/* -*- Mode: c; tab-width: 8; c-basic-offset: 4; indent-tabs-mode: t; -*- */

/* cairo - a vector graphics library with display and print output

 *

 * Copyright © 2002 University of Southern California

 * Copyright © 2005 Red Hat, Inc.

 * Copyright © 2009 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 University of Southern

 * California.

 *

 * Contributor(s):

 *  Carl D. Worth <cworth@cworth.org>

 *  Kristian Høgsberg <krh@redhat.com>

 *  Chris Wilson <chris@chris-wilson.co.uk>

 */

#include "cairoint.h"

#include "cairo-box-inline.h"

#include "cairo-clip-inline.h"

#include "cairo-clip-private.h"

#include "cairo-error-private.h"

#include "cairo-freed-pool-private.h"

#include "cairo-gstate-private.h"

#include "cairo-path-fixed-private.h"

#include "cairo-pattern-private.h"

#include "cairo-composite-rectangles-private.h"

#include "cairo-region-private.h"

static cairo_bool_t

_cairo_clip_contains_rectangle_box (const cairo_clip_t *clip,

            const cairo_rectangle_int_t *rect,

            const cairo_box_t *box)

{

    int i;

    /* clip == NULL means no clip, so the clip contains everything */

    if (clip == NULL)

  return TRUE;

    if (_cairo_clip_is_all_clipped (clip))

  return FALSE;

    /* If we have a non-trivial path, just say no */

    if (clip->path)

  return FALSE;

    if (! _cairo_rectangle_contains_rectangle (&clip->extents, rect))

  return FALSE;

    if (clip->num_boxes == 0)

  return TRUE;

    /* Check for a clip-box that wholly contains the rectangle */

    for (i = 0; i < clip->num_boxes; i++) {

  if (box->p1.x >= clip->boxes[i].p1.x &&

      box->p1.y >= clip->boxes[i].p1.y &&

      box->p2.x <= clip->boxes[i].p2.x &&

      box->p2.y <= clip->boxes[i].p2.y)

  {

      return TRUE;

  }

    }

    return FALSE;

}

cairo_bool_t

_cairo_clip_contains_box (const cairo_clip_t *clip,

        const cairo_box_t *box)

{

    cairo_rectangle_int_t rect;

    _cairo_box_round_to_rectangle (box, &rect);

    return _cairo_clip_contains_rectangle_box(clip, &rect, box);

}

cairo_bool_t

_cairo_clip_contains_rectangle (const cairo_clip_t *clip,

        const cairo_rectangle_int_t *rect)

{

    cairo_box_t box;

    _cairo_box_from_rectangle_int (&box, rect);

    return _cairo_clip_contains_rectangle_box (clip, rect, &box);

}

cairo_clip_t *

_cairo_clip_intersect_rectilinear_path (cairo_clip_t *clip,

          const cairo_path_fixed_t *path,

          cairo_fill_rule_t fill_rule,

          cairo_antialias_t antialias)

{

    cairo_status_t status;

    cairo_boxes_t boxes;

    _cairo_boxes_init (&boxes);

    status = _cairo_path_fixed_fill_rectilinear_to_boxes (path,

                fill_rule,

                antialias,

                &boxes);

    if (likely (status == CAIRO_STATUS_SUCCESS && boxes.num_boxes))

  clip = _cairo_clip_intersect_boxes (clip, &boxes);

    else

  clip = _cairo_clip_set_all_clipped (clip);

    _cairo_boxes_fini (&boxes);

    return clip;

}

static cairo_clip_t *

_cairo_clip_intersect_rectangle_box (cairo_clip_t *clip,

             const cairo_rectangle_int_t *r,

             const cairo_box_t *box)

{

    cairo_box_t extents_box;

    cairo_bool_t changed = FALSE;

    int i, j;

    if (clip == NULL) {

  clip = _cairo_clip_create ();

  if (clip == NULL)

      return _cairo_clip_set_all_clipped (clip);

    }

    if (clip->num_boxes == 0) {

  clip->boxes = &clip->embedded_box;

  clip->boxes[0] = *box;

  clip->num_boxes = 1;

  if (clip->path == NULL) {

      clip->extents = *r;

  } else {

      if (! _cairo_rectangle_intersect (&clip->extents, r))

    return _cairo_clip_set_all_clipped (clip);

  }

  if (clip->path == NULL)

      clip->is_region = _cairo_box_is_pixel_aligned (box);

  return clip;

    }

    /* Does the new box wholly subsume the clip? Perform a cheap check

     * for the common condition of a single clip rectangle.

     */

    if (clip->num_boxes == 1 &&

  clip->boxes[0].p1.x >= box->p1.x &&

  clip->boxes[0].p1.y >= box->p1.y &&

  clip->boxes[0].p2.x <= box->p2.x &&

  clip->boxes[0].p2.y <= box->p2.y)

    {

  return clip;

    }

    for (i = j = 0; i < clip->num_boxes; i++) {

  cairo_box_t *b = &clip->boxes[j];

  if (j != i)

      *b = clip->boxes[i];

  if (box->p1.x > b->p1.x)

      b->p1.x = box->p1.x, changed = TRUE;

  if (box->p2.x < b->p2.x)

      b->p2.x = box->p2.x, changed = TRUE;

  if (box->p1.y > b->p1.y)

      b->p1.y = box->p1.y, changed = TRUE;

  if (box->p2.y < b->p2.y)

      b->p2.y = box->p2.y, changed = TRUE;

  j += b->p2.x > b->p1.x && b->p2.y > b->p1.y;

    }

    clip->num_boxes = j;

    if (clip->num_boxes == 0)

  return _cairo_clip_set_all_clipped (clip);

    if (! changed)

  return clip;

    extents_box = clip->boxes[0];

    for (i = 1; i < clip->num_boxes; i++) {

      if (clip->boxes[i].p1.x < extents_box.p1.x)

    extents_box.p1.x = clip->boxes[i].p1.x;

      if (clip->boxes[i].p1.y < extents_box.p1.y)

    extents_box.p1.y = clip->boxes[i].p1.y;

      if (clip->boxes[i].p2.x > extents_box.p2.x)

    extents_box.p2.x = clip->boxes[i].p2.x;

      if (clip->boxes[i].p2.y > extents_box.p2.y)

    extents_box.p2.y = clip->boxes[i].p2.y;

    }

    if (clip->path == NULL) {

  _cairo_box_round_to_rectangle (&extents_box, &clip->extents);

    } else {

  cairo_rectangle_int_t extents_rect;

  _cairo_box_round_to_rectangle (&extents_box, &extents_rect);

  if (! _cairo_rectangle_intersect (&clip->extents, &extents_rect))

      return _cairo_clip_set_all_clipped (clip);

    }

    if (clip->region) {

  cairo_region_destroy (clip->region);

  clip->region = NULL;

    }

    clip->is_region = FALSE;

    return clip;

}

cairo_clip_t *

_cairo_clip_intersect_box (cairo_clip_t *clip,

         const cairo_box_t *box)

{

    cairo_rectangle_int_t r;

    if (_cairo_clip_is_all_clipped (clip))

  return clip;

    _cairo_box_round_to_rectangle (box, &r);

    if (r.width == 0 || r.height == 0)

  return _cairo_clip_set_all_clipped (clip);

    return _cairo_clip_intersect_rectangle_box (clip, &r, box);

}

/* Copy a box set to a clip

 *

 * @param boxes  The box set to copy from.

 * @param clip   The clip to copy to (return buffer).

 * @returns      Zero if the allocation failed (the clip will be set to

 *               all-clipped), otherwise non-zero.

 */

static cairo_bool_t

_cairo_boxes_copy_to_clip (const cairo_boxes_t *boxes, cairo_clip_t *clip)

{

    /* XXX cow-boxes? */

    if (boxes->num_boxes == 1) {

  clip->boxes = &clip->embedded_box;

  clip->boxes[0] = boxes->chunks.base[0];

  clip->num_boxes = 1;

  return TRUE;

    }

    clip->boxes = _cairo_boxes_to_array (boxes, &clip->num_boxes);

    if (unlikely (clip->boxes == NULL))

    {

  _cairo_clip_set_all_clipped (clip);

  return FALSE;

    }

    return TRUE;

}

cairo_clip_t *

_cairo_clip_intersect_boxes (cairo_clip_t *clip,

           const cairo_boxes_t *boxes)

{

    cairo_boxes_t clip_boxes;

    cairo_box_t limits;

    cairo_rectangle_int_t extents;

    if (_cairo_clip_is_all_clipped (clip))

  return clip;

    if (boxes->num_boxes == 0)

  return _cairo_clip_set_all_clipped (clip);

    if (boxes->num_boxes == 1)

  return _cairo_clip_intersect_box (clip, boxes->chunks.base);

    if (clip == NULL)

  clip = _cairo_clip_create ();

    if (clip->num_boxes) {

  _cairo_boxes_init_for_array (&clip_boxes, clip->boxes, clip->num_boxes);

  if (unlikely (_cairo_boxes_intersect (&clip_boxes, boxes, &clip_boxes))) {

      clip = _cairo_clip_set_all_clipped (clip);

      goto out;

  }

  if (clip->boxes != &clip->embedded_box)

      free (clip->boxes);

  clip->boxes = NULL;

  boxes = &clip_boxes;

    }

    if (boxes->num_boxes == 0) {

  clip = _cairo_clip_set_all_clipped (clip);

  goto out;

    }

    if (!_cairo_boxes_copy_to_clip (boxes, clip)) {

  clip = _cairo_clip_set_all_clipped (clip);

  goto out;

    }

    _cairo_boxes_extents (boxes, &limits);

    _cairo_box_round_to_rectangle (&limits, &extents);

    if (clip->path == NULL) {

  clip->extents = extents;

    } else if (! _cairo_rectangle_intersect (&clip->extents, &extents)) {

  clip = _cairo_clip_set_all_clipped (clip);

  goto out;

    }

    if (clip->region) {

  cairo_region_destroy (clip->region);

  clip->region = NULL;

    }

    clip->is_region = FALSE;

out:

    if (boxes == &clip_boxes)

  _cairo_boxes_fini (&clip_boxes);

    return clip;

}

cairo_clip_t *

_cairo_clip_intersect_rectangle (cairo_clip_t       *clip,

         const cairo_rectangle_int_t *r)

{

    cairo_box_t box;

    if (_cairo_clip_is_all_clipped (clip))

  return clip;

    if (r->width == 0 || r->height == 0)

  return _cairo_clip_set_all_clipped (clip);

    _cairo_box_from_rectangle_int (&box, r);

    return _cairo_clip_intersect_rectangle_box (clip, r, &box);

}

struct reduce {

    cairo_clip_t *clip;

    cairo_box_t limit;

    cairo_box_t extents;

    cairo_bool_t inside;

    cairo_point_t current_point;

    cairo_point_t last_move_to;

};

static void

_add_clipped_edge (struct reduce *r,

       const cairo_point_t *p1,

       const cairo_point_t *p2,

       int y1, int y2)

{

    cairo_fixed_t x;

    x = _cairo_edge_compute_intersection_x_for_y (p1, p2, y1);

    if (x < r->extents.p1.x)

  r->extents.p1.x = x;

    x = _cairo_edge_compute_intersection_x_for_y (p1, p2, y2);

    if (x > r->extents.p2.x)

  r->extents.p2.x = x;

    if (y1 < r->extents.p1.y)

  r->extents.p1.y = y1;

    if (y2 > r->extents.p2.y)

  r->extents.p2.y = y2;

    r->inside = TRUE;

}

static void

_add_edge (struct reduce *r,

     const cairo_point_t *p1,

     const cairo_point_t *p2)

{

    int top, bottom;

    int top_y, bot_y;

    int n;

    if (p1->y < p2->y) {

  top = p1->y;

  bottom = p2->y;

    } else {

  top = p2->y;

  bottom = p1->y;

    }

    if (bottom < r->limit.p1.y || top > r->limit.p2.y)

  return;

    if (p1->x > p2->x) {

  const cairo_point_t *t = p1;

  p1 = p2;

  p2 = t;

    }

    if (p2->x <= r->limit.p1.x || p1->x >= r->limit.p2.x)

  return;

    for (n = 0; n < r->clip->num_boxes; n++) {

  const cairo_box_t *limits = &r->clip->boxes[n];

  if (bottom < limits->p1.y || top > limits->p2.y)

      continue;

  if (p2->x <= limits->p1.x || p1->x >= limits->p2.x)

      continue;

  if (p1->x >= limits->p1.x && p2->x <= limits->p1.x) {

      top_y = top;

      bot_y = bottom;

  } else {

      int p1_y, p2_y;

      p1_y = _cairo_edge_compute_intersection_y_for_x (p1, p2,

                   limits->p1.x);

      p2_y = _cairo_edge_compute_intersection_y_for_x (p1, p2,

                   limits->p2.x);

      if (p1_y < p2_y) {

    top_y = p1_y;

    bot_y = p2_y;

      } else {

    top_y = p2_y;

    bot_y = p1_y;

      }

      if (top_y < top)

    top_y = top;

      if (bot_y > bottom)

    bot_y = bottom;

  }

  if (top_y < limits->p1.y)

      top_y = limits->p1.y;

  if (bot_y > limits->p2.y)

      bot_y = limits->p2.y;

  if (bot_y > top_y)

      _add_clipped_edge (r, p1, p2, top_y, bot_y);

    }

}

static cairo_status_t

_reduce_line_to (void *closure,

           const cairo_point_t *point)

{

    struct reduce *r = closure;

    _add_edge (r, &r->current_point, point);

    r->current_point = *point;

    return CAIRO_STATUS_SUCCESS;

}

static cairo_status_t

_reduce_close (void *closure)

{

    struct reduce *r = closure;

    return _reduce_line_to (r, &r->last_move_to);

}

static cairo_status_t

_reduce_move_to (void *closure,

     const cairo_point_t *point)

{

    struct reduce *r = closure;

    cairo_status_t status;

    /* close current subpath */

    status = _reduce_close (closure);

    /* make sure that the closure represents a degenerate path */

    r->current_point = *point;

    r->last_move_to = *point;

    return status;

}

static cairo_clip_t *

_cairo_clip_reduce_to_boxes (cairo_clip_t *clip)

{

    struct reduce r;

    cairo_clip_path_t *clip_path;

    cairo_status_t status;

  return clip;

    if (clip->path == NULL)

  return clip;

    r.clip = clip;

    r.extents.p1.x = r.extents.p1.y = INT_MAX;

    r.extents.p2.x = r.extents.p2.y = INT_MIN;

    r.inside = FALSE;

    r.limit.p1.x = _cairo_fixed_from_int (clip->extents.x);

    r.limit.p1.y = _cairo_fixed_from_int (clip->extents.y);

    r.limit.p2.x = _cairo_fixed_from_int (clip->extents.x + clip->extents.width);

    r.limit.p2.y = _cairo_fixed_from_int (clip->extents.y + clip->extents.height);

    clip_path = clip->path;

    do {

  r.current_point.x = 0;

  r.current_point.y = 0;

  r.last_move_to = r.current_point;

  status = _cairo_path_fixed_interpret_flat (&clip_path->path,

               _reduce_move_to,

               _reduce_line_to,

               _reduce_close,

               &r,

               clip_path->tolerance);

  assert (status == CAIRO_STATUS_SUCCESS);

  _reduce_close (&r);

    } while ((clip_path = clip_path->prev));

    if (! r.inside) {

  _cairo_clip_path_destroy (clip->path);

  clip->path = NULL;

    }

    return _cairo_clip_intersect_box (clip, &r.extents);

}

cairo_clip_t *

_cairo_clip_reduce_to_rectangle (const cairo_clip_t *clip,

         const cairo_rectangle_int_t *r)

{

    cairo_clip_t *copy;

    if (_cairo_clip_is_all_clipped (clip))

  return (cairo_clip_t *) clip;

    if (_cairo_clip_contains_rectangle (clip, r))

  return _cairo_clip_intersect_rectangle (NULL, r);

    copy = _cairo_clip_copy_intersect_rectangle (clip, r);

    if (_cairo_clip_is_all_clipped (copy))

  return copy;

    return _cairo_clip_reduce_to_boxes (copy);

}

cairo_clip_t *

_cairo_clip_reduce_for_composite (const cairo_clip_t *clip,

          cairo_composite_rectangles_t *extents)

{

    const cairo_rectangle_int_t *r;

    r = extents->is_bounded ? &extents->bounded : &extents->unbounded;

    return _cairo_clip_reduce_to_rectangle (clip, r);

}

cairo_clip_t *

_cairo_clip_from_boxes (const cairo_boxes_t *boxes)

{

    cairo_box_t extents;

    cairo_clip_t *clip = _cairo_clip_create ();

    if (clip == NULL)

  return _cairo_clip_set_all_clipped (clip);

    if (unlikely (! _cairo_boxes_copy_to_clip (boxes, clip)))

  return clip;

    _cairo_boxes_extents (boxes, &extents);

    _cairo_box_round_to_rectangle (&extents, &clip->extents);

    return clip;

}