Is it possible to orient the legend's symbols vertically instead of horizontally?

Is it possible to orient the legend's symbols vertically instead of horizontally?

In the following example, the red and blue lines in the legend are horizontally oriented, but I would like them to be vertically oriented within the legend:

x = linspace(0, 10, 100);
y1 = sin(x);
y2 = cos(x);
plot(x, y1, 'red', x, y2, 'blue');
hold on;
h1 = plot(nan, nan, 'red', 'LineWidth', 2); 
h2 = plot(nan, nan, 'blue', 'LineWidth', 2); 
legend([h1, h2], 'sin(x)', 'cos(x)');

Answer 1

[DGM]

It can be done by manipulating undocumented properties, but there's a good chance it might cause problems, particularly when trying to save the figure. It's up to you to accept the risk of extra complications. That said, I was able to save the figure without it breaking (at least in R2019b).

% the example code
x = linspace(0, 10, 100);
y1 = sin(x);
y2 = cos(x);
plot(x, y1, 'red', x, y2, 'blue');
grid on
hold on;
h1 = plot(nan, nan, 'red', 'LineWidth', 2); 
h2 = plot(nan, nan, 'blue', 'LineWidth', 2); 

% choose the legend orientation as needed
hl = legend([h1, h2], 'sin(x)', 'cos(x)', 'Orientation', 'vertical');

% rotate the legend icon lines so that they're vertical
drawnow % make sure everything is up to date
nlegicons = numel(hl.EntryContainer.Children);
for k = 1:nlegicons
    % this vertex data is of the form [x0 x1; y0 y1; z0 z1],
    % and are in normalized coordinates with respect to the little icon box area.
    hl.EntryContainer.Children(k).Icon.Transform.Children.Children.VertexData = single([0.5 0.5; 0 1; 0 0]);
end

% resize the icon column 
% like Les pointed out, this is canonically accessible in newer versions, 
% but i'm doing it this way since i'm using R2019b
oldtokensize = hl.ItemTokenSize;
hl.ItemTokenSize = oldtokensize.*[0.3; 1]; % reduce the width

●

Given that the tokensize is typically much wider than tall, this may become problematic when trying to also represent a line+marker style, especially with a heavy lineweight. I'm sure the vertical size of the legend entries could be adjusted, but it would be an extra complication. It's not directly adjustable via the tokensize parameter at least. It likely requires manipulation of the parent box and the positions of the contained objects, but I haven't dug that far yet.

[Thomas Pursche]

I can not recommend using this old undocumented features any more.

I also used undocumented features for an "old" figure application and now with ML2025a it crashes. When you just want to use it with an older version it should run until 24b but upgrading is then maybe caising heavy problems.

[Sim]

Thanks @DGM for your solution!

Thanks @Thomas Pursche for your comment, I will bear in mind it when I will change version :-)

[DGM]

@Benjamin Kraus's answer may work if you're using a newer version than I am.

Answer 2

[Thomas Pursche]

Hi,

yes it is possible. Just change

legend([h1, h2], 'sin(x)', 'cos(x)');

to

legend([h1, h2], 'sin(x)', 'cos(x)','Orientation','vertical');

by adding the property 'Location', you also can edit the position of the legend. For example: 'Location','southwest'

Best regards,

Thomas

[Les Beckham]

The 'Orientation' option for a legend doesn't set the orientation of the symbols in the legend, it sets the arrangement of the legend entries. The default is 'vertical', so the suggestion in this answer won't affect the appearance of the legend at all. See below for an example showing the effect of 'horizontal' orientation.

I know of no way to achieve what OP is looking for. Since 2024a, it is possible to control the size (width) of the symbols using the IconColumnWidth property. The example below also illustrates this, making the lines shorter.

x = linspace(0, 10, 100);
y1 = sin(x);
y2 = cos(x);
plot(x, y1, 'red', x, y2, 'blue');
grid on
hold on;
h1 = plot(nan, nan, 'red', 'LineWidth', 2); 
h2 = plot(nan, nan, 'blue', 'LineWidth', 2); 
legend([h1, h2], 'sin(x)', 'cos(x)', 'Orientation', 'horizontal', 'IconColumnWidth', 10);

●

[Sim]

Thanks @Les Beckham :-)

[Les Beckham]

Of course!

Answer 3

[Benjamin Kraus]

Does this work for you? This uses only fully documented features.

x = linspace(0, 10, 100);
y1 = sin(x);
y2 = cos(x);
plot(x, y1, 'red', x, y2, 'blue');
hold on;
h1 = plot(nan, nan, 'red', 'LineWidth', 2, 'Marker', '|', 'LineStyle','none'); 
h2 = plot(nan, nan, 'blue', 'LineWidth', 2, 'Marker', '|', 'LineStyle','none');
legend([h1, h2], 'sin(x)', 'cos(x)');

●

[DGM]

Well that was an unforeseen workaround. It's not a valid marker style in R2019b, but I think it was introduced in R2020b?

[Benjamin Kraus]

That's correct. The vertical bar and horizontal bar markers were added in R2020b.