Move Line on an Image with Up and Down Arrow

Question

Enea Baumann 2018-4-18

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/395845-move-line-on-an-image-with-up-and-down-arrow

评论： Jan 2018-4-21

Hi Everyone

I have a series of pictures which i want to process with Matlab. I should be able to open the first image, then move a line up and downwards with the up and down arrow and finally change to next picture with return.

I was able to define a callback function which registers the keyboard actions.

If I press the uparrow it adds 1 to a variable s.

If I press the downarrow it subtracts 1 from a variable s.

If I press return it adds 1 to a variable k.

    function y = KeyPressCb(~,evnt)
        fprintf('%s\n',evnt.Key);
        global s
        global k
        if strcmp(evnt.Key,'uparrow')==1
        s=s+1;
        elseif strcmp(evnt.Key, 'downarrow')==1
        s=s-1;
        elseif strcmp(evnt.Key, 'return')==1
        k = k + 1;
        end
    end

Now I want to return this values to the main program, so that i can use this two variables (k and s) to change the line coordinates and the image array counter. How do i do that?

Is there an other, easier way to do it?

Greetings

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Walter Roberson 2018-4-21

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Jan 2018-4-21

@Wunman Usam: Please do not remove the contents of your question after an answer has been given. This is considered to be impolite, because the nature of this forum is to share solutions in public. If you delete the question afterwards, the time spent for posting an answer is lost for the community.

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Answer 1

Walter Roberson 2018-4-18

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/395845-move-line-on-an-image-with-up-and-down-arrow#answer_315880

http://matlab.wikia.com/wiki/FAQ#How_can_I_share_data_between_callback_functions_in_my_GUI.28s.29.3F

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Walter Roberson 2018-4-19

在 MATLAB Online 中打开

 function driver
    y = 0;     %shared variable
    ax = gca;
    fig = ancestor(ax, 'figure');
    plot( ax, randn(1,50) * 10 );
    XL = get(ax, 'XLim');
    hold(ax, 'on')
    h = plot(ax, XL, [y y]);
    hold(ax, 'off');
    set(fig, 'WindowKeyPressFcn', @KeyPressCb);
    function KeyPressCb(~,evnt)
        if strcmp(evnt.Key,'uparrow')
          fprintf('up!\n');
          y = y + 1;
          set(h, 'YData', [y y]);
        elseif strcmp(evnt.Key, 'downarrow')
          fprintf('down!\n');
          y = y - 1;
          set(h, 'YData', [y y]);
        end
    end
  end