#711142 zooming in a gnuplot terminal yields blank contents when there should be a part of a segment

Package:
gnuplot-qt
Source:
gnuplot
Description:
Command-line driven interactive plotting program. QT-package
Submitter:
Vincent Lefevre
Date:
2015-11-04 02:00:38 UTC
Severity:
minor
#711142#5
Date:
2013-06-05 00:54:27 UTC
From:
To:
The "zoom" documentation says:

 Zooming is usually accomplished by holding down the left mouse button and
 dragging the mouse to delineate a zoom region.  Some platforms may require
 using a different mouse button.  The original plot can be restored by typing
 the 'u' hotkey in the plot window.  The hotkeys 'p' and 'n' step back and
 forth through a history of zoom operations.

 The option `zoomcoordinates` determines if the coordinates of the zoom box are
 drawn at the edges while zooming. This is on by default.

 If the option `zoomjump` is on, the mouse pointer will be automatically
 offset a small distance after starting a zoom region with button 3. This can
 be useful to avoid a tiny (or even empty) zoom region. `zoomjump` is off by
 default.

Under Debian, in a 'wxt' terminal (which is the default one), zooming
is actually initiated with the right mouse button. Anyway. Once done,
the zoomed window doesn't contain anything. For instance, run:

$ GNUTERM=wxt gnuplot -persist <<EOF
plot '-' using 1:2 t '' with line
0 0
10 10
e
EOF

One gets a straight line from (0,0) to (10,10). Then delimit a zoom area
from around (2,8) to (8,2), by clicking with the right button over (2,8)
and clicking with any button overs (8,2). The obtained result is blank
instead of containing a part of the line.
#711142#10
Date:
2013-06-05 06:03:59 UTC
From:
To:
Hi,

you help will be much more effective, if you report all of this bugs directly to
upstream instead of Debian BTS. I am sure, all of them are not Debian-specific,

If you do really want to see them fixed, please, do it.

Thank you,

Anton

2013/6/5 Vincent Lefevre <vincent@vinc17.net>:
#711142#15
Date:
2013-06-05 06:07:10 UTC
From:
To:
severity 711139 minor
severity 711141 minor
severity 711142 minor
thanks
#711142#22
Date:
2014-06-05 11:27:26 UTC
From:
To:
This was in my TODO list, but I didn't have the time. I'll do that.
In the mean time, since wxt is no longer supported, I'm closing
bug 711142.
#711142#27
Date:
2014-06-10 07:43:19 UTC
From:
To:
Same problem with the 'qt' terminal when zooming has an effect
(see bug 711141).
#711142#34
Date:
2014-06-10 07:51:49 UTC
From:
To:
Control: retitle -1 gnuplot-qt: zooming with the 'qt' and 'wxt' terminals yields blank contents
Control: reopen -1
Control: found -1 4.6.5-1

So, I'm reopening the bug (at least for the 'qt' terminal).
#711142#45
Date:
2014-06-11 12:44:08 UTC
From:
To:
Control: retitle 711142 gnuplot-qt: zooming with the  'wxt' terminals doesn't work with -persist
Control: notfound 711142 gnuplot/4.6.5-4
Control: found 711142 gnuplot/4.6.5-1

Actually the problem with the 'qt' terminal is due to the -persist;
this is discussed in bug 711139.

With the 'wxt' terminal, this is also due to the -persist, but this
was supposed to work. I get either blank contents or a crash (in
interactive use, after "quit") with error "stack smashing detected".

So, let's update the bug title again and close the bug since the
'wxt' terminal is no longer supported.
#711142#50
Date:
2014-06-11 12:50:27 UTC
From:
To:
Only the retitle wasn't taken into account.
Changed it again (and fixed it).
#711142#57
Date:
2014-06-12 08:45:21 UTC
From:
To:
Control: reopen -1
Control: retitle -1 zooming yields blank contents when there should be a part of a segment
Control: found -1 4.6.5-4

After some other tests, I also get blank contents without -persist,
but this bug seems to occur only when the result should be a part of
a segment. I've tried the latest version (4.6.5-4) with 'qt' (default)
and 'x11' only, as 'wxt' is no longer available.

A test without -persist:

xvii:~> GNUTERM=qt gnuplot

        G N U P L O T
        Version 4.6 patchlevel 5    last modified February 2014
        Build System: Linux x86_64

        Copyright (C) 1986-1993, 1998, 2004, 2007-2014
        Thomas Williams, Colin Kelley and many others

        gnuplot home:     http://www.gnuplot.info
        faq, bugs, etc:   type "help FAQ"
        immediate help:   type "help"  (plot window: hit 'h')

Terminal type set to 'qt'
gnuplot> plot '-' using 1:2 t '' with line
input data ('e' ends) > 0 0
input data ('e' ends) > 3 3
input data ('e' ends) > 6 8
input data ('e' ends) > e
gnuplot>

Then select any area that contains a part of a single segment
(e.g. (1,2) to (2,1), or (4,7) to (5,1)) with the right button.
I get a blank graph (only the axes). However if I select any
area that contains (3,3), I get the correct result.
#711142#68
Date:
2014-06-12 08:59:03 UTC
From:
To:
To summarize: this bug 711142 is about blank contents in the
particular case of a zoom where the result should be a part of a
segment, while bug 711139 (and 711141) is about issues related to
-persist.