@Panxto:
I used the following simple script:

## Step 1
a = rand (10, 10);
b = rand (10, 10);
plot (a(:, 1), a(:, 2), '*r');
hold on
grid on
plot (b(:, 1)+0.5, b(:, 2)+0.2, 'sg');
## Step 2
axis equal
## Step 3
axis tight

Matlab (r2020b):

• After step 1, we have a plot with unequal tick lengths but with "rounded" axes limits
• After step 2, the tick lengths are equal and X-limits are "tight" but not the Y-limits
• After step 3, also the Y-limits are "tight".

Then, when zooming in, the plotbox shape (aspect ratios) remain fixed. So when a zoom rectangle is selected with a shape wider (or taller) than the plot box, Matlab ensures that the X-axis (or Y-axis) fits the plot box width (or height) and increases the limits of the zoom rectangle Y-size (or X-size) so that it fits the plot box Y-axis (or X-axis).
When zoomed in, "axis tight" restores the original figure with the tight and equal axes.
When zooming out, Matlab refuses to zoom out beyond the original plot box.

Octave-8.0.0 (with patch from comment #13):

• After steps 1 & 2, same as Matlab
• After step 3: only the x-axis is "tight" (looks like a bug).

Then, when zooming in, Octave doesn't retain the original plot box ratios but instead accepts those of the zoom rectangle.
In that state, "axis tight" retains the new plot box size and again only makes the X-axis "tight". The Y-axis limits are expanded beyond the original Y-data. That looks like a bug as well, might be the same as above.
Furthermore, Octave happily zooms out beyond the original axis limits. When zooming out too far, it sometimes isn't able to zoom back in again - maybe due to single precision? (wild guess).

Octave-7.0.0 (from early Dec last year) behaves largely the same, be it that "axis tight" after zooming in retores the original figure just like Matlan does.

Just to be sure I've saved variables a and b in a mat file so one can try with the same data.


(file #52815)

Running the first part of the test for `camlookat` in Matlab R2021a, I see the following:

>> [x, y, z] = peaks ();
   s3 = surf (x, y, z/5);
   hold on
   [x, y, z] = sphere ();
   s2 = surf (x/2, y/2+1.5, z/2+2);
   s1 = mesh (x/2-4, 3*y, z/2 - 1);
   axis equal
   axis tight
>> get(gca, 'XLim')
ans =
   -4.5000    3.0000
>> get(gca, 'YLim')
ans =
    -3     3
>> get(gca, 'ZLim')
ans =
   -1.5000    2.5000

In Octave hg id 4b367bf5eb16, I see:

>> [x, y, z] = peaks ();
   s3 = surf (x, y, z/5);
   hold on
   [x, y, z] = sphere ();
   s2 = surf (x/2, y/2+1.5, z/2+2);
   s1 = mesh (x/2-4, 3*y, z/2 - 1);
   axis equal
   axis tight
>> get(gca, 'XLim')
ans =
  -4.5000   3.0000
>> get(gca, 'YLim')
ans =
  -3.7500   3.7500
>> get(gca, 'ZLim')
ans =
  -3.2500   4.2500

The axes limits (in y- and z-direction) after `axis tight` seem to be much tighter in Matlab than in Octave.

By simple script I did not mean a figure that I don't how you built :-). Anyways, I noticed that your axes have both "plotboxaspectratio" and "dataapsectratio" manual: in theory this fixes the ratio "diff (xlim)/ diff (ylim)" and you thus cannot expect tight limits in both directions unless your data have the exact correct extent. Am I wrong?

Can you reproduce your observations on the following simpler script? If so can you describe what Matlab does differently? How is the pbaspect affected by zooming for example?

figure ();

## An axes with both daspect and pbaspect fixed
axes ("dataaspectratio", [1 1 1], "plotboxaspectratio", [2 1 1])
hold on; box on;
plot (1:10);

For the example I showed that is a bit hard; several mapping package scripts are involved. (Those scripts merely plot some lines + markers + a grid, but the build-up is complicated).

I'll see if I can cook up a simple example. If that doesn't portray the issues, I can try to make up some .mat file + simple script to do that; hopefully by tomorrow evening I have time for that.

With the patch from comment #13, I see a few problems with XY (2D) plots. It may be that these already relate to the patch from comment #7 but I didn't note them till now, I'll check that later today (need to reinstall that Octave build).

• "axis tight" only seems to works for the Y-axis, the X-axis is too wide;
• (Maybe same issue as above?) when zooming in and then clicking the "Automatic limits ..." button, again just the Y-axis is "tight" but otherwise it looks like the shape of the zoomed-in part of the plot is retained. IOW if I zoom in to a rectangular very wide map shape, after the "Automatic limits ..." button click the Y-axis is "tight" but the X-axis is much too wide. Same for a very "high/narrow" zoom-in plot.
• When zooming out, the "Automatic limits for current axes" button doesn't work anymore, i.e., it won't zoom in back to fill the picture;

I've attached a pic (actually a composite map of boreholes and monitoring wells plotted over each other using "hold on") where in the left side the result of "axis tight" is shown and on the right what you get after zooming out (when "Automatic limits ..." doesn't zoom in anymore). In that latter pic you can see the boreholes that should make up the desired outer X,Y limits after "axis tight".

I don't know if it relevant: there is a ginput() call "hanging" on that map, but in earlier Octave builds this had no influence whatsoever on the zoom buttons and plot layouts. Clicking a zoom button simply "suspends" ginput (also in Matlab).

@arb: I fixed the typo in the doc here:

http://hg.savannah.gnu.org/hgweb/octave/rev/bf28cc6f2f46

Don't bother with comment #12. I ran the code in ML online and got approximately the same results in Octave with the attached patch.

@Rik: "hg blame" told me that you you were the one who had made the latest improvements to the "equal" option [1]. In the attached patch, I changed a bit the logic for "axis equal". In particular, I tried to follow ML doc and let the axes take as much space as possible rather than fixing the pbaspect to [1 1 1]. Is that OK?

I checked that none of the numerous bugs your change had fixed had reappeared, except the first one, bug #55619, which has already reappeared in Octave 6.4 for me.

[1] https://hg.savannah.gnu.org/hgweb/octave/rev/a7dfb00d5bf5

(file #52708)

@Panxto:
My apologies, I completely forgot about the follow-up actions for this bug report.
And thanks very much for fixing this; I tried at work (where I hit this the most with all kinds of maps and cross-sections) and it works perfectly now.

I guess this diff should be applied:

diff -r cedb4046b4fb doc/interpreter/genpropdoc.m
--- a/doc/interpreter/genpropdoc.m      Sat Jan 22 10:47:45 2022 +0100
+++ b/doc/interpreter/genpropdoc.m      Sat Jan 22 10:48:31 2022 +0100
@@ -984,7 +984,7 @@
 for the y-axis.  __modemsg__.  @xref{XREFylim, , @w{ylim function}}.";
         s.valid = valid_2elvec;

-      case "xlimitmethod"
+      case "ylimitmethod"
         s.doc = "Method used to determine the y axis limits when the \
 @code{xlimmode} property is @qcode{\"auto\"}.  The default value, \
 @qcode{\"tickaligned\"} makes limits align with the closest ticks.  With \
@@ -1031,7 +1031,7 @@
 for the z-axis.  __modemsg__.  @xref{XREFzlim, , @w{zlim function}}.";
         s.valid = valid_2elvec;

-      case "xlimitmethod"
+      case "zlimitmethod"
         s.doc = "Method used to determine the z axis limits when the \
 @code{xlimmode} property is @qcode{\"auto\"}.  The default value, \
 @qcode{\"tickaligned\"} makes limits align with the closest ticks.  With \

I went ahead and pushed the patch from comment #5 to default:

http://hg.savannah.gnu.org/hgweb/octave/rev/4c0c02102ba9

I attached an updated version of the patch. I think the documentation would benefit from being reread by a better english speaker, but apart from that the new feature works well AFAICS.

(file #52389)

I think this has already been partly discussed in the past, but I can't find the bug report.

For anything other than "axis auto", Octave sets custom "x(y,z)lim" and consequently "x(y,z)limmode" becomes manual. In other words auto limits cannot be tight.

According to Matlab's documentation for axis [1], e.g. the "tight" option should leave "x(y,z)limmode" unchanged and instead change the "x(y,z)limitmethod" property to "tight".

We thus need to add and implement "x(y,z)limitmethod" properties [2] and let the axes graphics object compute limits accordingly.

Changing release to "dev" since this looks like an important change.

[1] https://nl.mathworks.com/help/matlab/ref/axis.html#buk989s-1-style
[2] https://nl.mathworks.com/help/matlab/ref/matlab.graphics.axis.axes-properties.html#budumk7_sep_mw_7623f06d-1795-480f-b113-e08ce76e79d5

Was an "axis tight" command missing from your "Steps to reproduce"?

If I'm reading scripts/plot/util/private/__add_default_menu__.m correctly, the "automatic limits" button just executes

axis (H, "auto")

for all axes in the current figure that aren't legends.  What can it do differently to respect the "axis tight" setting?

Should

axis (H, "auto")

by itself just not reset the "tight" setting?  Are there other properties that should also be "sticky"?