Crop Code Loop End with a key Press

clc;
clearvars;
close all;
imtool close all; % Close all imtool figures.
workspace;
format longg;
format compact;
fontSize = 20;
tic;

% Have user browse for a file, from a specified "starting folder."
% For convenience in browsing, set a starting folder from which to browse.
startingFolder = 'C:\';
if ~exist(startingFolder, 'dir')
	% If that folder doesn't exist, just start in the current folder.
	startingFolder = pwd;
end
% Get the name of the file that the user wants to use.
defaultFileName = fullfile(startingFolder, '*.jpg');
[baseFileName, folder] = uigetfile(defaultFileName, 'Select a file');
if baseFileName == 0
	% User clicked the Cancel button.
	return;
end

fullFileName = fullfile(folder, baseFileName)
original = imread(fullFileName);
grayImage = original;

% Get the dimensions of the image. %LOOP STARTS%
% numberOfColorBands should be = 1.
[rows columns numberOfColorBands] = size(grayImage);
% Display the original gray scale image.
imshow(grayImage);
axis on;
title('Original Grayscale Image', 'FontSize', fontSize);

% Enlarge figure to full screen.
set(gcf, 'units','normalized','outerposition',[0 0 1 1]);

% Give a name to the title bar.
set(gcf,'name','Create an Object','numbertitle','off')

% Ask user to draw a box.
promptMessage = sprintf('Drag out a box on the region that you want to copy,\nor Cancel to abort processing?');
titleBarCaption = 'Continue?';
button = questdlg(promptMessage, titleBarCaption, 'Continue', 'Cancel', 'Continue');
if strcmpi(button, 'Cancel')
return;
end
k = waitforbuttonpress;
point1 = get(gca,'CurrentPoint'); 
finalRect = rbbox; % return figure units
point2 = get(gca,'CurrentPoint'); % button up detected
point1 = point1(1,1:2); % extract x and y
point2 = point2(1,1:2);
p1 = min(point1,point2); % calculate locations
offset = abs(point1-point2); % and dimensions

% Find the coordinates of the box.
xCoords = [p1(1) p1(1)+offset(1) p1(1)+offset(1) p1(1) p1(1)];
yCoords = [p1(2) p1(2) p1(2)+offset(2) p1(2)+offset(2) p1(2)];
x1 = round(xCoords(1));
x2 = round(xCoords(2));
y1 = round(yCoords(5));
y2 = round(yCoords(3));
hold on
axis manual
plot(xCoords, yCoords, 'b-'); % redraw in dataspace units

% Display the cropped image.
croppedImage = grayImage(y1:y2,x1:x2);
imshow(croppedImage);
axis on;
title('Region that you defined', 'FontSize', fontSize);

while(1)
% Paste it onto the original image
[rows2 columns2] = size(croppedImage)
promptMessage = sprintf('Click on the upper left point where you want to paste it,\nor Cancel to abort processing?');
titleBarCaption = 'Continue?';
button = questdlg(promptMessage, titleBarCaption, 'Continue', 'Cancel', 'Continue');
if strcmpi(button, 'Cancel')
return;
end
[x, y] = ginput(1)

% Determine the pasting boundaries.
r1 = int32(y);
c1 = int32(x);
r2 = r1 + rows2 - 1;
r2 = min([r2 rows]);
c2 = c1 + columns2 - 1;
c2 = min([c2, columns]);
plot([c1 c2 c2 c1 c1], [r1 r1 r2 r2 r1], 'r-');

% Paste as much of croppedImage as will fit into the original image.
grayImage(r1:r2, c1:c2) = croppedImage(1:(r2-r1+1), 1:(c2-c1+1));
imshow(grayImage);
axis on;
title('Cropped and duplicated object', 'FontSize', fontSize); %LOOP ENDS%
end

Hello,

I would like to impliment above code on my study but I need to end while loop in control. This means I need to start and stop it with a keyboard press or similar approach.

Any comment on this issue would be appreciated.

Answer 1

[Geoff Hayes]

Murat - you could use the WindowKeyPressFcn callback for your figure to exit the loop if a certain key is pressed. For example, in the below code we continue to update the plot until the 'q' character is pressed

function KeyPressTest
    hFig = figure;
    hPlot = plot(NaN,NaN);
    k = 1;
    xData = [];
    yData = [];
    set(hFig, 'WindowKeyPressFcn', @OnKeyPressEvent);
    keepGoing = true;
    while keepGoing
        xData = [xData ; k];
        yData = [yData ; k];
        set(hPlot, 'XData', xData, 'YData', yData);
        k = k + 1;
        drawnow;
    end
    
    function OnKeyPressEvent(source, data)
        if strcmp(data.Key, 'q')
            keepGoing = false;
        end
    end
end