[Octave-bug-tracker] [bug #53504] axis("equal") makes plot3 unusably small with graphics_toolkit("gnuplot")

[Dan Sebald]

Follow-up Comment #1, bug #53504 (project octave):

Initially I was going to ask for a screen shot, but I see the issue.  As a
slight aside, I know that gnuplot can do something like


linux@ ~ $ gnuplot

        G N U P L O T
        Version 5.3 patchlevel 0    last modified 2017-11-04 

        Copyright (C) 1986-1993, 1998, 2004, 2007-2017
        Thomas Williams, Colin Kelley and many others

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

Terminal type is now 'qt'
Options are '0 font "Sans,9"'
gnuplot> set view equal
gnuplot> splot sin(x+y)
gnuplot> 


then use the center mouse button-click-drag left and right to change the
scale.  So, in theory we should be able to adjust that.

But I look at the screen shot:

gnuplot_axis_equal_bug_Screenshot_from_2018-03-28_14-21-26.png

and I see in the footer that the scale is 1.0000, so this is nominal operating
range.  The fact the plot is so tiny suggests that the *border* must be used
up by something, be it a large title font, or large x/y/z label font.

That being said, the source of this problem seems more general than just
gnuplot.  I'm also attaching the result of your command sequence for the Qt
toolkit:

qt_opengl_axis_equal_bug_Screenshot_from_2018-03-28_14-23-21.png

Notice how it has the same issue, but perhaps not immediately obvious.  In the
Qt OpenGL case, the z-axis looks to be scrunched to one pixel where the x and
y-axis look reasonable.

As an observation, if for the gnuplot toolkit one uses that
center-mouse-click-drag-left-or-right feature to zoom in on the axis equal
plot, it looks similar to the Qt OpenGL plot where the x/y-axis is reasonable
but the z-axis is still scrunched to a single pixel.

So at this point, I'd say there looks to be something generally wrong with the
z-computation of the "axis equal" code.  As such, the category should be
changed to just "Plotting".

(file #43711, file #43712)
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Additional Item Attachment:

File name: gnuplot_axis_equal_bug_Screenshot_from_2018-03-28_14-21-26.png
Size:17 KB
File name: qt_opengl_axis_equal_bug_Screenshot_from_2018-03-28_14-23-21.png
Size:17 KB


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