Revert "[WIP] "abstract_ui" fixes and improvements"

runtime/plugin/matchparen.vim

@@ -45,7 +45,7 @@ function! s:Highlight_Matching_Pair()
 
   " Avoid that we remove the popup menu.
   " Return when there are no colors (looks like the cursor jumps).
-  if pumvisible() || (&term != 'abstract_ui' && &t_Co < 8 && !has("gui_running"))
+  if pumvisible() || (&t_Co < 8 && !has("gui_running"))
     return
   endif
 

src/nvim/edit.c

@@ -2294,7 +2294,8 @@ static int pum_wanted(void)
     return FALSE;
 
   /* The display looks bad on a B&W display. */
-  if (!abstract_ui && t_colors < 8)
+  if (t_colors < 8
+      )
     return FALSE;
   return TRUE;
 }

src/nvim/eval.c

@@ -14440,7 +14440,7 @@ static void f_synIDattr(typval_T *argvars, typval_T *rettv)
     if (modec != 't' && modec != 'c' && modec != 'g')
       modec = 0;        /* replace invalid with current */
   } else {
-    if (abstract_ui || t_colors > 1)
+    if (t_colors > 1)
       modec = 'c';
     else
       modec = 't';

src/nvim/ex_docmd.c

@@ -71,7 +71,6 @@
 #include "nvim/os/time.h"
 #include "nvim/ex_cmds_defs.h"
 #include "nvim/mouse.h"
-#include "nvim/msgpack_rpc/channel.h"
 
 static int quitmore = 0;
 static int ex_pressedreturn = FALSE;
@@ -5399,16 +5398,10 @@ static void ex_stop(exarg_T *eap)
   /*
    * Disallow suspending for "rvim".
    */
-  if (!check_restricted()) {
+  if (!check_restricted()
-    if (!eap->forceit) {
+      ) {
+    if (!eap->forceit)
       autowrite_all();
-    }
-
-    if (abstract_ui) {
-      channel_close(last_message_source);
-      return;
-    }
-
     windgoto((int)Rows - 1, 0);
     out_char('\n');
     out_flush();

src/nvim/globals.h

@@ -1245,9 +1245,6 @@ EXTERN int curr_tmode INIT(= TMODE_COOK); /* contains current terminal mode */
 EXTERN bool embedded_mode INIT(= false);
 // Using the "abstract_ui" termcap
 EXTERN bool abstract_ui INIT(= false);
-// Id of the last channel sent a message to nvim. Used to determine the target
-// of channel-specific actions such as suspending
-EXTERN uint64_t last_message_source INIT(= 0);
 
 /// Used to track the status of external functions.
 /// Currently only used for iconv().

src/nvim/main.c

@@ -281,7 +281,9 @@ int main(int argc, char **argv)
 
   event_init();
 
-  if (!abstract_ui) {
+  if (abstract_ui) {
+    t_colors = 256;
+  } else {
     // Print a warning if stdout is not a terminal TODO(tarruda): Remove this
     // check once the new terminal UI is implemented
     check_tty(&params);

src/nvim/msgpack_rpc/channel.c

@@ -45,7 +45,6 @@ typedef struct {
 
 typedef struct {
   uint64_t id;
-  size_t pending_requests;
   PMap(cstr_t) *subscribed_events;
   bool is_job, closed;
   msgpack_unpacker *unpacker;
@@ -84,6 +83,7 @@ static uint64_t next_id = 1;
 static PMap(uint64_t) *channels = NULL;
 static PMap(cstr_t) *event_strings = NULL;
 static msgpack_sbuffer out_buffer;
+static size_t pending_requests = 0;
 
 #ifdef INCLUDE_GENERATED_DECLARATIONS
 # include "msgpack_rpc/channel.c.generated.h"
@@ -103,7 +103,14 @@ void channel_init(void)
   }
 
   if (abstract_ui) {
+    // Add handler for "attach_ui"
     remote_ui_init();
+    String method = cstr_as_string("attach_ui");
+    MsgpackRpcRequestHandler handler = {.fn = remote_ui_attach, .defer = true};
+    msgpack_rpc_add_method_handler(method, handler);
+    method = cstr_as_string("detach_ui");
+    handler.fn = remote_ui_detach;
+    msgpack_rpc_add_method_handler(method, handler);
   }
 }
 
@@ -193,21 +200,20 @@ bool channel_send_event(uint64_t id, char *name, Array args)
     return false;
   }
 
-  if (channel) {
+  if (pending_requests) {
-    if (channel->pending_requests) {
+    DelayedNotification p = {
-      DelayedNotification p = {
+      .channel = channel,
-        .channel = channel,
+      .method = cstr_to_string(name),
-        .method = cstr_to_string(name),
+      .args = args
-        .args = args
+    };
-      };
+    // Pending request, queue the notification for sending later
-      // Pending request, queue the notification for sending later
+    *kl_pushp(DelayedNotification, delayed_notifications) = p;
-      *kl_pushp(DelayedNotification, delayed_notifications) = p;
+  } else {
-    } else {
+    if (channel) {
       send_event(channel, name, args);
+    } else {
+      broadcast_event(name, args);
     }
-  }  else {
-    // TODO(tarruda): Implement event broadcasting in vimscript
-    broadcast_event(name, args);
   }
 
   return true;
@@ -240,10 +246,10 @@ Object channel_send_call(uint64_t id,
   // Push the frame
   ChannelCallFrame frame = {request_id, false, false, NIL};
   kv_push(ChannelCallFrame *, channel->call_stack, &frame);
-  channel->pending_requests++;
+  pending_requests++;
   event_poll_until(-1, frame.returned);
   (void)kv_pop(channel->call_stack);
-  channel->pending_requests--;
+  pending_requests--;
 
   if (frame.errored) {
     api_set_error(err, Exception, "%s", frame.result.data.string.data);
@@ -255,7 +261,7 @@ Object channel_send_call(uint64_t id,
     free_channel(channel);
   }
 
-  if (!channel->pending_requests) {
+  if (!pending_requests) {
     send_delayed_notifications();
   }
 
@@ -486,7 +492,6 @@ static void on_request_event(Event event)
 {
   RequestEvent *e = event.data;
   Channel *channel = e->channel;
-  last_message_source = channel->id;
   MsgpackRpcRequestHandler handler = e->handler;
   Array args = e->args;
   uint64_t request_id = e->request_id;
@@ -639,7 +644,6 @@ static void close_channel(Channel *channel)
     uv_handle_t *handle = (uv_handle_t *)channel->data.streams.uv;
     if (handle) {
       uv_close(handle, close_cb);
-      free_channel(channel);
     } else {
       event_push((Event) { .handler = on_stdio_close }, false);
     }
@@ -683,7 +687,6 @@ static Channel *register_channel(void)
   rv->closed = false;
   rv->unpacker = msgpack_unpacker_new(MSGPACK_UNPACKER_INIT_BUFFER_SIZE);
   rv->id = next_id++;
-  rv->pending_requests = 0;
   rv->subscribed_events = pmap_new(cstr_t)();
   rv->next_request_id = 1;
   kv_init(rv->call_stack);

src/nvim/msgpack_rpc/remote_ui.c

@@ -26,44 +26,18 @@ static PMap(uint64_t) *connected_uis = NULL;
 void remote_ui_init(void)
 {
   connected_uis = pmap_new(uint64_t)();
-  // Add handler for "attach_ui"
-  String method = cstr_as_string("ui_attach");
-  MsgpackRpcRequestHandler handler = {.fn = remote_ui_attach, .defer = false};
-  msgpack_rpc_add_method_handler(method, handler);
-  method = cstr_as_string("ui_detach");
-  handler.fn = remote_ui_detach;
-  msgpack_rpc_add_method_handler(method, handler);
-  method = cstr_as_string("ui_try_resize");
-  handler.fn = remote_ui_try_resize;
-  msgpack_rpc_add_method_handler(method, handler);
 }
 
-void remote_ui_disconnect(uint64_t channel_id)
+Object remote_ui_attach(uint64_t channel_id, uint64_t request_id, Array args,
-{
+                        Error *error)
-  UI *ui = pmap_get(uint64_t)(connected_uis, channel_id);
-  if (!ui) {
-    return;
-  }
-  UIData *data = ui->data;
-  // destroy pending screen updates
-  api_free_array(data->buffer);
-  pmap_del(uint64_t)(connected_uis, channel_id);
-  free(ui->data);
-  ui_detach(ui);
-  free(ui);
-}
-
-static Object remote_ui_attach(uint64_t channel_id, uint64_t request_id,
-                               Array args, Error *error)
 {
   if (pmap_has(uint64_t)(connected_uis, channel_id)) {
     api_set_error(error, Exception, _("UI already attached for channel"));
     return NIL;
   }
 
-  if (args.size != 3 || args.items[0].type != kObjectTypeInteger
+  if (args.size != 2 || args.items[0].type != kObjectTypeInteger
       || args.items[1].type != kObjectTypeInteger
-      || args.items[2].type != kObjectTypeBoolean
       || args.items[0].data.integer <= 0 || args.items[1].data.integer <= 0) {
     api_set_error(error, Validation,
                   _("Arguments must be a pair of positive integers "
@@ -76,7 +50,6 @@ static Object remote_ui_attach(uint64_t channel_id, uint64_t request_id,
   UI *ui = xcalloc(1, sizeof(UI));
   ui->width = (int)args.items[0].data.integer;
   ui->height = (int)args.items[1].data.integer;
-  ui->rgb = args.items[2].data.boolean;
   ui->data = data;
   ui->resize = remote_ui_resize;
   ui->clear = remote_ui_clear;
@@ -94,16 +67,16 @@ static Object remote_ui_attach(uint64_t channel_id, uint64_t request_id,
   ui->put = remote_ui_put;
   ui->bell = remote_ui_bell;
   ui->visual_bell = remote_ui_visual_bell;
-  ui->update_fg = remote_ui_update_fg;
-  ui->update_bg = remote_ui_update_bg;
   ui->flush = remote_ui_flush;
+  ui->suspend = remote_ui_suspend;
   pmap_put(uint64_t)(connected_uis, channel_id, ui);
   ui_attach(ui);
+
   return NIL;
 }
 
-static Object remote_ui_detach(uint64_t channel_id, uint64_t request_id,
+Object remote_ui_detach(uint64_t channel_id, uint64_t request_id, Array args,
-                               Array args, Error *error)
+                        Error *error)
 {
   if (!pmap_has(uint64_t)(connected_uis, channel_id)) {
     api_set_error(error, Exception, _("UI is not attached for channel"));
@@ -113,30 +86,21 @@ static Object remote_ui_detach(uint64_t channel_id, uint64_t request_id,
   return NIL;
 }
 
-static Object remote_ui_try_resize(uint64_t channel_id, uint64_t request_id,
+void remote_ui_disconnect(uint64_t channel_id)
-                                   Array args, Error *error)
 {
-  if (!pmap_has(uint64_t)(connected_uis, channel_id)) {
-    api_set_error(error, Exception, _("UI is not attached for channel"));
-  }
-
-  if (args.size != 2 || args.items[0].type != kObjectTypeInteger
-      || args.items[1].type != kObjectTypeInteger
-      || args.items[0].data.integer <= 0 || args.items[1].data.integer <= 0) {
-    api_set_error(error, Validation,
-                  _("Arguments must be a pair of positive integers "
-                    "representing the remote screen width/height"));
-    return NIL;
-  }
-
   UI *ui = pmap_get(uint64_t)(connected_uis, channel_id);
-  ui->width = (int)args.items[0].data.integer;
+  if (!ui) {
-  ui->height = (int)args.items[1].data.integer;
+    return;
-  ui_refresh();
+  }
-  return NIL;
+  UIData *data = ui->data;
+  // destroy pending screen updates
+  api_free_array(data->buffer);
+  pmap_del(uint64_t)(connected_uis, channel_id);
+  free(ui->data);
+  ui_detach(ui);
+  free(ui);
 }
 
-
 static void push_call(UI *ui, char *name, Array args)
 {
   Array call = ARRAY_DICT_INIT;
@@ -250,6 +214,10 @@ static void remote_ui_highlight_set(UI *ui, HlAttrs attrs)
     PUT(hl, "bold", BOOLEAN_OBJ(true));
   }
 
+  if (attrs.standout) {
+    PUT(hl, "standout", BOOLEAN_OBJ(true));
+  }
+
   if (attrs.underline) {
     PUT(hl, "underline", BOOLEAN_OBJ(true));
   }
@@ -298,23 +266,15 @@ static void remote_ui_visual_bell(UI *ui)
   push_call(ui, "visual_bell", args);
 }
 
-static void remote_ui_update_fg(UI *ui, int fg)
-{
-  Array args = ARRAY_DICT_INIT;
-  ADD(args, INTEGER_OBJ(fg));
-  push_call(ui, "update_fg", args);
-}
-
-static void remote_ui_update_bg(UI *ui, int bg)
-{
-  Array args = ARRAY_DICT_INIT;
-  ADD(args, INTEGER_OBJ(bg));
-  push_call(ui, "update_bg", args);
-}
-
 static void remote_ui_flush(UI *ui)
 {
   UIData *data = ui->data;
   channel_send_event(data->channel_id, "redraw", data->buffer);
   data->buffer = (Array)ARRAY_DICT_INIT;
 }
+
+static void remote_ui_suspend(UI *ui)
+{
+  UIData *data = ui->data;
+  remote_ui_disconnect(data->channel_id);
+}

src/nvim/os/input.c

@@ -187,20 +187,14 @@ size_t input_enqueue(String keys)
     unsigned int new_size = trans_special((uint8_t **)&ptr, buf, false);
 
     if (!new_size) {
-      if (*ptr == '<') {
-        // Invalid key sequence, skip until the next '>' or until *end
-        do {
-          ptr++;
-        } while (ptr < end && *ptr != '>');
-        ptr++;
-        continue;
-      }
       // copy the character unmodified
       *buf = (uint8_t)*ptr++;
       new_size = 1;
     }
 
     new_size = handle_mouse_event(&ptr, buf, new_size);
+    // TODO(tarruda): Don't produce past unclosed '<' characters, except if
+    // there's a lot of characters after the '<'
     rbuffer_write(input_buffer, (char *)buf, new_size);
   }
 

src/nvim/os/shell.c

@@ -24,6 +24,7 @@
 #include "nvim/option_defs.h"
 #include "nvim/charset.h"
 #include "nvim/strings.h"
+#include "nvim/ui.h"
 
 #define DYNAMIC_BUFFER_INIT {NULL, 0, 0}
 
@@ -413,7 +414,6 @@ static size_t write_output(char *output, size_t remaining, bool to_buffer,
 
   char *start = output;
   size_t off = 0;
-  int lastrow = (int)Rows - 1;
   while (off < remaining) {
     if (output[off] == NL) {
       // Insert the line
@@ -421,8 +421,10 @@ static size_t write_output(char *output, size_t remaining, bool to_buffer,
       if (to_buffer) {
         ml_append(curwin->w_cursor.lnum++, (char_u *)output, 0, false);
       } else {
-        screen_del_lines(0, 0, 1, (int)Rows, true, NULL);
+        // pending data from the output buffer has been flushed to the screen,
-        screen_puts_len((char_u *)output, (int)off, lastrow, 0, 0);
+        // safe to call ui_write directly
+        ui_write((char_u *)output, (int)off);
+        ui_write((char_u *)"\r\n", 2);
       }
       size_t skip = off + 1;
       output += skip;
@@ -446,8 +448,8 @@ static size_t write_output(char *output, size_t remaining, bool to_buffer,
         // remember that the NL was missing
         curbuf->b_no_eol_lnum = curwin->w_cursor.lnum;
       } else {
-        screen_del_lines(0, 0, 1, (int)Rows, true, NULL);
+        ui_write((char_u *)output, (int)remaining);
-        screen_puts_len((char_u *)output, (int)remaining, lastrow, 0, 0);
+        ui_write((char_u *)"\r\n", 2);
       }
       output += remaining;
     } else if (to_buffer) {

src/nvim/screen.c

@@ -4548,7 +4548,7 @@ static void screen_line(int row, int coloff, int endcol, int clear_width, int rl
       int c;
 
       c = fillchar_vsep(&hl);
-      if (ScreenLines[off_to] != ((schar_T)c)
+      if (ScreenLines[off_to] != c
           || (enc_utf8 && (int)ScreenLinesUC[off_to]
               != (c >= 0x80 ? c : 0))
           || ScreenAttrs[off_to] != hl) {
@@ -6150,7 +6150,8 @@ void screen_fill(int start_row, int end_row, int start_col, int end_col, int c1,
     return;
 
   /* it's a "normal" terminal when not in a GUI or cterm */
-  norm_term = (!abstract_ui && t_colors <= 1);
+  norm_term = (
+    t_colors <= 1);
   for (row = start_row; row < end_row; ++row) {
     if (has_mbyte
         ) {
@@ -6674,7 +6675,7 @@ static void linecopy(int to, int from, win_T *wp)
  */
 int can_clear(char_u *p)
 {
-  return *p != NUL && ((!abstract_ui && t_colors <= 1)
+  return *p != NUL && (t_colors <= 1
                        || cterm_normal_bg_color == 0 || *T_UT != NUL);
 }
 
@@ -7701,7 +7702,8 @@ static void draw_tabline(void)
   int attr_fill = hl_attr(HLF_TPF);
   char_u      *p;
   int room;
-  int use_sep_chars = !abstract_ui && t_colors < 8;
+  int use_sep_chars = (t_colors < 8
+                       );
 
   redraw_tabline = FALSE;
 
@@ -8186,9 +8188,6 @@ void screen_resize(int width, int height, int mustset)
   check_shellsize();
 
   if (abstract_ui) {
-    // Clear the output buffer to ensure UIs don't receive redraw command meant
-    // for invalid screen sizes.
-    out_buf_clear();
     ui_resize(width, height);
   } else {
     mch_set_shellsize();

src/nvim/syntax.c

@@ -45,7 +45,6 @@
 #include "nvim/strings.h"
 #include "nvim/syntax_defs.h"
 #include "nvim/term.h"
-#include "nvim/ui.h"
 #include "nvim/os/os.h"
 #include "nvim/os/time.h"
 
@@ -5984,7 +5983,7 @@ init_highlight (
    * With 8 colors brown is equal to yellow, need to use black for Search fg
    * to avoid Statement highlighted text disappears.
    * Clear the attributes, needed when changing the t_Co value. */
-  if (abstract_ui || t_colors > 8)
+  if (t_colors > 8)
     do_highlight(
         (char_u *)(*p_bg == 'l'
                    ? "Visual cterm=NONE ctermbg=LightGrey"
@@ -6037,7 +6036,6 @@ int load_colors(char_u *name)
   apply_autocmds(EVENT_COLORSCHEME, name, curbuf->b_fname, FALSE, curbuf);
 
   recursive = FALSE;
-  ui_refresh();
 
   return retval;
 }
@@ -6433,9 +6431,7 @@ do_highlight (
             /* Use the _16 table to check if its a valid color name. */
             color = color_numbers_16[i];
             if (color >= 0) {
-              if (abstract_ui) {
+              if (t_colors == 8) {
-                color = color_numbers_256[i];
-              } else if (t_colors == 8) {
                 /* t_Co is 8: use the 8 colors table */
 #if defined(__QNXNTO__)
                 color = color_numbers_8_qansi[i];
@@ -6452,7 +6448,8 @@ do_highlight (
                     HL_TABLE()[idx].sg_cterm &= ~HL_BOLD;
                 }
                 color &= 7;             /* truncate to 8 colors */
-              } else if (t_colors == 16 || t_colors == 88 || t_colors == 256) {
+              } else if (t_colors == 16 || t_colors == 88
+                         || t_colors == 256) {
                 /*
                  * Guess: if the termcap entry ends in 'm', it is
                  * probably an xterm-like terminal.  Use the changed
@@ -6499,7 +6496,7 @@ do_highlight (
                 if (color >= 0) {
                   if (termcap_active)
                     term_bg_color(color);
-                  if (!abstract_ui && t_colors < 16)
+                  if (t_colors < 16)
                     i = (color == 0 || color == 4);
                   else
                     i = (color < 7 || color == 8);
@@ -6645,10 +6642,6 @@ do_highlight (
     if (is_normal_group) {
       HL_TABLE()[idx].sg_term_attr = 0;
       HL_TABLE()[idx].sg_cterm_attr = 0;
-      if (abstract_ui) {
-        // If the normal group has changed, it is simpler to refresh every UI
-        ui_refresh();
-      }
     } else
       set_hl_attr(idx);
     HL_TABLE()[idx].sg_scriptID = current_SID;
@@ -6877,7 +6870,7 @@ int hl_combine_attr(int char_attr, int prim_attr)
   if (char_attr <= HL_ALL && prim_attr <= HL_ALL)
     return char_attr | prim_attr;
 
-  if (abstract_ui || t_colors > 1) {
+  if (t_colors > 1) {
     if (char_attr > HL_ALL)
       char_aep = syn_cterm_attr2entry(char_attr);
     if (char_aep != NULL)
@@ -6941,7 +6934,7 @@ int syn_attr2attr(int attr)
 {
   attrentry_T *aep;
 
-  if (abstract_ui || t_colors > 1)
+  if (t_colors > 1)
     aep = syn_cterm_attr2entry(attr);
   else
     aep = syn_term_attr2entry(attr);
@@ -7211,10 +7204,9 @@ set_hl_attr (
    * For the color term mode: If there are other than "normal"
    * highlighting attributes, need to allocate an attr number.
    */
-  if (sgp->sg_cterm_fg == 0 && sgp->sg_cterm_bg == 0
+  if (sgp->sg_cterm_fg == 0 && sgp->sg_cterm_bg == 0)
-      && sgp->sg_rgb_fg == -1 && sgp->sg_rgb_bg == -1) {
     sgp->sg_cterm_attr = sgp->sg_cterm;
-  } else {
+  else {
     at_en.ae_attr = abstract_ui ? sgp->sg_gui : sgp->sg_cterm;
     at_en.ae_u.cterm.fg_color = sgp->sg_cterm_fg;
     at_en.ae_u.cterm.bg_color = sgp->sg_cterm_bg;
@@ -7369,7 +7361,7 @@ int syn_id2attr(int hl_id)
   hl_id = syn_get_final_id(hl_id);
   sgp = &HL_TABLE()[hl_id - 1];             /* index is ID minus one */
 
-  if (abstract_ui || t_colors > 1)
+  if (t_colors > 1)
     attr = sgp->sg_cterm_attr;
   else
     attr = sgp->sg_term_attr;

src/nvim/term.c

@@ -170,7 +170,6 @@ static struct builtin_term builtin_termcaps[] =
   {(int)KS_DL,   "\033|d"},
   {(int)KS_CDL,  "\033|%p1%dD"},
   {(int)KS_CS,   "\033|%p1%d;%p2%dR"},
-  {(int)KS_CSV,  "\033|%p1%d;%p2%dV"},
   {(int)KS_CL,   "\033|C"},
   // attributes switched on with 'h', off with * 'H'
   {(int)KS_ME,   "\033|31H"},  // HL_ALL
@@ -1818,20 +1817,17 @@ void term_write(char_u *s, size_t len)
 static char_u out_buf[OUT_SIZE + 1];
 static int out_pos = 0;                 /* number of chars in out_buf */
 
-// Clear the output buffer
-void out_buf_clear(void)
-{
-  out_pos = 0;
-}
-
 /*
  * out_flush(): flush the output buffer
  */
 void out_flush(void)
 {
-  int len = out_pos;
+  if (out_pos != 0) {
-  out_pos = 0;
+    /* set out_pos to 0 before ui_write, to avoid recursiveness */
-  ui_write(out_buf, len);
+    int len = out_pos;
+    out_pos = 0;
+    ui_write(out_buf, len);
+  }
 }
 
 /*

src/nvim/ui.c

@@ -60,8 +60,11 @@ static struct {
   int top, bot, left, right;
 } sr;
 static int current_highlight_mask = 0;
+static HlAttrs current_attrs = {
+  false, false, false, false, false, false, -1, -1
+};
 static bool cursor_enabled = true;
-static int height, width;
+static int height = INT_MAX, width = INT_MAX;
 
 // This set of macros allow us to use UI_CALL to invoke any function on
 // registered UI instances. The functions can have 0-5 arguments(configurable
@@ -95,10 +98,6 @@ void ui_write(uint8_t *s, int len)
     return;
   }
 
-  if (!len) {
-    return;
-  }
-
   char_u  *tofree = NULL;
 
   if (output_conv.vc_type != CONV_NONE) {
@@ -121,7 +120,9 @@ void ui_write(uint8_t *s, int len)
  */
 void ui_suspend(void)
 {
-  if (!abstract_ui) {
+  if (abstract_ui) {
+    UI_CALL(suspend);
+  } else {
     mch_suspend();
   }
 }
@@ -164,31 +165,8 @@ void ui_cursor_shape(void)
   }
 }
 
-void ui_refresh(void)
+void ui_resize(int width, int height)
 {
-  if (!ui_count) {
-    return;
-  }
-
-  int width = INT_MAX, height = INT_MAX;
-
-  for (size_t i = 0; i < ui_count; i++) {
-    UI *ui = uis[i];
-    width = ui->width < width ? ui->width : width;
-    height = ui->height < height ? ui->height : height;
-  }
-
-  screen_resize(width, height, true);
-}
-
-void ui_resize(int new_width, int new_height)
-{
-  width = new_width;
-  height = new_height;
-
-  UI_CALL(update_fg, (ui->rgb ? normal_fg : cterm_normal_fg_color - 1));
-  UI_CALL(update_bg, (ui->rgb ? normal_bg : cterm_normal_bg_color - 1));
-
   sr.top = 0;
   sr.bot = height - 1;
   sr.left = 0;
@@ -262,7 +240,7 @@ void ui_attach(UI *ui)
   }
 
   uis[ui_count++] = ui;
-  ui_refresh();
+  resized(ui);
 }
 
 void ui_detach(UI *ui)
@@ -289,8 +267,17 @@ void ui_detach(UI *ui)
 
   ui_count--;
 
+  if (ui->width == width || ui->height == height) {
+    // It is possible that the UI being detached had the smallest screen,
+    // so check for the new minimum dimensions
+    width = height = INT_MAX;
+    for (size_t i = 0; i < ui_count; i++) {
+      check_dimensions(uis[i]);
+    }
+  }
+
   if (ui_count) {
-    ui_refresh();
+    screen_resize(width, height, true);
   }
 }
 
@@ -308,7 +295,8 @@ static void highlight_start(int mask)
     return;
   }
 
-  set_highlight_args(current_highlight_mask);
+  set_highlight_args(current_highlight_mask, &current_attrs);
+  UI_CALL(highlight_set, current_attrs);
 }
 
 static void highlight_stop(int mask)
@@ -321,12 +309,12 @@ static void highlight_stop(int mask)
     current_highlight_mask &= ~mask;
   }
 
-  set_highlight_args(current_highlight_mask);
+  set_highlight_args(current_highlight_mask, &current_attrs);
+  UI_CALL(highlight_set, current_attrs);
 }
 
-static void set_highlight_args(int mask)
+static void set_highlight_args(int mask, HlAttrs *attrs)
 {
-  HlAttrs rgb_attrs = { false, false, false, false, false, -1, -1 };
   attrentry_T *aep = NULL;
 
   if (mask > HL_ALL) {
@@ -334,40 +322,18 @@ static void set_highlight_args(int mask)
     mask = aep ? aep->ae_attr : 0;
   }
 
-  rgb_attrs.bold = mask & HL_BOLD;
+  attrs->bold = mask & HL_BOLD;
-  rgb_attrs.underline = mask & HL_UNDERLINE;
+  attrs->standout = mask & HL_STANDOUT;
-  rgb_attrs.undercurl = mask & HL_UNDERCURL;
+  attrs->underline = mask & HL_UNDERLINE;
-  rgb_attrs.italic = mask & HL_ITALIC;
+  attrs->undercurl = mask & HL_UNDERCURL;
-  rgb_attrs.reverse = mask & (HL_INVERSE | HL_STANDOUT);
+  attrs->italic = mask & HL_ITALIC;
-  HlAttrs cterm_attrs = rgb_attrs;
+  attrs->reverse = mask & HL_INVERSE;
-
+  attrs->foreground = aep && aep->fg_color >= 0 ? aep->fg_color : normal_fg;
-  if (aep) {
+  attrs->background = aep && aep->bg_color >= 0 ? aep->bg_color : normal_bg;
-    if (aep->fg_color != normal_fg) {
-      rgb_attrs.foreground = aep->fg_color;
-    }
-
-    if (aep->bg_color != normal_bg) {
-      rgb_attrs.background = aep->bg_color;
-    }
-
-    if (cterm_normal_fg_color != aep->ae_u.cterm.fg_color) {
-      cterm_attrs.foreground = aep->ae_u.cterm.fg_color - 1;
-    }
-
-    if (cterm_normal_bg_color != aep->ae_u.cterm.bg_color) {
-      cterm_attrs.background = aep->ae_u.cterm.bg_color - 1;
-    }
-  }
-
-  UI_CALL(highlight_set, (ui->rgb ? rgb_attrs : cterm_attrs));
 }
 
 static void parse_abstract_ui_codes(uint8_t *ptr, int len)
 {
-  if (!ui_count) {
-    return;
-  }
-
   int arg1 = 0, arg2 = 0;
   uint8_t *end = ptr + len, *p, c;
   bool update_cursor = false;
@@ -478,9 +444,6 @@ static void parse_abstract_ui_codes(uint8_t *ptr, int len)
           UI_CALL(put, NULL, 0);
           col++;
         }
-        if (col >= width) {
-          ui_linefeed();
-        }
         p += clen;
       }
       ptr = p;
@@ -494,6 +457,25 @@ static void parse_abstract_ui_codes(uint8_t *ptr, int len)
   UI_CALL(flush);
 }
 
+static void resized(UI *ui)
+{
+  check_dimensions(ui);
+  screen_resize(width, height, true);
+}
+
+static void check_dimensions(UI *ui)
+{
+  // The internal screen dimensions are always the minimum required to fit on
+  // all connected screens
+  if (ui->width < width) {
+    width = ui->width;
+  }
+
+  if (ui->height < height) {
+    height = ui->height;
+  }
+}
+
 static void ui_linefeed(void)
 {
   int new_col = 0;

src/nvim/ui.h

@@ -6,14 +6,13 @@
 #include <stdint.h>
 
 typedef struct {
-  bool bold, underline, undercurl, italic, reverse;
+  bool bold, standout, underline, undercurl, italic, reverse;
   int foreground, background;
 } HlAttrs;
 
 typedef struct ui_t UI;
 
 struct ui_t {
-  bool rgb;
   int width, height;
   void *data;
   void (*resize)(UI *ui, int rows, int columns);
@@ -33,8 +32,7 @@ struct ui_t {
   void (*bell)(UI *ui);
   void (*visual_bell)(UI *ui);
   void (*flush)(UI *ui);
-  void (*update_fg)(UI *ui, int fg);
+  void (*suspend)(UI *ui);
-  void (*update_bg)(UI *ui, int bg);
 };
 
 #ifdef INCLUDE_GENERATED_DECLARATIONS

test/functional/legacy/066_visual_block_tab_spec.lua

@@ -23,18 +23,18 @@ describe('visual block shift and tab characters', function()
       abcdefghijklmnopqrstuvwxyz]])
 
     feed('gg')
-    feed([[fe<C-v>4jR<esc>ugvr1:'<lt>,'>yank A<cr>]])
+    feed([[fe<C-v>4jR<esc>ugvr1:'<,'>yank A<cr>]])
     execute('/^abcdefgh')
-    feed('<C-v>4jI    <esc>j<lt><lt>11|D')
+    feed('<C-v>4jI    <esc>j<<11|D')
     feed('j7|a		<esc>')
     feed('j7|a		   <esc>')
-    feed('j7|a	       	<esc>4k13|<C-v>4j<lt>')
+    feed('j7|a	       	<esc>4k13|<C-v>4j<')
     execute('$-5,$yank A')
     execute([[$-4,$s/\s\+//g]])
-    feed('<C-v>4kI    <esc>j<lt><lt>')
+    feed('<C-v>4kI    <esc>j<<')
     feed('j7|a		<esc>')
     feed('j7|a					<esc>')
-    feed('j7|a	       		<esc>4k13|<C-v>4j3<lt>')
+    feed('j7|a	       		<esc>4k13|<C-v>4j3<')
     execute('$-4,$yank A')
 
     -- Put @a and clean empty lines

test/functional/ui/highlight_spec.lua

@@ -142,6 +142,7 @@ describe('Default highlight groups', function()
   end)
 
   it('end of file markers', function()
+    nvim('command', 'hi Normal guibg=black')
     screen:expect([[
       ^                                                    |
       {1:~                                                    }|

test/functional/ui/screen.lua

@@ -99,6 +99,7 @@ function Screen.new(width, height)
     _mouse_enabled = true,
     _bell = false,
     _visual_bell = false,
+    _suspended = true,
     _attrs = {},
     _cursor = {
       enabled = true, row = 1, col = 1
@@ -114,11 +115,13 @@ function Screen:set_default_attr_ids(attr_ids)
 end
 
 function Screen:attach()
-  request('ui_attach', self._width, self._height, true)
+  request('attach_ui', self._width, self._height)
+  self._suspended = false
 end
 
 function Screen:detach()
-  request('ui_detach')
+  request('detach_ui')
+  self._suspended = true
 end
 
 function Screen:expect(expected, attr_ids)
@@ -187,7 +190,7 @@ end
 
 function Screen:_handle_eol_clear()
   local row, col = self._cursor.row, self._cursor.col
-  self:_clear_block(row, 1, col, self._scroll_region.right - col)
+  self:_clear_block(row, 1, col, self._width - col)
 end
 
 function Screen:_handle_cursor_goto(row, col)
@@ -275,12 +278,8 @@ function Screen:_handle_visual_bell()
   self._visual_bell = true
 end
 
-function Screen:_handle_update_fg(fg)
+function Screen:_handle_suspend()
-  self._fg = fg
+  self._suspended = true
-end
-
-function Screen:_handle_update_bg(bg)
-  self._bg = bg
 end
 
 function Screen:_clear_block(top, lines, left, columns)