fully functional, very speedy, not yet global variable, missing docum…

…entation

src/gui_gtk_x11.c

@@ -5595,18 +5595,11 @@ draw_under(int flags, int row, int col, int cells)
     int
 gui_gtk2_draw_string(int row, int col, char_u *s, int len, int flags)
 {
-    GdkRectangle	area;		    // area for clip mask
-    PangoGlyphString	*glyphs;	    // glyphs of current item
-    int			column_offset = 0;  // column offset in cells
-    int			i;
     char_u		*conv_buf = NULL;   // result of UTF-8 conversion
     char_u		*new_conv_buf;
     int			convlen;
     char_u		*sp, *bp;
     int			plen;
-#if GTK_CHECK_VERSION(3,0,0)
-    cairo_t		*cr;
-#endif
 
     if (gui.text_context == NULL || gtk_widget_get_window(gui.drawarea) == NULL)
 	return len;
@@ -5651,7 +5644,91 @@ gui_gtk2_draw_string(int row, int col, char_u *s, int len, int flags)
 	s = conv_buf;
 	len = convlen;
     }
+    vim_free(conv_buf);
+
+    // String may contain ascii, utf-8 chars or ligatures. Group them together to speed up output.
+
+    // currently fixed list, move it to global set something = 'character list'
+    // also map to record array to speed up lookup
+    char *ligatures = "!\"#$%&'()*+-./:;<=>?@[\\]^_`{|}~"; // removed comma char, does any ligature use it?
+    int ligatures_size = 31;
+
+    int	lensum = 0; // return value needs to add up since we are printing substrings
+    char_u *cs = s; // current *s pointer
+    int needs_pango = ((*cs & 0x80) || (memchr(ligatures, *cs, ligatures_size) != NULL) && 1); // look ahead, 0=ascii 1=unicode/ligatures
+    int should_need_pango;
+
+    // split string into ascii and non-ascii (ligatures + utf-8) substrings, print glyphs or use Pango
+    while (cs < s + len)
+    {
+	int slen = 0;
+	while (slen < len - lensum)
+	{
+            int is_ligature = memchr(ligatures, *(cs + slen), ligatures_size) != NULL;
+            int is_utf8 = *(cs + slen) & 0x80;
+            should_need_pango = (is_ligature || is_utf8) && 1;
+            if (needs_pango != should_need_pango) break; // mode switch
+            if (needs_pango)
+            {
+		if (is_ligature)
+		{
+                    slen++; // ligature char by char
+		}
+		else
+		{
+                    if (*(cs + slen) & 0xE0 == 0xC0) // + one byte utf8
+                    {
+                        slen++;
+                    }
+                    else if (*(cs + slen) & 0xF0 == 0xE0) // + two bytes utf8
+                    {
+                        slen += 2;
+                    }
+                    else if (*(cs + slen) & 0xF8 == 0xF0) // + three bytes utf8
+                    {
+                        slen += 3;
+                    }
+                    else if (*(cs + slen) & 0xC0 == 0x80) // a continuation, find 0xB0 == 0x80 but don't include it
+                    {
+			while ((slen < len - lensum) && (*(cs + slen) & 0x80 == 0x80)) slen++;
+			slen--;
+                    }
+                    else // this should not happen, try moving forward, Pango will catch it
+                    {
+			slen++;
+                    }
+		}
+            }
+            else
+            {
+                slen++; // ascii
+            }
+	}
+	// temporarily zero terminate substring, print, restore char, wrap
+	char_u backup_ch = *(cs + slen);
+	*(cs + slen) = 0;
+	//debug: uncomment to see splits in terminal
+	//printf("substr needs pango: %i: \n!%s@\n", needs_pango, cs);
+	//fflush(stdout);
+	int l = gui_gtk2_draw_string_ext(row, col + lensum, cs, slen, flags, needs_pango);
+	*(cs + slen) = backup_ch;
+	cs += slen;
+	needs_pango = should_need_pango;
+	lensum += l;
+    }
+    return lensum;
+}
 
+    int
+gui_gtk2_draw_string_ext(int row, int col, char_u *s, int len, int flags, int force_pango)
+{
+    GdkRectangle	area;		    // area for clip mask
+    PangoGlyphString	*glyphs;	    // glyphs of current item
+    int			column_offset = 0;  // column offset in cells
+    int			i;
+#if GTK_CHECK_VERSION(3,0,0)
+    cairo_t		*cr;
+#endif
     /*
      * Restrict all drawing to the current screen line in order to prevent
      * fuzzy font lookups from messing up the screen.
@@ -5679,7 +5756,8 @@ gui_gtk2_draw_string(int row, int col, char_u *s, int len, int flags)
      */
     if (!(flags & DRAW_ITALIC)
 	    && !((flags & DRAW_BOLD) && gui.font_can_bold)
-	    && gui.ascii_glyphs != NULL)
+	    && gui.ascii_glyphs != NULL
+	    && !force_pango)
     {
 	char_u *p;
 
@@ -5883,7 +5961,6 @@ gui_gtk2_draw_string(int row, int col, char_u *s, int len, int flags)
 #endif
 
     pango_glyph_string_free(glyphs);
-    vim_free(conv_buf);
 
 #if GTK_CHECK_VERSION(3,0,0)
     cairo_destroy(cr);

src/proto/gui_gtk_x11.pro

@@ -43,6 +43,7 @@ void gui_mch_set_fg_color(guicolor_T color);
 void gui_mch_set_bg_color(guicolor_T color);
 void gui_mch_set_sp_color(guicolor_T color);
 int gui_gtk2_draw_string(int row, int col, char_u *s, int len, int flags);
+int gui_gtk2_draw_string_ext(int row, int col, char_u *s, int len, int flags, int force_pango);
 int gui_mch_haskey(char_u *name);
 int gui_get_x11_windis(Window *win, Display **dis);
 Display *gui_mch_get_display(void);