[util] Add --ft-load-flags

Useful for performance testing.

Not hooked to cairo yet.  Just changes shaping, not rasterization.

util/helper-cairo.cc

@@ -125,7 +125,7 @@ helper_cairo_create_scaled_font (const font_options_t *font_opts)
     }
 #endif
 
-    cairo_face = cairo_ft_font_face_create_for_ft_face (ft_face, 0);
+    cairo_face = cairo_ft_font_face_create_for_ft_face (ft_face, font_opts->ft_load_flags);
   }
   cairo_matrix_t ctm, font_matrix;
   cairo_font_options_t *font_options;

util/options.cc

@@ -556,6 +556,7 @@ font_options_t::add_options (option_parser_t *parser)
     {"font-ppem",	0, 0, G_OPTION_ARG_CALLBACK,	(gpointer) &parse_font_ppem,	"Set x,y pixels per EM (default: 0; disabled)",	"1/2 integers"},
     {"font-ptem",	0, 0, G_OPTION_ARG_DOUBLE,	&this->ptem,			"Set font point-size (default: 0; disabled)",	"point-size"},
     {"font-funcs",	0, 0, G_OPTION_ARG_STRING,	&this->font_funcs,		text,						"impl"},
+    {"ft-load-flags",	0, 0, G_OPTION_ARG_INT,		&this->ft_load_flags,		"Set FreeType load-flags (default: 2)",		"integer"},
     {nullptr}
   };
   parser->add_group (entries,
@@ -717,6 +718,9 @@ font_options_t::get_font (void) const
     }
   }
   set_font_funcs (font);
+#ifdef HAVE_FREETYPE
+  hb_ft_font_set_load_flags (font, ft_load_flags);
+#endif
 
   return font;
 }

util/options.hh

@@ -454,6 +454,7 @@ struct font_options_t : option_group_t
     face_index = 0;
     font_size_x = font_size_y = default_font_size;
     font_funcs = nullptr;
+    ft_load_flags = 2;
 
     blob = nullptr;
     font = nullptr;
@@ -484,6 +485,7 @@ struct font_options_t : option_group_t
   mutable double font_size_x;
   mutable double font_size_y;
   char *font_funcs;
+  int ft_load_flags;
 
   private:
   mutable hb_font_t *font;