floats: z-index

9 files changed, 51 insertions, 21 deletions

diff --git a/src/nvim/api/private/helpers.c b/src/nvim/api/private/helpers.c
index 24ba6110c4..0f7008e150 100644
--- a/src/nvim/api/private/helpers.c
+++ b/src/nvim/api/private/helpers.c
@@ -1909,7 +1909,7 @@ bool parse_float_config(Dictionary config, FloatConfig *fconfig, bool reconf,
     } else if (strequal(key, "height")) {
       has_height = true;
       if (val.type == kObjectTypeInteger && val.data.integer > 0) {
-        fconfig->height= (int)val.data.integer;
+        fconfig->height = (int)val.data.integer;
       } else {
         api_set_error(err, kErrorTypeValidation,
                       "'height' key must be a positive Integer");
@@ -1983,6 +1983,14 @@ bool parse_float_config(Dictionary config, FloatConfig *fconfig, bool reconf,
                       "'focusable' key must be Boolean");
         return false;
       }
+    } else if (strequal(key, "zindex")) {
+      if (val.type == kObjectTypeInteger && val.data.integer > 0) {
+        fconfig->zindex = (int)val.data.integer;
+      } else {
+        api_set_error(err, kErrorTypeValidation,
+                      "'zindex' key must be a positive Integer");
+        return false;
+      }
     } else if (!strcmp(key, "border")) {
       parse_border_style(val, fconfig, err);
       if (ERROR_SET(err)) {
diff --git a/src/nvim/api/ui_events.in.h b/src/nvim/api/ui_events.in.h
index e934d5dc92..11e21a88ea 100644
--- a/src/nvim/api/ui_events.in.h
+++ b/src/nvim/api/ui_events.in.h
@@ -106,7 +106,8 @@ void win_pos(Integer grid, Window win, Integer startrow,
              Integer startcol, Integer width, Integer height)
   FUNC_API_SINCE(6) FUNC_API_REMOTE_ONLY;
 void win_float_pos(Integer grid, Window win, String anchor, Integer anchor_grid,
-                   Float anchor_row, Float anchor_col, Boolean focusable)
+                   Float anchor_row, Float anchor_col, Boolean focusable,
+                   Integer zindex)
   FUNC_API_SINCE(6) FUNC_API_REMOTE_ONLY;
 void win_external_pos(Integer grid, Window win)
   FUNC_API_SINCE(6) FUNC_API_REMOTE_ONLY;
diff --git a/src/nvim/api/vim.c b/src/nvim/api/vim.c
index e0eebd079f..e9a0b0df2e 100644
--- a/src/nvim/api/vim.c
+++ b/src/nvim/api/vim.c
@@ -1417,6 +1417,15 @@ void nvim_chan_send(Integer chan, String data, Error *err)
 ///   - `external`: GUI should display the window as an external
 ///       top-level window. Currently accepts no other positioning
 ///       configuration together with this.
+///   - `zindex`: Stacking order. floats with higher `zindex` go on top on
+///               floats with lower indices. Must be larger than zero. The
+///               following screen elements have hard-coded z-indices:
+///       - 100: insert completion popupmenu
+///       - 200: message scrollback
+///       - 250: cmdline completion popupmenu (when wildoptions+=pum)
+///     The default value for floats are 50.  In general, values below 100 are
+///     recommended, unless there is a good reason to overshadow builtin
+///     elements.
 ///   - `style`: Configure the appearance of the window. Currently only takes
 ///       one non-empty value:
 ///       - "minimal"  Nvim will display the window with many UI options
diff --git a/src/nvim/buffer_defs.h b/src/nvim/buffer_defs.h
index dd24db910e..0c839ba12a 100644
--- a/src/nvim/buffer_defs.h
+++ b/src/nvim/buffer_defs.h
@@ -1083,6 +1083,7 @@ typedef struct {
   FloatRelative relative;
   bool external;
   bool focusable;
+  int zindex;
   WinStyle style;
   bool border;
   bool shadow;
@@ -1096,6 +1097,7 @@ typedef struct {
                                           .row = 0, .col = 0, .anchor = 0, \
                                           .relative = 0, .external = false, \
                                           .focusable = true, \
+                                          .zindex = kZIndexFloatDefault, \
                                           .style = kWinStyleUnused })
 
 // Structure to store last cursor position and topline.  Used by check_lnums()
diff --git a/src/nvim/grid_defs.h b/src/nvim/grid_defs.h
index 3b34af46e4..724363674c 100644
--- a/src/nvim/grid_defs.h
+++ b/src/nvim/grid_defs.h
@@ -13,6 +13,15 @@
 typedef char_u schar_T[(MAX_MCO+1) * 4 + 1];
 typedef int sattr_T;
 
+enum {
+  kZIndexDefaultGrid = 0,
+  kZIndexFloatDefault = 50,
+  kZIndexPopupMenu = 100,
+  kZIndexMessages = 200,
+  kZIndexCmdlinePopupMenu = 250,
+};
+
+
 /// ScreenGrid represents a resizable rectuangular grid displayed by UI clients.
 ///
 /// chars[] contains the UTF-8 text that is currently displayed on the grid.
@@ -73,6 +82,9 @@ struct ScreenGrid {
   // whether the grid can be focused with mouse clicks.
   bool focusable;
 
+  // z-index: the order in the stack of grids.
+  int zindex;
+
   // Below is state owned by the compositor. Should generally not be set/read
   // outside this module, except for specific compatibilty hacks
 
@@ -96,7 +108,7 @@ struct ScreenGrid {
 };
 
 #define SCREEN_GRID_INIT { 0, NULL, NULL, NULL, NULL, NULL, 0, 0, false, \
-                           false, 0, 0, NULL, false, true, \
+                           false, 0, 0, NULL, false, true, 0, \
                            0, 0, 0, 0, 0,  false }
 
 #endif  // NVIM_GRID_DEFS_H
diff --git a/src/nvim/message.c b/src/nvim/message.c
index a34b895033..ec5dabbbc0 100644
--- a/src/nvim/message.c
+++ b/src/nvim/message.c
@@ -165,6 +165,7 @@ void msg_grid_validate(void)
     // TODO(bfredl): eventually should be set to "invalid". I e all callers
     // will use the grid including clear to EOS if necessary.
     grid_alloc(&msg_grid, Rows, Columns, false, true);
+    msg_grid.zindex = kZIndexMessages;
 
     xfree(msg_grid.dirty_col);
     msg_grid.dirty_col = xcalloc(Rows, sizeof(*msg_grid.dirty_col));
diff --git a/src/nvim/popupmnu.c b/src/nvim/popupmnu.c
index 32c9750628..7d452d6797 100644
--- a/src/nvim/popupmnu.c
+++ b/src/nvim/popupmnu.c
@@ -421,6 +421,10 @@ void pum_redraw(void)
   }
 
   grid_assign_handle(&pum_grid);
+
+  pum_grid.zindex = ((State == CMDLINE)
+                     ? kZIndexCmdlinePopupMenu : kZIndexPopupMenu);
+
   bool moved = ui_comp_put_grid(&pum_grid, pum_row, pum_col-col_off,
                                 pum_height, grid_width, false, true);
   bool invalid_grid = moved || pum_invalid;
@@ -439,7 +443,7 @@ void pum_redraw(void)
     int row_off = pum_above ? pum_height : 0;
     ui_call_win_float_pos(pum_grid.handle, -1, cstr_to_string(anchor),
                           pum_anchor_grid, pum_row-row_off, pum_col-col_off,
-                          false);
+                          false, pum_grid.zindex);
   }
 
 
diff --git a/src/nvim/ui_compositor.c b/src/nvim/ui_compositor.c
index c1e4a40ef2..1ec5189795 100644
--- a/src/nvim/ui_compositor.c
+++ b/src/nvim/ui_compositor.c
@@ -165,22 +165,13 @@ bool ui_comp_put_grid(ScreenGrid *grid, int row, int col, int height, int width,
     }
 #endif
 
-    // TODO(bfredl): this is pretty ad-hoc, add a proper z-order/priority
-    // scheme. For now:
-    // - msg_grid is always on top.
-    // - pum_grid is on top of all windows but not msg_grid. Except for when
-    //   wildoptions=pum, and completing the cmdline with scrolled messages,
-    //   then the pum has to be drawn over the scrolled messages.
     size_t insert_at = kv_size(layers);
-    bool cmd_completion = (grid == &pum_grid && (State & CMDLINE)
-                           && (wop_flags & WOP_PUM));
-    if (kv_A(layers, insert_at-1) == &msg_grid && !cmd_completion) {
-      insert_at--;
-    }
-    if (kv_A(layers, insert_at-1) == &pum_grid && (grid != &msg_grid)) {
+    while (insert_at > 0 && kv_A(layers, insert_at-1)->zindex > grid->zindex) {
       insert_at--;
     }
+
     if (curwin && kv_A(layers, insert_at-1) == &curwin->w_grid_alloc
+        && kv_A(layers, insert_at-1)->zindex == grid->zindex
         && !on_top) {
       insert_at--;
     }
@@ -279,12 +270,11 @@ static void ui_comp_grid_cursor_goto(UI *ui, Integer grid_handle,
   // should configure all grids before entering win_update()
   if (curgrid != &default_grid) {
     size_t new_index = kv_size(layers)-1;
-    if (kv_A(layers, new_index) == &msg_grid) {
-      new_index--;
-    }
-    if (kv_A(layers, new_index) == &pum_grid) {
+
+    while (new_index > 1 && kv_A(layers, new_index)->zindex > curgrid->zindex) {
       new_index--;
     }
+
     if (curgrid->comp_index < new_index) {
       ui_comp_raise_grid(curgrid, new_index);
     }
diff --git a/src/nvim/window.c b/src/nvim/window.c
index d4d00c0a71..0b28e8aa76 100644
--- a/src/nvim/window.c
+++ b/src/nvim/window.c
@@ -763,10 +763,13 @@ void ui_ext_win_position(win_T *wp)
       }
       api_clear_error(&dummy);
     }
+
+    wp->w_grid_alloc.zindex = wp->w_float_config.zindex;
     if (ui_has(kUIMultigrid)) {
       String anchor = cstr_to_string(float_anchor_str[c.anchor]);
       ui_call_win_float_pos(wp->w_grid_alloc.handle, wp->handle, anchor,
-                            grid->handle, row, col, c.focusable);
+                            grid->handle, row, col, c.focusable,
+                            wp->w_grid_alloc.zindex);
     } else {
       // TODO(bfredl): ideally, compositor should work like any multigrid UI
       // and use standard win_pos events.