Add sfntly library for font subsetting used in print preview.

third_party/sfntly/src/subsetter/font_subsetter.h

+/*
+ * Copyright 2011 Google Inc. All Rights Reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+// Font subsetting API

[Sheridan Rawlins, 2011/07/14 22:35:51]

nit: Move this down adjacent to function.

[arthurhsu, 2011/07/14 23:52:35]

Done.

+//
+// Input TTF/TTC/OTF fonts, specify the glyph IDs to subset, and the subset font
+// is returned in |output_buffer| (caller to delete[]).  Return value is the
+// length of output_buffer allocated.
+//
+// If subsetting failes, a negative value is returned.  If none of the glyph IDs
+// specified is found, the function will return 0.
+//
+// |font_name|      Font name of the font, required for TTC files.  If specified
+//                  NULL, the first available font is selected.
+// |original_font|  Original font file contents.
+// |font_size|      Size of |original_font| in bytes.
+// |glyph_ids|      Glyph IDs to subset.  If the specified glyph ID is not found
+//                  in the font file, it will be ignored silently.
+// |glyph_count|    Number of glyph IDs in |glyph_ids|
+// |output_buffer|  Generated subset font.
+
+#ifndef FONT_SUBSETTER_H_
+#define FONT_SUBSETTER_H_
+
+#include <cstddef>
+
+extern int subsetFont(const char* font_name,
+                      const unsigned char* original_font,
+                      const size_t font_size,
+                      const unsigned int* glyph_ids,
+                      const size_t glyph_count,
+                      unsigned char** output_buffer);
+
+#endif  // FONT_SUBSETTER_H_