harfbuzz/src/OT/glyf/Glyph.hh

#ifndef OT_GLYF_GLYPH_HH
#define OT_GLYF_GLYPH_HH


#include "../../hb-open-type.hh"

#include "GlyphHeader.hh"
#include "SimpleGlyph.hh"
#include "CompositeGlyph.hh"


namespace OT {

struct glyf_accelerator_t;

namespace glyf_impl {


enum phantom_point_index_t
{
  PHANTOM_LEFT   = 0,
  PHANTOM_RIGHT  = 1,
  PHANTOM_TOP    = 2,
  PHANTOM_BOTTOM = 3,
  PHANTOM_COUNT  = 4
};

struct Glyph
{
  enum glyph_type_t { EMPTY, SIMPLE, COMPOSITE };

  public:
  composite_iter_t get_composite_iterator () const
  {
    if (type != COMPOSITE) return composite_iter_t ();
    return CompositeGlyph (*header, bytes).iter ();
  }

  const hb_bytes_t trim_padding () const
  {
    switch (type) {
    case COMPOSITE: return CompositeGlyph (*header, bytes).trim_padding ();
    case SIMPLE:    return SimpleGlyph (*header, bytes).trim_padding ();
    default:        return bytes;
    }
  }

  void drop_hints ()
  {
    switch (type) {
    case COMPOSITE: CompositeGlyph (*header, bytes).drop_hints (); return;
    case SIMPLE:    SimpleGlyph (*header, bytes).drop_hints (); return;
    default:        return;
    }
  }

  void set_overlaps_flag ()
  {
    switch (type) {
    case COMPOSITE: CompositeGlyph (*header, bytes).set_overlaps_flag (); return;
    case SIMPLE:    SimpleGlyph (*header, bytes).set_overlaps_flag (); return;
    default:        return;
    }
  }

  void drop_hints_bytes (hb_bytes_t &dest_start, hb_bytes_t &dest_end) const
  {
    switch (type) {
    case COMPOSITE: CompositeGlyph (*header, bytes).drop_hints_bytes (dest_start); return;
    case SIMPLE:    SimpleGlyph (*header, bytes).drop_hints_bytes (dest_start, dest_end); return;
    default:        return;
    }
  }

  /* Note: Recursively calls itself.
   * all_points includes phantom points
   */
  template <typename accelerator_t>
  bool get_points (hb_font_t *font, const accelerator_t &glyf_accelerator,
		   contour_point_vector_t &all_points /* OUT */,
		   bool phantom_only = false,
		   unsigned int depth = 0) const
  {
    if (unlikely (depth > HB_MAX_NESTING_LEVEL)) return false;
    contour_point_vector_t stack_points;
    bool inplace = type == SIMPLE && all_points.length == 0;
    contour_point_vector_t &points = inplace ? all_points : stack_points;

    switch (type) {
    case COMPOSITE:
    {
      /* pseudo component points for each component in composite glyph */
      unsigned num_points = hb_len (CompositeGlyph (*header, bytes).iter ());
      if (unlikely (!points.resize (num_points))) return false;
      break;
    }
    case SIMPLE:
      /* Load into all_points if it's empty, as an optimization. */
      if (unlikely (!SimpleGlyph (*header, bytes).get_contour_points (points, phantom_only)))
	return false;
      break;
    }

    /* Init phantom points */
    if (unlikely (!points.resize (points.length + PHANTOM_COUNT))) return false;
    hb_array_t<contour_point_t> phantoms = points.sub_array (points.length - PHANTOM_COUNT, PHANTOM_COUNT);
    {
      int h_delta = (int) header->xMin -
		    glyf_accelerator.hmtx->get_side_bearing (gid);
      int v_orig  = (int) header->yMax +
#ifndef HB_NO_VERTICAL
		    glyf_accelerator.vmtx->get_side_bearing (gid)
#else
		    0
#endif
		    ;
      unsigned h_adv = glyf_accelerator.hmtx->get_advance (gid);
      unsigned v_adv =
#ifndef HB_NO_VERTICAL
		       glyf_accelerator.vmtx->get_advance (gid)
#else
		       - font->face->get_upem ()
#endif
		       ;
      phantoms[PHANTOM_LEFT].x = h_delta;
      phantoms[PHANTOM_RIGHT].x = h_adv + h_delta;
      phantoms[PHANTOM_TOP].y = v_orig;
      phantoms[PHANTOM_BOTTOM].y = v_orig - (int) v_adv;
    }

#ifndef HB_NO_VAR
    glyf_accelerator.gvar->apply_deltas_to_points (gid, font, points.as_array ());
#endif

    switch (type) {
    case SIMPLE:
      if (!inplace)
	all_points.extend (points.as_array ());
      break;
    case COMPOSITE:
    {
      unsigned int comp_index = 0;
      for (auto &item : get_composite_iterator ())
      {
	contour_point_vector_t comp_points;
	if (unlikely (!glyf_accelerator.glyph_for_gid (item.glyphIndex)
				       .get_points (font, glyf_accelerator, comp_points,
						    phantom_only, depth + 1)))
	  return false;

	/* Copy phantom points from component if USE_MY_METRICS flag set */
	if (item.is_use_my_metrics ())
	  for (unsigned int i = 0; i < PHANTOM_COUNT; i++)
	    phantoms[i] = comp_points[comp_points.length - PHANTOM_COUNT + i];

	/* Apply component transformation & translation */
	item.transform_points (comp_points);

	/* Apply translation from gvar */
	comp_points.translate (points[comp_index]);

	if (item.is_anchored ())
	{
	  unsigned int p1, p2;
	  item.get_anchor_points (p1, p2);
	  if (likely (p1 < all_points.length && p2 < comp_points.length))
	  {
	    contour_point_t delta;
	    delta.init (all_points[p1].x - comp_points[p2].x,
			all_points[p1].y - comp_points[p2].y);

	    comp_points.translate (delta);
	  }
	}

	all_points.extend (comp_points.sub_array (0, comp_points.length - PHANTOM_COUNT));

	comp_index++;
      }

      all_points.extend (phantoms);
    } break;
    default:
      all_points.extend (phantoms);
    }

    if (depth == 0) /* Apply at top level */
    {
      /* Undocumented rasterizer behavior:
       * Shift points horizontally by the updated left side bearing
       */
      contour_point_t delta;
      delta.init (-phantoms[PHANTOM_LEFT].x, 0.f);
      if (delta.x) all_points.translate (delta);
    }

    return !all_points.in_error ();
  }

  bool get_extents (hb_font_t *font, const glyf_accelerator_t &glyf_accelerator,
		    hb_glyph_extents_t *extents) const
  {
    if (type == EMPTY) return true; /* Empty glyph; zero extents. */
    return header->get_extents (font, glyf_accelerator, gid, extents);
  }

  hb_bytes_t get_bytes () const { return bytes; }

  Glyph (hb_bytes_t bytes_ = hb_bytes_t (),
	 hb_codepoint_t gid_ = (hb_codepoint_t) -1) : bytes (bytes_), gid (gid_),
						      header (bytes.as<GlyphHeader> ())
  {
    int num_contours = header->numberOfContours;
    if (unlikely (num_contours == 0)) type = EMPTY;
    else if (num_contours > 0) type = SIMPLE;
    else type = COMPOSITE; /* negative numbers */
  }

  protected:
  hb_bytes_t bytes;
  hb_codepoint_t gid;
  const GlyphHeader *header;
  unsigned type;
};


} /* namespace glyf_impl */
} /* namespace OT */


#endif /* OT_GLYF_GLYPH_HH */