Handle persistence of windows' scroll bar and fringes settings (Bug#36193)

* doc/lispref/display.texi (Fringe Size/Pos): Document new
argument PERSISTENT of 'set-window-fringes'.
(Scroll Bars): Document new argument PERSISTENT of
'set-window-scroll-bars'.  Mention that HORIZONTAL-TYPE must
be 'bottom' to show a horizontal scroll bar on mini windows.
* lisp/window.el (window-min-pixel-height): For mini windows the
minimum height is one line.
(window--min-size-1): Use value returned by
'window-min-pixel-height' when dealing with mini windows.
(window--resize-mini-window): Try to handle horizontal scroll
bars and size restrictions more accurately.
(window--state-put-2): Handle persistence of scroll bar
settings.
* src/frame.c (make_frame): Allow horizontal scroll bars in
mini windows.
(adjust_frame_size): Drop PIXELWISE argument in
'resize_frame_windows' calls.
* src/window.c (set_window_buffer): Don't override WINDOW's
scroll bar and fringe settings when marked as persistent.
(resize_frame_windows): Drop fourth argument PIXELWISE - SIZE
is always specified in terms of pixels.  Try to handle height
of mini windows more accurately.
(grow_mini_window, shrink_mini_window): Use body height of
mini window when calculating expected height change.  Take
horizontal scroll bars into account.
(struct saved_window): Two new members to handle persistence
of window fringes and scroll bars.
(Fset_window_configuration, save_window_save): Handle
persistence of fringes and scroll bars.
(set_window_fringes, set_window_scroll_bars): New arguments
PERSISTENT.  Make dimension checks more accurate.
(Fset_window_fringes): New argument PERSISTENT.
(Fwindow_fringes, Fwindow_scroll_bars): Add PERSISTENT to
return values.
(Fset_window_scroll_bars): New argument PERSISTENT.  In
doc-string mention that 'bottom' must be specified to get a
horizontal scroll bar in mini windows.
(compare_window_configurations): Add checks for persistence of
fringes and scroll bars.
* src/window.h (struct window): New boolean slots
'fringes_persistent' and 'scroll_bars_persistent'.
(WINDOW_HAS_HORIZONTAL_SCROLL_BAR): Allow horizontal scroll bars
for mini windows.
(resize_frame_windows): Remove fourth argument of
'resize_frame_windows' in external declaration.
* src/xdisp.c (resize_mini_window): Use box text height to
tell whether mini window height changed.
(set_horizontal_scroll_bar): Set mini window's horizontal
scroll bar when its type is specified as 'bottom'.
* etc/NEWS: Mention new options for 'set-window-fringes' and
'set-window-scroll-bars'.

1 files changed, 12 insertions, 2 deletions

diff --git a/src/window.h b/src/window.h
index 6b0f0e5d07c..dfbc6385312 100644
--- a/src/window.h
+++ b/src/window.h
@@ -422,6 +422,14 @@ struct window
        Otherwise draw them between margin areas and text.  */
     bool_bf fringes_outside_margins : 1;
 
+    /* True if this window's fringe specifications are persistent,
+       i.e., always survive Fset_window_buffer.  */
+    bool_bf fringes_persistent : 1;
+
+    /* True if this window's croll bar specifications are persistent,
+       i.e., always survive Fset_window_buffer.  */
+    bool_bf scroll_bars_persistent : 1;
+
     /* True if window_end_pos and window_end_vpos are truly valid.
        This is false if nontrivial redisplay is preempted since in that case
        the frame image that window_end_pos did not get onto the frame.  */
@@ -860,7 +868,9 @@ wset_next_buffers (struct window *w, Lisp_Object val)
    W.  Horizontal scrollbars exist for toolkit versions only.  */
 #if USE_HORIZONTAL_SCROLL_BARS
 #define WINDOW_HAS_HORIZONTAL_SCROLL_BAR(W)			\
-  ((WINDOW_PSEUDO_P (W) || MINI_NON_ONLY_WINDOW_P (W))		\
+  ((WINDOW_PSEUDO_P (W)						\
+    || (MINI_WINDOW_P (W)					\
+	&& !EQ (W->horizontal_scroll_bar_type, Qbottom)))	\
    ? false							\
    : EQ (W->horizontal_scroll_bar_type, Qt)			\
    ? FRAME_HAS_HORIZONTAL_SCROLL_BARS (WINDOW_XFRAME (W))	\
@@ -1059,7 +1069,7 @@ extern Lisp_Object minibuf_selected_window;
 extern Lisp_Object make_window (void);
 extern Lisp_Object window_from_coordinates (struct frame *, int, int,
                                             enum window_part *, bool);
-extern void resize_frame_windows (struct frame *, int, bool, bool);
+extern void resize_frame_windows (struct frame *, int, bool);
 extern void restore_window_configuration (Lisp_Object);
 extern void delete_all_child_windows (Lisp_Object);
 extern void grow_mini_window (struct window *, int);