/*

 * Copyright © 2022 Behdad Esfahbod

 *

 *  This is part of HarfBuzz, a text shaping library.

 *

 * Permission is hereby granted, without written agreement and without

 * license or royalty fees, to use, copy, modify, and distribute this

 * software and its documentation for any purpose, provided that the

 * above copyright notice and the following two paragraphs appear in

 * all copies of this software.

 *

 * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR

 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES

 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN

 * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH

 * DAMAGE.

 *

 * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,

 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND

 * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS

 * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO

 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.

 */

#ifndef HB_PAINT_EXTENTS_HH

#define HB_PAINT_EXTENTS_HH

#include "hb.hh"

#include "hb-paint.h"

#include "hb-geometry.hh"

typedef struct  hb_paint_extents_context_t hb_paint_extents_context_t;

struct hb_paint_extents_context_t

{

  void clear ()

  {

    transforms.clear ();

    clips.clear ();

    groups.clear ();

    /* COLR scratch storage is zero-allocated and reused without running

     * constructors.  Distinguish that state from an explicitly requested

     * zero budget. */

    if (unlikely (!budget_initialized))

    {

      budget = HB_BUDGET_DEFAULT;

      budget_initialized = true;

    }

    recharge_budget ();

    transforms.push (hb_transform_t<>{});

    clips.push (hb_bounds_t<>{hb_bounds_t<>::UNBOUNDED});

    groups.push (hb_bounds_t<>{hb_bounds_t<>::EMPTY});

  }

  hb_paint_extents_context_t ()

  {

    clear ();

  }

  hb_extents_t<> get_extents ()

  {

    return groups.tail().extents;

  }

  bool is_bounded ()

  {

    return groups.tail().status != hb_bounds_t<>::UNBOUNDED;

  }

  void push_transform (const hb_transform_t<> &trans)

  {

    hb_transform_t<> t = transforms.tail ();

    t.multiply (trans);

    transforms.push (t);

  }

  void pop_transform ()

  {

    transforms.pop ();

  }

  void push_clip (hb_extents_t<> extents)

  {

    /* Transform extents and push a new clip. */

    const hb_transform_t<> &t = transforms.tail ();

    t.transform_extents (extents);

    auto bounds = hb_bounds_t<> {extents};

    bounds.intersect (clips.tail ());

    clips.push (bounds);

  }

  void pop_clip ()

  {

    clips.pop ();

  }

  void push_group ()

  {

    groups.push (hb_bounds_t<> {hb_bounds_t<>::EMPTY});

  }

  void pop_group (hb_paint_composite_mode_t mode)

  {

    const hb_bounds_t<> src_bounds = groups.pop ();

    hb_bounds_t<> &backdrop_bounds = groups.tail ();

    // https://learn.microsoft.com/en-us/typography/opentype/spec/colr#format-32-paintcomposite

    switch ((int) mode)

    {

      case HB_PAINT_COMPOSITE_MODE_CLEAR:

  backdrop_bounds.status = hb_bounds_t<>::EMPTY;

  break;

      case HB_PAINT_COMPOSITE_MODE_SRC:

      case HB_PAINT_COMPOSITE_MODE_SRC_OUT:

  backdrop_bounds = src_bounds;

  break;

      case HB_PAINT_COMPOSITE_MODE_DEST:

      case HB_PAINT_COMPOSITE_MODE_DEST_OUT:

  break;

      case HB_PAINT_COMPOSITE_MODE_SRC_IN:

      case HB_PAINT_COMPOSITE_MODE_DEST_IN:

  backdrop_bounds.intersect (src_bounds);

  break;

      default:

  backdrop_bounds.union_ (src_bounds);

  break;

     }

  }

  void paint ()

  {

    const hb_bounds_t<> &clip = clips.tail ();

    hb_bounds_t<> &group = groups.tail ();

    group.union_ (clip);

  }

  /* Cumulative work budget for the current session; reset by clear().

   * Outline traversal and consumed segments charge the same live

   * counter. */

  int64_t budget = HB_BUDGET_DEFAULT;

  bool budget_initialized = true;

  int64_t budget_remaining = HB_BUDGET_GLYPH;

  void recharge_budget ()

  {

    budget_remaining = budget == HB_BUDGET_DEFAULT ?

           HB_BUDGET_GLYPH : budget;

  }

  protected:

  hb_vector_t<hb_transform_t<>> transforms;

  hb_vector_t<hb_bounds_t<>> clips;

  hb_vector_t<hb_bounds_t<>> groups;

};

HB_INTERNAL hb_paint_funcs_t *

hb_paint_extents_get_funcs ();

#endif /* HB_PAINT_EXTENTS_HH */