hb-ot-color-svg-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_SVG_TABLE_HH
#define HB_OT_COLOR_SVG_TABLE_HH

#include "hb-open-type.hh"

/*
 * SVG -- SVG (Scalable Vector Graphics)
 * https://docs.microsoft.com/en-us/typography/opentype/spec/svg
 */

#define HB_OT_TAG_SVG HB_TAG('S','V','G',' ')


namespace OT {


struct SVGDocumentIndexEntry
{
  int cmp (hb_codepoint_t g) const
  { return g < startGlyphID ? -1 : g > endGlyphID ? 1 : 0; }

  hb_blob_t *reference_blob (hb_blob_t *svg_blob, unsigned int index_offset) const
  {
    return hb_blob_create_sub_blob (svg_blob,
				    index_offset + (unsigned int) svgDoc,
				    svgDocLength);
  }

  bool sanitize (hb_sanitize_context_t *c, const void *base) const
  {
    TRACE_SANITIZE (this);
    return_trace (c->check_struct (this) &&
		  svgDoc.sanitize (c, base, svgDocLength));
  }

  protected:
  HBUINT16	startGlyphID;	/* The first glyph ID in the range described by
				 * this index entry. */
  HBUINT16	endGlyphID;	/* The last glyph ID in the range described by
				 * this index entry. Must be >= startGlyphID. */
  LNNOffsetTo<UnsizedArrayOf<HBUINT8>>
		svgDoc;		/* Offset from the beginning of the SVG Document Index
				 * to an SVG document. Must be non-zero. */
  HBUINT32	svgDocLength;	/* Length of the SVG document.
				 * Must be non-zero. */
  public:
  DEFINE_SIZE_STATIC (12);
};

struct SVG
{
  static constexpr hb_tag_t tableTag = HB_OT_TAG_SVG;

  bool has_data () const { return svgDocEntries; }

  struct accelerator_t
  {
    void init (hb_face_t *face)
    { table = hb_sanitize_context_t().reference_table<SVG> (face); }
    void fini () { table.destroy (); }

    hb_blob_t *reference_blob_for_glyph (hb_codepoint_t glyph_id) const
    {
      return table->get_glyph_entry (glyph_id).reference_blob (table.get_blob (),
							       table->svgDocEntries);
    }

    bool has_data () const { return table->has_data (); }

    private:
    hb_blob_ptr_t<SVG> table;
  };

  const SVGDocumentIndexEntry &get_glyph_entry (hb_codepoint_t glyph_id) const
  { return (this+svgDocEntries).bsearch (glyph_id); }

  bool sanitize (hb_sanitize_context_t *c) const
  {
    TRACE_SANITIZE (this);
    return_trace (likely (c->check_struct (this) &&
			  (this+svgDocEntries).sanitize_shallow (c)));
  }

  protected:
  HBUINT16	version;	/* Table version (starting at 0). */
  LOffsetTo<SortedArrayOf<SVGDocumentIndexEntry>>
		svgDocEntries;	/* Offset (relative to the start of the SVG table) to the
				 * SVG Documents Index. Must be non-zero. */
				/* Array of SVG Document Index Entries. */
  HBUINT32	reserved;	/* Set to 0. */
  public:
  DEFINE_SIZE_STATIC (10);
};

struct SVG_accelerator_t : SVG::accelerator_t {};

} /* namespace OT */


#endif /* HB_OT_COLOR_SVG_TABLE_HH */