/*

 * Copyright © 2009  Red Hat, Inc.

 * Copyright © 2012  Google, Inc.

 *

 *  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.

 *

 * Red Hat Author(s): Behdad Esfahbod

 * Google Author(s): Behdad Esfahbod

 */

#include "hb.hh"

#include "hb-shaper.hh"

#include "hb-shape-plan.hh"

#include "hb-buffer.hh"

#include "hb-font.hh"

#include "hb-machinery.hh"

#ifndef HB_NO_SHAPER

/**

 * SECTION:hb-shape

 * @title: hb-shape

 * @short_description: Conversion of text strings into positioned glyphs

 * @include: hb.h

 *

 * Shaping is the central operation of HarfBuzz. Shaping operates on buffers,

 * which are sequences of Unicode characters that use the same font and have

 * the same text direction, script, and language. After shaping the buffer

 * contains the output glyphs and their positions.

 **/

static inline void free_static_shaper_list ();

static const char * const nil_shaper_list[] = {nullptr};

static struct hb_shaper_list_lazy_loader_t : hb_lazy_loader_t<const char *,

                    hb_shaper_list_lazy_loader_t>

{

  static const char ** create ()

  {

    const char **shaper_list = (const char **) hb_calloc (1 + HB_SHAPERS_COUNT, sizeof (const char *));

    if (unlikely (!shaper_list))

      return nullptr;

    const hb_shaper_entry_t *shapers = _hb_shapers_get ();

    unsigned int i;

    for (i = 0; i < HB_SHAPERS_COUNT; i++)

      shaper_list[i] = shapers[i].name;

    shaper_list[i] = nullptr;

    hb_atexit (free_static_shaper_list);

    return shaper_list;

  }

  static void destroy (const char **l)

  { hb_free (l); }

  static const char * const * get_null ()

  { return nil_shaper_list; }

} static_shaper_list;

static inline

void free_static_shaper_list ()

{

  static_shaper_list.free_instance ();

}

/**

 * hb_shape_list_shapers:

 *

 * Retrieves the list of shapers supported by HarfBuzz.

 *

 * Return value: (transfer none) (array zero-terminated=1): a

 *    `NULL`-terminated array of supported shapers constant string.

 *    The returned array is owned by HarfBuzz and should not be

 *    modified or freed.

 *

 * Since: 0.9.2

 **/

const char **

hb_shape_list_shapers ()

{

  return static_shaper_list.get_unconst ();

}

/**

 * hb_shape_full:

 * @font: an #hb_font_t to use for shaping

 * @buffer: an #hb_buffer_t to shape

 * @features: (array length=num_features) (nullable): an array of user

 *    specified #hb_feature_t or `NULL`

 * @num_features: the length of @features array

 * @shaper_list: (array zero-terminated=1) (nullable): a `NULL`-terminated

 *    array of shapers to use or `NULL`

 *

 * See hb_shape() for details. If @shaper_list is not `NULL`, the specified

 * shapers will be used in the given order, otherwise the default shapers list

 * will be used.

 *

 * Return value: false if all shapers failed, true otherwise

 *

 * Since: 0.9.2

 **/

hb_bool_t

hb_shape_full (hb_font_t          *font,

         hb_buffer_t        *buffer,

         const hb_feature_t *features,

         unsigned int        num_features,

         const char * const *shaper_list)

{

  if (unlikely (!buffer->len))

    return true;

  buffer->enter ();

  hb_buffer_t *text_buffer = nullptr;

  if (buffer->flags & HB_BUFFER_FLAG_VERIFY)

  {

    text_buffer = hb_buffer_create ();

    hb_buffer_append (text_buffer, buffer, 0, -1);

  }

  hb_shape_plan_t *shape_plan = hb_shape_plan_create_cached2 (font->face, &buffer->props,

                    features, num_features,

                    font->coords, font->num_coords,

                    shaper_list);

  hb_bool_t res = hb_shape_plan_execute (shape_plan, font, buffer, features, num_features);

  if (buffer->max_ops <= 0)

    buffer->shaping_failed = true;

  hb_shape_plan_destroy (shape_plan);

  if (text_buffer)

  {

    if (res && buffer->successful && !buffer->shaping_failed

      && text_buffer->successful

      && !buffer->verify (text_buffer,

        font,

        features,

        num_features,

        shaper_list))

      res = false;

    hb_buffer_destroy (text_buffer);

  }

  buffer->leave ();

  return res;

}

/**

 * hb_shape:

 * @font: an #hb_font_t to use for shaping

 * @buffer: an #hb_buffer_t to shape

 * @features: (array length=num_features) (nullable): an array of user

 *    specified #hb_feature_t or `NULL`

 * @num_features: the length of @features array

 *

 * Shapes @buffer using @font turning its Unicode characters content to

 * positioned glyphs. If @features is not `NULL`, it will be used to control the

 * features applied during shaping. If two @features have the same tag but

 * overlapping ranges the value of the feature with the higher index takes

 * precedence.

 *

 * Since: 0.9.2

 **/

void

hb_shape (hb_font_t           *font,

    hb_buffer_t         *buffer,

    const hb_feature_t  *features,

    unsigned int         num_features)

{

  hb_shape_full (font, buffer, features, num_features, nullptr);

}

#ifdef HB_EXPERIMENTAL_API

static float

buffer_advance (hb_buffer_t *buffer)

{

  float a = 0;

  auto *pos = buffer->pos;

  unsigned count = buffer->len;

  if (HB_DIRECTION_IS_HORIZONTAL (buffer->props.direction))

    for (unsigned i = 0; i < count; i++)

      a += pos[i].x_advance;

  else

    for (unsigned i = 0; i < count; i++)

      a += pos[i].y_advance;

  return a;

}

static void

reset_buffer (hb_buffer_t *buffer,

        hb_array_t<const hb_glyph_info_t> text)

{

  assert (buffer->ensure (text.length));

  buffer->have_positions = false;

  buffer->len = text.length;

  hb_memcpy (buffer->info, text.arrayZ, text.length * sizeof (buffer->info[0]));

  hb_buffer_set_content_type (buffer, HB_BUFFER_CONTENT_TYPE_UNICODE);

}

/**

 * hb_shape_justify:

 * @font: a mutable #hb_font_t to use for shaping

 * @buffer: an #hb_buffer_t to shape

 * @features: (array length=num_features) (nullable): an array of user

 *    specified #hb_feature_t or `NULL`

 * @num_features: the length of @features array

 * @shaper_list: (array zero-terminated=1) (nullable): a `NULL`-terminated

 *    array of shapers to use or `NULL`

 * @min_target_advance: Minimum advance width/height to aim for.

 * @max_target_advance: Maximum advance width/height to aim for.

 * @advance: (inout): Input/output advance width/height of the buffer.

 * @var_tag: (out): Variation-axis tag used for justification.

 * @var_value: (out): Variation-axis value used to reach target justification.

 *

 * See hb_shape_full() for basic details. If @shaper_list is not `NULL`, the specified

 * shapers will be used in the given order, otherwise the default shapers list

 * will be used.

 *

 * In addition, justify the shaping results such that the shaping results reach

 * the target advance width/height, depending on the buffer direction.

 *

 * If the advance of the buffer shaped with hb_shape_full() is already known,

 * put that in *advance. Otherwise set *advance to zero.

 *

 * This API is currently experimental and will probably change in the future.

 *

 * Return value: false if all shapers failed, true otherwise

 *

 * XSince: EXPERIMENTAL

 **/

hb_bool_t

hb_shape_justify (hb_font_t          *font,

      hb_buffer_t        *buffer,

      const hb_feature_t *features,

      unsigned int        num_features,

      const char * const *shaper_list,

      float               min_target_advance,

      float               max_target_advance,

      float              *advance, /* IN/OUT */

      hb_tag_t           *var_tag, /* OUT */

      float              *var_value /* OUT */)

{

  // TODO Negative font scales?

  /* If default advance already matches target, nothing to do. Shape and return. */

  if (min_target_advance <= *advance && *advance <= max_target_advance)

  {

    *var_tag = HB_TAG_NONE;

    *var_value = 0.0f;

    return hb_shape_full (font, buffer,

        features, num_features,

        shaper_list);

  }

  hb_face_t *face = font->face;

  /* Choose variation tag to use for justification. */

  hb_tag_t tag = HB_TAG_NONE;

  hb_ot_var_axis_info_t axis_info;

  hb_tag_t tags[] =

  {

    HB_TAG ('j','s','t','f'),

    HB_TAG ('w','d','t','h'),

  };

  for (unsigned i = 0; i < ARRAY_LENGTH (tags); i++)

    if (hb_ot_var_find_axis_info (face, tags[i], &axis_info))

    {

      tag = *var_tag = tags[i];

      break;

    }

  /* If no suitable variation axis found, can't justify.  Just shape and return. */

  if (!tag)

  {

    *var_tag = HB_TAG_NONE;

    *var_value = 0.0f;

    if (hb_shape_full (font, buffer,

           features, num_features,

           shaper_list))

    {

      *advance = buffer_advance (buffer);

      return true;

    }

    else

      return false;

  }

  /* Copy buffer text as we need it so we can shape multiple times. */

  unsigned text_len = buffer->len;

  auto *text_info = (hb_glyph_info_t *) hb_malloc (text_len * sizeof (buffer->info[0]));

  if (unlikely (text_len && !text_info))

    return false;

  hb_memcpy (text_info, buffer->info, text_len * sizeof (buffer->info[0]));

  auto text = hb_array<const hb_glyph_info_t> (text_info, text_len);

  /* If default advance was not provided to us, calculate it. */

  if (!*advance)

  {

    hb_font_set_variation (font, tag, axis_info.default_value);

    if (!hb_shape_full (font, buffer,

      features, num_features,

      shaper_list))

      return false;

    *advance = buffer_advance (buffer);

  }

  /* If default advance already matches target, nothing to do. Shape and return.

   * Do this again, in case advance was just calculated.

   */

  if (min_target_advance <= *advance && *advance <= max_target_advance)

  {

    *var_tag = HB_TAG_NONE;

    *var_value = 0.0f;

    return true;

  }

  /* Prepare for running the solver. */

  double a, b, ya, yb;

  if (*advance < min_target_advance)

  {

    /* Need to expand. */

    ya = (double) *advance;

    a = (double) axis_info.default_value;

    b = (double) axis_info.max_value;

    /* Shape buffer for maximum expansion to use as other

     * starting point for the solver. */

    hb_font_set_variation (font, tag, (float) b);

    reset_buffer (buffer, text);

    if (!hb_shape_full (font, buffer,

      features, num_features,

      shaper_list))

      return false;

    yb = (double) buffer_advance (buffer);

    /* If the maximum expansion is less than max target,

     * there's nothing to solve for. Just return it. */

    if (yb <= (double) max_target_advance)

    {

      *var_value = (float) b;

      *advance = (float) yb;

      return true;

    }

  }

  else

  {

    /* Need to shrink. */

    yb = (double) *advance;

    a = (double) axis_info.min_value;

    b = (double) axis_info.default_value;

    /* Shape buffer for maximum shrinkate to use as other

     * starting point for the solver. */

    hb_font_set_variation (font, tag, (float) a);

    reset_buffer (buffer, text);

    if (!hb_shape_full (font, buffer,

      features, num_features,

      shaper_list))

      return false;

    ya = (double) buffer_advance (buffer);

    /* If the maximum shrinkate is more than min target,

     * there's nothing to solve for. Just return it. */

    if (ya >= (double) min_target_advance)

    {

      *var_value = (float) a;

      *advance = (float) ya;

      return true;

    }

  }

  /* Run the solver to find a var axis value that hits

   * the desired width. */

  double epsilon = (b - a) / (1<<14);

  bool failed = false;

  auto f = [&] (double x)

  {

    hb_font_set_variation (font, tag, (float) x);

    reset_buffer (buffer, text);

    if (unlikely (!hb_shape_full (font, buffer,

          features, num_features,

          shaper_list)))

    {

      failed = true;

      return (double) min_target_advance;

    }

    double w = (double) buffer_advance (buffer);

    DEBUG_MSG (JUSTIFY, nullptr, "Trying '%c%c%c%c' axis parameter %f. Advance %g. Target: min %g max %g",

         HB_UNTAG (tag), x, w,

         (double) min_target_advance, (double) max_target_advance);

    return w;

  };

  double y = 0;

  double itp = solve_itp (f,

        a, b,

        epsilon,

        (double) min_target_advance, (double) max_target_advance,

        ya, yb, y);

  hb_free (text_info);

  if (failed)

    return false;

  *var_value = (float) itp;

  *advance = (float) y;

  return true;

}

#endif

#endif