Implement horizontal scroll bars on NS

* lisp/scroll-bar.el (horizontal-scroll-bars-available-p): Remove NS
check.
* lisp/term/ns-win.el: Remove custom NS scroll-bar handlers and bind
scroll-bar mouse clicks to standard handlers.
* src/nsterm.h (EmacsScroller): Add 'horizontal' property and rename
pixel_height to pixel_length.
* src/nsterm.m (x_set_window_size): Remove left-hand scroll-bar code. It
caused scroll-bars to be over-drawn and the best working solution
appears to be complete removal.
(ns_set_horizontal_scroll_bar): Rewrite to handle horizontal scrollers
correctly.
(ns_set_vertical_scroll_bar): Set width to actual scroller width.
(setFrame): Handle horizontal case.
(dealloc): Handle horizontal case.
(judge): Handle horizontal case.
(setPosition): Rename pixel_height to pixel_length.
(sendScrollEventAtLoc): Handle horizontal case.
(mouseDown): Handle horizontal case and general tidy up of code.
(mouseDragged): Handle horizontal case. Call sendScrollEventAtLoc with
absolute pixel size instead of ratio.
* src/window.h: Remove NS check.

2 files changed, 5 insertions, 54 deletions

diff --git a/lisp/scroll-bar.el b/lisp/scroll-bar.el
index 5cfa2c4353b..838f9bf80cd 100644
--- a/lisp/scroll-bar.el
+++ b/lisp/scroll-bar.el
@@ -148,8 +148,7 @@ created in the future."
   "Return non-nil when horizontal scroll bars are available on this system."
   (and (display-graphic-p)
        (boundp 'x-toolkit-scroll-bars)
-       x-toolkit-scroll-bars
-       (not (eq (window-system) 'ns))))
+       x-toolkit-scroll-bars))
 
 (define-minor-mode horizontal-scroll-bar-mode
   "Toggle horizontal scroll bars on all frames (Horizontal Scroll Bar mode).
diff --git a/lisp/term/ns-win.el b/lisp/term/ns-win.el
index 452c68d0176..5080ed0a8f7 100644
--- a/lisp/term/ns-win.el
+++ b/lisp/term/ns-win.el
@@ -717,60 +717,12 @@ See the documentation of `create-fontset-from-fontset-spec' for the format.")
 
 ;;;; Scrollbar handling.
 
-(global-set-key [vertical-scroll-bar down-mouse-1] 'ns-handle-scroll-bar-event)
+(global-set-key [vertical-scroll-bar down-mouse-1] 'scroll-bar-toolkit-scroll)
+(global-set-key [horizontal-scroll-bar down-mouse-1] 'scroll-bar-toolkit-horizontal-scroll)
 (global-unset-key [vertical-scroll-bar mouse-1])
 (global-unset-key [vertical-scroll-bar drag-mouse-1])
-
-(declare-function scroll-bar-scale "scroll-bar" (num-denom whole))
-
-(defun ns-scroll-bar-move (event)
-  "Scroll the frame according to a Nextstep scroller event."
-  (interactive "e")
-  (let* ((pos (event-end event))
-         (window (nth 0 pos))
-         (scale (nth 2 pos)))
-    (with-current-buffer (window-buffer window)
-      (cond
-       ((eq (car scale) (cdr scale))
-        (goto-char (point-max)))
-       ((= (car scale) 0)
-        (goto-char (point-min)))
-       (t
-        (goto-char (+ (point-min) 1
-                      (scroll-bar-scale scale (- (point-max) (point-min)))))))
-      (beginning-of-line)
-      (set-window-start window (point))
-      (vertical-motion (/ (window-height window) 2) window))))
-
-(defun ns-handle-scroll-bar-event (event)
-  "Handle scroll bar EVENT to emulate Nextstep style scrolling."
-  (interactive "e")
-  (let* ((position (event-start event))
-         (bar-part (nth 4 position))
-         (window (nth 0 position))
-         (old-window (selected-window)))
-    (cond
-     ((eq bar-part 'ratio)
-      (ns-scroll-bar-move event))
-     ((eq bar-part 'handle)
-      (if (eq window (selected-window))
-          (track-mouse (ns-scroll-bar-move event))
-        ;; track-mouse faster for selected window, slower for unselected.
-        (ns-scroll-bar-move event)))
-     (t
-      (select-window window)
-      (cond
-       ((eq bar-part 'up)
-        (goto-char (window-start window))
-        (scroll-down 1))
-       ((eq bar-part 'above-handle)
-        (scroll-down))
-       ((eq bar-part 'below-handle)
-        (scroll-up))
-       ((eq bar-part 'down)
-        (goto-char (window-start window))
-        (scroll-up 1)))
-      (select-window old-window)))))
+(global-unset-key [horizontal-scroll-bar mouse-1])
+(global-unset-key [horizontal-scroll-bar drag-mouse-1])
 
 
 ;;;; Color support.