Try this:
ti = magic(32);
subplot(2, 1, 1);
imshow(ti, [], 'InitialMagnification', 1000)
g = gcf;
g.WindowState = 'maximized';
buttonText = 'OK';
while strcmpi(buttonText, 'OK')
subplot(2, 1, 1);
promptMessage = sprintf('Click a point');
titleBarCaption = 'Continue?';
buttonText = questdlg(promptMessage, titleBarCaption, 'OK', 'Quit', 'OK');
if contains(buttonText, 'Quit', 'IgnoreCase', true)
return; % or break or continue.
end
[x, y] = ginput(1);
column = round(x);
thisColumn = ti(:, column);
subplot(2, 1, 2);
plot(thisColumn, 'b-', 'LineWidth', 2);
grid on;
caption = sprintf('Column %d', column);
title(caption, 'FontSize', 16)
xlabel('Row', 'FontSize', 16)
ylabel('Value', 'FontSize', 16)
end
