## Copyright (C) 2020 Jens
## 
## This program is free software: you can redistribute it and/or modify it
## under the terms of the GNU General Public License as published by
## the Free Software Foundation, either version 3 of the License, or
## (at your option) any later version.
## 
## This program is distributed in the hope that it will be useful, but
## WITHOUT ANY WARRANTY; without even the implied warranty of
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
## GNU General Public License for more details.
## 
## You should have received a copy of the GNU General Public License
## along with this program.  If not, see
## <https://www.gnu.org/licenses/>.

## -*- texinfo -*- 
## @deftypefn {} {@var{retval} =} bluescreen (@var{input1}, @var{input2})
##
## @seealso{}
## @end deftypefn

## Author: Jens <jens@orion>
## Created: 2020-10-03

function retval = bluescreen (img_name, k_sb, k_ds, k_cw)
im = im2double(imread(img_name));
im_rgb = imresize(im, 1);
se = strel('square',3)

ref_rgb = toRef([0 0.5 1], size(im_rgb));

close all;

figure;
imshow(ref_rgb);

figure;
despilled_rgb_matte = im_rgb - k_sb*ref_rgb;
imshow(despilled_rgb_matte);

figure;
despilled_rgb = im_rgb - k_ds*ref_rgb;
imshow(despilled_rgb);

figure;
matte = min(1, k_cw*similarity(despilled_rgb_matte, ref_rgb));
imshow(matte);

figure;
final = despilled_rgb.*matte;
imshow(final);

figure;
edges = coloredges(despilled_rgb_matte, ref_rgb);
imshow(edges);

imwrite(final, 'final.png','png','alpha', matte);
imwrite(matte, 'alpha.png','png');

retval = 0;

function r = toRef(ref, d)
	r = repmat(reshape(ref,1, 1, 3), d(1), d(2));
endfunction

function s = similarity(im, ref)
	im = rgb2hsv(im);
	ref = rgb2hsv(ref);
	s = (im(:,:,1) - ref(:,:,1)).^2;
endfunction

function s = coloredges(im, ref)
	im = rgb2hsv(im);
	ref = rgb2hsv(ref);
	s = max(0, im(:,:,1) - ref(:,:,1));
endfunction

endfunction