Zooming into an image by clicking on it

Hello,

I'm in progress of making an algorithm that allows me to load a group of pictures and lets me save the X,Y position for where ever it is that i click on each file (in my case the most distal part of a fly's leg) onto an xls file. I have most of the code done, however i would also like to add a zoom on click function to it, as at times it's hard to see the ends of the legs. Here is what i have:

 function Leg_Selection_Multiple_Images()

    %Creates the file that the data will be saved to.

    helpmsg1 = 'Save File As';
    [xlsname1,xlspath] = uiputfilehelp('*.xls', 'Save File As', 'helpmsg',helpmsg1);
    pathtoxlsfile = [xlspath, xlsname1]; 

    %Loads folder where images are stored.
    helpmsg1 = 'Choose Picture to Analyse';

    [imgname1,imgpath] = uigetfilehelp('*.*','Choose Picture to Analyse','helpmsg',helpmsg1);

    if isnumeric(imgname1) && imgname1 == 0,
        return;
    end

    myFolder = imgpath;
    filePattern = fullfile(myFolder, '*.tif');
    tiffFiles = dir(filePattern);

    for k = 1:length(tiffFiles)

        baseFileName = tiffFiles(k).name;
        fullFileName = fullfile(myFolder, baseFileName);
        fprintf(1, 'Now reading %s\n', fullFileName);
        imageArray = imread(fullFileName);
        imshow(imageArray);  % Display image.
        drawnow; % Force display to update immediately.

        set(gcf,'Units','normalized','Position',[0 0 1 1])%zooms in
        set(gca,'Units','normalized','Position',[0  0 1 1]);%Zooms in
        fprintf([ 'Select the plot origin with the left mouse button ...\n' ])
        [XLegs,YLegs] = ginput(6); %X,Y position for the legs.
    end
end

I would like to zoom in without using a GUI, as i don't know how to program those yet, and i know that it should go before line 37 ( [XLegs,YLegs] = ginput(6); ) however, i'm not sure how to make it so that i could zoom in to the spot by clicking where the fly is and then going onto the ginput to select the ends of each leg.

PS i trimmed out the remaining of the code that does the arithmetic work i need done, as well as the saving to the xls file as i already knew how to do that, and it wasn't necesary for what i do need.

Thanks in advance.

[Image Analyst]

How would it know if your were clicking to zoom, or clicking to indicate the leg's x,y location? You could do what I do: have a slider control on the Gui for zooming. Search the newsgroup for zoomLevel or zoomFactor or something like that - I've posted code there before.

Answer 1

[Jan]

By which amount do you want to zoom in? What about dragging a rectangle (e.g. rbbox or dragrect) to define the visible part of the image? Have you read the help text of the function "zoom"?

Answer 2

[Guillermo]

Actually, zoom on by itself was what i originally was interested in, as i could zoom in/out of the area I chose, however, I wasn't able to get it to work because it would go on to the next section (ginput) without allowing me to zoom in. I figured out that i just needed to place a pause after zoom on to let me zoom in the picture to the size i want. Thanks for helping Jan.