/*
 * ***** BEGIN GPL LICENSE BLOCK *****
 *
 * 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 2
 * 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, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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/** \file blender/freestyle/intern/image/ImagePyramid.cpp
 *  \ingroup freestyle
 *  \brief Class to represent a pyramid of images
 *  \author Stephane Grabli
 *  \date 25/12/2003
 */

#include <iostream>

#include "GaussianFilter.h"
#include "Image.h"
#include "ImagePyramid.h"

using namespace std;

namespace Freestyle {

#if 0
ImagePyramid::ImagePyramid(const GrayImage& level0, unsigned nbLevels)
{
	BuildPyramid(level0,nbLevels);
}
#endif

ImagePyramid::ImagePyramid(const ImagePyramid& /*iBrother*/)
{
	if (!_levels.empty()) {
		for (vector<GrayImage*>::iterator im = _levels.begin(), imend = _levels.end(); im != imend; ++im) {
			_levels.push_back(new GrayImage(**im));
		}
	}
}

ImagePyramid::~ImagePyramid()
{
	if (!_levels.empty()) {
		for (vector<GrayImage*>::iterator im = _levels.begin(), imend = _levels.end(); im != imend; ++im) {
			delete (*im);
		}
		_levels.clear();
	}
}

GrayImage * ImagePyramid::getLevel(int l)
{
	return _levels[l];
}

float ImagePyramid::pixel(int x, int y, int level)
{
	GrayImage *img = _levels[level];
	if (0 == level) {
		return img->pixel(x, y);
	}
	unsigned int i  = 1 << level;
	unsigned int sx = x >> level;
	unsigned int sy = y >> level;
	if (sx >= img->width())
		sx = img->width() - 1;
	if (sy >= img->height())
		sy = img->height() - 1;

	// bilinear interpolation
	float A = i * (sx + 1) - x;
	float B = x - i * sx;
	float C = i * (sy + 1) - y;
	float D = y - i * sy;

	float P1(0), P2(0);
	P1 = A * img->pixel(sx, sy);
	if (sx < img->width() - 1) {
		if (x % i != 0)
			P1 += B * img->pixel(sx + 1, sy);
	}
	else {
		P1 += B * img->pixel(sx, sy);
	}
	if (sy < img->height() - 1) {
		if (y % i != 0) {
			P2 = A * img->pixel(sx, sy + 1);
			if (sx < img->width() - 1) {
				if (x % i != 0)
					P2 += B * img->pixel(sx + 1, sy + 1);
			}
			else {
				P2 += B * img->pixel(sx, sy + 1);
			}
		}
	}
	else {
		P2 = P1;
	}
	return (1.0f / (float)(1 << (2 * level))) * (C * P1 + D * P2);
}

int ImagePyramid::width(int level)
{
	return _levels[level]->width();
}

int ImagePyramid::height(int level)
{
	return _levels[level]->height();
}

GaussianPyramid::GaussianPyramid(const GrayImage& level0, unsigned nbLevels, float iSigma) : ImagePyramid()
{
	_sigma = iSigma;
	BuildPyramid(level0, nbLevels);
}

GaussianPyramid::GaussianPyramid(GrayImage *level0, unsigned nbLevels, float iSigma) : ImagePyramid()
{
	_sigma = iSigma;
	BuildPyramid(level0, nbLevels);
}

GaussianPyramid::GaussianPyramid(const GaussianPyramid& iBrother) : ImagePyramid(iBrother)
{
	_sigma = iBrother._sigma;
}

void GaussianPyramid::BuildPyramid(const GrayImage& level0, unsigned nbLevels)
{
	GrayImage *pLevel = new GrayImage(level0);
	BuildPyramid(pLevel, nbLevels);
}

void GaussianPyramid::BuildPyramid(GrayImage *level0, unsigned nbLevels)
{
	GrayImage *pLevel = level0;
	_levels.push_back(pLevel);
	GaussianFilter gf(_sigma);
	// build the nbLevels:
	unsigned w = pLevel->width();
	unsigned h = pLevel->height();
	if (nbLevels != 0) {
		for (unsigned int i = 0; i < nbLevels; ++i) { //soc
			w = pLevel->width() >> 1;
			h = pLevel->height() >> 1;
			GrayImage *img = new GrayImage(w, h);
			for (unsigned int y = 0; y < h; ++y) {
				for (unsigned int x = 0; x < w; ++x) {
					float v = gf.getSmoothedPixel<GrayImage>(pLevel, 2 * x, 2 * y);
					img->setPixel(x, y, v);
				}
			}
			_levels.push_back(img);
			pLevel = img;
		}
	}
	else {
		while ((w > 1) && (h > 1)) {
			w = pLevel->width() >> 1;
			h = pLevel->height() >> 1;
			GrayImage *img = new GrayImage(w, h);
			for (unsigned int y = 0; y < h; ++y) {
				for (unsigned int x = 0; x < w; ++x) {
					float v = gf.getSmoothedPixel<GrayImage>(pLevel, 2 * x, 2 * y);
					img->setPixel(x, y, v);
				}
			}
			_levels.push_back(img);
			pLevel = img;
		}
	}
}

} /* namespace Freestyle */
