SUN_source_code_v1/code/LabelMeToolbox/LMimpad.m

function [annotation, img] = LMimpad(annotation, img, PADSIZE, PADVAL)
% [annotation, img] = LMimpad(annotation, img, PADSIZE, PADVAL)
%
% [annotation, img] = LMimpad(annotation, img, [256 256], 0)
% PADSIZE = nrows x ncols (final image size)
% PADVAL = value for the border

[nrows, ncols, cols]=size(img);

if PADSIZE(1)<nrows | PADSIZE(2)<ncols
    error('ERROR: image is larger than target size. Use LMimcrop instead.')
end

Dy = fix((PADSIZE(1)-nrows)/2);
Dx = fix((PADSIZE(2)-ncols)/2);


img = [repmat(PADVAL, [PADSIZE(1) Dx cols]) ...
    [repmat(PADVAL, [Dy ncols cols]); img; repmat(PADVAL, [PADSIZE(1)-nrows-Dy ncols cols])] ...
    repmat(PADVAL, [PADSIZE(1) PADSIZE(2)-ncols-Dx cols])];

% Change the polygon coordinates
if isfield(annotation, 'object')
    Nobjects = length(annotation.object); n=0;
    for i = 1:Nobjects
        Npoints = length(annotation.object(i).polygon.pt);
        for j = 1:Npoints
            x=str2num(annotation.object(i).polygon.pt(j).x);
            y=str2num(annotation.object(i).polygon.pt(j).y);

            x = round(x + Dx);
            y = round(y + Dy);

            annotation.object(i).polygon.pt(j).x = num2str(x);
            annotation.object(i).polygon.pt(j).y = num2str(y);
        end
    end
end