Add ability to change macOS WM theme (bug#27973)

* src/frame.c (make_frame, frame_parms, syms_of_frame)
[NS_IMPL_COCOA]: Add ns-appearance and ns-transparent-titlebar
options.
* src/frame.h (ns_appearance_type) [NS_IMPL_COCOA]: Add enum to
represent NSAppearance options.
(struct frame) [NS_IMPL_COCOA]: Add ns_appearance and
ns_transparent_titlebar frame parameters.
* src/nsfns.m (ns_frame_parm_handlers) [NS_IMPL_COCOA]: Add
ns_set_appearance and ns_set_transparent_titlebar handlers.
(Sx_create_frame): Handle ns-appearance and ns-transparent-titlebar
frame parameters.
(Qdark): Add new symbol for use with ns-appearance.
* src/nsterm.h (ns_set_appearance, ns_set_transparent_titlebar)
[NS_IMPL_COCOA]: Add prototypes.
* src/nsterm.m (ns_set_appearance, ns_set_transparent_titlebar)
[NS_IMPL_COCOA]: New functions.
(initFrameFromEmacs) [NS_IMPL_COCOA]: Handle ns-appearance and
ns-transparent-titlebar frame parameters.
* doc/lispref/frames.texi (Window Management Parameters): Document
ns-apperance and ns-transparent-titlebar.

1 files changed, 12 insertions, 0 deletions

diff --git a/src/frame.c b/src/frame.c
index 1e5e4bbdb48..5099f75be4d 100644
--- a/src/frame.c
+++ b/src/frame.c
@@ -834,6 +834,10 @@ make_frame (bool mini_p)
 #if ! defined (USE_GTK) && ! defined (HAVE_NS)
   f->last_tool_bar_item = -1;
 #endif
+#ifdef NS_IMPL_COCOA
+  f->ns_appearance = ns_appearance_aqua;
+  f->ns_transparent_titlebar = false;
+#endif
 #endif
 
   root_window = make_window ();
@@ -3520,6 +3524,10 @@ static const struct frame_parm_table frame_parms[] =
   {"z-group",                   SYMBOL_INDEX (Qz_group)},
   {"override-redirect",         SYMBOL_INDEX (Qoverride_redirect)},
   {"no-special-glyphs",         SYMBOL_INDEX (Qno_special_glyphs)},
+#ifdef NS_IMPL_COCOA
+  {"ns-appearance",             SYMBOL_INDEX (Qns_appearance)},
+  {"ns-transparent-titlebar",   SYMBOL_INDEX (Qns_transparent_titlebar)},
+#endif
 };
 
 #ifdef HAVE_WINDOW_SYSTEM
@@ -5646,6 +5654,10 @@ syms_of_frame (void)
 #ifdef HAVE_NS
   DEFSYM (Qns_parse_geometry, "ns-parse-geometry");
 #endif
+#ifdef NS_IMPL_COCOA
+  DEFSYM (Qns_appearance, "ns-appearance");
+  DEFSYM (Qns_transparent_titlebar, "ns-transparent-titlebar");
+#endif
 
   DEFSYM (Qalpha, "alpha");
   DEFSYM (Qauto_lower, "auto-lower");