[subset] add --hinting flag

src/hb-subset-private.hh

@@ -43,6 +43,7 @@ struct hb_subset_input_t {
   hb_set_t *unicodes;
   hb_set_t *glyphs;
 
+  hb_bool_t retain_hints;
   /* TODO
    *
    * features

util/hb-subset.cc

@@ -29,6 +29,7 @@
 
 #include "main-font-text.hh"
 #include "hb-subset.h"
+#include "hb-subset-private.hh"
 
 /*
  * Command line interface to the harfbuzz font subsetter.
@@ -37,7 +38,7 @@
 struct subset_consumer_t
 {
   subset_consumer_t (option_parser_t *parser)
-      : failed (false), options (parser), font (nullptr), input (nullptr) {}
+      : failed (false), options (parser), subset_options (parser), font (nullptr), input (nullptr) {}
 
   void init (hb_buffer_t  *buffer_,
              const font_options_t *font_opts)
@@ -89,6 +90,8 @@ struct subset_consumer_t
 
   void finish (const font_options_t *font_opts)
   {
+    input->retain_hints = subset_options.hinting;
+
     hb_subset_profile_t *subset_profile = hb_subset_profile_create();
     hb_face_t *face = hb_font_get_face (font);
 
@@ -111,6 +114,7 @@ struct subset_consumer_t
 
   private:
   output_options_t options;
+  subset_options_t subset_options;
   hb_font_t *font;
   hb_subset_input_t *input;
 };

util/options.cc

@@ -986,3 +986,18 @@ format_options_t::serialize_buffer_of_glyphs (hb_buffer_t  *buffer,
   serialize_glyphs (buffer, font, output_format, format_flags, gs);
   g_string_append_c (gs, '\n');
 }
+
+void
+subset_options_t::add_options (option_parser_t *parser)
+{
+  GOptionEntry entries[] =
+  {
+    {"hinting", 0, 0, G_OPTION_ARG_NONE,  &this->hinting,   "Whether to retain or drop hints",   nullptr},
+    {nullptr}
+  };
+  parser->add_group (entries,
+         "subset",
+         "Subset options:",
+         "Options subsetting",
+         this);
+}

util/options.hh

@@ -649,6 +649,20 @@ struct format_options_t : option_group_t
   hb_bool_t trace;
 };
 
+struct subset_options_t : option_group_t
+{
+  subset_options_t (option_parser_t *parser)
+  {
+    hinting = true;
+
+    add_options (parser);
+  }
+
+  void add_options (option_parser_t *parser);
+
+  hb_bool_t hinting;
+};
+
 /* fallback implementation for scalbn()/scalbnf() for pre-2013 MSVC */
 #if defined (_MSC_VER) && (_MSC_VER < 1800)