api/window: add style="minimal" flag to nvim_open_win()

8 files changed, 98 insertions, 19 deletions

diff --git a/src/nvim/api/vim.c b/src/nvim/api/vim.c
index 8e5650633a..dbe3b66fd5 100644
--- a/src/nvim/api/vim.c
+++ b/src/nvim/api/vim.c
@@ -1064,6 +1064,19 @@ fail:
 ///   - `external`: GUI should display the window as an external
 ///       top-level window. Currently accepts no other positioning
 ///       configuration together with this.
+///   - `style`: Configure the apparance of the window. Currently only takes
+///       one non-empty value:
+///       - "minimal"  Nvim will display the window with many UI options
+///                    disabled. This is useful when displaing a temporary
+///                    float where the text should not be edited. Disables
+///                    'number', 'relativenumber', 'cursorline', 'cursorcolumn',
+///                    'spell' and 'list' options. 'signcolumn' is changed to
+///                    `auto`. The end-of-buffer region is hidden by setting
+///                    `eob` flag of 'fillchars' to a space char, and clearing
+///                    the |EndOfBuffer| region in 'winhighlight'.
+///
+///       top-level window. Currently accepts no other positioning
+///       configuration together with this.
 /// @param[out] err Error details, if any
 ///
 /// @return Window handle, or 0 on error
@@ -1085,6 +1098,11 @@ Window nvim_open_win(Buffer buffer, Boolean enter, Dictionary config,
   if (buffer > 0) {
     nvim_win_set_buf(wp->handle, buffer, err);
   }
+
+  if (fconfig.style == kWinStyleMinimal) {
+    win_set_minimal_style(wp);
+    didset_window_options(wp);
+  }
   return wp->handle;
 }
 
diff --git a/src/nvim/api/window.c b/src/nvim/api/window.c
index 9fd1818a5c..4922dd7efc 100644
--- a/src/nvim/api/window.c
+++ b/src/nvim/api/window.c
@@ -13,6 +13,7 @@
 #include "nvim/vim.h"
 #include "nvim/buffer.h"
 #include "nvim/cursor.h"
+#include "nvim/option.h"
 #include "nvim/window.h"
 #include "nvim/screen.h"
 #include "nvim/move.h"
@@ -475,6 +476,10 @@ void nvim_win_set_config(Window window, Dictionary config, Error *err)
     win_config_float(win, fconfig);
     win->w_pos_changed = true;
   }
+  if (fconfig.style == kWinStyleMinimal) {
+    win_set_minimal_style(win);
+    didset_window_options(win);
+  }
 }
 
 /// Return window configuration.
diff --git a/src/nvim/buffer.c b/src/nvim/buffer.c
index 5678f518f5..cd31adbaff 100644
--- a/src/nvim/buffer.c
+++ b/src/nvim/buffer.c
@@ -2543,6 +2543,11 @@ void get_winopts(buf_T *buf)
   } else
     copy_winopt(&curwin->w_allbuf_opt, &curwin->w_onebuf_opt);
 
+  if (curwin->w_float_config.style == kWinStyleMinimal) {
+    didset_window_options(curwin);
+    win_set_minimal_style(curwin);
+  }
+
   // Set 'foldlevel' to 'foldlevelstart' if it's not negative.
   if (p_fdls >= 0) {
     curwin->w_p_fdl = p_fdls;
diff --git a/src/nvim/buffer_defs.h b/src/nvim/buffer_defs.h
index ad10f6baa2..a27672488e 100644
--- a/src/nvim/buffer_defs.h
+++ b/src/nvim/buffer_defs.h
@@ -972,7 +972,6 @@ struct matchitem {
 };
 
 typedef int FloatAnchor;
-typedef int FloatRelative;
 
 enum {
   kFloatAnchorEast  = 1,
@@ -985,15 +984,20 @@ enum {
 // SE -> kFloatAnchorSouth | kFloatAnchorEast
 EXTERN const char *const float_anchor_str[] INIT(= { "NW", "NE", "SW", "SE" });
 
-enum {
+typedef enum {
   kFloatRelativeEditor = 0,
   kFloatRelativeWindow = 1,
   kFloatRelativeCursor = 2,
-};
+} FloatRelative;
 
 EXTERN const char *const float_relative_str[] INIT(= { "editor", "window",
                                                        "cursor" });
 
+typedef enum {
+  kWinStyleUnused = 0,
+  kWinStyleMinimal,  /// Minimal UI: no number column, eob markers, etc
+} WinStyle;
+
 typedef struct {
   Window window;
   int height, width;
@@ -1002,12 +1006,14 @@ typedef struct {
   FloatRelative relative;
   bool external;
   bool focusable;
+  WinStyle style;
 } FloatConfig;
 
 #define FLOAT_CONFIG_INIT ((FloatConfig){ .height = 0, .width = 0, \
                                           .row = 0, .col = 0, .anchor = 0, \
                                           .relative = 0, .external = false, \
-                                          .focusable = true })
+                                          .focusable = true, \
+                                          .style = kWinStyleUnused })
 
 // Structure to store last cursor position and topline.  Used by check_lnums()
 // and reset_lnums().
diff --git a/src/nvim/highlight.c b/src/nvim/highlight.c
index 15c3d0eb7b..e5cbb4f944 100644
--- a/src/nvim/highlight.c
+++ b/src/nvim/highlight.c
@@ -141,10 +141,12 @@ int hl_get_ui_attr(int idx, int final_id, bool optional)
   HlAttrs attrs = HLATTRS_INIT;
   bool available = false;
 
-  int syn_attr = syn_id2attr(final_id);
-  if (syn_attr != 0) {
-    attrs = syn_attr2entry(syn_attr);
-    available = true;
+  if (final_id > 0) {
+    int syn_attr = syn_id2attr(final_id);
+    if (syn_attr != 0) {
+      attrs = syn_attr2entry(syn_attr);
+      available = true;
+    }
   }
 
   if (HLF_PNI <= idx && idx <= HLF_PST) {
@@ -176,15 +178,14 @@ void update_window_hl(win_T *wp, bool invalid)
 
   // determine window specific background set in 'winhighlight'
   bool float_win = wp->w_floating && !wp->w_float_config.external;
-  if (wp != curwin && wp->w_hl_ids[HLF_INACTIVE] > 0) {
+  if (wp != curwin && wp->w_hl_ids[HLF_INACTIVE] != 0) {
     wp->w_hl_attr_normal = hl_get_ui_attr(HLF_INACTIVE,
                                           wp->w_hl_ids[HLF_INACTIVE],
                                           !has_blend);
-  } else if (float_win && wp->w_hl_ids[HLF_NFLOAT] > 0) {
+  } else if (float_win && wp->w_hl_ids[HLF_NFLOAT] != 0) {
     wp->w_hl_attr_normal = hl_get_ui_attr(HLF_NFLOAT,
-    // 'cursorline'
                                           wp->w_hl_ids[HLF_NFLOAT], !has_blend);
-  } else if (wp->w_hl_id_normal > 0) {
+  } else if (wp->w_hl_id_normal != 0) {
     wp->w_hl_attr_normal = hl_get_ui_attr(-1, wp->w_hl_id_normal, !has_blend);
   } else {
     wp->w_hl_attr_normal = float_win ? HL_ATTR(HLF_NFLOAT) : 0;
@@ -199,14 +200,14 @@ void update_window_hl(win_T *wp, bool invalid)
     }
   }
 
-  if (wp != curwin) {
+  if (wp != curwin && wp->w_hl_ids[HLF_INACTIVE] == 0) {
     wp->w_hl_attr_normal = hl_combine_attr(HL_ATTR(HLF_INACTIVE),
                                            wp->w_hl_attr_normal);
   }
 
   for (int hlf = 0; hlf < (int)HLF_COUNT; hlf++) {
     int attr;
-    if (wp->w_hl_ids[hlf] > 0) {
+    if (wp->w_hl_ids[hlf] != 0) {
       attr = hl_get_ui_attr(hlf, wp->w_hl_ids[hlf], false);
     } else {
       attr = HL_ATTR(hlf);
diff --git a/src/nvim/option.c b/src/nvim/option.c
index e8e246c277..2c96dae64e 100644
--- a/src/nvim/option.c
+++ b/src/nvim/option.c
@@ -3762,7 +3762,8 @@ static bool parse_winhl_opt(win_T *wp)
     size_t nlen = (size_t)(colon-p);
     char *hi = colon+1;
     char *commap = xstrchrnul(hi, ',');
-    int hl_id = syn_check_group((char_u *)hi, (int)(commap-hi));
+    int len = (int)(commap-hi);
+    int hl_id = len ? syn_check_group((char_u *)hi, len) : -1;
 
     if (strncmp("Normal", p, nlen) == 0) {
       w_hl_id_normal = hl_id;
diff --git a/src/nvim/screen.c b/src/nvim/screen.c
index acff44164f..94887e113a 100644
--- a/src/nvim/screen.c
+++ b/src/nvim/screen.c
@@ -1612,7 +1612,8 @@ static void win_draw_end(win_T *wp, int c1, int c2, bool draw_margin, int row,
     }
   }
 
-  int attr = hl_combine_attr(wp->w_hl_attr_normal, win_hl_attr(wp, hl));
+  int attr = hl_combine_attr(wp->w_hl_attr_normal,
+                             hl ? win_hl_attr(wp, hl) : 0);
 
   if (wp->w_p_rl) {
     grid_fill(&wp->w_grid, row, endrow, wp->w_wincol, W_ENDCOL(wp) - 1 - n,
diff --git a/src/nvim/window.c b/src/nvim/window.c
index a3b1efeaaa..acaff8327d 100644
--- a/src/nvim/window.c
+++ b/src/nvim/window.c
@@ -584,15 +584,43 @@ win_T *win_new_float(win_T *wp, FloatConfig fconfig, Error *err)
   wp->w_status_height = 0;
   wp->w_vsep_width = 0;
 
-  // TODO(bfredl): use set_option_to() after merging #9110 ?
-  wp->w_p_nu = false;
-  wp->w_allbuf_opt.wo_nu = false;
   win_config_float(wp, fconfig);
   wp->w_pos_changed = true;
   redraw_win_later(wp, VALID);
   return wp;
 }
 
+void win_set_minimal_style(win_T *wp)
+{
+  wp->w_p_nu = false;
+  wp->w_p_rnu = false;
+  wp->w_p_cul = false;
+  wp->w_p_cuc = false;
+  wp->w_p_spell = false;
+  wp->w_p_list = false;
+
+  // Hide EOB region: use " " fillchar and cleared highlighting
+  if (wp->w_p_fcs_chars.eob != ' ') {
+    char_u *old = wp->w_p_fcs;
+    wp->w_p_fcs = ((*old == NUL)
+                   ? (char_u *)xstrdup("eob: ")
+                   : concat_str(old, (char_u *)",eob: "));
+    xfree(old);
+  }
+  if (wp->w_hl_ids[HLF_EOB] != -1) {
+    char_u *old = wp->w_p_winhl;
+    wp->w_p_winhl = ((*old == NUL)
+                     ? (char_u *)xstrdup("EndOfBuffer:")
+                     : concat_str(old, (char_u *)",EndOfBuffer:"));
+    xfree(old);
+  }
+
+  if (wp->w_p_scl[0] != 'a') {
+    xfree(wp->w_p_scl);
+    wp->w_p_scl = (char_u *)xstrdup("auto");
+  }
+}
+
 void win_config_float(win_T *wp, FloatConfig fconfig)
 {
   wp->w_width = MAX(fconfig.width, 1);
@@ -821,6 +849,20 @@ bool parse_float_config(Dictionary config, FloatConfig *fconfig, bool reconf,
                       "'focusable' key must be Boolean");
         return false;
       }
+    } else if (!strcmp(key, "style")) {
+      if (val.type != kObjectTypeString) {
+        api_set_error(err, kErrorTypeValidation,
+                      "'style' key must be String");
+        return false;
+      }
+      if (val.data.string.data[0] == NUL) {
+        fconfig->style = kWinStyleUnused;
+      } else if (striequal(val.data.string.data, "minimal")) {
+        fconfig->style = kWinStyleMinimal;
+      }  else {
+        api_set_error(err, kErrorTypeValidation,
+                      "Invalid value of 'style' key");
+      }
     } else {
       api_set_error(err, kErrorTypeValidation,
                     "Invalid key '%s'", key);