tui: Eliminate superfluous SGR resets.

Track whether the terminal is in no attribute mode, assuming that it starts
this way, and do not attempt to reset back to that mode if already in it.

1 files changed, 14 insertions, 1 deletions

diff --git a/src/nvim/tui/tui.c b/src/nvim/tui/tui.c
index 83198ee33c..84f23062ff 100644
--- a/src/nvim/tui/tui.c
+++ b/src/nvim/tui/tui.c
@@ -90,6 +90,7 @@ typedef struct {
   bool busy;
   cursorentry_T cursor_shapes[SHAPE_IDX_COUNT];
   HlAttrs print_attrs;
+  bool default_attr;
   ModeShape showing_mode;
   TermType term;
   struct {
@@ -155,6 +156,7 @@ static void terminfo_start(UI *ui)
   data->scroll_region_is_full_screen = true;
   data->bufpos = 0;
   data->bufsize = sizeof(data->buf) - CNORM_COMMAND_MAX_SIZE;
+  data->default_attr = false;
   data->showing_mode = SHAPE_IDX_N;
   data->unibi_ext.enable_mouse = -1;
   data->unibi_ext.disable_mouse = -1;
@@ -336,7 +338,10 @@ static void update_attrs(UI *ui, HlAttrs attrs)
   }
 
   data->print_attrs = attrs;
-  unibi_out(ui, unibi_exit_attribute_mode);
+  if (!data->default_attr) {
+    data->default_attr = true;
+    unibi_out(ui, unibi_exit_attribute_mode);
+  }
   UGrid *grid = &data->grid;
 
   int fg = attrs.foreground != -1 ? attrs.foreground : grid->fg;
@@ -348,6 +353,7 @@ static void update_attrs(UI *ui, HlAttrs attrs)
       data->params[1].i = (fg >> 8) & 0xff;   // green
       data->params[2].i = fg & 0xff;          // blue
       unibi_out(ui, data->unibi_ext.set_rgb_foreground);
+      data->default_attr = false;
     }
 
     if (bg != -1) {
@@ -355,30 +361,37 @@ static void update_attrs(UI *ui, HlAttrs attrs)
       data->params[1].i = (bg >> 8) & 0xff;   // green
       data->params[2].i = bg & 0xff;          // blue
       unibi_out(ui, data->unibi_ext.set_rgb_background);
+      data->default_attr = false;
     }
   } else {
     if (fg != -1) {
       data->params[0].i = fg;
       unibi_out(ui, unibi_set_a_foreground);
+      data->default_attr = false;
     }
 
     if (bg != -1) {
       data->params[0].i = bg;
       unibi_out(ui, unibi_set_a_background);
+      data->default_attr = false;
     }
   }
 
   if (attrs.bold) {
     unibi_out(ui, unibi_enter_bold_mode);
+    data->default_attr = false;
   }
   if (attrs.italic) {
     unibi_out(ui, unibi_enter_italics_mode);
+    data->default_attr = false;
   }
   if (attrs.underline || attrs.undercurl) {
     unibi_out(ui, unibi_enter_underline_mode);
+    data->default_attr = false;
   }
   if (attrs.reverse) {
     unibi_out(ui, unibi_enter_reverse_mode);
+    data->default_attr = false;
   }
 }