Question

I cannot achieve to plot a square in Octave.
I cannot force equally scaled axes, so I am getting a rectangle instead:

The following trials are not working:

x = [0, 1, 1, 0, 0]';
y = [0, 0, 1, 1, 0];
plot(x, y), axis equal, axis([-1,2, -1,2])
% figure('Position', [10,10,100,100]); %[startx,starty,width,height]
% plot(x, y)

Probably I would need to specify a fixed window size and equally
scaled axes. I would be satisfied, when the first such display window
would show a correct square. A luxury solution would make the window
(or its content)
not interactively resizable.

Remarks:

1. I have Octave 3.2.4 on Windows XP.
2. The suggestion in Stackoverflow
   does not work.

Answer 1

I believe this is an issue with Gnuplot’s windows output device. Compare it against the wxt device:

Gnuplot 4.4.3, WinXP

# Gnuplot, wxWidgets terminal
set terminal wxt size 200,400
set size ratio -1        # set size square
plot x

# Gnuplot, Windows terminal
set terminal windows size 200,400
set size ratio -1        # set size square
plot x

Note that for the “win terminal”, size affects the figure size including window title bar and status bar, while for the “wx terminal” it only sets the inner drawing area

---

Octave 3.4.2, WinXP

Unfortunately, when I tried this in Octave, it still was not what it should be for both terminal types. In fact, the problem is that resizing the figure using set(gcf,'position',[..]) had no effect:

# Octave, backend=Gnuplot, terminal=wxt/windows
graphics_toolkit gnuplot     # backend gnuplot
setenv('GNUTERM','wx')       # wx/windows
figure, set(gcf,'position',[100 100 200 400])
plot(-10:10, -10:10, 'r'), legend('x')
axis([-10 10 -10 10])
axis equal                   # axis square

Therefore, I had to manually resize the figures using the mouse to the specified size (200,400) (yes, I actually pulled a virtual ruler and measured the pixels!). Finally call refresh command to replot:

The good news is that once you correctly set the figure size, axis equal is working for both terminals types.

On the other hand, the new FLTK backend is behaving correctly without any hacks, so you might wanna switch to it:

# Octave, backend=FLTK
graphics_toolkit fltk        # backend fltk
figure, set(gcf,'position',[100 100 200 400])
plot(-10:10, -10:10, 'r'), legend('x')
axis([-10 10 -10 10])
axis equal

---

MATLAB

For reference, here is the MATLAB output:

%# MATLAB
figure, set(gcf,'position',[100 100 200 400])
plot(-10:10, -10:10, 'r'), legend('x')
axis equal
axis([-10 10 -10 10])