[Octave-bug-tracker] [bug #39731] Scroll only if the current scroll bar slider is near the bottom of the history window.

[Dan Sebald]

URL:
  <http://savannah.gnu.org/bugs/?39731>

                 Summary: Scroll only if the current scroll bar slider is near
the bottom of the history window.
                 Project: GNU Octave
            Submitted by: sebald
            Submitted on: Thu 08 Aug 2013 05:01:42 PM GMT
                Category: GUI
                Severity: 3 - Normal
                Priority: 5 - Normal
              Item Group: None
                  Status: None
             Assigned to: None
         Originator Name: 
        Originator Email: 
             Open/Closed: Open
         Discussion Lock: Any
                 Release: dev
        Operating System: Any

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Details:

This isn't so much a bug as it is finding the desired behavior.  

If the history always scrolls when a command is issued, the history window has
the undesirable property of moving when double-clicking some command far back
in the history list when the user probably wants to remain in place and
possibly use other nearby commands at that point in history.

If the history never scrolls then at start up its as though history is not
being updated.

The attached patch is meant to strike a balance.  If the user ever
intentionally scrolls away from the most recent history, the history will not
scroll to bottom with a new command.  If the user moves the slider back to the
bottom, then it will scroll again with new commands.  That is the general
idea.  The algorithm is to scroll if max - value < 5.  Not 5%, but 5.  It
seems to be fairly good as an initial start, but there might be similar
algorithms.

Can either apply this and see what the response is, or hold off for a bit and
see if there isn't something better.  The one dodgy area might be if the user
wants to get at commands that are just beyond the upper edge of the history
window, i.e., "fairly recent" history and the window keeps scrolling back
pushing the desired commands just off the edge of the window.  Since the user
is more apt to use fairly history, this might be common.

Could make it an exact bottom, i.e., if max - value < 1, but I'm wondering if
users will find that too stringent.  I'll experiment.




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File Attachments:


-------------------------------------------------------
Date: Thu 08 Aug 2013 05:01:42 PM GMT  Name:
octave-history_scroll_action-2013aug08.patch  Size: 1kB   By: sebald

<http://savannah.gnu.org/bugs/download.php?file_id=28798>

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