getrect - cancel user input

Hi, Is it possible to cancel the getrect when the user presses (for example) escape button on the keyboard? I wrote a GUI which uses the getrect to select a rect in the image. In the case the user presses esc (when the matlab waits for rect selection, i.e. while in getrect), I want to keep the previously selected area, and return from the calculation with the new rect.

Code example:

----------------

P = getrect(handles.im1);
if (<user pressed esc event> )
     return;

----------------

Is it possible to identify such event?

Thanks Hilit

[Uday]

I was facing similar issue and struggled to find a solution for couple of days. Finally the following seems to work.

Replace

rect=getrect()

with

h=imrect();
rect=getPosition(h);
delete(h);

Key events will work fine now.

Answer 1

[Image Analyst]

You can use imrect() instead of getrect():

imshow('moon.tif') % Sample image.
uiwait(helpdlg('Click and drag out a rectangle.'));
title('Double-click inside rectangle to accept it, or type Esc to bail out');
someAxesHandle = gca;
% Have user draw rectangle.
hRect = imrect(someAxesHandle)
position = wait(hRect)
% Check if they typed Esc or double clicked.
if isempty(position)
  uiwait(helpdlg('You typed Esc.'));
else
  uiwait(helpdlg('You drew a rectangle!'));
end
fprintf('Done!\n');

Answer 2

[uido]

This question is old, but still getting hits, so I'll try to answer it:

What blocks the ui is the following line inside the getrect function (line 106 in current 06-05-2016 code):

waitfor(GETRECT_H1, 'UserData', 'Completed');

in order to free this lock you need to do (line 251):

set(GETRECT_H1, 'UserData', 'Completed');

I had to do a toggle button with repeated getrect calls as long as it is pressed. I did something like:

function callback(do)
% i'm calling this with callback(get(toggle1,'Value))

    global getrect_do
    getrect_do = do;
    while getrect_do
        % rubberand selection.
        try
        % using try to catch user clicking something else, and then repeating getrect call
            r = getrect(someAxesHandle);
        catch
            continue
        end
        if getrect_do
            % user did mark a rectangle!
            someProcess([r(1),r(1)+r(3)]);

        else
            % user abort. while loop will terminate
        end
    end

    % force getrect to end
    global GETRECT_H1
    getrect_do = false;
    set(GETRECT_H1, 'UserData', 'Completed');

Callbacks still execute even during waitfor().

Ido