Customize get points function over an image function

Dear all,

I ned to create a GUI wich shows an image and the user must be able to perform the following:

1 - Select several points using the mouse;

2 - When the user is done, hit "RETURN"*;

3 - After hiting "RETURN", IF the user wants to edit the one of the points, he/she must click over the desired point and drag it to where he/she wants.

I created this function:

function [x, y] = test(img)

[lin, col] = size(img);
fig = figure('WindowButtonDownFcn', {@func, lin, col}, 'KeyPressFcn', @keyfunc);
imshow(img, []);
% axs = axes('position', [1 col 1 lin]);
set(gca, 'Ydir', 'reverse');
x = [];
y = [];
uiwait(fig);

      function func(src, callback, lin, col)
          seltype = get(fig, 'SelectionType');
          set(gca, 'Ydir', 'reverse');
          if strcmp(seltype, 'normal')
              set(fig, 'Pointer', 'circle');
              cp = get(fig, 'CurrentPoint');
              xinit = cp(1, 1);
              yinit = cp(1, 2);
              x = [x, xinit];
              y = [y, yinit];
              hl = line('XData', xinit, 'YData', yinit, 'color', 'b', 'Marker', '.');
              set(fig, 'WindowButtonMotionFcn', {@moveMouse, lin, col});
              set(fig, 'WindowButtonUpFcn', @mouseRelease);
          end

          function moveMouse(src, callback, lin, col)
              cp = get(fig, 'CurrentPoint');
              xdata = [xinit, cp(1, 1)];
              ydata = [yinit, cp(1, 2)];
              set(hl, 'XData', xdata);
              set(hl, 'YData', ydata);
              drawnow;
          end

          function mouseRelease(src, callback)
              last_selection = get(fig, 'SelectionType');
              if strcmp(last_selection, 'alt')
                  set(fig, 'Pointer', 'arrow');
                  set(fig, 'WindowButtonMotionFcn','');
                  set(fig, 'WindowButtonUpFcn','');
              else
                  return;
              end
          end        
      end

      function keyfunc(src, callback)
          keypressed = get(fig, 'CurrentCharacter');
          if keypressed == 13
              uiresume(fig);
          end
      end

end

Q1 - It can plot the image but the coordinate system has its zero at the top-left edge of the figure. How can I move it to the left-top of the image?

Q2 - How can I implement the item number 3 (IF the user wants to edit the one of the points, he/she must click over the desired point and drag it to where he/she wants)?

Thank you all in advance,

Answer 1

[Geoff Hayes]

Gabriel - see the answer to your question http://www.mathworks.com/matlabcentral/answers/286840-how-can-i-edit-the-coordinate-of-a-point-ploted-on-an-image which should contain enough information for you to register mouse events against the axes as opposed to the figure, and how to drag and drop a pixel from one location to another.