Add patch to display wide glyphs

The patch is taken from
https://github.com/exg/rxvt-unicode/compare/master...blueyed:display-wide-glyphs

It was posted to the mailing list in 2014q4, where it was rejected, because
"the fonts are bad/wrong", ignoring the usefulness of special glyphs
that are meant to intentionally span multiple cells.
http://lists.schmorp.de/pipermail/rxvt-unicode/2014q4/002042.html.

1 files changed, 274 insertions, 0 deletions

diff --git a/enable-wide-glyphs.patch b/enable-wide-glyphs.patch
new file mode 100644
index 000000000000..0160324009f8
--- /dev/null
+++ b/enable-wide-glyphs.patch
@@ -0,0 +1,274 @@
+diff --git a/config.h.in b/config.h.in
+index 9547145..d88d6cb 100644
+--- a/config.h.in
++++ b/config.h.in
+@@ -18,6 +18,9 @@
+ /* Define if you want your background to use the parent window background */
+ #undef ENABLE_TRANSPARENCY
+ 
++/* Define if you want to display wide glyphs */
++#undef ENABLE_WIDE_GLYPHS
++
+ /* Define if you want european extended codesets */
+ #undef ENCODING_EU
+ 
+diff --git a/configure b/configure
+index c756724..fc4fedd 100755
+--- a/configure
++++ b/configure
+@@ -717,6 +717,7 @@ enable_unicode3
+ enable_combining
+ enable_xft
+ enable_font_styles
++enable_wide_glyphs
+ enable_pixbuf
+ enable_startup_notification
+ enable_transparency
+@@ -1390,6 +1391,7 @@ Optional Features:
+   --enable-combining      enable composition of base and combining characters
+   --enable-xft            enable xft support on systems that have it
+   --enable-font-styles    enable bold and italic support
++  --enable-wide-glyphs    enable displaying of wide glyphs
+   --enable-pixbuf         enable integration with gdk-pixbuf for background images
+   --enable-startup-notification  enable freedesktop startup notification support
+   --enable-transparency   enable transparent backgrounds
+@@ -4723,6 +4725,7 @@ if test "${enable_everything+set}" = set; then :
+        support_8bitctrls=no
+        support_iso14755=no
+        support_styles=no
++       support_wide_glyphs=no
+        support_perl=no
+        codesets=
+     fi
+@@ -4751,6 +4754,7 @@ if test "${enable_everything+set}" = set; then :
+        #support_8bitctrls=yes
+        support_iso14755=yes
+        support_styles=yes
++       support_wide_glyphs=yes
+        support_perl=yes
+        codesets=all
+     fi
+@@ -4852,6 +4856,14 @@ if test "${enable_font_styles+set}" = set; then :
+ fi
+ 
+ 
++# Check whether --enable-wide-glyphs was given.
++if test "${enable_wide_glyphs+set}" = set; then :
++  enableval=$enable_wide_glyphs; if test x$enableval = xyes -o x$enableval = xno; then
++    support_wide_glyphs=$enableval
++  fi
++fi
++
++
+ # Check whether --enable-pixbuf was given.
+ if test "${enable_pixbuf+set}" = set; then :
+   enableval=$enable_pixbuf; if test x$enableval = xyes -o x$enableval = xno; then
+@@ -7684,6 +7696,11 @@ if test x$support_styles = xyes; then
+ $as_echo "#define ENABLE_STYLES 1" >>confdefs.h
+ 
+ fi
++if test x$support_wide_glyphs = xyes; then
++
++$as_echo "#define ENABLE_WIDE_GLYPHS 1" >>confdefs.h
++
++fi
+ if test x$support_iso14755 = xyes; then
+ 
+ $as_echo "#define ISO_14755 1" >>confdefs.h
+diff --git a/configure.ac b/configure.ac
+index 813b16e..714b96f 100644
+--- a/configure.ac
++++ b/configure.ac
+@@ -132,6 +132,7 @@ AC_ARG_ENABLE(everything,
+        support_8bitctrls=no
+        support_iso14755=no
+        support_styles=no
++       support_wide_glyphs=no
+        support_perl=no
+        codesets=
+     fi
+@@ -160,6 +161,7 @@ AC_ARG_ENABLE(everything,
+        #support_8bitctrls=yes
+        support_iso14755=yes
+        support_styles=yes
++       support_wide_glyphs=yes
+        support_perl=yes
+        codesets=all
+     fi
+@@ -225,6 +227,12 @@ AC_ARG_ENABLE(font-styles,
+     support_styles=$enableval
+   fi])
+ 
++AC_ARG_ENABLE(wide-glyphs,
++  [  --enable-wide-glyphs    enable displaying of wide glyphs],
++  [if test x$enableval = xyes -o x$enableval = xno; then
++    support_wide_glyphs=$enableval
++  fi])
++
+ AC_ARG_ENABLE(pixbuf,
+   [  --enable-pixbuf         enable integration with gdk-pixbuf for background images],
+   [if test x$enableval = xyes -o x$enableval = xno; then
+@@ -660,6 +668,9 @@ fi
+ if test x$support_styles = xyes; then
+   AC_DEFINE(ENABLE_STYLES, 1, Define if you want bold and italic support)
+ fi
++if test x$support_wide_glyphs = xyes; then
++  AC_DEFINE(ENABLE_WIDE_GLYPHS, 1, Define if you want to display wide glyphs)
++fi
+ if test x$support_iso14755 = xyes; then
+   AC_DEFINE(ISO_14755, 1, Define if you want ISO 14755 extended support)
+ fi
+diff --git a/src/rxvtfont.C b/src/rxvtfont.C
+index 5dcd125..b50b678 100644
+--- a/src/rxvtfont.C
++++ b/src/rxvtfont.C
+@@ -299,6 +299,9 @@ struct rxvt_font_default : rxvt_font {
+   {
+     careful = false;
+ 
++    if (unicode == 0x0020)
++      return true;
++
+     if (unicode <= 0x001f)
+       return true;
+ 
+@@ -471,6 +474,7 @@ rxvt_font_default::draw (rxvt_drawable &d, int x, int y,
+       else
+         switch (t)
+           {
++            case ' ':
+             case '\t':
+             case ZERO_WIDTH_CHAR:
+             case NOCHAR:
+@@ -1026,8 +1030,10 @@ rxvt_font_x11::has_char (unicode_t unicode, const rxvt_fontprop *prop, bool &car
+ 
+   careful = xcs->lbearing < 0 || xcs->rbearing > prop->width * wcw;
+ 
++#if !ENABLE_WIDE_GLYPHS
+   if (careful && !OVERLAP_OK (w, wcw, prop))
+     return false;
++#endif
+ 
+   return true;
+ }
+@@ -1345,12 +1351,14 @@ rxvt_font_xft::has_char (unicode_t unicode, const rxvt_fontprop *prop, bool &car
+ 
+   careful = g.x > 0 || w > prop->width * wcw;
+ 
++#if !ENABLE_WIDE_GLYPHS
+   if (careful && !OVERLAP_OK (w, wcw, prop))
+     return false;
+ 
+   // this weeds out _totally_ broken fonts, or glyphs
+   if (!OVERLAP_OK (g.xOff, wcw, prop))
+     return false;
++#endif
+ 
+   return true;
+ }
+@@ -1395,6 +1403,10 @@ rxvt_font_xft::draw (rxvt_drawable &d, int x, int y,
+ 
+           ep->glyph = glyph;
+           ep->x = x_ + (cwidth - extents.xOff >> 1);
++#if ENABLE_WIDE_GLYPHS
++          /* Left-align to bounding box, do not overlap to the left. */
++          max_it(ep->x, x_);
++#endif
+           ep->y = y_ + ascent;
+ 
+           if (extents.xOff == 0)
+diff --git a/src/screen.C b/src/screen.C
+index 41f874b..b7a8fd9 100644
+--- a/src/screen.C
++++ b/src/screen.C
+@@ -935,7 +935,61 @@ rxvt_term::scr_add_lines (const wchar_t *str, int len, int minlines) NOTHROW
+ # endif
+ #endif
+ 
+-          rend_t rend = SET_FONT (rstyle, FONTSET (rstyle)->find_font (c));
++          rend_t rend;
++#if ENABLE_WIDE_GLYPHS
++          // Re-use previous font for space characters.
++          // This allows for better display of wider chars with regard to
++          // backtracking (which uses RS_SAME).
++          if (c != ' ')
++            {
++#endif
++            rend = SET_FONT (rstyle, FONTSET (rstyle)->find_font (c));
++#if ENABLE_WIDE_GLYPHS
++
++            }
++          else
++            {
++              // Code taken from ENABLE_COMBINING - might get refactored.
++              line_t *linep;
++              text_t *tp;
++              rend_t *rp = NULL;
++
++              if (screen.cur.col > 0)
++                {
++                  linep = line;
++                  tp = line->t + screen.cur.col - 1;
++                  rp = line->r + screen.cur.col - 1;
++                }
++              else if (screen.cur.row > 0
++                       && ROW(screen.cur.row - 1).is_longer ())
++                {
++                  linep = &ROW(screen.cur.row - 1);
++                  tp = linep->t + ncol - 1;
++                  rp = linep->r + ncol - 1;
++                }
++
++              if (rp)
++                {
++                  // XXX: this font does not show up in iso-14755 mode for the space!?
++                  if (*tp == NOCHAR)
++                    {
++                      while (*tp == NOCHAR && tp > linep->t)
++                        tp--, rp--;
++
++                      // first try to find a precomposed character
++                      unicode_t n = rxvt_compose (*tp, c);
++                      if (n == NOCHAR)
++                        n = rxvt_composite.compose (*tp, c);
++
++                      *tp = n;
++                      *rp = SET_FONT (*rp, FONTSET (*rp)->find_font (*tp));
++                    }
++                  rend = SET_FONT (rstyle, GET_FONT(*rp));
++                }
++              else
++                rend = SET_FONT (rstyle, FONTSET (rstyle)->find_font (c));
++            }
++#endif
+ 
+           // if the character doesn't fit into the remaining columns...
+           if (ecb_unlikely (screen.cur.col > ncol - width && ncol >= width))
+@@ -2399,7 +2453,12 @@ rxvt_term::scr_refresh () NOTHROW
+                 text--, count++, xpixel -= fwidth;
+ 
+               // force redraw after "careful" characters to avoid pixel droppings
+-              for (int i = 0; srp[col + i] & RS_Careful && col + i < ncol - 1; i++)
++              for (int i = 0;
++#if ENABLE_WIDE_GLYPHS
++              // But not for spaces.
++                      stp[col + i + 1] != ' ' &&
++#endif
++                      srp[col + i] & RS_Careful && col + i < ncol - 1; i++)
+                 drp[col + i + 1] = srp[col + i + 1] ^ RS_redraw;
+ 
+               // force redraw before "careful" characters to avoid pixel droppings
+diff --git a/src/xdefaults.C b/src/xdefaults.C
+index 2308844..f7e034a 100644
+--- a/src/xdefaults.C
++++ b/src/xdefaults.C
+@@ -302,6 +302,9 @@ static const char optionsstring[] = "options: "
+ #if ENABLE_STYLES
+                                     "styles,"
+ #endif
++#if ENABLE_WIDE_GLYPHS
++                                    "wide-glyphs,"
++#endif
+ #if ENABLE_COMBINING
+                                     "combining,"
+ #endif