Apply Ligatures patch

Homepage link: https://st.suckless.org/patches/ligatures/
Patch links:
    https://st.suckless.org/patches/ligatures/0.8.3/st-ligatures-boxdraw-20200430-0.8.3.diff
    https://st.suckless.org/patches/ligatures/0.8.3/st-ligatures-scrollback-20200430-0.8.3.diff
Additional info: the patch was applied by mixing the two patches linked
above in order to provide compatibility with both BoxDraw and Scrollback
patches.

1 files changed, 13 insertions, 3 deletions

diff --git a/x.c b/x.c
index 58c2d98..0f95d60 100644
--- a/x.c
+++ b/x.c
@@ -19,6 +19,7 @@ static char *argv0;
 #include "arg.h"
 #include "st.h"
 #include "win.h"
+#include "hb.h"
 
 /* types used in config.h */
 typedef struct {
@@ -1117,6 +1118,9 @@ xunloadfont(Font *f)
 void
 xunloadfonts(void)
 {
+    /* Clear Harfbuzz font cache. */
+    hbunloadfonts();
+
         /* Free the loaded fonts in the font cache.  */
         while (frclen > 0)
                 XftFontClose(xw.dpy, frc[--frclen].font);
@@ -1320,7 +1324,7 @@ xmakeglyphfontspecs(XftGlyphFontSpec *specs, const Glyph *glyphs, int len, int x
                 mode = glyphs[i].mode;
 
                 /* Skip dummy wide-character spacing. */
-                if (mode == ATTR_WDUMMY)
+        if (mode & ATTR_WDUMMY)
                         continue;
 
                 /* Determine font for glyph if different from previous glyph. */
@@ -1432,6 +1436,9 @@ xmakeglyphfontspecs(XftGlyphFontSpec *specs, const Glyph *glyphs, int len, int x
                 numspecs++;
         }
 
+    /* Harfbuzz transformation for ligatures. */
+    hbtransform(specs, glyphs, len, x, y);
+
         return numspecs;
 }
 
@@ -1585,14 +1592,17 @@ xdrawglyph(Glyph g, int x, int y)
 }
 
 void
-xdrawcursor(int cx, int cy, Glyph g, int ox, int oy, Glyph og)
+xdrawcursor(int cx, int cy, Glyph g, int ox, int oy, Glyph og, Line line, int len)
 {
         Color drawcol;
 
         /* remove the old cursor */
         if (selected(ox, oy))
                 og.mode ^= ATTR_REVERSE;
-        xdrawglyph(og, ox, oy);
+
+    /* Redraw the line where cursor was previously.
+     * It will restore the ligatures broken by the cursor. */
+    xdrawline(line, 0, oy, len);
 
         if (IS_SET(MODE_HIDE))
                 return;