show.m

Using the idea from Seam Carving for Content-Aware Image Resizing, the codes enables a selected im

function show(I,M)
%show - show content aware image resizing
%
% show(I,M) opens a figure window to allow interactive resizing of I
% in one direction based on the seam removal map M.

%% determine whether seams are horizontal or vertical

[h,w] = size(M);
horiz = all(sum(M,1)==sum(1:h));
vert = all(sum(M,2)==sum(1:w));
%if ~xor(horiz,vert), error('seams not horizontal or vertical?!'); end

%% set up figure

fh = figure;
set(fh,'DoubleBuffer','on');
set(fh,'WindowButtonDownFcn',@mouseDown);
set(fh,'WindowButtonMotionFcn',@mouseMove);
set(fh,'WindowButtonUpFcn',@mouseUp);
set(fh,'WindowScrollWheelFcn',@mouseWheel);
% set(fh,'Interruptible','off');
% set(fh,'BusyAction','queue');

% ensure figure is large enough for 200% resizing
if horiz,
    ih = imshow(cat(1,I,I));
    title('horizontal seams');
else
    ih = imshow(cat(2,I,I));
    title('vertical seams');
end

% show the initial image
set(ih,'CData',I);

%% resizing

n = 0; % how many seams we are removing total

% pre-transpose data if we have vertial seams
if vert,
    I = permute(I,[2,1,3]);
    M = M';
end

    function move(dn)
        % remove (or add) an additional dn seams
        n = n + dn;
        J = retarget(I,M,n);
        if vert, J = permute(J,[2,1,3]); end
        set(ih,'CData',J);
        drawnow;
    end

%% mouse callbacks

p0 = []; % location of mouse down event
drag = false; % is the mouse being dragged?
resizing = false; % are we resizing the image?

    function mouseDown(src,evt)
        p0 = get(fh,'CurrentPoint');
        drag = true;
    end

    function mouseMove(src,evt)
        if ~drag, return; end
        if resizing, return; end % serialize execution of this function
        resizing = true;
        p = get(fh,'CurrentPoint');
        if horiz,
            move( p(2) - p0(2) );
        else
            move( p0(1) - p(1) );
        end
        p0 = p;
        resizing = false;
    end

    function mouseWheel(src,evt)
        move( -evt.VerticalScrollCount * evt.VerticalScrollAmount );
    end

    function mouseUp(src,evt)
        drag = false;
    end

end