1 files changed, 135 insertions, 0 deletions
diff --git a/thirdparty/harfbuzz/src/OT/glyf/path-builder.hh b/thirdparty/harfbuzz/src/OT/glyf/path-builder.hh
new file mode 100644
index 0000000000..9bfc45a1a6
--- /dev/null
+++ b/thirdparty/harfbuzz/src/OT/glyf/path-builder.hh
@@ -0,0 +1,135 @@
+#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 = 0.;
+    float y = 0.;
+
+    optional_point_t lerp (optional_point_t p, float t)
+    { return optional_point_t (x + t * (p.x - x), y + t * (p.y - y)); }
+  } first_oncurve, first_offcurve, last_offcurve;
+
+  path_builder_t (hb_font_t *font_, hb_draw_session_t &draw_session_)
+  {
+    font = font_;
+    draw_session = &draw_session_;
+    first_oncurve = first_offcurve = last_offcurve = optional_point_t ();
+  }
+
+  /* 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 */
+  void consume_point (const contour_point_t &point)
+  {
+    bool is_on_curve = point.flag & glyf_impl::SimpleGlyph::FLAG_ON_CURVE;
+    optional_point_t p (font->em_fscalef_x (point.x), font->em_fscalef_y (point.y));
+    if (!first_oncurve)
+    {
+      if (is_on_curve)
+      {
+	first_oncurve = p;
+	draw_session->move_to (p.x, p.y);
+      }
+      else
+      {
+	if (first_offcurve)
+	{
+	  optional_point_t mid = first_offcurve.lerp (p, .5f);
+	  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)
+	{
+	  draw_session->quadratic_to (last_offcurve.x, last_offcurve.y,
+				     p.x, p.y);
+	  last_offcurve = optional_point_t ();
+	}
+	else
+	{
+	  optional_point_t mid = last_offcurve.lerp (p, .5f);
+	  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;
+      }
+    }
+
+    if (point.is_end_point)
+    {
+      if (first_offcurve && last_offcurve)
+      {
+	optional_point_t mid = last_offcurve.lerp (first_offcurve, .5f);
+	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)
+	draw_session->quadratic_to (first_offcurve.x, first_offcurve.y,
+				   first_oncurve.x, first_oncurve.y);
+      else if (last_offcurve && first_oncurve)
+	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 = 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 */