Re: [Plplot-devel] Other problems with -locate option on x01c

[Joao C. <jc...@fe...>]

On Sunday 03 March 2002 17:01, Alan W. Irwin wrote:
| On Sun, 3 Mar 2002, Maurice LeBrun wrote:
| > Alan W. Irwin writes:
| >  > Thanks for answering my questions/comments.
| >  >
| >  > I suggest you could improve the design by printing a warning
| >  > message when outside a viewport but continue to stay in locate
| >  > mode for that situation so that subsequent clicks inside
| >  > viewports still work (without having to reinvoke L).=20
| >  > Otherwise, for an example like x01c with lots of area outside
| >  > viewports, the first impression is that locate mode is
| >  > severely broken. (At least that was my impression....;-)) Of
| >  > course to finish locate mode you don't have to click on an
| >  > area with no viewport.  Instead, simply type <ESC> as now.
| >
| > I only just now got around to looking into this.  As it stands,
| > "it's a feature, not a bug".
| >
| > When I was putting this in, Geoff and I discussed the issue and
| > decided the best course on invalid input -- i.e. clicking outside
| > a viewport/window -- was to simply turn off locate mode.  The
| > program's stdout (or stderr) isn't always handy so it's handy to
| > have a graphical cue that you're giving bogus input, and aborting
| > locate mode at that point seems reasonable.  I'm still happy with
| > this decision, but I'll admit documentation is a problem (has
| > been, for a while, but better recently :).
|
| I am now only mildly unhappy with this since I can always use L to
| get into locate mode again.  However, it might be worth changing it
| to put in some warning message (e.g., "Locate mode is terminated
| because you are outside a viewport.  To restart use L") so that if,
| e.g., plwarn works, then the user will get this message.

There is a difference -- when the xhairs appear as a result of a call=20
to plGetCursor() (using -locate in x01c), the user program will=20
receive the button events, while when the xhairs appear as a result=20
of typing 'L', the event are just printed, and the user program has=20
no knowledge of that.

And I think that the visual clue, disappearing of the xhairs, is=20
enought (the xwin driver is not fully interactive -- it hasn't a=20
message area, e.g.): the user program knows that plGetCursor() has=20
failed and the xhairs have disapeared, and if necessary it will=20
invoke the call again, while if invoked via the 'L' key, the user=20
sees the xhair disappearing, and will reinvoke the xhairs again.

Joao

| >  > By the way, before you (and recently somebody else also)
| >  > mentioned the L command and now <ESC> I had never heard of
| >  > them and had no idea you could use locate mode for any of the
| >  > examples other than x01c.
| >  >
| >  > Part of the reason it is taking me so long to get up to speed
| >  > on this interactive stuff is I cannot find any documentation.=20
| >  > Are there any other "locate" commands besides L and <ESC>?  Do
| >  > all interactive drivers have this capability?

Yes, the tk driver share those "driver invoked" capabilities, but has=20
other capabilities as well, use the button Help->on keys

| >  >  Is there some
| >  > documentation that I have missed?  If you point me to some
| >  > documentation or provide me with some, I will put it in the
| >  > docbook documentation form so everybody can easily find it.=20
| >  > Probably the best place would be
| >  > http://plplot.sourceforge.net/resources/docbook-manual/plplotd
| >  >oc-html-0.4.3/interactive-devices.html.

I have several empty drivers/README.<driver> in my local plplot cvs=20
copy, but I had not yet the time to write them. I intend to give an=20
overview of the common cmd line options for all drivers, the driver=20
specific cmd line options, driver capabilities and special uses,=20
required libs, etc. Those can then be incorporated in a drivers=20
manual chapter.


| >
| > The internally recognized keys in normal (plotting) mode in the
| > xwin driver are featured in xwin.c:ProcessKey().  These are:
| >
| > /* Handle internal events */
| >
| >     switch (gin->keysym) {
| >
| >     case PLK_Return:
| >     case PLK_Linefeed:
| >     case PLK_Next:
| >     /* Advance to next page (i.e. terminate event loop) on a
| > <eol> */ /* Check for both <CR> and <LF> for portability, also a
| > <Page Down> */ dev->exit_eventloop =3D TRUE;
| >         break;
| >
| >     case 'Q':
| >     /* Terminate on a 'Q' (not 'q', since it's too easy to hit by
| > mistake) */ pls->nopause =3D TRUE;
| >         plexit("");
| >         break;
| >
| >     case 'L':
| >     /* Begin locate mode */
| >         dev->locate_mode =3D LOCATE_INVOKED_VIA_DRIVER;
| >         CreateXhairs(pls);
| >         break;
| >     }
|
| Thanks for this.  I have noticed experimentally, that
| right-clicking the mouse when outside locate mode advances to the
| next page like CR, but I don't see that right-click implemented
| above.

The above code is for the keys, other code deal with mouse events.

|  Also, from the above I don't see how <ESC> is used to leave
| locate mode.  So the above code must only be part of the
| interactive story.

Yes, while in locate mode you can also use the cursor keys (with=20
SHIT, CTRL, ALT, etc modifiers) to move the cursor.

Joao

|
| Alan