imrect in infinite loop

I have a Matlab UI where I want the user to input several areas using imrect as soon as a radiobutton is selected. It is unknown how many areas will be selected so the selection needs to be in an infinite loop.

As soon as another radiobutton is selected, the imrect input should stop, which I cannot get to work.

Here is a minimal working example:

function mwe
ax = axes('Position', [0 0 1 1]);
bg = uibuttongroup('Position',[0 0 .15 1], 'SelectionChangedFcn',{@bselection, ax});
r1 = uicontrol(bg, 'Style','radiobutton', 'String','Option 1', 'Position',[10 250 100 30]);
r2 = uicontrol(bg, 'Style','radiobutton', 'String','Option 2', 'Position',[10 225 100 30], 'Value',1);

function bselection(source, event, ax)
  switch event.NewValue.String
    case 'Option 1'
      while true
        h = imrect(ax);
        % do stuff
        delete(h);
      end
    case 'Option 2'
      % do not show imrect and do other stuff
  end

I appreciate any help.

[Adam]

Can you not just test the state of the radiobutton within your while loop rather than use the callback to deal with 'Option 2'?

Answer 1

[Jan]

switch event.NewValue.String
  case 'Option 1'
    set(ax, 'UserData', 1);
    while get(ax, 'UserData') == 1
      h = imrect(ax);
      % do stuff
      delete(h);
    end
  case 'Option 2'
    set(ax, 'UserData', 0);
end

Do you want to cancel the currently active input of the rectangle? Does the original code contain a pos = wait(h) ?

[jojo9540]

Thank you very much for your help! Your solutions works quite well.

I found a short way to check the radiobutton selection by replacing while true with

while strcmp(source.SelectedObject.String, 'Option 1')

The only problem though is that after changing the radiobutton selection, imrect will still be executed one last time. To solve this I use a workaround by simulating an escape button press when Option 2 is selected, so in case 'Option 2' I have added

robot = java.awt.Robot;
robot.keyPress(java.awt.event.KeyEvent.VK_ESCAPE);
robot.keyRelease(java.awt.event.KeyEvent.VK_ESCAPE);

Full code:

function mwe
ax = axes('Position', [0 0 1 1]);
bg = uibuttongroup('Position',[0 0 .15 1], 'SelectionChangedFcn',{@bselection, ax});
r1 = uicontrol(bg, 'Style','radiobutton', 'String','Option 1', 'Position',[10 250 100 30]);
r2 = uicontrol(bg, 'Style','radiobutton', 'String','Option 2', 'Position',[10 225 100 30], 'Value',1);

function bselection(source, event, ax)
  switch event.NewValue.String
    case 'Option 1'
      while strcmp(source.SelectedObject.String, 'Option 1')
        h = imrect(ax);
        % do stuff
        delete(h);
      end
    case 'Option 2'
      robot = java.awt.Robot;
      robot.keyPress(java.awt.event.KeyEvent.VK_ESCAPE);
      robot.keyRelease(java.awt.event.KeyEvent.VK_ESCAPE);
      % do other stuff
  end