[perf] benchmark subsetting via glyphs.

perf/benchmark-subset.cc

@@ -17,6 +17,16 @@ void AddCodepoints(const hb_set_t* codepoints_in_font,
   }
 }
 
+void AddGlyphs(unsigned num_glyphs_in_font,
+               unsigned subset_size,
+               hb_subset_input_t* input)
+{
+  for (unsigned i = 0; i < subset_size && i < num_glyphs_in_font; i++) {
+    // TODO(garretrieger): pick randomly.
+    hb_set_add (hb_subset_input_glyph_set (input), i);
+  }
+}
+
 /* benchmark for subsetting a font */
 static void BM_subset_codepoints (benchmark::State &state,
                                   const char *font_path)
@@ -86,4 +96,72 @@ BENCHMARK_CAPTURE (BM_subset_codepoints, subset_notocjk,
     ->Range(10, 100000);
 #endif
 
+
+static void BM_subset_glyphs (benchmark::State &state,
+                              const char *font_path)
+{
+  unsigned subset_size = state.range(0);
+
+  hb_face_t *face;
+  {
+    hb_blob_t *blob = hb_blob_create_from_file_or_fail (font_path);
+    assert (blob);
+    face = hb_face_create (blob, 0);
+    hb_blob_destroy (blob);
+  }
+
+  hb_subset_input_t* input = hb_subset_input_create_or_fail ();
+  assert (input);
+
+  {
+    unsigned num_glyphs = hb_face_get_glyph_count (face);
+
+    AddGlyphs(num_glyphs, subset_size, input);
+  }
+
+  for (auto _ : state)
+  {
+    hb_face_t* subset = hb_subset_or_fail (face, input);
+    assert (subset);
+    hb_face_destroy (subset);
+  }
+
+  hb_subset_input_destroy (input);
+  hb_face_destroy (face);
+}
+
+BENCHMARK_CAPTURE (BM_subset_glyphs, subset_roboto,
+                   "perf/fonts/Roboto-Regular.ttf")
+    ->Unit(benchmark::kMillisecond)
+    ->Range(10, 4000);
+
+BENCHMARK_CAPTURE (BM_subset_glyphs, subset_amiri,
+                   "perf/fonts/Amiri-Regular.ttf")
+    ->Unit(benchmark::kMillisecond)
+    ->Range(10, 4000);
+
+BENCHMARK_CAPTURE (BM_subset_glyphs, subset_noto_nastaliq_urdu,
+                   "perf/fonts/NotoNastaliqUrdu-Regular.ttf")
+    ->Unit(benchmark::kMillisecond)
+    ->Range(10, 1000);
+
+BENCHMARK_CAPTURE (BM_subset_glyphs, subset_noto_devangari,
+                   "perf/fonts/NotoSansDevanagari-Regular.ttf")
+    ->Unit(benchmark::kMillisecond)
+    ->Range(10, 1000);
+
+BENCHMARK_CAPTURE (BM_subset_glyphs, subset_mplus1p,
+                   "test/subset/data/fonts/Mplus1p-Regular.ttf")
+    ->Unit(benchmark::kMillisecond)
+    ->Range(10, 10000);
+
+#if 0
+BENCHMARK_CAPTURE (BM_subset_glyphs, subset_notocjk,
+                   "perf/fonts/NotoSansCJKsc-VF.ttf")
+    ->Unit(benchmark::kMillisecond)
+    ->Range(10, 100000);
+#endif
+
+
+
 BENCHMARK_MAIN();