#include "igs_density.h"

namespace

{

double accum_by_trans_(

	const double src_value /* 元値(R,G,B) */

	,

	const double transparent /* src_valueの透明度(0...1) */

	,

	const int integer_part /* 濃度値の整数部分(0...) */

	,

	const double fractional_part /* 濃度値の少数部分(0...1) */

	)

{

	double accumulation = src_value;

	if (1 <= integer_part) {

		for (int ii = 1; ii < integer_part; ++ii) {

			accumulation = accumulation * transparent + src_value;

		}

		if (0.0 < fractional_part) {

			accumulation +=

				((accumulation * transparent + src_value) -

				 accumulation) *

				fractional_part;

		}

	} else { /* 整数部分がゼロ以下のとき */

		if (0.0 < fractional_part) {

			accumulation *= fractional_part;

		} else { /* 少数部分もゼロ以下のとき */

			accumulation = 0.0;

		}

	}

	return (1.0 < accumulation) ? 1.0 : (

											(accumulation < 0.0) ? 0.0 : accumulation);

}

}

#include <limits>			/* std::numeric_limits */</limits>

#include "igs_ifx_common.h" /* igs::image::rgba */

namespace

{

template <class class="" it,="" rt=""></class>

void change_template_(

	IT *image_array, const int height, const int width, const int channels

	,

	const RT *ref /* 求める画像と同じ高、幅、ch数 */

	,

	const int ref_mode /* 0=R,1=G,2=B,3=A,4=Luminance,5=Nothing */

	,

	const double density)

{

	const int integer_part = (int)density;

	const double fractional_part = density - (int)density;

	const double maxi = std::numeric_limits<it>::max();</it>

	using namespace igs::image::rgba;

	const int pixsize = height * width;

	const int r_max = std::numeric_limits<rt>::max();</rt>

	for (int ii = 0; ii < pixsize; ++ii, image_array += channels) {

		const double rr1 = (double)(image_array[red]) / maxi;

		const double gg1 = (double)(image_array[gre]) / maxi;

		const double bb1 = (double)(image_array[blu]) / maxi;

		const double aa1 = (double)(image_array[alp]) / maxi;

		double rr2 = accum_by_trans_(rr1,

									 1.0 - aa1, integer_part, fractional_part);

		double gg2 = accum_by_trans_(gg1,

									 1.0 - aa1, integer_part, fractional_part);

		double bb2 = accum_by_trans_(bb1,

									 1.0 - aa1, integer_part, fractional_part);

		double aa2 = accum_by_trans_(aa1,

									 1.0 - aa1, integer_part, fractional_part);

		/* 参照画像あればピクセル単位の画像変化 */

		if (ref != 0) {

			const double refv = igs::color::ref_value(

				ref, channels, r_max, ref_mode);

			ref += channels; /* continue;の前に行うこと */

			rr2 = (rr2 - rr1) * refv + rr1;

			gg2 = (gg2 - gg1) * refv + gg1;

			bb2 = (bb2 - bb1) * refv + bb1;

			aa2 = (aa2 - aa1) * refv + aa1;

		}

		image_array[red] = static_cast<it>(rr2 * (maxi + 0.999999));</it>

		image_array[gre] = static_cast<it>(gg2 * (maxi + 0.999999));</it>

		image_array[blu] = static_cast<it>(bb2 * (maxi + 0.999999));</it>

		image_array[alp] = static_cast<it>(aa2 * (maxi + 0.999999));</it>

	}

}

}

#include <stdexcept> /* std::domain_error(-) */</stdexcept>

void igs::density::change(

	unsigned char *image_array /* RGBAでなければならない */

	,

	const int height, const int width, const int channels /* 4(=RGBAでなければならない) */

	,

	const int bits

	,

	const unsigned char *ref /* 求める画像と同じ高、幅、ch数 */

	,

	const int ref_bits /* refがゼロのときはここもゼロ */

	,

	const int ref_mode /* 0=R,1=G,2=B,3=A,4=Luminance,5=Nothing */

	,

	const double density)

{

	if (igs::image::rgba::siz != channels) {

		throw std::domain_error("Bad channels,Not rgba");

	}

	if ((std::numeric_limits<unsigned char="">::digits == bits) && ((std::numeric_limits<unsigned char="">::digits == ref_bits) || (0 == ref_bits))) {</unsigned></unsigned>

		change_template_(

			image_array, height, width, channels, ref, ref_mode, density);

	} else if ((std::numeric_limits<unsigned short="">::digits == bits) && ((std::numeric_limits<unsigned char="">::digits == ref_bits) || (0 == ref_bits))) {</unsigned></unsigned>

		change_template_(

			reinterpret_cast<unsigned *="" short="">(image_array), height, width, channels, ref, ref_mode, density);</unsigned>

	} else if ((std::numeric_limits<unsigned short="">::digits == bits) && (std::numeric_limits<unsigned short="">::digits == ref_bits)) {</unsigned></unsigned>

		change_template_(

			reinterpret_cast<unsigned *="" short="">(image_array), height, width, channels, reinterpret_cast<const *="" short="" unsigned="">(ref), ref_mode, density);</const></unsigned>

	} else if ((std::numeric_limits<unsigned short="">::digits == bits) && (std::numeric_limits<unsigned short="">::digits == ref_bits)) {</unsigned></unsigned>

		change_template_(

			image_array, height, width, channels, reinterpret_cast<const *="" short="" unsigned="">(ref), ref_mode, density);</const>

	} else {

		throw std::domain_error("Bad bits,Not uchar/ushort");

	}

}