Merge pull request #10451 from bfredl/floatbuf

anchor float to buffer position

8 files changed, 231 insertions, 19 deletions

diff --git a/src/nvim/api/vim.c b/src/nvim/api/vim.c
index 2034fea770..27344fc093 100644
--- a/src/nvim/api/vim.c
+++ b/src/nvim/api/vim.c
@@ -1059,6 +1059,12 @@ fail:
 ///      - "SE" south-east
 ///   - `height`: window height (in character cells). Minimum of 1.
 ///   - `width`: window width (in character cells). Minimum of 1.
+///   - 'bufpos': position float relative text inside the window `win` (only
+///               when relative="win"). Takes a tuple of [line, column] where
+///               both are zero-index. Note: `row` and `col` if present, still
+///               applies relative this positio. By default `row=1` and `col=0`
+///               is used (with default NW anchor), to make the float
+///               behave like a tooltip under the buffer text.
 ///   - `row`: row position. Screen cell height are used as unit. Can be
 ///       floating point.
 ///   - `col`: column position. Screen cell width is used as unit. Can be
diff --git a/src/nvim/api/window.c b/src/nvim/api/window.c
index e279edebde..02670c0513 100644
--- a/src/nvim/api/window.c
+++ b/src/nvim/api/window.c
@@ -503,25 +503,33 @@ Dictionary nvim_win_get_config(Window window, Error *err)
     return rv;
   }
 
-  PUT(rv, "focusable", BOOLEAN_OBJ(wp->w_float_config.focusable));
-  PUT(rv, "external", BOOLEAN_OBJ(wp->w_float_config.external));
+  FloatConfig *config = &wp->w_float_config;
+
+  PUT(rv, "focusable", BOOLEAN_OBJ(config->focusable));
+  PUT(rv, "external", BOOLEAN_OBJ(config->external));
 
   if (wp->w_floating) {
-    PUT(rv, "width", INTEGER_OBJ(wp->w_float_config.width));
-    PUT(rv, "height", INTEGER_OBJ(wp->w_float_config.height));
-    if (!wp->w_float_config.external) {
-      if (wp->w_float_config.relative == kFloatRelativeWindow) {
-        PUT(rv, "win", INTEGER_OBJ(wp->w_float_config.window));
+    PUT(rv, "width", INTEGER_OBJ(config->width));
+    PUT(rv, "height", INTEGER_OBJ(config->height));
+    if (!config->external) {
+      if (config->relative == kFloatRelativeWindow) {
+        PUT(rv, "win", INTEGER_OBJ(config->window));
+        if (config->bufpos.lnum >= 0) {
+          Array pos = ARRAY_DICT_INIT;
+          ADD(pos, INTEGER_OBJ(config->bufpos.lnum));
+          ADD(pos, INTEGER_OBJ(config->bufpos.col));
+          PUT(rv, "bufpos", ARRAY_OBJ(pos));
+        }
       }
       PUT(rv, "anchor", STRING_OBJ(cstr_to_string(
-          float_anchor_str[wp->w_float_config.anchor])));
-      PUT(rv, "row", FLOAT_OBJ(wp->w_float_config.row));
-      PUT(rv, "col", FLOAT_OBJ(wp->w_float_config.col));
+          float_anchor_str[config->anchor])));
+      PUT(rv, "row", FLOAT_OBJ(config->row));
+      PUT(rv, "col", FLOAT_OBJ(config->col));
     }
   }
 
-  const char *rel = (wp->w_floating && !wp->w_float_config.external
-                     ? float_relative_str[wp->w_float_config.relative] : "");
+  const char *rel = (wp->w_floating && !config->external
+                     ? float_relative_str[config->relative] : "");
   PUT(rv, "relative", STRING_OBJ(cstr_to_string(rel)));
 
   return rv;
diff --git a/src/nvim/buffer_defs.h b/src/nvim/buffer_defs.h
index 5e700940b0..83b8531b8b 100644
--- a/src/nvim/buffer_defs.h
+++ b/src/nvim/buffer_defs.h
@@ -1006,7 +1006,7 @@ typedef enum {
   kFloatRelativeCursor = 2,
 } FloatRelative;
 
-EXTERN const char *const float_relative_str[] INIT(= { "editor", "window",
+EXTERN const char *const float_relative_str[] INIT(= { "editor", "win",
                                                        "cursor" });
 
 typedef enum {
@@ -1016,6 +1016,7 @@ typedef enum {
 
 typedef struct {
   Window window;
+  lpos_T bufpos;
   int height, width;
   double row, col;
   FloatAnchor anchor;
@@ -1026,6 +1027,7 @@ typedef struct {
 } FloatConfig;
 
 #define FLOAT_CONFIG_INIT ((FloatConfig){ .height = 0, .width = 0, \
+                                          .bufpos = { -1, 0 }, \
                                           .row = 0, .col = 0, .anchor = 0, \
                                           .relative = 0, .external = false, \
                                           .focusable = true, \
diff --git a/src/nvim/eval.c b/src/nvim/eval.c
index fa9777b651..70f38b793d 100644
--- a/src/nvim/eval.c
+++ b/src/nvim/eval.c
@@ -14781,6 +14781,32 @@ static void f_screencol(typval_T *argvars, typval_T *rettv, FunPtr fptr)
   rettv->vval.v_number = ui_current_col() + 1;
 }
 
+/// "screenpos({winid}, {lnum}, {col})" function
+static void f_screenpos(typval_T *argvars, typval_T *rettv, FunPtr fptr)
+{
+  pos_T pos;
+  int row = 0;
+  int scol = 0, ccol = 0, ecol = 0;
+
+  tv_dict_alloc_ret(rettv);
+  dict_T *dict = rettv->vval.v_dict;
+
+  win_T *wp = find_win_by_nr_or_id(&argvars[0]);
+  if (wp == NULL) {
+    return;
+  }
+
+  pos.lnum = tv_get_number(&argvars[1]);
+  pos.col = tv_get_number(&argvars[2]) - 1;
+  pos.coladd = 0;
+  textpos2screenpos(wp, &pos, &row, &scol, &ccol, &ecol, false);
+
+  tv_dict_add_nr(dict, S_LEN("row"), row);
+  tv_dict_add_nr(dict, S_LEN("col"), scol);
+  tv_dict_add_nr(dict, S_LEN("curscol"), ccol);
+  tv_dict_add_nr(dict, S_LEN("endcol"), ecol);
+}
+
 /*
  * "screenrow()" function
  */
diff --git a/src/nvim/eval.lua b/src/nvim/eval.lua
index 0ad9ef5dac..ab5ff57c2f 100644
--- a/src/nvim/eval.lua
+++ b/src/nvim/eval.lua
@@ -266,6 +266,7 @@ return {
     screenattr={args=2},
     screenchar={args=2},
     screencol={},
+    screenpos={args=3},
     screenrow={},
     search={args={1, 4}},
     searchdecl={args={1, 3}},
diff --git a/src/nvim/move.c b/src/nvim/move.c
index 4a87f82eb7..e6fee9999f 100644
--- a/src/nvim/move.c
+++ b/src/nvim/move.c
@@ -95,6 +95,8 @@ static void comp_botline(win_T *wp)
   wp->w_valid |= VALID_BOTLINE|VALID_BOTLINE_AP;
 
   set_empty_rows(wp, done);
+
+  win_check_anchored_floats(wp);
 }
 
 void reset_cursorline(void)
@@ -310,6 +312,7 @@ void update_topline(void)
     }
   }
   curwin->w_valid |= VALID_TOPLINE;
+  win_check_anchored_floats(curwin);
 
   /*
    * Need to redraw when topline changed.
@@ -827,7 +830,8 @@ void curs_columns(
         new_leftcol = 0;
       if (new_leftcol != (int)curwin->w_leftcol) {
         curwin->w_leftcol = new_leftcol;
-        /* screen has to be redrawn with new curwin->w_leftcol */
+        win_check_anchored_floats(curwin);
+        // screen has to be redrawn with new curwin->w_leftcol
         redraw_later(NOT_VALID);
       }
     }
@@ -943,6 +947,74 @@ void curs_columns(
   curwin->w_valid |= VALID_WCOL|VALID_WROW|VALID_VIRTCOL;
 }
 
+/// Compute the screen position of text character at "pos" in window "wp"
+/// The resulting values are one-based, zero when character is not visible.
+///
+/// @param[out] rowp screen row
+/// @param[out] scolp start screen column
+/// @param[out] ccolp cursor screen column
+/// @param[out] ecolp end screen column
+void textpos2screenpos(win_T *wp, pos_T *pos, int *rowp, int *scolp,
+                       int *ccolp, int *ecolp, bool local)
+{
+  colnr_T scol = 0, ccol = 0, ecol = 0;
+  int row = 0;
+  int rowoff = 0;
+  colnr_T coloff = 0;
+  bool visible_row = false;
+
+  if (pos->lnum >= wp->w_topline && pos->lnum < wp->w_botline) {
+    row = plines_m_win(wp, wp->w_topline, pos->lnum - 1) + 1;
+    visible_row = true;
+  } else if (pos->lnum < wp->w_topline) {
+    row = 0;
+  } else {
+    row = wp->w_height_inner;
+  }
+
+  bool existing_row = (pos->lnum > 0
+                       && pos->lnum <= wp->w_buffer->b_ml.ml_line_count);
+
+  if ((local && existing_row) || visible_row) {
+    colnr_T off;
+    colnr_T col;
+    int     width;
+
+    getvcol(wp, pos, &scol, &ccol, &ecol);
+
+    // similar to what is done in validate_cursor_col()
+    col = scol;
+    off = win_col_off(wp);
+    col += off;
+    width = wp->w_width - off + win_col_off2(wp);
+
+    // long line wrapping, adjust row
+    if (wp->w_p_wrap && col >= (colnr_T)wp->w_width && width > 0) {
+      // use same formula as what is used in curs_columns()
+      rowoff = visible_row ? ((col - wp->w_width) / width + 1) : 0;
+      col -= rowoff * width;
+    }
+
+    col -= wp->w_leftcol;
+
+    if (col >= 0 && col < width) {
+      coloff = col - scol + (local ? 0 : wp->w_wincol) + 1;
+    } else {
+      scol = ccol = ecol = 0;
+      // character is left or right of the window
+      if (local) {
+        coloff = col < 0 ? -1 : wp->w_width_inner + 1;
+      } else {
+        row = 0;
+      }
+    }
+  }
+  *rowp = (local ? 0 : wp->w_winrow) + row + rowoff;
+  *scolp = scol + coloff;
+  *ccolp = ccol + coloff;
+  *ecolp = ecol + coloff;
+}
+
 /*
  * Scroll the current window down by "line_count" logical lines.  "CTRL-Y"
  */
@@ -1099,6 +1171,7 @@ check_topfill (
       }
     }
   }
+  win_check_anchored_floats(curwin);
 }
 
 /*
diff --git a/src/nvim/testdir/test_cursor_func.vim b/src/nvim/testdir/test_cursor_func.vim
index 6bc9535aaf..037918fa31 100644
--- a/src/nvim/testdir/test_cursor_func.vim
+++ b/src/nvim/testdir/test_cursor_func.vim
@@ -64,3 +64,31 @@ func Test_curswant_with_cursorline()
   call assert_equal(6, winsaveview().curswant)
   quit!
 endfunc
+
+func Test_screenpos()
+  rightbelow new
+  rightbelow 20vsplit
+  call setline(1, ["\tsome text", "long wrapping line here", "next line"])
+  redraw
+  let winid = win_getid()
+  let [winrow, wincol] = win_screenpos(winid)
+  call assert_equal({'row': winrow,
+    \ 'col': wincol + 0,
+    \ 'curscol': wincol + 7,
+    \ 'endcol': wincol + 7}, screenpos(winid, 1, 1))
+  call assert_equal({'row': winrow,
+    \ 'col': wincol + 13,
+    \ 'curscol': wincol + 13,
+    \ 'endcol': wincol + 13}, screenpos(winid, 1, 7))
+  call assert_equal({'row': winrow + 2,
+    \ 'col': wincol + 1,
+    \ 'curscol': wincol + 1,
+    \ 'endcol': wincol + 1}, screenpos(winid, 2, 22))
+  setlocal number
+  call assert_equal({'row': winrow + 3,
+    \ 'col': wincol + 9,
+    \ 'curscol': wincol + 9,
+    \ 'endcol': wincol + 9}, screenpos(winid, 2, 22))
+  close
+  bwipe!
+endfunc
diff --git a/src/nvim/window.c b/src/nvim/window.c
index 6861e19ca7..315b5ef759 100644
--- a/src/nvim/window.c
+++ b/src/nvim/window.c
@@ -652,6 +652,17 @@ void win_config_float(win_T *wp, FloatConfig fconfig)
   }
 }
 
+void win_check_anchored_floats(win_T *win)
+{
+  for (win_T *wp = lastwin; wp && wp->w_floating; wp = wp->w_prev) {
+    // float might be anchored to moved window
+    if (wp->w_float_config.relative == kFloatRelativeWindow
+        && wp->w_float_config.window == win->handle) {
+      wp->w_pos_changed = true;
+    }
+  }
+}
+
 static void ui_ext_win_position(win_T *wp)
 {
   if (!wp->w_floating) {
@@ -673,6 +684,13 @@ static void ui_ext_win_position(win_T *wp)
         screen_adjust_grid(&grid, &row_off, &col_off);
         row += row_off;
         col += col_off;
+        if (c.bufpos.lnum >= 0) {
+          pos_T pos = { c.bufpos.lnum+1, c.bufpos.col, 0 };
+          int trow, tcol, tcolc, tcole;
+          textpos2screenpos(win, &pos, &trow, &tcol, &tcolc, &tcole, true);
+          row += trow-1;
+          col += tcol-1;
+        }
       }
       api_clear_error(&dummy);
     }
@@ -745,6 +763,18 @@ static bool parse_float_relative(String relative, FloatRelative *out)
   return true;
 }
 
+static bool parse_float_bufpos(Array bufpos, lpos_T *out)
+{
+  if (bufpos.size != 2
+      || bufpos.items[0].type != kObjectTypeInteger
+      || bufpos.items[1].type != kObjectTypeInteger) {
+    return false;
+  }
+  out->lnum = bufpos.items[0].data.integer;
+  out->col = bufpos.items[1].data.integer;
+  return true;
+}
+
 bool parse_float_config(Dictionary config, FloatConfig *fconfig, bool reconf,
                         Error *err)
 {
@@ -753,6 +783,7 @@ bool parse_float_config(Dictionary config, FloatConfig *fconfig, bool reconf,
   bool has_row = false, has_col = false, has_relative = false;
   bool has_external = false, has_window = false;
   bool has_width = false, has_height = false;
+  bool has_bufpos = false;
 
   for (size_t i = 0; i < config.size; i++) {
     char *key = config.items[i].key.data;
@@ -832,6 +863,18 @@ bool parse_float_config(Dictionary config, FloatConfig *fconfig, bool reconf,
         return false;
       }
       fconfig->window = val.data.integer;
+    } else if (!strcmp(key, "bufpos")) {
+      if (val.type != kObjectTypeArray) {
+        api_set_error(err, kErrorTypeValidation,
+                      "'bufpos' key must be Array");
+        return false;
+      }
+      if (!parse_float_bufpos(val.data.array, &fconfig->bufpos)) {
+        api_set_error(err, kErrorTypeValidation,
+                      "Invalid value of 'bufpos' key");
+        return false;
+      }
+      has_bufpos = true;
     } else if (!strcmp(key, "external")) {
       if (val.type == kObjectTypeInteger) {
         fconfig->external = val.data.integer;
@@ -886,6 +929,21 @@ bool parse_float_config(Dictionary config, FloatConfig *fconfig, bool reconf,
     fconfig->window = curwin->handle;
   }
 
+  if (has_window && !has_bufpos) {
+    fconfig->bufpos.lnum = -1;
+  }
+
+  if (has_bufpos) {
+    if (!has_row) {
+      fconfig->row = (fconfig->anchor & kFloatAnchorSouth) ? 0 : 1;
+      has_row = true;
+    }
+    if (!has_col) {
+      fconfig->col = 0;
+      has_col = true;
+    }
+  }
+
   if (has_relative && has_external) {
     api_set_error(err, kErrorTypeValidation,
                   "Only one of 'relative' and 'external' must be used");
@@ -4732,7 +4790,8 @@ void shell_new_rows(void)
   if (!frame_check_height(topframe, h))
     frame_new_height(topframe, h, FALSE, FALSE);
 
-  (void)win_comp_pos();                 /* recompute w_winrow and w_wincol */
+  (void)win_comp_pos();  // recompute w_winrow and w_wincol
+  win_reconfig_floats();  // The size of floats might change
   compute_cmdrow();
   curtab->tp_ch_used = p_ch;
 
@@ -4753,7 +4812,8 @@ void shell_new_columns(void)
     frame_new_width(topframe, Columns, false, false);
   }
 
-  (void)win_comp_pos();                 /* recompute w_winrow and w_wincol */
+  (void)win_comp_pos();  // recompute w_winrow and w_wincol
+  win_reconfig_floats();  // The size of floats might change
 }
 
 /*
@@ -4809,15 +4869,23 @@ int win_comp_pos(void)
 
   frame_comp_pos(topframe, &row, &col);
 
-  // Too often, but when we support anchoring floats to split windows,
-  // this will be needed
   for (win_T *wp = lastwin; wp && wp->w_floating; wp = wp->w_prev) {
-    win_config_float(wp, wp->w_float_config);
+    // float might be anchored to moved window
+    if (wp->w_float_config.relative == kFloatRelativeWindow) {
+      wp->w_pos_changed = true;
+    }
   }
 
   return row;
 }
 
+void win_reconfig_floats(void)
+{
+  for (win_T *wp = lastwin; wp && wp->w_floating; wp = wp->w_prev) {
+    win_config_float(wp, wp->w_float_config);
+  }
+}
+
 /*
  * Update the position of the windows in frame "topfrp", using the width and
  * height of the frames.