fix(float)!: always anchor to corner of window including border #15832

N, W, S, E are all inclusive, i.e., always anchor to the exact corner of the
window (including border). This line may also need change in this case (change
0 to -1):

This is most consistent and easiest to reason about, especially with GUIs whose
border do not need to have width/height of 1/1 in cell units.

Fix #15789

2 files changed, 7 insertions, 5 deletions

diff --git a/src/nvim/api/vim.c b/src/nvim/api/vim.c
index 3be45d0cf7..8e0502e03b 100644
--- a/src/nvim/api/vim.c
+++ b/src/nvim/api/vim.c
@@ -1360,7 +1360,9 @@ void nvim_chan_send(Integer chan, String data, Error *err)
 ///   - `bufpos`: Places float relative to buffer text (only when
 ///               relative="win"). Takes a tuple of zero-indexed [line, column].
 ///               `row` and `col` if given are applied relative to this
-///               position, else they default to `row=1` and `col=0`
+///               position, else they default to:
+///               - `row=1` and `col=0` if `anchor` is "NW" or "NE"
+///               - `row=0` and `col=0` if `anchor` is "SW" or "SE"
 ///               (thus like a tooltip near the buffer text).
 ///   - `row`: Row position in units of "screen cell height", may be fractional.
 ///   - `col`: Column position in units of "screen cell width", may be
diff --git a/src/nvim/window.c b/src/nvim/window.c
index c0f537aab3..ff97eaa757 100644
--- a/src/nvim/window.c
+++ b/src/nvim/window.c
@@ -853,12 +853,12 @@ void ui_ext_win_position(win_T *wp)
       bool east = c.anchor & kFloatAnchorEast;
       bool south = c.anchor & kFloatAnchorSouth;
 
-      int comp_row = (int)row - (south ? wp->w_height : 0);
-      int comp_col = (int)col - (east ? wp->w_width : 0);
+      int comp_row = (int)row - (south ? wp->w_height_outer : 0);
+      int comp_col = (int)col - (east ? wp->w_width_outer : 0);
       comp_row += grid->comp_row;
       comp_col += grid->comp_col;
-      comp_row = MAX(MIN(comp_row, Rows-wp->w_height_outer-1), 0);
-      comp_col = MAX(MIN(comp_col, Columns-wp->w_width_outer), 0);
+      comp_row = MAX(MIN(comp_row, Rows - wp->w_height_outer - 1), 0);
+      comp_col = MAX(MIN(comp_col, Columns - wp->w_width_outer), 0);
       wp->w_winrow = comp_row;
       wp->w_wincol = comp_col;
       bool valid = (wp->w_redr_type == 0);