BLF: New Font Stack for Better Language Coverage

Replace our existing two fonts with a stack of new fonts to increase
and improve language coverage and to add many new symbols and icons.
Covers glyphs of top 44 languages - 1.5 billion more potential users.

See D10887 for lots of details.

Differential Revision: https://developer.blender.org/D10887

Reviewed by Brecht Van Lommel

source/blender/blenfont/BLF_api.h

@@ -18,10 +18,10 @@ extern "C" {
 #define BLF_DATAFILES_FONTS_DIR "fonts"
 
 /* File name of the default variable-width font. */
-#define BLF_DEFAULT_PROPORTIONAL_FONT "droidsans.ttf"
+#define BLF_DEFAULT_PROPORTIONAL_FONT "DejaVuSans.woff2"
 
 /* File name of the default fixed-pitch font. */
-#define BLF_DEFAULT_MONOSPACED_FONT "bmonofont-i18n.ttf"
+#define BLF_DEFAULT_MONOSPACED_FONT "DejaVuSansMono.woff2"
 
 /* enable this only if needed (unused circa 2016) */
 #define BLF_BLUR_ENABLE 0

source/blender/blenfont/intern/blf_glyph.c

@@ -594,6 +594,10 @@ static FT_UInt blf_glyph_index_from_charcode(FontBLF **font, const uint charcode
     }
   }
 
+#ifdef DEBUG
+  printf("Unicode character U+%04X not found in loaded fonts. \n", charcode);
+#endif
+
   /* Not found in the stack, return from Last Resort if there is one. */
   if (last_resort && blf_ensure_face(last_resort)) {
     glyph_index = FT_Get_Char_Index(last_resort->face, charcode);