Merging in the gui branch

[John W. Eaton]

On 18-Jan-2012, Jordi Gutiérrez Hermoso wrote:

| The gui branch was supposed to be a temporary fix to not interfere
| with the release of 3.6. Now that 3.6.0 is pretty much out and it
| doesn't need the default branch anymore, I propose to make the bold
| move to merge the gui branch onto default and close it.
| 
| This would mean our next stable release will probably have to have
| some sort of GUI, perhaps still not compiled by default, but
| available, sort of like what we have been doing with OpenGL plotting.
| 
| Objections?

At first I was hesitant to do this now, but I'm warming up to the
idea.

I built Octave with the current GUI sources.  It looks promising, but
I did not do a lot of testing.  From my brief experience with it, I
see the following things that I would like to see done:

  * Remove the IRC client.  There are plenty of IRC clients around and
    I see no need to have one built in to Octave.  We don't need to
    add this extra code that we have to maintain.

  * Using the terminal and reading the documentation should be
    possible at the same time.  The current tabbed interface does not
    seem to allow this way of working.

  * Reading the documentation should not require a network
    connection.  I also don't think we need to build a web browser
    into Octave itself.  Similar to the IRC client issue, there are
    plenty of web browsers to choose from.  We don't need to have
    another one and embed it in Octave.  There's no need for us to add
    this extra code that we have to maintain.

  * I noticed some redisplay problems when trying to use keyboard
    commands for navigating the history.  For example, using C-p to
    retrieve previous history items garbled the display.

  * If we are going with Qt for the GUI, then we need to use Qt for
    the graphics windows instead of FLTK.

  * The code must be integrated with the current sources and build
    system.  The GUI will be part of Octave, not a separate program,
    and it must be possible to build it in a separate directory tree
    as is usual with the GNU build system.

Is it likely that these things can be done before the next release?

I can see the value of the GUI for some things, but Octave should stay
focused on numerical programming, not web browsing and IRC.  We have
limited resources.  I think it will be enough work making the GUI work
well without including these extra features.

jwe