How to assign zero value to plotted lines

Hi,

I have the following codes to plot lines on an image. I want to assign zero value to the lines plotted by the following codes. How can I do this ?

plot([xleft xleft],[ytop ybottom],'b','LineWidth',2); 
plot([xright xright],[ytop ybottom],'b','LineWidth',2);
plot([xleft xright],[ymiddle ymiddle],'r','LineWidth',2); 

plot([xmiddle xright],[ytop ymiddle],'y','LineWidth',2);  
plot([xmiddle xright],[ybottom ymiddle],'y','LineWidth',2); 
plot([floor(xmiddle/2) xright],[ytop ymiddle],'g','LineWidth',2); 
plot([floor(xmiddle/2) xright],[ybottom ymiddle],'g','LineWidth',2);

[Stephen23]

S C. Carl's "Answer" moved here:

I want to make more clear my question ;

I want to assign zero value to pixels that show lines plotted by the above codes How to do this ?

[Stephen23]

Can you explain what you mean by "assign zero value to pixels"? A line is simply some colored pixels, what would they be like if zero was "assigned" to them? How could this be checked or used?

[Jan]

It does not makes sense to assign a number to a pixel or to a line. What do you expect as result of such an "assignment"?

[Geoff Hayes]

@S.C. - are you trying to draw a box (square or rectangle) on an image (perhaps shown with imshow) with its lines coloured black (zero for each of the red, green, and blue pixel along these lines)?

Answer 1

[harjeet singh]

hello dear use this code

clear all
close all
clc

x_left=10;
y_left=10;
x_right=100;
y_right=100;

img(1:200,1:200,1:3)=255;
img=uint8(img);

img(x_left:x_right,y_left,:)=0;
img(x_left:x_right,y_right,:)=0;
img(x_left,y_left:y_right,:)=0;
img(x_right,y_left:y_right,:)=0;

figure(1)
imshow(img)