I am trying to color a box on a plot.

i have a box with text in it that moves along a line on a plot. i need there to be background color in the box under the text. Right now I can only get it to show on top of the text.

Answer 1

[Chunru]

You can change the face color of the box:

square = rectangle('Position', [0, 0, 2.5, 15], 'EdgeColor','b','LineWidth',2,"FaceColor", "g");

You also need to change the order of box and text. MATLAB draw the object layer by layer. If you want to show text on top of box, you have to plot box first.

%% Header
% Written by C. Vogen
% Date Written:3/3/2024
% Modified: None
%% Variable Glossery
% t_start = 0; % seconds
% t_end = 10; % seconds
% x_final = 10; % meters
% y_final = 0; % meters
% g = 9.81 % m/s^2
% m = 150;
% 
%% Code Statements
clear; clc; close all;
t_start = 0; % seconds
t_end = 10; % seconds
x_final = 10; % meters
y_final = 0; % meters
g = 9.81; % m/s^2
v_x0 = x_final/t_end; % finding initial x velocity
v_y0 = (y_final + (g*0.5*(t_end^2)))/t_end; % finding initial y velocity
m = 11;
T = zeros(m,2);
incrv = (t_end - t_start)/(m-1);
startCannon =[0,0]; endCannon = [.175,10]; % starts the cannon
Cannon = [startCannon;endCannon]; 

figure
plot(Cannon(:,1),Cannon(:,2),'LineWidth',5)
xlabel('x [m]');xlim([-1 13])
ylabel('y [m]');ylim([0 150])
hold on
pause(1)
Color_start = [.25 .25 .25];
Color_end = [1 1 0];
Color_incv = (Color_end - Color_start)/(m-1);
square = rectangle('Position', [0, 0, 2.5, 15], 'EdgeColor','b','LineWidth',2,"FaceColor", "g");
flag_text = text(0, 0, '', 'HorizontalAlignment', 'left','VerticalAlignment','bottom', 'FontWeight', 'bold');

for i = 1:m
    t = t_start +(i-1)*incrv;
    x = v_x0 * t;
    y = (v_y0 * t) - ((g * t^2)/2);
    Color = Color_start +(i-1)*Color_incv;
    pause(0.4)
    if i>1
        delete(ball) % removing the previous marker
        delete(line) % removes the line connecting the box to the point
    end
    ball = plot(x,y,'o','MarkerFaceColor','r'); % plotting inside the loop
    set(ball, 'XData',x, 'YData',y)
    set(flag_text, 'Position', [x+0.2, 30], 'String', {['X: ', num2str(x)], ['Y: ', num2str(y)],['I: ', num2str(i)],['T: ',num2str(t)]})
    set(square, 'Position', [x, 25, 2.5, 38]);
    line = plot([x,x],[0,30],'b','LineWidth',2);
    axis normal
    title('Visual Loop')
    xlabel('x [m]');xlim([-1 13])
    ylabel('y [m]');ylim([0 150])
    grid on
    
end

[Charlie]

It worked! Thankyou very much for helping me

Answer 2

[Chunru]

Try the following

figure;
an = annotation("textbox", "Color", "r", "BackgroundColor", "g", "String", "Text Box");
for i=0:0.01:0.9
    an.Position= [i, 0.5, 0.1, 0.1];
    drawnow
end

[Charlie]

Sorry my promp is very vague, but this is the format taht i have my box in and I guess am wondering of it would be possible in this format?

set(square, 'Position', [x, y + 30, 2.5, 38],'FaceColor',Color);

The color is a gradient that I calculate elsewhere in the code

[Chunru]

What is square object? Can you show how it is created?

[Charlie]

I'll just send the whole code

%% Header
% Written by C. Vogen
% Date Written:3/3/2024
% Modified: None
%% Variable Glossery
% t_start = 0; % seconds
% t_end = 10; % seconds
% x_final = 10; % meters
% y_final = 0; % meters
% g = 9.81 % m/s^2
% m = 150;
% 
%% Code Statements
clear; clc; close all;
t_start = 0; % seconds
t_end = 10; % seconds
x_final = 10; % meters
y_final = 0; % meters
g = 9.81; % m/s^2
v_x0 = x_final/t_end; % finding initial x velocity
v_y0 = (y_final + (g*0.5*(t_end^2)))/t_end; % finding initial y velocity
m = 11;
T = zeros(m,2);
incrv = (t_end - t_start)/(m-1);
startCannon =[0,0]; endCannon = [.175,10]; % starts the cannon
Cannon = [startCannon;endCannon]; 
figure
plot(Cannon(:,1),Cannon(:,2),'LineWidth',5)
xlabel('x [m]');xlim([-1 13])
ylabel('y [m]');ylim([0 150])
hold on
pause(1)
flag_text = text(0, 0, '', 'HorizontalAlignment', 'left','VerticalAlignment','bottom', 'FontWeight', 'bold');
Color_start = [.25 .25 .25];
Color_end = [1 1 0];
Color_incv = (Color_end - Color_start)/(m-1);
square = rectangle('Position', [0, 0, 2.5, 15], 'EdgeColor','b','LineWidth',2);
for i = 1:m
    t = t_start +(i-1)*incrv;
    x = v_x0 * t;
    y = (v_y0 * t) - ((g * t^2)/2);
    Color = Color_start +(i-1)*Color_incv;
    pause(0.4)
    if i>1
        delete(ball) % removing the previous marker
        delete(line) % removes the line connecting the box to the point
    end
    ball = plot(x,y,'o','MarkerFaceColor','r'); % plotting inside the loop
    set(ball, 'XData',x, 'YData',y)
    set(flag_text, 'Position', [x+0.2, 30], 'String', {['X: ', num2str(x)], ['Y: ', num2str(y)],['I: ', num2str(i)],['T: ',num2str(t)]})
    set(square, 'Position', [x, 25, 2.5, 38]);
    line = plot([x,x],[0,30],'b','LineWidth',2);
    axis normal
    title('Visual Loop')
    xlabel('x [m]');xlim([-1 13])
    ylabel('y [m]');ylim([0 150])
    grid on
    
end

[Chunru]

See the new answer.