret = 0;
	int64_t msec_to_repaint;

	/* We're not ready yet; come back to make a decision later. */
	if (output->repaint_status != REPAINT_SCHEDULED)
		return ret;

	msec_to_repaint = timespec_sub_to_msec(&output->next_repaint, now);
	if (msec_to_repaint > 1)
		return ret;

	/* If we're sleeping, drop the repaint machinery entirely; we will
	 * explicitly repaint all outputs when we come back. */
	if (compositor->state == WESTON_COMPOSITOR_SLEEPING ||
	    compositor->state == WESTON_COMPOSITOR_OFFSCREEN)
		goto err;

	/* We don't actually need to repaint this output; drop it from
	 * repaint until something causes damage. */
	if (!output->repaint_needed)
		goto err;

	/* If repaint fails, we aren't going to get weston_output_finish_frame
	 * to trigger a new repaint, so drop it from repaint and hope
	 * something schedules a successful repaint later. As repainting may
	 * take some time, re-read our clock as a courtesy to the next
	 * output. */
	ret = weston_output_repaint(output, repaint_data);
	weston_compositor_read_presentation_clock(compositor, now);
	if (ret != 0)
		goto err;

	output->repainted = true;
	return ret;

err:
	weston_output_schedule_repaint_reset(output);
	return ret;
}

static void
output_repaint_timer_arm(struct weston_compositor *compositor)
{
	struct weston_output *output;
	bool any_should_repaint = false;
	struct timespec now;
	int64_t msec_to_next = INT64_MAX;

	weston_compositor_read_presentation_clock(compositor, &now);

	wl_list_for_each(output, &compositor->output_list, link) {
		int64_t msec_to_this;

		if (output->repaint_status != REPAINT_SCHEDULED)
			continue;

		msec_to_this = timespec_sub_to_msec(&output->next_repaint,
						    &now);
		if (!any_should_repaint || msec_to_this < msec_to_next)
			msec_to_next = msec_to_this;

		any_should_repaint = true;
	}

	if (!any_should_repaint)
		return;

	/* Even if we should repaint immediately, add the minimum 1 ms delay.
	 * This is a workaround to allow coalescing multiple output repaints
	 * particularly from weston_output_finish_frame()
	 * into the same call, which would not happen if we called
	 * output_repaint_timer_handler() directly.
	 */
	if (msec_to_next < 1)
		msec_to_next = 1;

	wl_event_source_timer_update(compositor->repaint_timer, msec_to_next);
}

static int
output_repaint_timer_handler(void *data)
{
	struct weston_compositor *compositor = data;
	struct weston_output *output;
	struct timespec now;
	void *repaint_data = NULL;
	int ret = 0;

	weston_compositor_read_presentation_clock(compositor, &now);

	if (compositor->backend->repaint_begin)
		repaint_data = compositor->backend->repaint_begin(compositor);

	wl_list_for_each(output, &compositor->output_list, link) {
		ret = weston_output_maybe_repaint(output, &now, repaint_data);
		if (ret)
			break;
	}

	if (ret == 0) {
		if (compositor->backend->repaint_flush)
			compositor->backend->repaint_flush(compositor,
							   repaint_data);
	} else {
		wl_list_for_each(output, &compositor->output_list, link) {
			if (output->repainted)
				weston_output_schedule_repaint_reset(output);
		}

		if (compositor->backend->repaint_cancel)
			compositor->backend->repaint_cancel(compositor,
							    repaint_data);
	}

	wl_list_for_each(output, &compositor->output_list, link)
		output->repainted = false;

	output_repaint_timer_arm(compositor);

	return 0;
}

WL_EXPORT void
weston_output_finish_frame(struct weston_output *output,
			   const struct timespec *stamp,
			   uint32_t presented_flags)
{
	struct weston_compositor *compositor = output->compositor;
	int32_t refresh_nsec;
	struct timespec now;
	int64_t msec_rel;


	assert(output->repaint_status == REPAINT_AWAITING_COMPLETION);
	assert(stamp || (presented_flags & WP_PRESENTATION_FEEDBACK_INVALID));

	weston_compositor_read_presentation_clock(compositor, &now);

	/* If we haven't been supplied any timestamp at all, we don't have a
	 * timebase to work against, so any delay just wastes time. Push a
	 * repaint as soon as possible so we can get on with it. */
	if (!stamp) {
		output->next_repaint = now;
		goto out;
	}

	TL_POINT("core_repaint_finished", TLP_OUTPUT(output),
		 TLP_VBLANK(stamp), TLP_END);

	refresh_nsec = millihz_to_nsec(output->current_mode->refresh);
	weston_presentation_feedback_present_list(&output->feedback_list,
						  output, refresh_nsec, stamp,
						  output->msc,
						  presented_flags);

	output->frame_time = *stamp;

	timespec_add_nsec(&output->next_repaint, stamp, refresh_nsec);
	timespec_add_msec(&output->next_repaint, &output->next_repaint,
			  -compositor->repaint_msec);
	msec_rel = timespec_sub_to_msec(&output->next_repaint, &now);

	if (msec_rel < -1000 || msec_rel > 1000) {
		static bool warned;

		if (!warned)
			weston_log("Warning: computed repaint delay is "
				   "insane: %lld msec\n", (long long) msec_rel);
		warned = true;

		output->next_repaint = now;
	}

	/* Called from restart_repaint_loop and restart happens already after
	 * the deadline given by repaint_msec? In that case we delay until
	 * the deadline of the next frame, to give clients a more predictable
	 * timing of the repaint cycle to lock on. */
	if (presented_flags == WP_PRESENTATION_FEEDBACK_INVALID &&
	    msec_rel < 0) {
		while (timespec_sub_to_nsec(&output->next_repaint, &now) < 0) {
			timespec_add_nsec(&output->next_repaint,
					  &output->next_repaint,
					  refresh_nsec);
		}
	}

out:
	output->repaint_status = REPAINT_SCHEDULED;
	output_repaint_timer_arm(compositor);
}

static void
idle_repaint(void *data)
{
	struct weston_output *output = data;

	assert(output->repaint_status == REPAINT_BEGIN_FROM_IDLE);
	output->repaint_status = REPAINT_AWAITING_COMPLETION;
	output->idle_repaint_source = NULL;
	output->start_repaint_loop(output);
}

WL_EXPORT void
weston_layer_entry_insert(struct weston_layer_entry *list,
			  struct weston_layer_entry *entry)
{
	wl_list_insert(&list->link, &entry->link);
	entry->layer = list->layer;
}

WL_EXPORT void
weston_layer_entry_remove(struct weston_layer_entry *entry)
{
	wl_list_remove(&entry->link);
	wl_list_init(&entry->link);
	entry->layer = NULL;
}


/** Initialize the weston_layer struct.
 *
 * \param compositor The compositor instance
 * \param layer The layer to initialize
 */
WL_EXPORT void
weston_layer_init(struct weston_layer *layer,
		  struct weston_compositor *compositor)
{
	layer->compositor = compositor;
	wl_list_init(&layer->link);
	wl_list_init(&layer->view_list.link);
	layer->view_list.layer = layer;
	weston_layer_set_mask_infinite(layer);
}

/** Sets the position of the layer in the layer list. The layer will be placed
 * below any layer with the same position value, if any.
 * This function is safe to call if the layer is already on the list, but the
 * layer may be moved below other layers at the same position, if any.
 *
 * \param layer The layer to modify
 * \param position The position the layer will be placed at
 */
WL_EXPORT void
weston_layer_set_position(struct weston_layer *layer,
			  enum weston_layer_position position)
{
	struct weston_layer *below;

	wl_list_remove(&layer->link);

	/* layer_list is ordered from top to bottom, the last layer being the
	 * background with the smallest position value */

	layer->position = position;
	wl_list_for_each_reverse(below, &layer->compositor->layer_list, link) {
		if (below->position >= layer->position) {
			wl_list_insert(&below->link, &layer->link);
			return;
		}
	}
	wl_list_insert(&layer->compositor->layer_list, &layer->link);
}

/** Hide a layer by taking it off the layer list.
 * This function is safe to call if the layer is not on the list.
 *
 * \param layer The layer to hide
 */
WL_EXPORT void
weston_layer_unset_position(struct weston_layer *layer)
{
	wl_list_remove(&layer->link);
	wl_list_init(&layer->link);
}

WL_EXPORT void
weston_layer_set_mask(struct weston_layer *layer,
		      int x, int y, int width, int height)
{
	struct weston_view *view;

	layer->mask.x1 = x;
	layer->mask.x2 = x + width;
	layer->mask.y1 = y;
	layer->mask.y2 = y + height;

	wl_list_for_each(view, &layer->view_list.link, layer_link.link) {
		weston_view_geometry_dirty(view);
	}
}

WL_EXPORT void
weston_layer_set_mask_infinite(struct weston_layer *layer)
{
	weston_layer_set_mask(layer, INT32_MIN, INT32_MIN,
				     UINT32_MAX, UINT32_MAX);
}

WL_EXPORT void
weston_output_schedule_repaint(struct weston_output *output)
{
	struct weston_compositor *compositor = output->compositor;
	struct wl_event_loop *loop;

	if (compositor->state == WESTON_COMPOSITOR_SLEEPING ||
	    compositor->state == WESTON_COMPOSITOR_OFFSCREEN)
		return;

	if (!output->repaint_needed)
		TL_POINT("core_repaint_req", TLP_OUTPUT(output), TLP_END);

	loop = wl_display_get_event_loop(compositor->wl_display);
	output->repaint_needed = true;

	/* If we already have a repaint scheduled for our idle handler,
	 * no need to set it again. If the repaint has been called but
	 * not finished, then weston_output_finish_frame() will notice
	 * that a repaint is needed and schedule one. */
	if (output->repaint_status != REPAINT_NOT_SCHEDULED)
		return;

	output->repaint_status = REPAINT_BEGIN_FROM_IDLE;
	assert(!output->idle_repaint_source);
	output->idle_repaint_source = wl_event_loop_add_idle(loop, idle_repaint,
							     output);
	TL_POINT("core_repaint_enter_loop", TLP_OUTPUT(output), TLP_END);
}

WL_EXPORT void
weston_compositor_schedule_repaint(struct weston_compositor *compositor)
{
	struct weston_output *output;

	wl_list_for_each(output, &compositor->output_list, link)
		weston_output_schedule_repaint(output);
}

static void
surface_destroy(struct wl_client *client, struct wl_resource *resource)
{
	wl_resource_destroy(resource);
}

static void
surface_attach(struct wl_client *client,
	       struct wl_resource *resource,
	       struct wl_resource *buffer_resource, int32_t sx, int32_t sy)
{
	struct weston_surface *surface = wl_resource_get_user_data(resource);
	struct weston_buffer *buffer = NULL;

	if (buffer_resource) {
		buffer = weston_buffer_from_resource(buffer_resource);
		if (buffer == NULL) {
			wl_client_post_no_memory(client);
			return;
		}
	}

	/* Attach, attach, without commit in between does not send
	 * wl_buffer.release. */
	weston_surface_state_set_buffer(&surface->pending, buffer);

	surface->pending.sx = sx;
	surface->pending.sy = sy;
	surface->pending.newly_attached = 1;
}

static void
surface_damage(struct wl_client *client,
	       struct wl_resource *resource,
	       int32_t x, int32_t y, int32_t width, int32_t height)
{
	struct weston_surface *surface = wl_resource_get_user_data(resource);

	if (width <= 0 || height <= 0)
		return;

	pixman_region32_union_rect(&surface->pending.damage_surface,
				   &surface->pending.damage_surface,
				   x, y, width, height);
}

static void
surface_damage_buffer(struct wl_client *client,
		      struct wl_resource *resource,
		      int32_t x, int32_t y, int32_t width, int32_t height)
{
	struct weston_surface *surface = wl_resource_get_user_data(resource);

	if (width <= 0 || height <= 0)
		return;

	pixman_region32_union_rect(&surface->pending.damage_buffer,
				   &surface->pending.damage_buffer,
				   x, y, width, height);
}

static void
destroy_frame_callback(struct wl_resource *resource)
{
	struct weston_frame_callback *cb = wl_resource_get_user_data(resource);

	wl_list_remove(&cb->link);
	free(cb);
}

static void
surface_frame(struct wl_client *client,
	      struct wl_resource *resource, uint32_t callback)
{
	struct weston_frame_callback *cb;
	struct weston_surface *surface = wl_resource_get_user_data(resource);

	cb = malloc(sizeof *cb);
	if (cb == NULL) {
		wl_resource_post_no_memory(resource);
		return;
	}

	cb->resource = wl_resource_create(client, &wl_callback_interface, 1,
					  callback);
	if (cb->resource == NULL) {
		free(cb);
		wl_resource_post_no_memory(resource);
		return;
	}

	wl_resource_set_implementation(cb->resource, NULL, cb,
				       destroy_frame_callback);

	wl_list_insert(surface->pending.frame_callback_list.prev, &cb->link);
}

static void
surface_set_opaque_region(struct wl_client *client,
			  struct wl_resource *resource,
			  struct wl_resource *region_resource)
{
	struct weston_surface *surface = wl_resource_get_user_data(resource);
	struct weston_region *region;

	if (region_resource) {
		region = wl_resource_get_user_data(region_resource);
		pixman_region32_copy(&surface->pending.opaque,
				     &region->region);
	} else {
		pixman_region32_clear(&surface->pending.opaque);
	}
}

static void
surface_set_input_region(struct wl_client *client,
			 struct wl_resource *resource,
			 struct wl_resource *region_resource)
{
	struct weston_surface *surface = wl_resource_get_user_data(resource);
	struct weston_region *region;

	if (region_resource) {
		region = wl_resource_get_user_data(region_resource);
		pixman_region32_copy(&surface->pending.input,
				     &region->region);
	} else {
		pixman_region32_fini(&surface->pending.input);
		region_init_infinite(&surface->pending.input);
	}
}

/* Cause damage to this sub-surface and all its children.
 *
 * This is useful when there are state changes that need an implicit
 * damage, e.g. a z-order change.
 */
static void
weston_surface_damage_subsurfaces(struct weston_subsurface *sub)
{
	struct weston_subsurface *child;

	weston_surface_damage(sub->surface);
	sub->reordered = false;

	wl_list_for_each(child, &sub->surface->subsurface_list, parent_link)
		if (child != sub)
			weston_surface_damage_subsurfaces(child);
}

static void
weston_surface_commit_subsurface_order(struct weston_surface *surface)
{
	struct weston_subsurface *sub;

	wl_list_for_each_reverse(sub, &surface->subsurface_list_pending,
				 parent_link_pending) {
		wl_list_remove(&sub->parent_link);
		wl_list_insert(&surface->subsurface_list, &sub->parent_link);

		if (sub->reordered)
			weston_surface_damage_subsurfaces(sub);
	}
}

static void
weston_surface_build_buffer_matrix(const struct weston_surface *surface,
				   struct weston_matrix *matrix)
{
	const struct weston_buffer_viewport *vp = &surface->buffer_viewport;
	double src_width, src_height, dest_width, dest_height;

	weston_matrix_init(matrix);

	if (vp->buffer.src_width == wl_fixed_from_int(-1)) {
		src_width = surface->width_from_buffer;
		src_height = surface->height_from_buffer;
	} else {
		src_width = wl_fixed_to_double(vp->buffer.src_width);
		src_height = wl_fixed_to_double(vp->buffer.src_height);
	}

	if (vp->surface.width == -1) {
		dest_width = src_width;
		dest_height = src_height;
	} else {
		dest_width = vp->surface.width;
		dest_height = vp->surface.height;
	}

	if (src_width != dest_width || src_height != dest_height)
		weston_matrix_scale(matrix,
				    src_width / dest_width,
				    src_height / dest_height, 1);

	if (vp->buffer.src_width != wl_fixed_from_int(-1))
		weston_matrix_translate(matrix,
					wl_fixed_to_double(vp->buffer.src_x),
					wl_fixed_to_double(vp->buffer.src_y),
					0);

	switch (vp->buffer.transform) {
	case WL_OUTPUT_TRANSFORM_FLIPPED:
	case WL_OUTPUT_TRANSFORM_FLIPPED_90:
	case WL_OUTPUT_TRANSFORM_FLIPPED_180:
	case WL_OUTPUT_TRANSFORM_FLIPPED_270:
		weston_matrix_scale(matrix, -1, 1, 1);
		weston_matrix_translate(matrix,
					surface->width_from_buffer, 0, 0);
		break;
	}

	switch (vp->buffer.transform) {
	default:
	case WL_OUTPUT_TRANSFORM_NORMAL:
	case WL_OUTPUT_TRANSFORM_FLIPPED:
		break;
	case WL_OUTPUT_TRANSFORM_90:
	case WL_OUTPUT_TRANSFORM_FLIPPED_90:
		weston_matrix_rotate_xy(matrix, 0, 1);
		weston_matrix_translate(matrix,
					surface->height_from_buffer, 0, 0);
		break;
	case WL_OUTPUT_TRANSFORM_180:
	case WL_OUTPUT_TRANSFORM_FLIPPED_180:
		weston_matrix_rotate_xy(matrix, -1, 0);
		weston_matrix_translate(matrix,
					surface->width_from_buffer,
					surface->height_from_buffer, 0);
		break;
	case WL_OUTPUT_TRANSFORM_270:
	case WL_OUTPUT_TRANSFORM_FLIPPED_270:
		weston_matrix_rotate_xy(matrix, 0, -1);
		weston_matrix_translate(matrix,
					0, surface->width_from_buffer, 0);
		break;
	}

	weston_matrix_scale(matrix, vp->buffer.scale, vp->buffer.scale, 1);
}

/**
 * Compute a + b > c while being safe to overflows.
 */
static bool
fixed_sum_gt(wl_fixed_t a, wl_fixed_t b, wl_fixed_t c)
{
	return (int64_t)a + (int64_t)b > (int64_t)c;
}

static bool
weston_surface_is_pending_viewport_source_valid(
	const struct weston_surface *surface)
{
	const struct weston_surface_state *pend = &surface->pending;
	const struct weston_buffer_viewport *vp = &pend->buffer_viewport;
	int width_from_buffer = 0;
	int height_from_buffer = 0;
	wl_fixed_t w;
	wl_fixed_t h;

	/* If viewport source rect is not set, it is always ok. */
	if (vp->buffer.src_width == wl_fixed_from_int(-1))
		return true;

	if (pend->newly_attached) {
		if (pend->buffer) {
			convert_size_by_transform_scale(&width_from_buffer,
							&height_from_buffer,
							pend->buffer->width,
							pend->buffer->height,
							vp->buffer.transform,
							vp->buffer.scale);
		} else {
			/* No buffer: viewport is irrelevant. */
			return true;
		}
	} else {
		width_from_buffer = surface->width_from_buffer;
		height_from_buffer = surface->height_from_buffer;
	}

	assert((width_from_buffer == 0) == (height_from_buffer == 0));
	assert(width_from_buffer >= 0 && height_from_buffer >= 0);

	/* No buffer: viewport is irrelevant. */
	if (width_from_buffer == 0 || height_from_buffer == 0)
		return true;

	/* overflow checks for wl_fixed_from_int() */
	if (width_from_buffer > wl_fixed_to_int(INT32_MAX))
		return false;
	if (height_from_buffer > wl_fixed_to_int(INT32_MAX))
		return false;

	w = wl_fixed_from_int(width_from_buffer);
	h = wl_fixed_from_int(height_from_buffer);

	if (fixed_sum_gt(vp->buffer.src_x, vp->buffer.src_width, w))
		return false;
	if (fixed_sum_gt(vp->buffer.src_y, vp->buffer.src_height, h))
		return false;

	return true;
}

static bool
fixed_is_integer(wl_fixed_t v)
{
	return (v & 0xff) == 0;
}</