Print curly braces in a plot

Hello everyone,

I am trying draw a curly brace to indicate a distance in a plot (with some accompanying text). The brace should be "stretchable", i.e. vary its length according to a beginning and end point.

This exact same question has been asked in the Newsreader but no answer was obtained.

Any suggestions?

Answer 1

[Patrick Kalita]

There's nothing that ships with MATLAB that does exactly what you want. The 'doublearrow' annotation is probably the thing that comes the closest. It can be used to indicate a distance in a plot, but it's clearly not a brace.

If you're really committed to having a brace, I would just draw some kind of brace-like shape using the line command. The task then becomes generating x-data and y-data that define your brace. This can be as simple or as complicated as you like. Here's one idea:

% Here's the plot I'm annotating
plot(1:10)

% These define the placement and size of the brace
x = 6;
y1 = 0;
y2 = 6;
width = 0.2;

% Make some x-data and y-data
line_x = x  + [0, 0.5, 0.5, 1, 0.5, 0.5, 0]*width;
line_y = y1 + [0, 0.02, 0.48, 0.5, 0.52, 0.98, 1]*(y2-y1);

% Draw the brace and some text, too, for fun.
line(line_x, line_y, 'Color', 'k')
text(x+1.5*width, y1 + 0.5*(y2-y1), 'Whoaaa! Look at this gap!');

You can see that's a relatively primitive brace. If I wanted to make it fancier, I might start looking at using Bézier curves.

Answer 2

[Pål Næverlid Sævik]

I know this is one year old, but I had the same problem. I therefore wrote a function which plots a curly brace on the current figure. The code can be found at http://www.mathworks.com/matlabcentral/fileexchange/38716-curly-brace-annotation, or by searching Matlab File Exchange for "Curly Brace Annotation".

Answer 3

[Sean de Wolski]

I would recommend starting by reading the tutorial in:

doc

MATLAB>User Guide>Graphics>Annotating Graphs>Adding Text Annotations to Graphs

Answer 4

[Joe Lettieri]

Another idea is to use the text command and a LaTeX math mode brace and just rotate it and change the font size...

clear; clc;
x = linspace(0,2*pi,100);
y = sin(x);

figure(1); clf;
plot(x,y) 
grid on;
ylim([-1.25, 1.25]);
text(2.8, 0.75, '$\{$', 'rotation', 210, 'fontsize', 40, ...
    'interpreter', 'latex');
text(2.85, 0.75, 'My favorite part', 'fontsize', 14, ...
    'interpreter', 'latex');

[Jozef Lukac]

Latex commands \overbrace and \underbrace can be used here. They stretch the brace according to the content. The stretch can be set usting \hspace, e.g. \hspace{3cm}.

\overbrace{some base-text}^{upper annotation}

\underbrace{some base-text}_{lower annotation}

text(2.3, 0.9, '$\overbrace{\hspace{3cm}}^{}$',...
    'rotation', -63, 'fontsize', 10, 'interpreter', 'latex');