src/hb-ot-color-sbix-table.hh

/*
 * Copyright © 2018  Ebrahim Byagowi
 *
 *  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_OT_COLOR_SBIX_TABLE_HH
#define HB_OT_COLOR_SBIX_TABLE_HH

#include "hb-open-type.hh"

/*
 * sbix -- Standard Bitmap Graphics
 * https://docs.microsoft.com/en-us/typography/opentype/spec/sbix
 * https://developer.apple.com/fonts/TrueType-Reference-Manual/RM06/Chap6sbix.html
 */
#define HB_OT_TAG_sbix HB_TAG('s','b','i','x')


namespace OT {


struct SBIXGlyph
{
  HBINT16	xOffset;	/* The horizontal (x-axis) offset from the left
				 * edge of the graphic to the glyph’s origin.
				 * That is, the x-coordinate of the point on the
				 * baseline at the left edge of the glyph. */
  HBINT16	yOffset;	/* The vertical (y-axis) offset from the bottom
				 * edge of the graphic to the glyph’s origin.
				 * That is, the y-coordinate of the point on the
				 * baseline at the left edge of the glyph. */
  Tag		graphicType;	/* Indicates the format of the embedded graphic
				 * data: one of 'jpg ', 'png ' or 'tiff', or the
				 * special format 'dupe'. */
  UnsizedArrayOf<HBUINT8>
		data;		/* The actual embedded graphic data. The total
				 * length is inferred from sequential entries in
				 * the glyphDataOffsets array and the fixed size
				 * (8 bytes) of the preceding fields. */
  public:
  DEFINE_SIZE_ARRAY (8, data);
};

struct SBIXStrike
{
  friend struct sbix;

  inline bool sanitize (hb_sanitize_context_t *c) const
  {
    TRACE_SANITIZE (this);
    return_trace (c->check_struct (this) &&
		  imageOffsetsZ.sanitize_shallow (c, c->get_num_glyphs () + 1));
  }

  protected:
  HBUINT16	ppem;		/* The PPEM size for which this strike was designed. */
  HBUINT16	resolution;	/* The device pixel density (in PPI) for which this
				 * strike was designed. (E.g., 96 PPI, 192 PPI.) */
  UnsizedArrayOf<LOffsetTo<SBIXGlyph> >
		imageOffsetsZ;	/* Offset from the beginning of the strike data header
				 * to bitmap data for an individual glyph ID. */
  public:
  DEFINE_SIZE_STATIC (8);
};

struct sbix
{
  static const hb_tag_t tableTag = HB_OT_TAG_sbix;

  inline bool sanitize (hb_sanitize_context_t *c) const
  {
    TRACE_SANITIZE (this);
    return_trace (likely (c->check_struct (this) && strikes.sanitize (c, this)));
  }

  struct accelerator_t
  {
    inline void init (hb_face_t *face)
    {
      sbix_blob = hb_sanitize_context_t().reference_table<sbix> (face);
      sbix_len = hb_blob_get_length (sbix_blob);
      sbix_table = sbix_blob->as<sbix> ();
    }

    inline void fini (void)
    {
      hb_blob_destroy (sbix_blob);
    }

    inline void dump (void (*callback) (const uint8_t* data, unsigned int length,
					unsigned int group, unsigned int gid)) const
    {
      for (unsigned group = 0; group < sbix_table->strikes.len; ++group)
      {
	const SBIXStrike &strike = sbix_table->strikes[group](sbix_table);
	for (unsigned int glyph = 0; glyph < num_glyphs; ++glyph)
	  if (strike.imageOffsetsZ[glyph + 1] - strike.imageOffsetsZ[glyph] > 0)
	  {
	    const SBIXGlyph &sbixGlyph = strike.imageOffsetsZ[glyph]((const void *) &strike);
	    callback ((const uint8_t*) &sbixGlyph.data,
		      strike.imageOffsetsZ[glyph + 1] - strike.imageOffsetsZ[glyph] - 8,
		      group, glyph);
	  }
      }
    }

    private:
    hb_blob_t *sbix_blob;
    const sbix *sbix_table;

    unsigned int sbix_len;
    unsigned int num_glyphs;
  };

  protected:
  HBUINT16	version;	/* Table version number — set to 1 */
  HBUINT16	flags;		/* Bit 0: Set to 1. Bit 1: Draw outlines.
				 * Bits 2 to 15: reserved (set to 0). */
  LArrayOf<LOffsetTo<SBIXStrike> >
		strikes;	/* Offsets from the beginning of the 'sbix'
				 * table to data for each individual bitmap strike. */
  public:
  DEFINE_SIZE_ARRAY (8, strikes);
};

} /* namespace OT */

#endif /* HB_OT_COLOR_SBIX_TABLE_HH */