How to create fixed rectangle and crop it?

I want a fixed 257x257 rectangle and want to crop according to the rectangle of my image.What is the code would be?

[KSSV]

Read about imcrop.

Answer 1

[yanqi liu]

img = imread('https://www.mathworks.com/matlabcentral/answers/uploaded_files/927339/image.jpeg');
figure; imshow(img, []);
h = imrect(gca, [1 1 257 257]);
title('please move the rect');
% now you can set the rect
pos = wait(h);
hold on; rectangle('position', pos, 'EdgeColor', 'g', 'LineWidth', 2)
img2 = imcrop(img, round(pos));
figure; imshow(img2, []);

[DGM]

You can just do imcrop(img) directly for interactive cropping. If you want to preserve the rect parameter for later, you can do

[croppedimg croprect] = imcrop(img);