Re: NS port horizontal scroll-bars

[YAMAMOTO Mitsuharu <mituharu@math.s.chiba-u.ac.jp>]

>>>>> On Tue, 26 Apr 2016 10:51:57 +0100, Alan Third <alan@idiocy.org> said:

> It's actually the other end of the process that I'm struggling
> with. I write pixel values for dragging the scroll-bar into an
> emacs_event struct (location of mouse in scroll-bar and total length
> of scroll-bar), and when that data pops back out in scroll-bar.el it
> doesn't seem to be any use to the standard scroll-bar functions.

Ah, that reminds me of something.  You can see how the Mac port
handles that (in the `work' branch based on Emacs 25.0.93 pretest).

https://bitbucket.org/mituharu/emacs-mac/src/472fe59bac472a9076cbb6e86e0ea92908f7b78d/src/macappkit.m?at=work&fileviewer=file-view-default#macappkit.m-6002

  6690	      if (bar->horizontal && whole > 0)
  6691		{
  6692		  /* The default horizontal scroll bar drag handler assumes
  6693		     previously-set `whole' value to be preserved and doesn't
  6694		     want overscrolling.  */
  6695		  int position = lround (whole * minEdge / maximum);
  6696	
  6697		  if (position > whole - portion)
  6698		    position = whole - portion;
  6699		  XSETINT (inputEvent.x, position);
  6700		  XSETINT (inputEvent.y, whole);
  6701		}
  6702	      else
  6703		{
  6704		  XSETINT (inputEvent.x, minEdge);
  6705		  XSETINT (inputEvent.y, maximum);
  6706		}
  6707	    }

> The vertical scroll-bars in the NS port have their own functions
> defined in ns-win.el, rather than using the functions in
> scroll-bar.el. I think this is, at least in part, to enable clicking
> directional arrows in older versions of OS X (and GNUSTEP), but it's
> doing something different with dragging too.

The Mac port (and its predecessors) has been using the standard
toolkit scroll bar handler in scroll-bar.el as it is, and there has
been no problem even in the old OS X versions having the directional
arrows.

				     YAMAMOTO Mitsuharu
				mituharu@math.s.chiba-u.ac.jp