MATLAB: Animate a rectangle, for loop used

for loopgetframemovie

Hello! The code below takes a large matrix (x) and shows 'o' moving up and down on a plot. I would like to change the 'o' into a rectangle moving in the same way, hanging by a string. How would I do this?

for i = 1:125

plot(x(i),'o')

axis([0 5 -5 5])

y(i) = getframe

end

movie(y,25,25)

Best Answer

Use the rectangle() function. Get it's handle so you can delete the old one when you want to place a new one.

Related Solutions

MATLAB: How to write this expression in matlab

Just assign a(1) and put that expression in a for loop from 2 to whatever.

clc;    % Clear the command window.
close all;  % Close all figures (except those of imtool.)
imtool close all;  % Close all imtool figures if you have the Image Processing Toolbox.
clear;  % Erase all existing variables. Or clearvars if you want.
workspace;  % Make sure the workspace panel is showing.
format long g;
format compact;
fontSize = 40;
a(1) = 1;
k = 3; % Whatever.
for n = 2 : 30
  a(n) = sqrt(a(n-1))*(n+1)^(1/(2*k));
end
plot(1:length(a), a, 'b*-', 'LineWidth', 2, 'MarkerSize', 15);
xlabel('n', 'FontSize', fontSize);
ylabel('a', 'FontSize', fontSize);
ylim([0,4]);
grid on;
% Enlarge figure to full screen.
set(gcf, 'Units', 'Normalized', 'OuterPosition', [0 0 1 1]);
% Give a name to the title bar.
set(gcf, 'Name', 'Demo by ImageAnalyst', 'NumberTitle', 'Off')

MATLAB: Peak Width at Half Height

See this demo:

% Initialization steps.
clc;    % Clear the command window.
close all;  % Close all figures (except those of imtool.)
clear;  % Erase all existing variables. Or clearvars if you want.
workspace;  % Make sure the workspace panel is showing.
format long g;
format compact;
fontSize = 24;
% Make Gaussian https://en.wikipedia.org/wiki/Gaussian_function
x = linspace(0, 100, 1024);
amp = 50;
mu = 35;
sigma = 20;
y = amp * exp(-(x - mu).^2 / (2 * sigma^2));
hFig = figure;
plot(x, y, 'b-', 'LineWidth', 2);
grid on;
xlabel('x', 'FontSize', fontSize);
ylabel('y', 'FontSize', fontSize);
hFig.WindowState = 'maximized';
% Find the half height - midway between min and max y values.
halfHeight = (min(y) + max(y)) / 2;
hold on;
yline(halfHeight, 'Color', 'g', 'LineWidth', 2);
% Find left edge
index1 = find(y >= halfHeight, 1, 'first');
x1 = x(index1)
line([x1, x1], [0, y(index1)], 'Color', 'r', 'LineWidth', 2);
text(x1+1, 5, sprintf('x1 = %.2f', x1), 'FontSize', fontSize, 'Color', 'r');
% Find right edge
index2 = find(y >= halfHeight, 1, 'last');
x2 = x(index2)
line([x2, x2], [0, y(index2)], 'Color', 'r', 'LineWidth', 2);
text(x2+1, 5, sprintf('x2 = %.2f', x2), 'FontSize', fontSize, 'Color', 'r');
% Compute the full width, half max.
fwhm = x2 - x1
text(mu, halfHeight+2, sprintf('width = %.2f', fwhm), 'FontSize', fontSize, 'Color', 'r', 'HorizontalAlignment', 'center');
caption = sprintf('Full Width, Half Max = %.2f', x2 - x1);
title(caption,  'FontSize', fontSize);

Adapt code as needed for your variable names.

Best Answer

Related Solutions

MATLAB: How to write this expression in matlab

MATLAB: Peak Width at Half Height

Related Question