Redrawing on a UIpanel

Hi.

I am wanting to rescale a montaged image I have created on a uipanel. i.e change the grayscale scaling (globally) and redraw it. My typical montage is created by reading in image files, resizeing and drawing on a uipanel using subplot and position vector format, using two for loops for x & y.

The montage is created by the 1st image being at the top left (labelled 1 in the montage) and the last being last being the bottom right (labelled 260), both highlighted in yellow here.

Within this loop, I assign each image i read from file (resized to thumbnail size) to a cell array:

   allImgs{x1,y1} = IM1 ;

Outside the loops I then do:

     montageImg = cell2mat(allImgs);
     setappdata(0,'mtg',montageImg); % set global for later use

Inside a seperate button callback (for rescaling) I recall the saved montaged image.

montageImg=getappdata(0,'mtg');

Then rescale using values from edit boxes:

   mlo=str2num(get(handles.editMLow,'String'));
   mhi=str2num(get(handles.editMHi,'String'));
   if mlo>mhi
       mlo=0;
   end

Delete whats currently displayed on the uipanel

   delete(get(handles.uipanelM,'Children'))
   drawnow
   guidata(hObject, handles);

Now for the redrawing (this is where my problem is)

I get the handle of the uipanel

   hp = handles.uipanelM;

and I want to use the following to rescale and redraw on the now blank uipanel.

 *positionVector = [x, y, width, height]*
 h=subplot('Position',positionVector,'Parent',hp); %to enable deleting use handles
 imshow(montageImg,[mlo mhi]);
 colormap(jet);

It appears when I try and calculate the new position vector of this "composite image" its not placing the image exactly int he same location and size as the original one.

For the x & y values, I use the x from the 1st thumbnail and the y from the last thumbnail (as these positions are always from the bottom left). So if First is the position vector of the thumnail 1 and last is the thumbnail shown here as 260

new position vector = [First(1), Last(2), width, height]

the width I take as the difference in the x's plus 1 thumnail width, so

 width = Last(1)-First(1)+thumbnailwidth

and the height similary as:

height = First(1)-First(2)+thumnailheight

But its not mimicing the original shape when I redraw.

I can't see my obvious mistake Jason

[Jason]

Also, how can I retain the numbers that I text to each thumbnail? thanks

[Geoff Hayes]

What are the width and height? The width calculation seems fine, but that for height is fishy

 height = First(1)-First(2)+thumnailheight

Don't you mean instead

 height = First(2) - Last(2) + thumbnailheight

[Jason]

Hi, yes I do have the height as you have it, just a typo on this page. the width and height of the original thumnails are specified just before the montage is being created, and are fixed values.

[Geoff Hayes]

Do the height and width values make sense? When the montage is drawn using these parameters, where does it fall short - in the height or width, or does it's upper left corner not start where the first subplot started?

[Jason]

Hi, its seems to be in the width dimension, width and starting place. Please see attached. Im wonder if its trying to maintain the original aspect ratio of the raw images?