Add WRAP_UNICODE feature

Setting this feature allows breaking lines according to the Unicode
Line Breaking Algorithm and is incompatible with VSFilter.
This is useful for non-ASS renderers utilising libass, especially for
languages typically not using ASCII-spaces to separate words, but
also to correctly break on punctuation even in languages that do. It
does not allow breaking words apart, so line overflow might still occur.
For this to work a new optional dependency on libunibrak is added.
We assume FriBidi's and libunibreak's utf32/glyph type match.

This is based on an earlier patch by GitHub user siikamiika.

1 files changed, 7 insertions, 0 deletions

diff --git a/libass/ass_library.c b/libass/ass_library.c
index 745798e..42cabbd 100644
--- a/libass/ass_library.c
+++ b/libass/ass_library.c
@@ -24,6 +24,9 @@
 #include <stdlib.h>
 #include <string.h>
 #include <stdarg.h>
+#ifdef CONFIG_UNIBREAK
+#include <linebreak.h>
+#endif
 
 #include "ass.h"
 #include "ass_library.h"
@@ -44,6 +47,10 @@ ASS_Library *ass_library_init(void)
     ASS_Library* lib = calloc(1, sizeof(*lib));
     if (lib)
         lib->msg_callback = ass_msg_handler;
+    #ifdef CONFIG_UNIBREAK
+    // libunibreak works without, but its docs suggest this improves performance
+    init_linebreak();
+    #endif
     return lib;
 }