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/*

 * Copyright © 2004 Carl Worth

 * Copyright © 2006 Red Hat, Inc.

 * Copyright © 2008 Chris Wilson

 *

 * This library is free software; you can redistribute it and/or

 * modify it either under the terms of the GNU Lesser General Public

 * License version 2.1 as published by the Free Software Foundation

 * (the "LGPL") or, at your option, under the terms of the Mozilla

 * Public License Version 1.1 (the "MPL"). If you do not alter this

 * notice, a recipient may use your version of this file under either

 * the MPL or the LGPL.

 *

 * You should have received a copy of the LGPL along with this library

 * in the file COPYING-LGPL-2.1; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA 02110-1335, USA

 * You should have received a copy of the MPL along with this library

 * in the file COPYING-MPL-1.1

 *

 * The contents of this file are subject to the Mozilla Public License

 * Version 1.1 (the "License"); you may not use this file except in

 * compliance with the License. You may obtain a copy of the License at

 * http://www.mozilla.org/MPL/

 *

 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY

 * OF ANY KIND, either express or implied. See the LGPL or the MPL for

 * the specific language governing rights and limitations.

 *

 * The Original Code is the cairo graphics library.

 *

 * The Initial Developer of the Original Code is Carl Worth

 *

 * Contributor(s):

 *	Carl D. Worth 

 *	Chris Wilson 

 */

/* Provide definitions for standalone compilation */

#include "cairoint.h"

#include "cairo-boxes-private.h"

#include "cairo-combsort-inline.h"

#include "cairo-error-private.h"

#include "cairo-traps-private.h"

typedef struct _cairo_bo_edge cairo_bo_edge_t;

typedef struct _cairo_bo_trap cairo_bo_trap_t;

/* A deferred trapezoid of an edge */

struct _cairo_bo_trap {

    cairo_bo_edge_t *right;

    int32_t top;

};

struct _cairo_bo_edge {

    cairo_edge_t edge;

    cairo_bo_edge_t *prev;

    cairo_bo_edge_t *next;

    cairo_bo_trap_t deferred_trap;

};

typedef enum {

    CAIRO_BO_EVENT_TYPE_START,

    CAIRO_BO_EVENT_TYPE_STOP

} cairo_bo_event_type_t;

typedef struct _cairo_bo_event {

    cairo_bo_event_type_t type;

    cairo_point_t point;

    cairo_bo_edge_t *edge;

} cairo_bo_event_t;

typedef struct _cairo_bo_sweep_line {

    cairo_bo_event_t **events;

    cairo_bo_edge_t *head;

    cairo_bo_edge_t *stopped;

    int32_t current_y;

    cairo_bo_edge_t *current_edge;

} cairo_bo_sweep_line_t;

static inline int

_cairo_point_compare (const cairo_point_t *a,

		      const cairo_point_t *b)

{

    int cmp;

    cmp = a->y - b->y;

    if (likely (cmp))

	return cmp;

    return a->x - b->x;

}

static inline int

_cairo_bo_edge_compare (const cairo_bo_edge_t	*a,

			const cairo_bo_edge_t	*b)

{

    int cmp;

    cmp = a->edge.line.p1.x - b->edge.line.p1.x;

    if (likely (cmp))

	return cmp;

    return b->edge.bottom - a->edge.bottom;

}

static inline int

cairo_bo_event_compare (const cairo_bo_event_t *a,

			const cairo_bo_event_t *b)

{

    int cmp;

    cmp = _cairo_point_compare (&a->point, &b->point);

    if (likely (cmp))

	return cmp;

    cmp = a->type - b->type;

    if (cmp)

	return cmp;

    return a - b;

}

static inline cairo_bo_event_t *

_cairo_bo_event_dequeue (cairo_bo_sweep_line_t *sweep_line)

{

    return *sweep_line->events++;

}

CAIRO_COMBSORT_DECLARE (_cairo_bo_event_queue_sort,

			cairo_bo_event_t *,

			cairo_bo_event_compare)

static void

_cairo_bo_sweep_line_init (cairo_bo_sweep_line_t *sweep_line,

			   cairo_bo_event_t	**events,

			   int			  num_events)

{

    _cairo_bo_event_queue_sort (events, num_events);

    events[num_events] = NULL;

    sweep_line->events = events;

    sweep_line->head = NULL;

    sweep_line->current_y = INT32_MIN;

    sweep_line->current_edge = NULL;

}

static void

_cairo_bo_sweep_line_insert (cairo_bo_sweep_line_t	*sweep_line,

			     cairo_bo_edge_t		*edge)

{

    if (sweep_line->current_edge != NULL) {

	cairo_bo_edge_t *prev, *next;

	int cmp;

	cmp = _cairo_bo_edge_compare (sweep_line->current_edge, edge);

	if (cmp < 0) {

	    prev = sweep_line->current_edge;

	    next = prev->next;

	    while (next != NULL && _cairo_bo_edge_compare (next, edge) < 0)

		prev = next, next = prev->next;

	    prev->next = edge;

	    edge->prev = prev;

	    edge->next = next;

	    if (next != NULL)

		next->prev = edge;

	} else if (cmp > 0) {

	    next = sweep_line->current_edge;

	    prev = next->prev;

	    while (prev != NULL && _cairo_bo_edge_compare (prev, edge) > 0)

		next = prev, prev = next->prev;

	    next->prev = edge;

	    edge->next = next;

	    edge->prev = prev;

	    if (prev != NULL)

		prev->next = edge;

	    else

		sweep_line->head = edge;

	} else {

	    prev = sweep_line->current_edge;

	    edge->prev = prev;

	    edge->next = prev->next;

	    if (prev->next != NULL)

		prev->next->prev = edge;

	    prev->next = edge;

	}

    } else {

	sweep_line->head = edge;

    }

    sweep_line->current_edge = edge;

}

static void

_cairo_bo_sweep_line_delete (cairo_bo_sweep_line_t	*sweep_line,

			     cairo_bo_edge_t	*edge)

{

    if (edge->prev != NULL)

	edge->prev->next = edge->next;

    else

	sweep_line->head = edge->next;

    if (edge->next != NULL)

	edge->next->prev = edge->prev;

    if (sweep_line->current_edge == edge)

	sweep_line->current_edge = edge->prev ? edge->prev : edge->next;

}

static inline cairo_bool_t

edges_collinear (const cairo_bo_edge_t *a, const cairo_bo_edge_t *b)

{

    return a->edge.line.p1.x == b->edge.line.p1.x;

}

static cairo_status_t

_cairo_bo_edge_end_trap (cairo_bo_edge_t	*left,

			 int32_t		 bot,

			 cairo_bool_t		 do_traps,

			 void			*container)

{

    cairo_bo_trap_t *trap = &left->deferred_trap;

    cairo_status_t status = CAIRO_STATUS_SUCCESS;

    /* Only emit (trivial) non-degenerate trapezoids with positive height. */

    if (likely (trap->top < bot)) {

	if (do_traps) {

	    _cairo_traps_add_trap (container,

				   trap->top, bot,

				   &left->edge.line, &trap->right->edge.line);

	    status =  _cairo_traps_status ((cairo_traps_t *) container);

	} else {

	    cairo_box_t box;

	    box.p1.x = left->edge.line.p1.x;

	    box.p1.y = trap->top;

	    box.p2.x = trap->right->edge.line.p1.x;

	    box.p2.y = bot;

	    status = _cairo_boxes_add (container, CAIRO_ANTIALIAS_DEFAULT, &box);

	}

    }

    trap->right = NULL;

    return status;

}

/* Start a new trapezoid at the given top y coordinate, whose edges

 * are `edge' and `edge->next'. If `edge' already has a trapezoid,

 * then either add it to the traps in `traps', if the trapezoid's

 * right edge differs from `edge->next', or do nothing if the new

 * trapezoid would be a continuation of the existing one. */

static inline cairo_status_t

_cairo_bo_edge_start_or_continue_trap (cairo_bo_edge_t	*left,

				       cairo_bo_edge_t  *right,

				       int               top,

				       cairo_bool_t	 do_traps,

				       void		*container)

{

    cairo_status_t status;

    if (left->deferred_trap.right == right)

	return CAIRO_STATUS_SUCCESS;

    if (left->deferred_trap.right != NULL) {

	if (right != NULL && edges_collinear (left->deferred_trap.right, right))

	{

	    /* continuation on right, so just swap edges */

	    left->deferred_trap.right = right;

	    return CAIRO_STATUS_SUCCESS;

	}

	status = _cairo_bo_edge_end_trap (left, top, do_traps, container);

	if (unlikely (status))

	    return status;

    }

    if (right != NULL && ! edges_collinear (left, right)) {

	left->deferred_trap.top = top;

	left->deferred_trap.right = right;

    }

    return CAIRO_STATUS_SUCCESS;

}

static inline cairo_status_t

_active_edges_to_traps (cairo_bo_edge_t		*left,

			int32_t			 top,

			cairo_fill_rule_t	 fill_rule,

			cairo_bool_t		 do_traps,

			void			*container)

{

    cairo_bo_edge_t *right;

    cairo_status_t status;

    if (fill_rule == CAIRO_FILL_RULE_WINDING) {

	while (left != NULL) {

	    int in_out;

	    /* Greedily search for the closing edge, so that we generate the

	     * maximal span width with the minimal number of trapezoids.

	     */

	    in_out = left->edge.dir;

	    /* Check if there is a co-linear edge with an existing trap */

	    right = left->next;

	    if (left->deferred_trap.right == NULL) {

		while (right != NULL && right->deferred_trap.right == NULL)

		    right = right->next;

		if (right != NULL && edges_collinear (left, right)) {

		    /* continuation on left */

		    left->deferred_trap = right->deferred_trap;

		    right->deferred_trap.right = NULL;

		}

	    }

	    /* End all subsumed traps */

	    right = left->next;

	    while (right != NULL) {

		if (right->deferred_trap.right != NULL) {

		    status = _cairo_bo_edge_end_trap (right, top, do_traps, container);

		    if (unlikely (status))

			return status;

		}

		in_out += right->edge.dir;

		if (in_out == 0) {

		    /* skip co-linear edges */

		    if (right->next == NULL ||

			! edges_collinear (right, right->next))

		    {

			break;

		    }

		}

		right = right->next;

	    }

	    status = _cairo_bo_edge_start_or_continue_trap (left, right, top,

							    do_traps, container);

	    if (unlikely (status))

		return status;

	    left = right;

	    if (left != NULL)

		left = left->next;

	}

    } else {

	while (left != NULL) {

	    int in_out = 0;

	    right = left->next;

	    while (right != NULL) {

		if (right->deferred_trap.right != NULL) {

		    status = _cairo_bo_edge_end_trap (right, top, do_traps, container);

		    if (unlikely (status))

			return status;

		}

		if ((in_out++ & 1) == 0) {

		    cairo_bo_edge_t *next;

		    cairo_bool_t skip = FALSE;

		    /* skip co-linear edges */

		    next = right->next;

		    if (next != NULL)

			skip = edges_collinear (right, next);

		    if (! skip)

			break;

		}

		right = right->next;

	    }

	    status = _cairo_bo_edge_start_or_continue_trap (left, right, top,

							    do_traps, container);

	    if (unlikely (status))

		return status;

	    left = right;

	    if (left != NULL)

		left = left->next;

	}

    }

    return CAIRO_STATUS_SUCCESS;

}

static cairo_status_t

_cairo_bentley_ottmann_tessellate_rectilinear (cairo_bo_event_t   **start_events,

					       int			 num_events,

					       cairo_fill_rule_t	 fill_rule,

					       cairo_bool_t		 do_traps,

					       void			*container)

{

    cairo_bo_sweep_line_t sweep_line;

    cairo_bo_event_t *event;

    cairo_status_t status;

    _cairo_bo_sweep_line_init (&sweep_line, start_events, num_events);

    while ((event = _cairo_bo_event_dequeue (&sweep_line))) {

	if (event->point.y != sweep_line.current_y) {

	    status = _active_edges_to_traps (sweep_line.head,

					     sweep_line.current_y,

					     fill_rule, do_traps, container);

	    if (unlikely (status))

		return status;

	    sweep_line.current_y = event->point.y;

	}

	switch (event->type) {

	case CAIRO_BO_EVENT_TYPE_START:

	    _cairo_bo_sweep_line_insert (&sweep_line, event->edge);

	    break;

	case CAIRO_BO_EVENT_TYPE_STOP:

	    _cairo_bo_sweep_line_delete (&sweep_line, event->edge);

	    if (event->edge->deferred_trap.right != NULL) {

		status = _cairo_bo_edge_end_trap (event->edge,

						  sweep_line.current_y,

						  do_traps, container);

		if (unlikely (status))

		    return status;

	    }

	    break;

	}

    }

    return CAIRO_STATUS_SUCCESS;

}

cairo_status_t

_cairo_bentley_ottmann_tessellate_rectilinear_polygon_to_boxes (const cairo_polygon_t *polygon,

								cairo_fill_rule_t	  fill_rule,

								cairo_boxes_t *boxes)

{

    cairo_status_t status;

    cairo_bo_event_t stack_events[CAIRO_STACK_ARRAY_LENGTH (cairo_bo_event_t)];

    cairo_bo_event_t *events;

    cairo_bo_event_t *stack_event_ptrs[ARRAY_LENGTH (stack_events) + 1];

    cairo_bo_event_t **event_ptrs;

    cairo_bo_edge_t stack_edges[ARRAY_LENGTH (stack_events)];

    cairo_bo_edge_t *edges;

    int num_events;

    int i, j;

    if (unlikely (polygon->num_edges == 0))

	return CAIRO_STATUS_SUCCESS;

    num_events = 2 * polygon->num_edges;

    events = stack_events;

    event_ptrs = stack_event_ptrs;

    edges = stack_edges;

    if (num_events > ARRAY_LENGTH (stack_events)) {

	events = _cairo_malloc_ab_plus_c (num_events,

					  sizeof (cairo_bo_event_t) +

					  sizeof (cairo_bo_edge_t) +

					  sizeof (cairo_bo_event_t *),

					  sizeof (cairo_bo_event_t *));

	if (unlikely (events == NULL))

	    return _cairo_error (CAIRO_STATUS_NO_MEMORY);

	event_ptrs = (cairo_bo_event_t **) (events + num_events);

	edges = (cairo_bo_edge_t *) (event_ptrs + num_events + 1);

    }

    for (i = j = 0; i < polygon->num_edges; i++) {

	edges[i].edge = polygon->edges[i];

	edges[i].deferred_trap.right = NULL;

	edges[i].prev = NULL;

	edges[i].next = NULL;

	event_ptrs[j] = &events[j];

	events[j].type = CAIRO_BO_EVENT_TYPE_START;

	events[j].point.y = polygon->edges[i].top;

	events[j].point.x = polygon->edges[i].line.p1.x;

	events[j].edge = &edges[i];

	j++;

	event_ptrs[j] = &events[j];

	events[j].type = CAIRO_BO_EVENT_TYPE_STOP;

	events[j].point.y = polygon->edges[i].bottom;

	events[j].point.x = polygon->edges[i].line.p1.x;

	events[j].edge = &edges[i];

	j++;

    }

    status = _cairo_bentley_ottmann_tessellate_rectilinear (event_ptrs, j,

							    fill_rule,

							    FALSE, boxes);

    if (events != stack_events)

	free (events);

    return status;

}

cairo_status_t

_cairo_bentley_ottmann_tessellate_rectilinear_traps (cairo_traps_t *traps,

						     cairo_fill_rule_t fill_rule)

{

    cairo_bo_event_t stack_events[CAIRO_STACK_ARRAY_LENGTH (cairo_bo_event_t)];

    cairo_bo_event_t *events;

    cairo_bo_event_t *stack_event_ptrs[ARRAY_LENGTH (stack_events) + 1];

    cairo_bo_event_t **event_ptrs;

    cairo_bo_edge_t stack_edges[ARRAY_LENGTH (stack_events)];

    cairo_bo_edge_t *edges;

    cairo_status_t status;

    int i, j, k;

    if (unlikely (traps->num_traps == 0))

	return CAIRO_STATUS_SUCCESS;

    assert (traps->is_rectilinear);

    i = 4 * traps->num_traps;

    events = stack_events;

    event_ptrs = stack_event_ptrs;

    edges = stack_edges;

    if (i > ARRAY_LENGTH (stack_events)) {

	events = _cairo_malloc_ab_plus_c (i,

					  sizeof (cairo_bo_event_t) +

					  sizeof (cairo_bo_edge_t) +

					  sizeof (cairo_bo_event_t *),

					  sizeof (cairo_bo_event_t *));

	if (unlikely (events == NULL))

	    return _cairo_error (CAIRO_STATUS_NO_MEMORY);

	event_ptrs = (cairo_bo_event_t **) (events + i);

	edges = (cairo_bo_edge_t *) (event_ptrs + i + 1);

    }

    for (i = j = k = 0; i < traps->num_traps; i++) {

	edges[k].edge.top = traps->traps[i].top;

	edges[k].edge.bottom = traps->traps[i].bottom;

	edges[k].edge.line = traps->traps[i].left;

	edges[k].edge.dir = 1;

	edges[k].deferred_trap.right = NULL;

	edges[k].prev = NULL;

	edges[k].next = NULL;

	event_ptrs[j] = &events[j];

	events[j].type = CAIRO_BO_EVENT_TYPE_START;

	events[j].point.y = traps->traps[i].top;

	events[j].point.x = traps->traps[i].left.p1.x;

	events[j].edge = &edges[k];

	j++;

	event_ptrs[j] = &events[j];

	events[j].type = CAIRO_BO_EVENT_TYPE_STOP;

	events[j].point.y = traps->traps[i].bottom;

	events[j].point.x = traps->traps[i].left.p1.x;

	events[j].edge = &edges[k];

	j++;

	k++;

	edges[k].edge.top = traps->traps[i].top;

	edges[k].edge.bottom = traps->traps[i].bottom;

	edges[k].edge.line = traps->traps[i].right;

	edges[k].edge.dir = -1;

	edges[k].deferred_trap.right = NULL;

	edges[k].prev = NULL;

	edges[k].next = NULL;

	event_ptrs[j] = &events[j];

	events[j].type = CAIRO_BO_EVENT_TYPE_START;

	events[j].point.y = traps->traps[i].top;

	events[j].point.x = traps->traps[i].right.p1.x;

	events[j].edge = &edges[k];

	j++;

	event_ptrs[j] = &events[j];

	events[j].type = CAIRO_BO_EVENT_TYPE_STOP;

	events[j].point.y = traps->traps[i].bottom;

	events[j].point.x = traps->traps[i].right.p1.x;

	events[j].edge = &edges[k];

	j++;

	k++;

    }

    _cairo_traps_clear (traps);

    status = _cairo_bentley_ottmann_tessellate_rectilinear (event_ptrs, j,

							    fill_rule,

							    TRUE, traps);

    traps->is_rectilinear = TRUE;

    if (events != stack_events)

	free (events);

    return status;

}