Strange behaviour of scrollbars on MacOSX

Strange behaviour of scrollbars on MacOSX

[Piet van Oostrum]

With CVS Carbon Emacs on MacOSX the scrollbars behave quite strangely
compared to other MacOSX applications, and I would say, probably strange
compared to other OSs.

In another application when you click on the blue slider in the scrollbar
and don't move the mouse, everything stays as it was, no scrolling takes
place. On MacOSX, however, when you do this, either the scrollbar changes
position (just when you click on it) or the scrollbar stays put but the
text scrolls. Sometimes it is possible to scroll through your buffer
(probably with gaps) with repeatedly clicking on the same location in the
slider without moving the mouse. Sometimes it goes back and forth. I know
that emacs has different ideas about scrollbars but is there a way to get
the same behaviour as other apps?
-- 
Piet van Oostrum <piet@cs.uu.nl>
URL: http://www.cs.uu.nl/~piet [PGP]
Private email: P.van.Oostrum@hccnet.nl

Re: Strange behaviour of scrollbars on MacOSX

[Steven Tamm]

The scrollbar thumb code is the most tetchy of the gui code.  It is 
trying to emulate the "Mac" way of doing things by modifications to the 
NT scroll-bar code.  But it is very difficult to handle the thumb 
correctly.  This is because Carbon "wants" you to use 
TrackMousePosition and block waiting for a change in the mouse.  
Instead we are doing the thumb handling by hand.

For example, it responds differently to a "hold" on the thumb vs. a 
"click" on the thumb.  Try it and you'll see.  There's a bug there 
someplace, and I would suspect it's someplace in 
x_scroll_bar_report_motion.   I couldn't get a real stack trace for the 
call to report_motion (from XTmouse_position)

I can't debug this just now; if anyone can help it would be much 
appreciated.

-Steven

On May 2, 2004, at 4:32 AM, Piet van Oostrum wrote:

> With CVS Carbon Emacs on MacOSX the scrollbars behave quite strangely
> compared to other MacOSX applications, and I would say, probably 
> strange
> compared to other OSs.
>
> In another application when you click on the blue slider in the 
> scrollbar
> and don't move the mouse, everything stays as it was, no scrolling 
> takes
> place. On MacOSX, however, when you do this, either the scrollbar 
> changes
> position (just when you click on it) or the scrollbar stays put but the
> text scrolls. Sometimes it is possible to scroll through your buffer
> (probably with gaps) with repeatedly clicking on the same location in 
> the
> slider without moving the mouse. Sometimes it goes back and forth. I 
> know
> that emacs has different ideas about scrollbars but is there a way to 
> get
> the same behaviour as other apps?
> -- 
> Piet van Oostrum <piet@cs.uu.nl>
> URL: http://www.cs.uu.nl/~piet [PGP]
> Private email: P.van.Oostrum@hccnet.nl
>
>
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