util/shape-options.hh - third_party/harfbuzz - Git at Google

 /*
  * Copyright © 2011  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.
  *
  * Google Author(s): Behdad Esfahbod
  */

 #ifndef SHAPE_OPTIONS_HH
 #define SHAPE_OPTIONS_HH

 #include "options.hh"

 struct shape_options_t
 {
   ~shape_options_t ()
   {
     g_free (direction);
     g_free (language);
     g_free (script);
     free (features);
     g_strfreev (shapers);
   }

   void add_options (option_parser_t *parser);

   void setup_buffer (hb_buffer_t *buffer)
   {
     hb_buffer_set_direction (buffer, hb_direction_from_string (direction, -1));
     hb_buffer_set_script (buffer, hb_script_from_string (script, -1));
     hb_buffer_set_language (buffer, hb_language_from_string (language, -1));
     hb_buffer_set_flags (buffer, (hb_buffer_flags_t)
 				 (HB_BUFFER_FLAG_DEFAULT |
 				  (bot ? HB_BUFFER_FLAG_BOT : 0) |
 				  (eot ? HB_BUFFER_FLAG_EOT : 0) |
 				  (verify ? HB_BUFFER_FLAG_VERIFY : 0) |
 				  (unsafe_to_concat ? HB_BUFFER_FLAG_PRODUCE_UNSAFE_TO_CONCAT : 0) |
 				  (safe_to_insert_tatweel ? HB_BUFFER_FLAG_PRODUCE_SAFE_TO_INSERT_TATWEEL : 0) |
 				  (preserve_default_ignorables ? HB_BUFFER_FLAG_PRESERVE_DEFAULT_IGNORABLES : 0) |
 				  (remove_default_ignorables ? HB_BUFFER_FLAG_REMOVE_DEFAULT_IGNORABLES : 0) |
 				  0));
     hb_buffer_set_invisible_glyph (buffer, invisible_glyph);
     hb_buffer_set_not_found_glyph (buffer, not_found_glyph);
     hb_buffer_set_cluster_level (buffer, cluster_level);
     hb_buffer_guess_segment_properties (buffer);
   }

   void populate_buffer (hb_buffer_t *buffer, const char *text, int text_len,
 			const char *text_before, const char *text_after,
 			hb_font_t *font)
   {
     hb_buffer_clear_contents (buffer);

     if (glyphs)
     {
       /* Call the setup_buffer first while the buffer is empty,
        * as guess_segment_properties doesn't like glyphs in the buffer. */

       setup_buffer (buffer);
       char *glyphs_text = (char *) text;
       int glyphs_len = text_len;
       if (glyphs_len < 0)
 	glyphs_len = strlen (glyphs_text);

       if (glyphs_len && glyphs_text[glyphs_len - 1] != ']')
       {
 	glyphs_text = g_strdup_printf ("%*s]", glyphs_len, glyphs_text);
 	glyphs_len = -1;
       }

       hb_buffer_deserialize_glyphs (buffer,
 				    glyphs_text, glyphs_len,
 				    nullptr,
 				    font,
 				    HB_BUFFER_SERIALIZE_FORMAT_TEXT);

       if (!strchr (glyphs_text, '+'))
       {
         scale_advances = false;
         unsigned count;
 	hb_direction_t direction = hb_buffer_get_direction (buffer);
 	hb_glyph_info_t *infos = hb_buffer_get_glyph_infos (buffer, &count);
 	hb_glyph_position_t *positions = hb_buffer_get_glyph_positions (buffer, &count);
 	for (unsigned i = 0; i < count; i++)
 	  hb_font_get_glyph_advance_for_direction (font,
 						   infos[i].codepoint,
 						   direction,
 						   &positions[i].x_advance,
 						   &positions[i].y_advance);
       }

       if (glyphs_text != text)
         g_free (glyphs_text);

       return;
     }

     if (text_before) {
       unsigned int len = strlen (text_before);
       hb_buffer_add_utf8 (buffer, text_before, len, len, 0);
     }
     hb_buffer_add_utf8 (buffer, text, text_len, 0, text_len);
     if (text_after) {
       hb_buffer_add_utf8 (buffer, text_after, -1, 0, 0);
     }

     if (!utf8_clusters) {
       /* Reset cluster values to refer to Unicode character index
        * instead of UTF-8 index. */
       unsigned int num_glyphs = hb_buffer_get_length (buffer);
       hb_glyph_info_t *info = hb_buffer_get_glyph_infos (buffer, nullptr);
       for (unsigned int i = 0; i < num_glyphs; i++)
       {
 	info->cluster = i;
 	info++;
       }
     }

     setup_buffer (buffer);
   }

   hb_bool_t shape (hb_font_t *font, hb_buffer_t *buffer, const char **error=nullptr)
   {
     if (glyphs)
     {
       /* Scale positions. */
       int x_scale, y_scale;
       hb_font_get_scale (font, &x_scale, &y_scale);
       unsigned upem = hb_face_get_upem (hb_font_get_face (font));
       unsigned count;
       auto *positions = hb_buffer_get_glyph_positions (buffer, &count);
       for (unsigned i = 0; i < count; i++)
       {
 	auto &pos = positions[i];
 	pos.x_offset = pos.x_offset * x_scale / upem;
 	pos.y_offset = pos.y_offset * y_scale / upem;
 	if (scale_advances)
 	{
 	  pos.x_advance = pos.x_advance * x_scale / upem;
 	  pos.y_advance = pos.y_advance * y_scale / upem;
 	}
       }
     }
     else
     {
       if (advance <= 0)
       {
 	if (!hb_shape_full (font, buffer, features, num_features, shapers))
 	{
 	  if (error)
 	    *error = "Shaping failed.";
 	  goto fail;
 	}

 	if (advance < 0)
 	{
 	  float unit = (1 << SUBPIXEL_BITS);

 	  /* Calculate buffer advance */
 	  float w = 0;
 	  unsigned count = 0;
 	  hb_glyph_position_t *pos = hb_buffer_get_glyph_positions (buffer, &count);
 	  if (HB_DIRECTION_IS_HORIZONTAL (hb_buffer_get_direction (buffer)))
 	    for (unsigned i = 0; i < count; i++)
 	      w += pos[i].x_advance;
 	  else
 	    for (unsigned i = 0; i < count; i++)
 	      w += pos[i].y_advance;

 	  printf ("Default size: %u\n", (unsigned) roundf (w / unit));
 	  exit (0);
 	}
       }
 #ifdef HB_EXPERIMENTAL_API
       else
       {
         float unit = (1 << SUBPIXEL_BITS);
         float target_advance = advance * unit;
 	float w = 0;
 	hb_tag_t var_tag;
 	float var_value;
 	if (!hb_shape_justify (font, buffer, features, num_features, shapers,
 			       target_advance - unit * 0.5f, target_advance + unit * 0.5f,
 			       &w, &var_tag, &var_value))
 	{
 	  if (error)
 	    *error = "Shaping failed.";
 	  goto fail;
 	}
       }
 #endif
     }

     if (normalize_glyphs)
       hb_buffer_normalize_glyphs (buffer);

     return true;

   fail:
     return false;
   }

   void shape_closure (const char *text, int text_len,
 		      hb_font_t *font, hb_buffer_t *buffer,
 		      hb_set_t *glyphs)
   {
     hb_buffer_reset (buffer);
     hb_buffer_add_utf8 (buffer, text, text_len, 0, text_len);
     setup_buffer (buffer);
     hb_ot_shape_glyphs_closure (font, buffer, features, num_features, glyphs);
   }

   /* Buffer properties */
   char *direction = nullptr;
   char *language = nullptr;
   char *script = nullptr;

   /* Buffer flags */
   hb_bool_t bot = false;
   hb_bool_t eot = false;
   hb_bool_t preserve_default_ignorables = false;
   hb_bool_t remove_default_ignorables = false;

   hb_feature_t *features = nullptr;
   unsigned int num_features = 0;
   char **shapers = nullptr;
   signed advance = 0;
   hb_bool_t utf8_clusters = false;
   hb_codepoint_t invisible_glyph = 0;
   hb_codepoint_t not_found_glyph = 0;
   hb_buffer_cluster_level_t cluster_level = HB_BUFFER_CLUSTER_LEVEL_DEFAULT;
   hb_bool_t normalize_glyphs = false;
   hb_bool_t glyphs = false;
   bool scale_advances = true;
   hb_bool_t verify = false;
   hb_bool_t unsafe_to_concat = false;
   hb_bool_t safe_to_insert_tatweel = false;
   unsigned int num_iterations = 1;
 };


 static gboolean
 parse_shapers (const char *name G_GNUC_UNUSED,
 	       const char *arg,
 	       gpointer    data,
 	       GError    **error)
 {
   shape_options_t *shape_opts = (shape_options_t *) data;
   char **shapers = g_strsplit (arg, ",", 0);

   for (char **shaper = shapers; *shaper; shaper++)
   {
     bool found = false;
     for (const char **hb_shaper = hb_shape_list_shapers (); *hb_shaper; hb_shaper++) {
       if (strcmp (*shaper, *hb_shaper) == 0)
       {
 	found = true;
 	break;
       }
     }
     if (!found)
     {
       g_set_error (error, G_OPTION_ERROR, G_OPTION_ERROR_BAD_VALUE,
 		   "Unknown or unsupported shaper: %s", *shaper);
       g_strfreev (shapers);
       return false;
     }
   }

   g_strfreev (shape_opts->shapers);
   shape_opts->shapers = shapers;
   return true;
 }

 static G_GNUC_NORETURN gboolean
 list_shapers (const char *name G_GNUC_UNUSED,
 	      const char *arg G_GNUC_UNUSED,
 	      gpointer    data G_GNUC_UNUSED,
 	      GError    **error G_GNUC_UNUSED)
 {
   for (const char **shaper = hb_shape_list_shapers (); *shaper; shaper++)
     g_printf ("%s\n", *shaper);

   exit(0);
 }


 static gboolean
 parse_features (const char *name G_GNUC_UNUSED,
 		const char *arg,
 		gpointer    data,
 		GError    **error G_GNUC_UNUSED)
 {
   shape_options_t *shape_opts = (shape_options_t *) data;
   char *s = (char *) arg;
   size_t l = strlen (s);
   char *p;

   shape_opts->num_features = 0;
   g_free (shape_opts->features);
   shape_opts->features = nullptr;

   /* if the string is quoted, strip the quotes */
   if (s[0] == s[l - 1] && (s[0] == '\"' || s[0] == '\''))
   {
     s[l - 1] = '\0';
     s++;
   }

   if (!*s)
     return true;

   /* count the features first, so we can allocate memory */
   p = s;
   do {
     shape_opts->num_features++;
     p = strpbrk (p, ", ");
     if (p)
       p++;
   } while (p);

   shape_opts->features = (hb_feature_t *) calloc (shape_opts->num_features, sizeof (*shape_opts->features));
   if (!shape_opts->features)
     return false;

   /* now do the actual parsing */
   p = s;
   shape_opts->num_features = 0;
   while (p && *p) {
     char *end = strpbrk (p, ", ");
     if (hb_feature_from_string (p, end ? end - p : -1, &shape_opts->features[shape_opts->num_features]))
       shape_opts->num_features++;
     p = end ? end + 1 : nullptr;
   }

   return true;
 }

 void
 shape_options_t::add_options (option_parser_t *parser)
 {
   GOptionEntry entries[] =
   {
     {"list-shapers",	0, G_OPTION_FLAG_NO_ARG,
 			      G_OPTION_ARG_CALLBACK,	(gpointer) &list_shapers,	"List available shapers and quit",	nullptr},
     {"shaper",		0, G_OPTION_FLAG_HIDDEN,
 			      G_OPTION_ARG_CALLBACK,	(gpointer) &parse_shapers,	"Hidden duplicate of --shapers",	nullptr},
     {"shapers",		0, 0, G_OPTION_ARG_CALLBACK,	(gpointer) &parse_shapers,	"Set comma-separated list of shapers to try","list"},
     {"direction",	0, 0, G_OPTION_ARG_STRING,	&this->direction,		"Set text direction (default: auto)",	"ltr/rtl/ttb/btt"},
     {"language",	0, 0, G_OPTION_ARG_STRING,	&this->language,		"Set text language (default: $LANG)",	"BCP 47 tag"},
     {"script",		0, 0, G_OPTION_ARG_STRING,	&this->script,			"Set text script (default: auto)",	"ISO-15924 tag"},
     {"bot",		0, 0, G_OPTION_ARG_NONE,	&this->bot,			"Treat text as beginning-of-paragraph",	nullptr},
     {"eot",		0, 0, G_OPTION_ARG_NONE,	&this->eot,			"Treat text as end-of-paragraph",	nullptr},
 #ifdef HB_EXPERIMENTAL_API
     {"justify-to",	0, 0,
 			      G_OPTION_ARG_INT,		&this->advance,			"Target size to justify to",		"SIZE, or -1"},
 #endif
     {"preserve-default-ignorables",0, 0, G_OPTION_ARG_NONE,	&this->preserve_default_ignorables,	"Preserve Default-Ignorable characters",	nullptr},
     {"remove-default-ignorables",0, 0, G_OPTION_ARG_NONE,	&this->remove_default_ignorables,	"Remove Default-Ignorable characters",	nullptr},
     {"invisible-glyph",	0, 0, G_OPTION_ARG_INT,		&this->invisible_glyph,		"Glyph value to replace Default-Ignorables with",	nullptr},
     {"not-found-glyph",	0, 0, G_OPTION_ARG_INT,		&this->not_found_glyph,		"Glyph value to replace not-found characters with",	nullptr},
     {"utf8-clusters",	0, 0, G_OPTION_ARG_NONE,	&this->utf8_clusters,		"Use UTF8 byte indices, not char indices",	nullptr},
     {"cluster-level",	0, 0, G_OPTION_ARG_INT,		&this->cluster_level,		"Cluster merging level (default: 0)",	"0/1/2"},
     {"normalize-glyphs",0, 0, G_OPTION_ARG_NONE,	&this->normalize_glyphs,	"Rearrange glyph clusters in nominal order",	nullptr},
     {"unsafe-to-concat",0, 0, G_OPTION_ARG_NONE,	&this->unsafe_to_concat,	"Produce unsafe-to-concat glyph flag",	nullptr},
     {"safe-to-insert-tatweel",0, 0, G_OPTION_ARG_NONE,	&this->safe_to_insert_tatweel,	"Produce safe-to-insert-tatweel glyph flag",	nullptr},
     {"glyphs",		0, 0, G_OPTION_ARG_NONE,	&this->glyphs,			"Interpret input as glyph string",	nullptr},
     {"verify",		0, 0, G_OPTION_ARG_NONE,	&this->verify,			"Perform sanity checks on shaping results",	nullptr},
     {"num-iterations",	'n',G_OPTION_FLAG_IN_MAIN,
 			      G_OPTION_ARG_INT,		&this->num_iterations,		"Run shaper N times (default: 1)",	"N"},
     {nullptr}
   };
   parser->add_group (entries,
 		     "shape",
 		     "Shape options:",
 		     "Options for the shaping process",
 		     this);

   const gchar *features_help = "Comma-separated list of font features\n"
     "\n"
     "    Features can be enabled or disabled, either globally or limited to\n"
     "    specific character ranges.  The format for specifying feature settings\n"
     "    follows.  All valid CSS font-feature-settings values other than 'normal'\n"
     "    and the global values are also accepted, though not documented below.\n"
     "    CSS string escapes are not supported."
     "\n"
     "    The range indices refer to the positions between Unicode characters,\n"
     "    unless the --utf8-clusters is provided, in which case range indices\n"
     "    refer to UTF-8 byte indices. The position before the first character\n"
     "    is always 0.\n"
     "\n"
     "    The format is Python-esque.  Here is how it all works:\n"
     "\n"
     "      Syntax:       Value:    Start:    End:\n"
     "\n"
     "    Setting value:\n"
     "      \"kern\"        1         0         ∞         # Turn feature on\n"
     "      \"+kern\"       1         0         ∞         # Turn feature on\n"
     "      \"-kern\"       0         0         ∞         # Turn feature off\n"
     "      \"kern=0\"      0         0         ∞         # Turn feature off\n"
     "      \"kern=1\"      1         0         ∞         # Turn feature on\n"
     "      \"aalt=2\"      2         0         ∞         # Choose 2nd alternate\n"
     "\n"
     "    Setting index:\n"
     "      \"kern[]\"      1         0         ∞         # Turn feature on\n"
     "      \"kern[:]\"     1         0         ∞         # Turn feature on\n"
     "      \"kern[5:]\"    1         5         ∞         # Turn feature on, partial\n"
     "      \"kern[:5]\"    1         0         5         # Turn feature on, partial\n"
     "      \"kern[3:5]\"   1         3         5         # Turn feature on, range\n"
     "      \"kern[3]\"     1         3         3+1       # Turn feature on, single char\n"
     "\n"
     "    Mixing it all:\n"
     "\n"
     "      \"aalt[3:5]=2\" 2         3         5         # Turn 2nd alternate on for range";

   GOptionEntry entries2[] =
   {
     {"features",	0, 0, G_OPTION_ARG_CALLBACK,	(gpointer) &parse_features,	features_help,	"list"},
     {nullptr}
   };
   parser->add_group (entries2,
 		     "features",
 		     "Features options:",
 		     "Options for font features used",
 		     this);
 }

 #endif
	/*
	* Copyright © 2011 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.
	*
	* Google Author(s): Behdad Esfahbod
	*/

	#ifndef SHAPE_OPTIONS_HH
	#define SHAPE_OPTIONS_HH

	#include "options.hh"

	struct shape_options_t
	{
	~shape_options_t ()
	{
	g_free (direction);
	g_free (language);
	g_free (script);
	free (features);
	g_strfreev (shapers);
	}

	void add_options (option_parser_t *parser);

	void setup_buffer (hb_buffer_t *buffer)
	{
	hb_buffer_set_direction (buffer, hb_direction_from_string (direction, -1));
	hb_buffer_set_script (buffer, hb_script_from_string (script, -1));
	hb_buffer_set_language (buffer, hb_language_from_string (language, -1));
	hb_buffer_set_flags (buffer, (hb_buffer_flags_t)
	(HB_BUFFER_FLAG_DEFAULT \|
	(bot ? HB_BUFFER_FLAG_BOT : 0) \|
	(eot ? HB_BUFFER_FLAG_EOT : 0) \|
	(verify ? HB_BUFFER_FLAG_VERIFY : 0) \|
	(unsafe_to_concat ? HB_BUFFER_FLAG_PRODUCE_UNSAFE_TO_CONCAT : 0) \|
	(safe_to_insert_tatweel ? HB_BUFFER_FLAG_PRODUCE_SAFE_TO_INSERT_TATWEEL : 0) \|
	(preserve_default_ignorables ? HB_BUFFER_FLAG_PRESERVE_DEFAULT_IGNORABLES : 0) \|
	(remove_default_ignorables ? HB_BUFFER_FLAG_REMOVE_DEFAULT_IGNORABLES : 0) \|
	0));
	hb_buffer_set_invisible_glyph (buffer, invisible_glyph);
	hb_buffer_set_not_found_glyph (buffer, not_found_glyph);
	hb_buffer_set_cluster_level (buffer, cluster_level);
	hb_buffer_guess_segment_properties (buffer);
	}

	void populate_buffer (hb_buffer_t buffer, const char text, int text_len,
	const char text_before, const char text_after,
	hb_font_t *font)
	{
	hb_buffer_clear_contents (buffer);

	if (glyphs)
	{
	/* Call the setup_buffer first while the buffer is empty,
	* as guess_segment_properties doesn't like glyphs in the buffer. */

	setup_buffer (buffer);
	char glyphs_text = (char ) text;
	int glyphs_len = text_len;
	if (glyphs_len < 0)
	glyphs_len = strlen (glyphs_text);

	if (glyphs_len && glyphs_text[glyphs_len - 1] != ']')
	{
	glyphs_text = g_strdup_printf ("%*s]", glyphs_len, glyphs_text);
	glyphs_len = -1;
	}

	hb_buffer_deserialize_glyphs (buffer,
	glyphs_text, glyphs_len,
	nullptr,
	font,
	HB_BUFFER_SERIALIZE_FORMAT_TEXT);

	if (!strchr (glyphs_text, '+'))
	{
	scale_advances = false;
	unsigned count;
	hb_direction_t direction = hb_buffer_get_direction (buffer);
	hb_glyph_info_t *infos = hb_buffer_get_glyph_infos (buffer, &count);
	hb_glyph_position_t *positions = hb_buffer_get_glyph_positions (buffer, &count);
	for (unsigned i = 0; i < count; i++)
	hb_font_get_glyph_advance_for_direction (font,
	infos[i].codepoint,
	direction,
	&positions[i].x_advance,
	&positions[i].y_advance);
	}

	if (glyphs_text != text)
	g_free (glyphs_text);

	return;
	}

	if (text_before) {
	unsigned int len = strlen (text_before);
	hb_buffer_add_utf8 (buffer, text_before, len, len, 0);
	}
	hb_buffer_add_utf8 (buffer, text, text_len, 0, text_len);
	if (text_after) {
	hb_buffer_add_utf8 (buffer, text_after, -1, 0, 0);
	}

	if (!utf8_clusters) {
	/* Reset cluster values to refer to Unicode character index
	* instead of UTF-8 index. */
	unsigned int num_glyphs = hb_buffer_get_length (buffer);
	hb_glyph_info_t *info = hb_buffer_get_glyph_infos (buffer, nullptr);
	for (unsigned int i = 0; i < num_glyphs; i++)
	{
	info->cluster = i;
	info++;
	}
	}

	setup_buffer (buffer);
	}

	hb_bool_t shape (hb_font_t font, hb_buffer_t buffer, const char **error=nullptr)
	{
	if (glyphs)
	{
	/* Scale positions. */
	int x_scale, y_scale;
	hb_font_get_scale (font, &x_scale, &y_scale);
	unsigned upem = hb_face_get_upem (hb_font_get_face (font));
	unsigned count;
	auto *positions = hb_buffer_get_glyph_positions (buffer, &count);
	for (unsigned i = 0; i < count; i++)
	{
	auto &pos = positions[i];
	pos.x_offset = pos.x_offset * x_scale / upem;
	pos.y_offset = pos.y_offset * y_scale / upem;
	if (scale_advances)
	{
	pos.x_advance = pos.x_advance * x_scale / upem;
	pos.y_advance = pos.y_advance * y_scale / upem;
	}
	}
	}
	else
	{
	if (advance <= 0)
	{
	if (!hb_shape_full (font, buffer, features, num_features, shapers))
	{
	if (error)
	*error = "Shaping failed.";
	goto fail;
	}

	if (advance < 0)
	{
	float unit = (1 << SUBPIXEL_BITS);

	/* Calculate buffer advance */
	float w = 0;
	unsigned count = 0;
	hb_glyph_position_t *pos = hb_buffer_get_glyph_positions (buffer, &count);
	if (HB_DIRECTION_IS_HORIZONTAL (hb_buffer_get_direction (buffer)))
	for (unsigned i = 0; i < count; i++)
	w += pos[i].x_advance;
	else
	for (unsigned i = 0; i < count; i++)
	w += pos[i].y_advance;

	printf ("Default size: %u\n", (unsigned) roundf (w / unit));
	exit (0);
	}
	}
	#ifdef HB_EXPERIMENTAL_API
	else
	{
	float unit = (1 << SUBPIXEL_BITS);
	float target_advance = advance * unit;
	float w = 0;
	hb_tag_t var_tag;
	float var_value;
	if (!hb_shape_justify (font, buffer, features, num_features, shapers,
	target_advance - unit * 0.5f, target_advance + unit * 0.5f,
	&w, &var_tag, &var_value))
	{
	if (error)
	*error = "Shaping failed.";
	goto fail;
	}
	}
	#endif
	}

	if (normalize_glyphs)
	hb_buffer_normalize_glyphs (buffer);

	return true;

	fail:
	return false;
	}

	void shape_closure (const char *text, int text_len,
	hb_font_t font, hb_buffer_t buffer,
	hb_set_t *glyphs)
	{
	hb_buffer_reset (buffer);
	hb_buffer_add_utf8 (buffer, text, text_len, 0, text_len);
	setup_buffer (buffer);
	hb_ot_shape_glyphs_closure (font, buffer, features, num_features, glyphs);
	}

	/* Buffer properties */
	char *direction = nullptr;
	char *language = nullptr;
	char *script = nullptr;

	/* Buffer flags */
	hb_bool_t bot = false;
	hb_bool_t eot = false;
	hb_bool_t preserve_default_ignorables = false;
	hb_bool_t remove_default_ignorables = false;

	hb_feature_t *features = nullptr;
	unsigned int num_features = 0;
	char **shapers = nullptr;
	signed advance = 0;
	hb_bool_t utf8_clusters = false;
	hb_codepoint_t invisible_glyph = 0;
	hb_codepoint_t not_found_glyph = 0;
	hb_buffer_cluster_level_t cluster_level = HB_BUFFER_CLUSTER_LEVEL_DEFAULT;
	hb_bool_t normalize_glyphs = false;
	hb_bool_t glyphs = false;
	bool scale_advances = true;
	hb_bool_t verify = false;
	hb_bool_t unsafe_to_concat = false;
	hb_bool_t safe_to_insert_tatweel = false;
	unsigned int num_iterations = 1;
	};


	static gboolean
	parse_shapers (const char *name G_GNUC_UNUSED,
	const char *arg,
	gpointer data,
	GError **error)
	{
	shape_options_t shape_opts = (shape_options_t ) data;
	char **shapers = g_strsplit (arg, ",", 0);

	for (char *shaper = shapers; shaper; shaper++)
	{
	bool found = false;
	for (const char *hb_shaper = hb_shape_list_shapers (); hb_shaper; hb_shaper++) {
	if (strcmp (shaper, hb_shaper) == 0)
	{
	found = true;
	break;
	}
	}
	if (!found)
	{
	g_set_error (error, G_OPTION_ERROR, G_OPTION_ERROR_BAD_VALUE,
	"Unknown or unsupported shaper: %s", *shaper);
	g_strfreev (shapers);
	return false;
	}
	}

	g_strfreev (shape_opts->shapers);
	shape_opts->shapers = shapers;
	return true;
	}

	static G_GNUC_NORETURN gboolean
	list_shapers (const char *name G_GNUC_UNUSED,
	const char *arg G_GNUC_UNUSED,
	gpointer data G_GNUC_UNUSED,
	GError **error G_GNUC_UNUSED)
	{
	for (const char *shaper = hb_shape_list_shapers (); shaper; shaper++)
	g_printf ("%s\n", *shaper);

	exit(0);
	}


	static gboolean
	parse_features (const char *name G_GNUC_UNUSED,
	const char *arg,
	gpointer data,
	GError **error G_GNUC_UNUSED)
	{
	shape_options_t shape_opts = (shape_options_t ) data;
	char s = (char ) arg;
	size_t l = strlen (s);
	char *p;

	shape_opts->num_features = 0;
	g_free (shape_opts->features);
	shape_opts->features = nullptr;

	/* if the string is quoted, strip the quotes */
	if (s[0] == s[l - 1] && (s[0] == '\"' \|\| s[0] == '\''))
	{
	s[l - 1] = '\0';
	s++;
	}

	if (!*s)
	return true;

	/* count the features first, so we can allocate memory */
	p = s;
	do {
	shape_opts->num_features++;
	p = strpbrk (p, ", ");
	if (p)
	p++;
	} while (p);

	shape_opts->features = (hb_feature_t ) calloc (shape_opts->num_features, sizeof (shape_opts->features));
	if (!shape_opts->features)
	return false;

	/* now do the actual parsing */
	p = s;
	shape_opts->num_features = 0;
	while (p && *p) {
	char *end = strpbrk (p, ", ");
	if (hb_feature_from_string (p, end ? end - p : -1, &shape_opts->features[shape_opts->num_features]))
	shape_opts->num_features++;
	p = end ? end + 1 : nullptr;
	}

	return true;
	}

	void
	shape_options_t::add_options (option_parser_t *parser)
	{
	GOptionEntry entries[] =
	{
	{"list-shapers", 0, G_OPTION_FLAG_NO_ARG,
	G_OPTION_ARG_CALLBACK, (gpointer) &list_shapers, "List available shapers and quit", nullptr},
	{"shaper", 0, G_OPTION_FLAG_HIDDEN,
	G_OPTION_ARG_CALLBACK, (gpointer) &parse_shapers, "Hidden duplicate of --shapers", nullptr},
	{"shapers", 0, 0, G_OPTION_ARG_CALLBACK, (gpointer) &parse_shapers, "Set comma-separated list of shapers to try","list"},
	{"direction", 0, 0, G_OPTION_ARG_STRING, &this->direction, "Set text direction (default: auto)", "ltr/rtl/ttb/btt"},
	{"language", 0, 0, G_OPTION_ARG_STRING, &this->language, "Set text language (default: $LANG)", "BCP 47 tag"},
	{"script", 0, 0, G_OPTION_ARG_STRING, &this->script, "Set text script (default: auto)", "ISO-15924 tag"},
	{"bot", 0, 0, G_OPTION_ARG_NONE, &this->bot, "Treat text as beginning-of-paragraph", nullptr},
	{"eot", 0, 0, G_OPTION_ARG_NONE, &this->eot, "Treat text as end-of-paragraph", nullptr},
	#ifdef HB_EXPERIMENTAL_API
	{"justify-to", 0, 0,
	G_OPTION_ARG_INT, &this->advance, "Target size to justify to", "SIZE, or -1"},
	#endif
	{"preserve-default-ignorables",0, 0, G_OPTION_ARG_NONE, &this->preserve_default_ignorables, "Preserve Default-Ignorable characters", nullptr},
	{"remove-default-ignorables",0, 0, G_OPTION_ARG_NONE, &this->remove_default_ignorables, "Remove Default-Ignorable characters", nullptr},
	{"invisible-glyph", 0, 0, G_OPTION_ARG_INT, &this->invisible_glyph, "Glyph value to replace Default-Ignorables with", nullptr},
	{"not-found-glyph", 0, 0, G_OPTION_ARG_INT, &this->not_found_glyph, "Glyph value to replace not-found characters with", nullptr},
	{"utf8-clusters", 0, 0, G_OPTION_ARG_NONE, &this->utf8_clusters, "Use UTF8 byte indices, not char indices", nullptr},
	{"cluster-level", 0, 0, G_OPTION_ARG_INT, &this->cluster_level, "Cluster merging level (default: 0)", "0/1/2"},
	{"normalize-glyphs",0, 0, G_OPTION_ARG_NONE, &this->normalize_glyphs, "Rearrange glyph clusters in nominal order", nullptr},
	{"unsafe-to-concat",0, 0, G_OPTION_ARG_NONE, &this->unsafe_to_concat, "Produce unsafe-to-concat glyph flag", nullptr},
	{"safe-to-insert-tatweel",0, 0, G_OPTION_ARG_NONE, &this->safe_to_insert_tatweel, "Produce safe-to-insert-tatweel glyph flag", nullptr},
	{"glyphs", 0, 0, G_OPTION_ARG_NONE, &this->glyphs, "Interpret input as glyph string", nullptr},
	{"verify", 0, 0, G_OPTION_ARG_NONE, &this->verify, "Perform sanity checks on shaping results", nullptr},
	{"num-iterations", 'n',G_OPTION_FLAG_IN_MAIN,
	G_OPTION_ARG_INT, &this->num_iterations, "Run shaper N times (default: 1)", "N"},
	{nullptr}
	};
	parser->add_group (entries,
	"shape",
	"Shape options:",
	"Options for the shaping process",
	this);

	const gchar *features_help = "Comma-separated list of font features\n"
	"\n"
	" Features can be enabled or disabled, either globally or limited to\n"
	" specific character ranges. The format for specifying feature settings\n"
	" follows. All valid CSS font-feature-settings values other than 'normal'\n"
	" and the global values are also accepted, though not documented below.\n"
	" CSS string escapes are not supported."
	"\n"
	" The range indices refer to the positions between Unicode characters,\n"
	" unless the --utf8-clusters is provided, in which case range indices\n"
	" refer to UTF-8 byte indices. The position before the first character\n"
	" is always 0.\n"
	"\n"
	" The format is Python-esque. Here is how it all works:\n"
	"\n"
	" Syntax: Value: Start: End:\n"
	"\n"
	" Setting value:\n"
	" \"kern\" 1 0 ∞ # Turn feature on\n"
	" \"+kern\" 1 0 ∞ # Turn feature on\n"
	" \"-kern\" 0 0 ∞ # Turn feature off\n"
	" \"kern=0\" 0 0 ∞ # Turn feature off\n"
	" \"kern=1\" 1 0 ∞ # Turn feature on\n"
	" \"aalt=2\" 2 0 ∞ # Choose 2nd alternate\n"
	"\n"
	" Setting index:\n"
	" \"kern[]\" 1 0 ∞ # Turn feature on\n"
	" \"kern[:]\" 1 0 ∞ # Turn feature on\n"
	" \"kern[5:]\" 1 5 ∞ # Turn feature on, partial\n"
	" \"kern[:5]\" 1 0 5 # Turn feature on, partial\n"
	" \"kern[3:5]\" 1 3 5 # Turn feature on, range\n"
	" \"kern[3]\" 1 3 3+1 # Turn feature on, single char\n"
	"\n"
	" Mixing it all:\n"
	"\n"
	" \"aalt[3:5]=2\" 2 3 5 # Turn 2nd alternate on for range";

	GOptionEntry entries2[] =
	{
	{"features", 0, 0, G_OPTION_ARG_CALLBACK, (gpointer) &parse_features, features_help, "list"},
	{nullptr}
	};
	parser->add_group (entries2,
	"features",
	"Features options:",
	"Options for font features used",
	this);
	}

	#endif