kc3-lang/harfbuzz/src/OT/glyf/path-builder.hh

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• Hash : 7222c1e5
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  Date : 2025-02-25T15:13:20
  

  [path-builder] Add a constexpr
  

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• src/OT/glyf/path-builder.hh

• #ifndef OT_GLYF_PATH_BUILDER_HH
  #define OT_GLYF_PATH_BUILDER_HH
  
  
  #include "../../hb.hh"
  
  
  namespace OT {
  namespace glyf_impl {
  
  
  struct path_builder_t
  {
    hb_font_t *font;
    hb_draw_session_t *draw_session;
  
    struct optional_point_t
    {
      optional_point_t () {}
      optional_point_t (float x_, float y_) : has_data (true), x (x_), y (y_) {}
      operator bool () const { return has_data; }
  
      bool has_data = false;
      float x;
      float y;
  
      optional_point_t mid (optional_point_t p)
      { return optional_point_t ((x + p.x) * 0.5f, (y + p.y) * 0.5f); }
    } first_oncurve, first_offcurve, first_offcurve2, last_offcurve, last_offcurve2;
  
    path_builder_t (hb_font_t *font_, hb_draw_session_t &draw_session_) :
      font (font_), draw_session (&draw_session_) {}
  
    /* based on https://github.com/RazrFalcon/ttf-parser/blob/4f32821/src/glyf.rs#L287
       See also:
       * https://developer.apple.com/fonts/TrueType-Reference-Manual/RM01/Chap1.html
       * https://stackoverflow.com/a/20772557
       *
       * Cubic support added. */
    HB_ALWAYS_INLINE
    void consume_point (const contour_point_t &point)
    {
      bool is_on_curve = point.flag & glyf_impl::SimpleGlyph::FLAG_ON_CURVE;
  #ifdef HB_NO_CUBIC_GLYF
      constexpr bool is_cubic = false;
  #else
      bool is_cubic = !is_on_curve && (point.flag & glyf_impl::SimpleGlyph::FLAG_CUBIC);
  #endif
      optional_point_t p (font->em_fscalef_x (point.x), font->em_fscalef_y (point.y));
      if (unlikely (!first_oncurve))
      {
        if (is_on_curve)
        {
  	first_oncurve = p;
  	draw_session->move_to (p.x, p.y);
        }
        else
        {
  	if (is_cubic && !first_offcurve2)
  	{
  	  first_offcurve2 = first_offcurve;
  	  first_offcurve = p;
  	}
  	else if (first_offcurve)
  	{
  	  optional_point_t mid = first_offcurve.mid (p);
  	  first_oncurve = mid;
  	  last_offcurve = p;
  	  draw_session->move_to (mid.x, mid.y);
  	}
  	else
  	  first_offcurve = p;
        }
      }
      else
      {
        if (last_offcurve)
        {
  	if (is_on_curve)
  	{
  	  if (last_offcurve2)
  	  {
  	    draw_session->cubic_to (last_offcurve2.x, last_offcurve2.y,
  				    last_offcurve.x, last_offcurve.y,
  				    p.x, p.y);
  	    last_offcurve2 = optional_point_t ();
  	  }
  	  else
  	    draw_session->quadratic_to (last_offcurve.x, last_offcurve.y,
  				       p.x, p.y);
  	  last_offcurve = optional_point_t ();
  	}
  	else
  	{
  	  if (is_cubic && !last_offcurve2)
  	  {
  	    last_offcurve2 = last_offcurve;
  	    last_offcurve = p;
  	  }
  	  else
  	  {
  	    optional_point_t mid = last_offcurve.mid (p);
  
  	    if (is_cubic)
  	    {
  	      draw_session->cubic_to (last_offcurve2.x, last_offcurve2.y,
  				      last_offcurve.x, last_offcurve.y,
  				      mid.x, mid.y);
  	      last_offcurve2 = optional_point_t ();
  	    }
  	    else
  	      draw_session->quadratic_to (last_offcurve.x, last_offcurve.y,
  					 mid.x, mid.y);
  	    last_offcurve = p;
  	  }
  	}
        }
        else
        {
  	if (is_on_curve)
  	  draw_session->line_to (p.x, p.y);
  	else
  	  last_offcurve = p;
        }
      }
  
    }
  
    void contour_end ()
    {
      if (first_offcurve && last_offcurve)
      {
        optional_point_t mid = last_offcurve.mid (first_offcurve2 ?
  						first_offcurve2 :
  						first_offcurve);
        if (last_offcurve2)
  	draw_session->cubic_to (last_offcurve2.x, last_offcurve2.y,
  				last_offcurve.x, last_offcurve.y,
  				mid.x, mid.y);
        else
  	draw_session->quadratic_to (last_offcurve.x, last_offcurve.y,
  				   mid.x, mid.y);
        last_offcurve = optional_point_t ();
      }
      /* now check the rest */
  
      if (first_offcurve && first_oncurve)
      {
        if (first_offcurve2)
  	draw_session->cubic_to (first_offcurve2.x, first_offcurve2.y,
  				first_offcurve.x, first_offcurve.y,
  				first_oncurve.x, first_oncurve.y);
        else
  	draw_session->quadratic_to (first_offcurve.x, first_offcurve.y,
  				   first_oncurve.x, first_oncurve.y);
      }
      else if (last_offcurve && first_oncurve)
      {
        if (last_offcurve2)
  	draw_session->cubic_to (last_offcurve2.x, last_offcurve2.y,
  				last_offcurve.x, last_offcurve.y,
  				first_oncurve.x, first_oncurve.y);
        else
  	draw_session->quadratic_to (last_offcurve.x, last_offcurve.y,
  				   first_oncurve.x, first_oncurve.y);
      }
      else if (first_oncurve)
        draw_session->line_to (first_oncurve.x, first_oncurve.y);
      else if (first_offcurve)
      {
        float x = first_offcurve.x, y = first_offcurve.y;
        draw_session->move_to (x, y);
        draw_session->quadratic_to (x, y, x, y);
      }
  
      /* Getting ready for the next contour */
      first_oncurve = first_offcurve = last_offcurve = last_offcurve2 = optional_point_t ();
      draw_session->close_path ();
    }
  
    void points_end () {}
  
    bool is_consuming_contour_points () { return true; }
    contour_point_t *get_phantoms_sink () { return nullptr; }
  };
  
  
  } /* namespace glyf_impl */
  } /* namespace OT */
  
  
  #endif /* OT_GLYF_PATH_BUILDER_HH */
  

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