src/hb-ot-font.cc - third_party/harfbuzz - Git at Google

 /*
  * Copyright © 2011,2014  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, Roozbeh Pournader
  */

 #include "hb-private.hh"

 #include "hb-ot.h"

 #include "hb-font-private.hh"

 #include "hb-ot-cmap-table.hh"
 #include "hb-ot-hhea-table.hh"
 #include "hb-ot-hmtx-table.hh"


 struct hb_ot_face_metrics_accelerator_t
 {
   unsigned int num_metrics;
   unsigned int num_advances;
   unsigned int default_advance;
   const OT::_mtx *table;
   hb_blob_t *blob;

   inline void init (hb_face_t *face,
 		    hb_tag_t _hea_tag, hb_tag_t _mtx_tag,
 		    unsigned int default_advance_)
   {
     this->default_advance = default_advance_;
     this->num_metrics = face->get_num_glyphs ();

     hb_blob_t *_hea_blob = OT::Sanitizer<OT::_hea>::sanitize (face->reference_table (_hea_tag));
     const OT::_hea *_hea = OT::Sanitizer<OT::_hea>::lock_instance (_hea_blob);
     this->num_advances = _hea->numberOfLongMetrics;
     hb_blob_destroy (_hea_blob);

     this->blob = OT::Sanitizer<OT::_mtx>::sanitize (face->reference_table (_mtx_tag));
     if (unlikely (!this->num_advances ||
 		  2 * (this->num_advances + this->num_metrics) < hb_blob_get_length (this->blob)))
     {
       this->num_metrics = this->num_advances = 0;
       hb_blob_destroy (this->blob);
       this->blob = hb_blob_get_empty ();
     }
     this->table = OT::Sanitizer<OT::_mtx>::lock_instance (this->blob);
   }

   inline void fini (void)
   {
     hb_blob_destroy (this->blob);
   }

   inline unsigned int get_advance (hb_codepoint_t glyph) const
   {
     if (unlikely (glyph >= this->num_metrics))
     {
       /* If this->num_metrics is zero, it means we don't have the metrics table
        * for this direction: return one EM.  Otherwise, it means that the glyph
        * index is out of bound: return zero. */
       if (this->num_metrics)
 	return 0;
       else
 	return this->default_advance;
     }

     if (glyph >= this->num_advances)
       glyph = this->num_advances - 1;

     return this->table->longMetric[glyph].advance;
   }
 };

 struct hb_ot_face_cmap_accelerator_t
 {
   const OT::CmapSubtable *table;
   const OT::CmapSubtable *uvs_table;
   hb_blob_t *blob;

   inline void init (hb_face_t *face)
   {
     this->blob = OT::Sanitizer<OT::cmap>::sanitize (face->reference_table (HB_OT_TAG_cmap));
     const OT::cmap *cmap = OT::Sanitizer<OT::cmap>::lock_instance (this->blob);
     const OT::CmapSubtable *subtable = NULL;
     const OT::CmapSubtable *subtable_uvs = NULL;

     /* 32-bit subtables. */
     if (!subtable) subtable = cmap->find_subtable (3, 10);
     if (!subtable) subtable = cmap->find_subtable (0, 6);
     if (!subtable) subtable = cmap->find_subtable (0, 4);
     /* 16-bit subtables. */
     if (!subtable) subtable = cmap->find_subtable (3, 1);
     if (!subtable) subtable = cmap->find_subtable (0, 3);
     if (!subtable) subtable = cmap->find_subtable (0, 2);
     if (!subtable) subtable = cmap->find_subtable (0, 1);
     if (!subtable) subtable = cmap->find_subtable (0, 0);
     if (!subtable) subtable = cmap->find_subtable (3, 0);
     /* Meh. */
     if (!subtable) subtable = &OT::Null(OT::CmapSubtable);

     /* UVS subtable. */
     if (!subtable_uvs) subtable_uvs = cmap->find_subtable (0, 5);
     /* Meh. */
     if (!subtable_uvs) subtable_uvs = &OT::Null(OT::CmapSubtable);

     this->table = subtable;
     this->uvs_table = subtable_uvs;
   }

   inline void fini (void)
   {
     hb_blob_destroy (this->blob);
   }

   inline bool get_glyph (hb_codepoint_t  unicode,
 			 hb_codepoint_t  variation_selector,
 			 hb_codepoint_t *glyph) const
   {
     if (unlikely (variation_selector))
     {
       switch (this->uvs_table->get_glyph_variant (unicode,
 						  variation_selector,
 						  glyph))
       {
 	case OT::GLYPH_VARIANT_NOT_FOUND:	return false;
 	case OT::GLYPH_VARIANT_FOUND:		return true;
 	case OT::GLYPH_VARIANT_USE_DEFAULT:	break;
       }
     }

     return this->table->get_glyph (unicode, glyph);
   }
 };


 struct hb_ot_font_t
 {
   hb_ot_face_cmap_accelerator_t cmap;
   hb_ot_face_metrics_accelerator_t h_metrics;
   hb_ot_face_metrics_accelerator_t v_metrics;
 };


 static hb_ot_font_t *
 _hb_ot_font_create (hb_font_t *font)
 {
   hb_ot_font_t *ot_font = (hb_ot_font_t *) calloc (1, sizeof (hb_ot_font_t));
   hb_face_t *face = font->face;

   if (unlikely (!ot_font))
     return NULL;

   unsigned int upem = face->get_upem ();

   ot_font->cmap.init (face);
   ot_font->h_metrics.init (face, HB_OT_TAG_hhea, HB_OT_TAG_hmtx, upem>>1);
   ot_font->v_metrics.init (face, HB_OT_TAG_vhea, HB_OT_TAG_vmtx, upem); /* TODO Can we do this lazily? */

   return ot_font;
 }

 static void
 _hb_ot_font_destroy (hb_ot_font_t *ot_font)
 {
   ot_font->cmap.fini ();
   ot_font->h_metrics.fini ();
   ot_font->v_metrics.fini ();

   free (ot_font);
 }


 static hb_bool_t
 hb_ot_get_glyph (hb_font_t *font HB_UNUSED,
 		 void *font_data,
 		 hb_codepoint_t unicode,
 		 hb_codepoint_t variation_selector,
 		 hb_codepoint_t *glyph,
 		 void *user_data HB_UNUSED)

 {
   const hb_ot_font_t *ot_font = (const hb_ot_font_t *) font_data;
   return ot_font->cmap.get_glyph (unicode, variation_selector, glyph);
 }

 static hb_position_t
 hb_ot_get_glyph_h_advance (hb_font_t *font HB_UNUSED,
 			   void *font_data,
 			   hb_codepoint_t glyph,
 			   void *user_data HB_UNUSED)
 {
   const hb_ot_font_t *ot_font = (const hb_ot_font_t *) font_data;
   return font->em_scale_x (ot_font->h_metrics.get_advance (glyph));
 }

 static hb_position_t
 hb_ot_get_glyph_v_advance (hb_font_t *font HB_UNUSED,
 			   void *font_data,
 			   hb_codepoint_t glyph,
 			   void *user_data HB_UNUSED)
 {
   const hb_ot_font_t *ot_font = (const hb_ot_font_t *) font_data;
   return font->em_scale_y (-(int) ot_font->v_metrics.get_advance (glyph));
 }

 static hb_bool_t
 hb_ot_get_glyph_h_origin (hb_font_t *font HB_UNUSED,
 			  void *font_data HB_UNUSED,
 			  hb_codepoint_t glyph HB_UNUSED,
 			  hb_position_t *x HB_UNUSED,
 			  hb_position_t *y HB_UNUSED,
 			  void *user_data HB_UNUSED)
 {
   /* We always work in the horizontal coordinates. */
   return true;
 }

 static hb_bool_t
 hb_ot_get_glyph_v_origin (hb_font_t *font HB_UNUSED,
 			  void *font_data,
 			  hb_codepoint_t glyph,
 			  hb_position_t *x,
 			  hb_position_t *y,
 			  void *user_data HB_UNUSED)
 {
   /* TODO */
   return false;
 }

 static hb_position_t
 hb_ot_get_glyph_h_kerning (hb_font_t *font,
 			   void *font_data,
 			   hb_codepoint_t left_glyph,
 			   hb_codepoint_t right_glyph,
 			   void *user_data HB_UNUSED)
 {
   /* TODO */
   return 0;
 }

 static hb_position_t
 hb_ot_get_glyph_v_kerning (hb_font_t *font HB_UNUSED,
 			   void *font_data HB_UNUSED,
 			   hb_codepoint_t top_glyph HB_UNUSED,
 			   hb_codepoint_t bottom_glyph HB_UNUSED,
 			   void *user_data HB_UNUSED)
 {
   /* OpenType doesn't have vertical-kerning other than GPOS. */
   return 0;
 }

 static hb_bool_t
 hb_ot_get_glyph_extents (hb_font_t *font HB_UNUSED,
 			 void *font_data,
 			 hb_codepoint_t glyph,
 			 hb_glyph_extents_t *extents,
 			 void *user_data HB_UNUSED)
 {
   /* TODO */
   return false;
 }

 static hb_bool_t
 hb_ot_get_glyph_contour_point (hb_font_t *font HB_UNUSED,
 			       void *font_data,
 			       hb_codepoint_t glyph,
 			       unsigned int point_index,
 			       hb_position_t *x,
 			       hb_position_t *y,
 			       void *user_data HB_UNUSED)
 {
   /* TODO */
   return false;
 }

 static hb_bool_t
 hb_ot_get_glyph_name (hb_font_t *font HB_UNUSED,
 		      void *font_data,
 		      hb_codepoint_t glyph,
 		      char *name, unsigned int size,
 		      void *user_data HB_UNUSED)
 {
   /* TODO */
   return false;
 }

 static hb_bool_t
 hb_ot_get_glyph_from_name (hb_font_t *font HB_UNUSED,
 			   void *font_data,
 			   const char *name, int len, /* -1 means nul-terminated */
 			   hb_codepoint_t *glyph,
 			   void *user_data HB_UNUSED)
 {
   /* TODO */
   return false;
 }


 static hb_font_funcs_t *
 _hb_ot_get_font_funcs (void)
 {
   static const hb_font_funcs_t ot_ffuncs = {
     HB_OBJECT_HEADER_STATIC,

     true, /* immutable */

     {
 #define HB_FONT_FUNC_IMPLEMENT(name) hb_ot_get_##name,
       HB_FONT_FUNCS_IMPLEMENT_CALLBACKS
 #undef HB_FONT_FUNC_IMPLEMENT
     }
   };

   return const_cast<hb_font_funcs_t *> (&ot_ffuncs);
 }


 /**
  * Since: 0.9.28
  **/
 void
 hb_ot_font_set_funcs (hb_font_t *font)
 {
   hb_ot_font_t *ot_font = _hb_ot_font_create (font);
   if (unlikely (!ot_font))
     return;

   hb_font_set_funcs (font,
 		     _hb_ot_get_font_funcs (),
 		     ot_font,
 		     (hb_destroy_func_t) _hb_ot_font_destroy);
 }
	/*
	* Copyright © 2011,2014 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, Roozbeh Pournader
	*/

	#include "hb-private.hh"

	#include "hb-ot.h"

	#include "hb-font-private.hh"

	#include "hb-ot-cmap-table.hh"
	#include "hb-ot-hhea-table.hh"
	#include "hb-ot-hmtx-table.hh"


	struct hb_ot_face_metrics_accelerator_t
	{
	unsigned int num_metrics;
	unsigned int num_advances;
	unsigned int default_advance;
	const OT::_mtx *table;
	hb_blob_t *blob;

	inline void init (hb_face_t *face,
	hb_tag_t _hea_tag, hb_tag_t _mtx_tag,
	unsigned int default_advance_)
	{
	this->default_advance = default_advance_;
	this->num_metrics = face->get_num_glyphs ();

	hb_blob_t *_hea_blob = OT::Sanitizer<OT::_hea>::sanitize (face->reference_table (_hea_tag));
	const OT::_hea *_hea = OT::Sanitizer<OT::_hea>::lock_instance (_hea_blob);
	this->num_advances = _hea->numberOfLongMetrics;
	hb_blob_destroy (_hea_blob);

	this->blob = OT::Sanitizer<OT::_mtx>::sanitize (face->reference_table (_mtx_tag));
	if (unlikely (!this->num_advances \|\|
	2 * (this->num_advances + this->num_metrics) < hb_blob_get_length (this->blob)))
	{
	this->num_metrics = this->num_advances = 0;
	hb_blob_destroy (this->blob);
	this->blob = hb_blob_get_empty ();
	}
	this->table = OT::Sanitizer<OT::_mtx>::lock_instance (this->blob);
	}

	inline void fini (void)
	{
	hb_blob_destroy (this->blob);
	}

	inline unsigned int get_advance (hb_codepoint_t glyph) const
	{
	if (unlikely (glyph >= this->num_metrics))
	{
	/* If this->num_metrics is zero, it means we don't have the metrics table
	* for this direction: return one EM. Otherwise, it means that the glyph
	* index is out of bound: return zero. */
	if (this->num_metrics)
	return 0;
	else
	return this->default_advance;
	}

	if (glyph >= this->num_advances)
	glyph = this->num_advances - 1;

	return this->table->longMetric[glyph].advance;
	}
	};

	struct hb_ot_face_cmap_accelerator_t
	{
	const OT::CmapSubtable *table;
	const OT::CmapSubtable *uvs_table;
	hb_blob_t *blob;

	inline void init (hb_face_t *face)
	{
	this->blob = OT::Sanitizer<OT::cmap>::sanitize (face->reference_table (HB_OT_TAG_cmap));
	const OT::cmap *cmap = OT::Sanitizer<OT::cmap>::lock_instance (this->blob);
	const OT::CmapSubtable *subtable = NULL;
	const OT::CmapSubtable *subtable_uvs = NULL;

	/* 32-bit subtables. */
	if (!subtable) subtable = cmap->find_subtable (3, 10);
	if (!subtable) subtable = cmap->find_subtable (0, 6);
	if (!subtable) subtable = cmap->find_subtable (0, 4);
	/* 16-bit subtables. */
	if (!subtable) subtable = cmap->find_subtable (3, 1);
	if (!subtable) subtable = cmap->find_subtable (0, 3);
	if (!subtable) subtable = cmap->find_subtable (0, 2);
	if (!subtable) subtable = cmap->find_subtable (0, 1);
	if (!subtable) subtable = cmap->find_subtable (0, 0);
	if (!subtable) subtable = cmap->find_subtable (3, 0);
	/* Meh. */
	if (!subtable) subtable = &OT::Null(OT::CmapSubtable);

	/* UVS subtable. */
	if (!subtable_uvs) subtable_uvs = cmap->find_subtable (0, 5);
	/* Meh. */
	if (!subtable_uvs) subtable_uvs = &OT::Null(OT::CmapSubtable);

	this->table = subtable;
	this->uvs_table = subtable_uvs;
	}

	inline void fini (void)
	{
	hb_blob_destroy (this->blob);
	}

	inline bool get_glyph (hb_codepoint_t unicode,
	hb_codepoint_t variation_selector,
	hb_codepoint_t *glyph) const
	{
	if (unlikely (variation_selector))
	{
	switch (this->uvs_table->get_glyph_variant (unicode,
	variation_selector,
	glyph))
	{
	case OT::GLYPH_VARIANT_NOT_FOUND: return false;
	case OT::GLYPH_VARIANT_FOUND: return true;
	case OT::GLYPH_VARIANT_USE_DEFAULT: break;
	}
	}

	return this->table->get_glyph (unicode, glyph);
	}
	};


	struct hb_ot_font_t
	{
	hb_ot_face_cmap_accelerator_t cmap;
	hb_ot_face_metrics_accelerator_t h_metrics;
	hb_ot_face_metrics_accelerator_t v_metrics;
	};


	static hb_ot_font_t *
	_hb_ot_font_create (hb_font_t *font)
	{
	hb_ot_font_t ot_font = (hb_ot_font_t ) calloc (1, sizeof (hb_ot_font_t));
	hb_face_t *face = font->face;

	if (unlikely (!ot_font))
	return NULL;

	unsigned int upem = face->get_upem ();

	ot_font->cmap.init (face);
	ot_font->h_metrics.init (face, HB_OT_TAG_hhea, HB_OT_TAG_hmtx, upem>>1);
	ot_font->v_metrics.init (face, HB_OT_TAG_vhea, HB_OT_TAG_vmtx, upem); /* TODO Can we do this lazily? */

	return ot_font;
	}

	static void
	_hb_ot_font_destroy (hb_ot_font_t *ot_font)
	{
	ot_font->cmap.fini ();
	ot_font->h_metrics.fini ();
	ot_font->v_metrics.fini ();

	free (ot_font);
	}


	static hb_bool_t
	hb_ot_get_glyph (hb_font_t *font HB_UNUSED,
	void *font_data,
	hb_codepoint_t unicode,
	hb_codepoint_t variation_selector,
	hb_codepoint_t *glyph,
	void *user_data HB_UNUSED)

	{
	const hb_ot_font_t ot_font = (const hb_ot_font_t ) font_data;
	return ot_font->cmap.get_glyph (unicode, variation_selector, glyph);
	}

	static hb_position_t
	hb_ot_get_glyph_h_advance (hb_font_t *font HB_UNUSED,
	void *font_data,
	hb_codepoint_t glyph,
	void *user_data HB_UNUSED)
	{
	const hb_ot_font_t ot_font = (const hb_ot_font_t ) font_data;
	return font->em_scale_x (ot_font->h_metrics.get_advance (glyph));
	}

	static hb_position_t
	hb_ot_get_glyph_v_advance (hb_font_t *font HB_UNUSED,
	void *font_data,
	hb_codepoint_t glyph,
	void *user_data HB_UNUSED)
	{
	const hb_ot_font_t ot_font = (const hb_ot_font_t ) font_data;
	return font->em_scale_y (-(int) ot_font->v_metrics.get_advance (glyph));
	}

	static hb_bool_t
	hb_ot_get_glyph_h_origin (hb_font_t *font HB_UNUSED,
	void *font_data HB_UNUSED,
	hb_codepoint_t glyph HB_UNUSED,
	hb_position_t *x HB_UNUSED,
	hb_position_t *y HB_UNUSED,
	void *user_data HB_UNUSED)
	{
	/* We always work in the horizontal coordinates. */
	return true;
	}

	static hb_bool_t
	hb_ot_get_glyph_v_origin (hb_font_t *font HB_UNUSED,
	void *font_data,
	hb_codepoint_t glyph,
	hb_position_t *x,
	hb_position_t *y,
	void *user_data HB_UNUSED)
	{
	/* TODO */
	return false;
	}

	static hb_position_t
	hb_ot_get_glyph_h_kerning (hb_font_t *font,
	void *font_data,
	hb_codepoint_t left_glyph,
	hb_codepoint_t right_glyph,
	void *user_data HB_UNUSED)
	{
	/* TODO */
	return 0;
	}

	static hb_position_t
	hb_ot_get_glyph_v_kerning (hb_font_t *font HB_UNUSED,
	void *font_data HB_UNUSED,
	hb_codepoint_t top_glyph HB_UNUSED,
	hb_codepoint_t bottom_glyph HB_UNUSED,
	void *user_data HB_UNUSED)
	{
	/* OpenType doesn't have vertical-kerning other than GPOS. */
	return 0;
	}

	static hb_bool_t
	hb_ot_get_glyph_extents (hb_font_t *font HB_UNUSED,
	void *font_data,
	hb_codepoint_t glyph,
	hb_glyph_extents_t *extents,
	void *user_data HB_UNUSED)
	{
	/* TODO */
	return false;
	}

	static hb_bool_t
	hb_ot_get_glyph_contour_point (hb_font_t *font HB_UNUSED,
	void *font_data,
	hb_codepoint_t glyph,
	unsigned int point_index,
	hb_position_t *x,
	hb_position_t *y,
	void *user_data HB_UNUSED)
	{
	/* TODO */
	return false;
	}

	static hb_bool_t
	hb_ot_get_glyph_name (hb_font_t *font HB_UNUSED,
	void *font_data,
	hb_codepoint_t glyph,
	char *name, unsigned int size,
	void *user_data HB_UNUSED)
	{
	/* TODO */
	return false;
	}

	static hb_bool_t
	hb_ot_get_glyph_from_name (hb_font_t *font HB_UNUSED,
	void *font_data,
	const char name, int len, / -1 means nul-terminated */
	hb_codepoint_t *glyph,
	void *user_data HB_UNUSED)
	{
	/* TODO */
	return false;
	}


	static hb_font_funcs_t *
	_hb_ot_get_font_funcs (void)
	{
	static const hb_font_funcs_t ot_ffuncs = {
	HB_OBJECT_HEADER_STATIC,

	true, /* immutable */

	{
	#define HB_FONT_FUNC_IMPLEMENT(name) hb_ot_get_##name,
	HB_FONT_FUNCS_IMPLEMENT_CALLBACKS
	#undef HB_FONT_FUNC_IMPLEMENT
	}
	};

	return const_cast<hb_font_funcs_t *> (&ot_ffuncs);
	}


	/**
	* Since: 0.9.28
	**/
	void
	hb_ot_font_set_funcs (hb_font_t *font)
	{
	hb_ot_font_t *ot_font = _hb_ot_font_create (font);
	if (unlikely (!ot_font))
	return;

	hb_font_set_funcs (font,
	_hb_ot_get_font_funcs (),
	ot_font,
	(hb_destroy_func_t) _hb_ot_font_destroy);
	}