HarfBuzz shaping support

Split up text into runs with the same direction, font face and font
size, shape these runs with HarfBuzz and reorder accordingly.

This noticeably improves Arabic shaping and should make shaping for many
other scripts work. HarfBuzz also does kerning for Latin text.

1 files changed, 4 insertions, 0 deletions

diff --git a/libass/ass_render.h b/libass/ass_render.h
index 8b446e6..ea29c79 100644
--- a/libass/ass_render.h
+++ b/libass/ass_render.h
@@ -100,6 +100,8 @@ typedef struct {
     unsigned symbol;
     unsigned skip;              // skip glyph when layouting text
     ASS_Font *font;
+    int face_index;
+    int glyph_index;
     double font_size;
     ASS_Drawing *drawing;
     FT_Outline *outline;
@@ -109,6 +111,7 @@ typedef struct {
     Bitmap *bm_s;               // shadow bitmap
     FT_BBox bbox;
     FT_Vector pos;
+    FT_Vector offset;
     char linebreak;             // the first (leading) glyph of some line ?
     uint32_t c[4];              // colors
     FT_Vector advance;          // 26.6
@@ -131,6 +134,7 @@ typedef struct {
     int flags;
 
     int bm_run_id;
+    int shape_run_id;
 
     BitmapHashKey hash_key;
 } GlyphInfo;