// blend1.cpp : DLL アプリケーションのエントリ ポイントを定義します。
//

#include "stdafx.h"
#include <math.h>


#ifdef _MANAGED
#pragma managed(push, off)
#endif



extern "C" {
typedef unsigned char n_byte;

int __stdcall get_blend_func_count();
char* __stdcall get_blend_func_key(int no);
char* __stdcall get_blend_func_name(int no);
void __stdcall blend(unsigned char* dst,const unsigned char* col,const unsigned char* alpha,int col_step
								 ,int alpha_step,int num_channel,int num_pixel,int no);



//追加する合成方法の数を返す。
int __stdcall get_blend_func_count()
{
    return 3;
}


//psdファイルに保存するときのkeyを返す。
/*
'norm' = normal
'dark' = darken
'lite' = lighten
'hue ' = hue
'sat ' = saturation
'colr' = color
'lum ' = luminosity
'mul ' = multiply
'scrn' = screen
'diss' = dissolve
'over' = overlay
'hLit' = hard light
'sLit' = soft light
'diff' = difference
'smud' = exlusion
'div ' = color dodge
'idiv' = color burn
*/

char* __stdcall get_blend_func_key(int no) 
{
	if (no == 0) {//ビビットライト
		return "vLit";
	}
	if (no == 1) {//リニアライト
		return "lLit";
	}
	if (no == 2) {//ピンライト
		return "pLit";
	}
	return 0;
}

//合成方法の名前を返す。
char* __stdcall get_blend_func_name(int no)
{
	if (no == 0) {
		return "ビビットライト";
	}
	if (no == 1) {
		return "リニアライト";
	}
	if (no == 2) {
		return "ピンライト";
	}
	return "";
}


//合成を行う関数。
//num_channel チャンネル数。グレーモードの場合は１、カラーモードの場合は３

void __stdcall blend(unsigned char* dst,const unsigned char* col,const unsigned char* alpha,int col_step,int alpha_step
					,int num_channel,int num_pixel,int no)
{
	if (no == 0) {//ビビットライト
// 計算サイト　http://stackoverflow.com/questions/5919663/how-does-photoshop-blend-two-images-together
//		255 - ((255 - bg) *256 ) / (fg*2)
//　　(A << 8 ) / (255 - (2 * (B - 128)))

		if (num_channel == 1) {// ビビットライト グレスケ
			const unsigned char* col_end = col + num_pixel * col_step;
			while (col < col_end) {

				double d = 0;
				if(*col<128 && 0<*col) { d = 255 - ((255 - *dst) *256) / (*col*2);}
				else if(*col<=0) { d = 0;}
					else	{ d = (*dst *256 ) / (255 - (2 * (*col - 128))) ;}

					d = d < 0 ? 0 : ( d < 255 ? d : 255);

					*dst = (d * *alpha/255.00) + (*dst * (1.00-*alpha/255.00))+0.5;

				alpha += alpha_step;
				col += col_step;
				dst += col_step;
			}
		}

		else if (num_channel == 3) { // ビビットライト カラー
			const unsigned char* col_end = col + num_pixel * col_step;
			while (col < col_end) {

				double d = 0;
				if(*col<128 && 0<*col) { d = 255 - ((255 - *dst) *256) / (*col*2);}
				else if(*col<=0) { d = 0;}
					else	{ d = (*dst *256 ) / (255 - (2 * (*col - 128))) ;}
				double d1 = 0;
				if(*(col+1)<128 && 0<*(col+1)) { d1 = 255 - ((255 - *(dst+1)) *256) / (*(col+1)*2);}
				else if(*(col+1)<=0) { d1 = 0;}
					else	{ d1 = (*(dst+1) *256 ) / (255 - (2 * (*(col+1) - 128))) ;}
				double d2 = 0;
				if(*(col+2)<128 && 0<*(col+2)) { d2 = 255 - ((255 - *(dst+2)) *256) / (*(col+2)*2);}
				else if(*(col+2)<=0) { d2 = 0;}
					else	{ d2 = (*(dst+2) *256 ) / (255 - (2 * (*(col+2) - 128))) ;}

				d = d < 0 ? 0 : ( d < 255 ? d : 255);
				d1 = d1 < 0 ? 0 : ( d1 < 255 ? d1 : 255);
				d2 = d2 < 0 ? 0 : ( d2 < 255 ? d2 : 255);

				// レイヤーの色×不透明度　＋　下のレイヤーの色×(100％-不透明度)

					*dst = (d * *alpha/255.00) + (*dst * (1.00-*alpha/255.00))+0.5;
					*(dst + 1) = d1 * *alpha/255.00 + *(dst+1) * (1.00-*alpha/255.00)+0.5;
					*(dst + 2) = d2 * *alpha/255.00 + *(dst+2) * (1.00-*alpha/255.00)+0.5;

				alpha += alpha_step;
				col += col_step;
				dst += col_step;
			}
		}
	}
	
	
//----------------------------

	if (no == 1) {//リニアライト
// 計算サイト　http://www.bea.hi-ho.ne.jp/gaku-iwa/color/conjn.html

		if (num_channel == 1) { // リニアライト グレスケ
			const unsigned char* col_end = col + num_pixel * col_step;
			while (col < col_end) {

					double d = *col *2 + *dst -256;

					d = d < 0 ? 0 : ( d < 255 ? d : 255);

					*dst = (d * *alpha/255.00) + (*dst * (1.00-*alpha/255.00))+0.5;

				alpha += alpha_step;
				col += col_step;
				dst += col_step;
			}
		}
		else if (num_channel == 3) { // リニアライト カラー
			const unsigned char* col_end = col + num_pixel * col_step;
			while (col < col_end) {

				double d = *col *2 + *dst -256;
				double d1 = *(col + 1) *2 + *(dst + 1) -256;
				double d2 = *(col + 2) *2 + *(dst + 2) -256;

				d = d < 0 ? 0 : ( d < 255 ? d : 255);
				d1 = d1 < 0 ? 0 : ( d1 < 255 ? d1 : 255);
				d2 = d2 < 0 ? 0 : ( d2 < 255 ? d2 : 255);

				// レイヤーの色×不透明度　＋　下のレイヤーの色×(100％-不透明度)

					*dst = (d * *alpha/255.00) + (*dst * (1.00-*alpha/255.00))+0.5;
					*(dst + 1) = d1 * *alpha/255.00 + *(dst+1) * (1.00-*alpha/255.00)+0.5;
					*(dst + 2) = d2 * *alpha/255.00 + *(dst+2) * (1.00-*alpha/255.00)+0.5;

				alpha += alpha_step;
				col += col_step;
				dst += col_step;
			}
		}
	}
//----------------------------

	if (no == 2) {//ピンライト
// 計算サイト　http://dunnbypaul.net/blends/
//  f (Blend > 1/2) R = max(Base,2*(Blend-1/2))
//  if (Blend <= 1/2) R = min(Base,2*Blend)

		if (num_channel == 1) { // ピンライト グレスケ
			const unsigned char* col_end = col + num_pixel * col_step;
			while (col < col_end) {

				double d = 0;
				if(*col<128) { d = (int)min(*dst, *col *2) ;}
					else	{ d = (int)max(*dst,(*col-128)*2) ;}

					*dst = (d * *alpha/255.00) + (*dst * (1.00-*alpha/255.00))+0.5;

				alpha += alpha_step;
				col += col_step;
				dst += col_step;
			}
		}
		else if (num_channel == 3) { // ピンライト カラー
			const unsigned char* col_end = col + num_pixel * col_step;
			while (col < col_end) {

				double d = 0;
				if(*col<128) { d = (int)min(*dst, *col *2) ;}
					else	{ d = (int)max(*dst,(*col-128)*2) ;}
				double d1 = 0;
				if(*(col+1)<128) { d1 = (int)min(*(dst+1), *(col+1) *2) ;}
					else	{ d1 = (int)max(*(dst+1),(*(col+1)-128)*2) ;}
				double d2 = 0;
				if(*(col+2)<128) { d2 = (int)min(*(dst+2), *(col+2) *2) ;}
					else	{ d2 = (int)max(*(dst+2),(*(col+2)-128)*2) ;}

				// レイヤーの色×不透明度　＋　下のレイヤーの色×(100％-不透明度)

					*dst = (d * *alpha/255.00) + (*dst * (1.00-*alpha/255.00))+0.5;
					*(dst + 1) = d1 * *alpha/255.00 + *(dst+1) * (1.00-*alpha/255.00)+0.5;
					*(dst + 2) = d2 * *alpha/255.00 + *(dst+2) * (1.00-*alpha/255.00)+0.5;


				alpha += alpha_step;
				col += col_step;
				dst += col_step;
			}
		}
	}
}

//下のレイヤーと結合で使用される
void __stdcall merge(n_byte* dst,const n_byte* col,const n_byte* base_col,const n_byte* alpha,const n_byte* base_alpha
					 ,int col_step,int alpha_step,int base_alpha_step,int num_channel,int num_pixel,int no)
{
if (no == 0) {//ビビットライト
		if (num_channel == 1) {//グレースケールモード
			const unsigned char* col_end = col + num_pixel * col_step;
			while (col < col_end) {
				unsigned int a0 = *base_alpha;
				unsigned int a1 = *alpha;

				if (a1 != 0) {
				double d = 0;
				if(*col<128 && 0<*col) { d = (int)( 255 - ((255 - *base_col) *256) / (*col*2) );}
				else if(*col<=0) { d = 0;}
					else	{ d = (int)( (*base_col *256 ) / (255 - (2 * (*col - 128)))  );}

					d = d < 0 ? 0 : ( d < 255 ? d : 255);

				// 不透明度を入れた計算
				// Ca = 1-(1-Fa)*(1-Ba)
				//=( Fa *Ba * func(Bc,Fc) + Fa *(1-Ba) * Fc + (1-Fa)*Ba * Bc ) / Ca
				//http://www.greenwood.co.jp/~k-aki/article/pixel_composite.html

				double ca = 1 - (1- a1/255.0) * (1-a0/255.0) ;

					*dst = (a1/255.0 *(a0/255.0) * d + (a1/255.0) *(1-a0/255.0) * *col + (1-a1/255.0)*(a0/255.0) * *base_col ) / ca +0.5;

					*(dst + 1) = n_byte(((a0 + a1) * 255 - a0 * a1) / 255);	
				}
				else {
					*dst = *base_col;
					*(dst + 1) = *base_alpha;
				}

				dst += 2;
				col += col_step;
				base_col += col_step;
				alpha += alpha_step;
				base_alpha += alpha_step;
			}
		}

		else if (num_channel == 3) {
			const unsigned char* col_end = col + num_pixel * col_step;
			while (col < col_end) {
				unsigned int a0 = *base_alpha;
				unsigned int a1 = *alpha;

				if (a1 != 0) {
				double d = 0;
				if(*col<128 && 0<*col) { d = (int)( 255 - ((255 - *base_col) *256) / (*col*2) );}
				else if(*col<=0) { d = 0;}
					else	{ d = (int)( (*base_col *256 ) / (255 - (2 * (*col - 128)))  );}
				double d1 = 0;
				if(*(col+1)<128 && 0<*(col+1)) { d1 = (int)( 255 - ((255 - *(base_col+1)) *256) / (*(col+1)*2) );}
				else if(*(col+1)<=0) { d1 = 0;}
					else	{ d1 = (int)( (*(base_col+1) *256 ) / (255 - (2 * (*(col+1) - 128)))  );}
				double d2 = 0;
				if(*(col+2)<128 && 0<*(col+2)) { d2 = (int)( 255 - ((255 - *(base_col+2)) *256) / (*(col+2)*2) );}
				else if(*(col+2)<=0) { d2 = 0;}
					else	{ d2 = (int)( (*(base_col+2) *256 ) / (255 - (2 * (*(col+2) - 128)))  );}
					
				d = d < 0 ? 0 : ( d < 255 ? d : 255);
				d1 = d1 < 0 ? 0 : ( d1 < 255 ? d1 : 255);
				d2 = d2 < 0 ? 0 : ( d2 < 255 ? d2 : 255);

				// 不透明度を入れた計算
				// Ca = 1-(1-Fa)*(1-Ba)
				//=( Fa *Ba * func(Bc,Fc) + Fa *(1-Ba) * Fc + (1-Fa)*Ba * Bc ) / Ca
				//http://www.greenwood.co.jp/~k-aki/article/pixel_composite.html

				double ca = 1 - (1- a1/255.0) * (1-a0/255.0) ;

					*dst = (a1/255.0 *(a0/255.0) * d + (a1/255.0) *(1-a0/255.0) * *col + (1-a1/255.0)*(a0/255.0) * *base_col ) / ca +0.5;
					*(dst + 1) = (a1/255.0 *(a0/255.0) * d1 + (a1/255.0) *(1-a0/255.0) * *(col+1) + (1-a1/255.0)*(a0/255.0) * *(base_col+1) ) / ca +0.5;
					*(dst + 2) = (a1/255.0 *(a0/255.0) * d2 + (a1/255.0) *(1-a0/255.0) * *(col+2) + (1-a1/255.0)*(a0/255.0) * *(base_col+2) ) / ca +0.5;

					*(dst + 3) = n_byte(((a0 + a1) * 255 - a0 * a1) / 255);	
				}
				else {
					*dst = *base_col;
					*(dst + 1) = *(base_col + 1);
					*(dst + 2) = *(base_col + 2);
					*(dst + 3) = *base_alpha;
				}

				dst += 4;
				col += col_step;
				base_col += col_step;
				alpha += alpha_step;
				base_alpha += base_alpha_step;
			}
		}
	}

//----------------------------

	if (no == 1) {//リニアライト
		if (num_channel == 1) {
			const unsigned char* col_end = col + num_pixel * col_step;
			while (col < col_end) {
				unsigned int a0 = *base_alpha;
				unsigned int a1 = *alpha;

				if (a1 != 0) {
				double d = *col *2 + *base_col -256;

				d = d < 0 ? 0 : ( d < 255 ? d : 255);
	
				// 不透明度を入れた計算
				// Ca = 1-(1-Fa)*(1-Ba)
				//=( Fa *Ba * func(Bc,Fc) + Fa *(1-Ba) * Fc + (1-Fa)*Ba * Bc ) / Ca
				//http://www.greenwood.co.jp/~k-aki/article/pixel_composite.html

				double ca = 1 - (1- a1/255.0) * (1-a0/255.0) ;

					*dst = (a1/255.0 *(a0/255.0) * d + (a1/255.0) *(1-a0/255.0) * *col + (1-a1/255.0)*(a0/255.0) * *base_col ) / ca +0.5;

					*(dst + 1) = n_byte(((a0 + a1) * 255 - a0 * a1) / 255);	
				}
				else {
					*dst = *base_col;
					*(dst + 1) = *base_alpha;
				}

				dst += 2;
				col += col_step;
				base_col += col_step;
				alpha += alpha_step;
				base_alpha += alpha_step;
			}
		}
		else if (num_channel == 3) {
			const unsigned char* col_end = col + num_pixel * col_step;
			while (col < col_end) {
				unsigned int a0 = *base_alpha;
				unsigned int a1 = *alpha;

				if (a1 != 0) {
				double d = *col *2 + *base_col -256;
				double d1 = *(col + 1) *2 + *(base_col + 1) -256;
				double d2 = *(col + 2) *2 + *(base_col + 2) -256;

				d = d < 0 ? 0 : ( d < 255 ? d : 255);
				d1 = d1 < 0 ? 0 : ( d1 < 255 ? d1 : 255);
				d2 = d2 < 0 ? 0 : ( d2 < 255 ? d2 : 255);

				// 不透明度を入れた計算
				// Ca = 1-(1-Fa)*(1-Ba)
				//=( Fa *Ba * func(Bc,Fc) + Fa *(1-Ba) * Fc + (1-Fa)*Ba * Bc ) / Ca
				//http://www.greenwood.co.jp/~k-aki/article/pixel_composite.html

				double ca = 1 - (1- a1/255.0) * (1-a0/255.0) ;

					*dst = (a1/255.0 *(a0/255.0) * d + (a1/255.0) *(1-a0/255.0) * *col + (1-a1/255.0)*(a0/255.0) * *base_col ) / ca +0.5;
					*(dst + 1) = (a1/255.0 *(a0/255.0) * d1 + (a1/255.0) *(1-a0/255.0) * *(col+1) + (1-a1/255.0)*(a0/255.0) * *(base_col+1) ) / ca +0.5;
					*(dst + 2) = (a1/255.0 *(a0/255.0) * d2 + (a1/255.0) *(1-a0/255.0) * *(col+2) + (1-a1/255.0)*(a0/255.0) * *(base_col+2) ) / ca +0.5;

					*(dst + 3) = n_byte(((a0 + a1) * 255 - a0 * a1) / 255);	
				}
				else {
					*dst = *base_col;
					*(dst + 1) = *(base_col + 1);
					*(dst + 2) = *(base_col + 2);
					*(dst + 3) = *base_alpha;
				}

				dst += 4;
				col += col_step;
				base_col += col_step;
				alpha += alpha_step;
				base_alpha += base_alpha_step;
			}
		}
	}

//----------------------------

	if (no == 2) {//ピンライト
		if (num_channel == 1) {
			const unsigned char* col_end = col + num_pixel * col_step;
			while (col < col_end) {
				unsigned int a0 = *base_alpha;
				unsigned int a1 = *alpha;

				if (a1 != 0) {
				double d = 0;
				if(*col<128) { d = (int)min(*base_col, *col *2) ;}
					else	{ d = (int)max(*base_col,(*col-128)*2) ;}

				// 不透明度を入れた計算
				// Ca = 1-(1-Fa)*(1-Ba)
				//=( Fa *Ba * func(Bc,Fc) + Fa *(1-Ba) * Fc + (1-Fa)*Ba * Bc ) / Ca
				//http://www.greenwood.co.jp/~k-aki/article/pixel_composite.html

				double ca = 1 - (1- a1/255.0) * (1-a0/255.0) ;

					*dst = (a1/255.0 *(a0/255.0) * d + (a1/255.0) *(1-a0/255.0) * *col + (1-a1/255.0)*(a0/255.0) * *base_col ) / ca +0.5;

					*(dst + 1) = n_byte(((a0 + a1) * 255 - a0 * a1) / 255);	
				}
				else {
					*dst = *base_col;
					*(dst + 1) = *base_alpha;
				}

				dst += 2;
				col += col_step;
				base_col += col_step;
				alpha += alpha_step;
				base_alpha += alpha_step;
			}
		}
		else if (num_channel == 3) {
			const unsigned char* col_end = col + num_pixel * col_step;
			while (col < col_end) {
				unsigned int a0 = *base_alpha;
				unsigned int a1 = *alpha;

				if (a1 != 0) {
				
				double d = 0;
				if(*col<128) { d = (int)min(*base_col, *col *2) ;}
					else	{ d = (int)max(*base_col,(*col-128)*2) ;}
				double d1 = 0;
				if(*(col+1)<128) { d1 = (int)min(*(base_col+1), *(col+1) *2) ;}
					else	{ d1 = (int)max(*(base_col+1),(*(col+1)-128)*2) ;}
				double d2 = 0;
				if(*(col+2)<128) { d2 = (int)min(*(base_col+2), *(col+2) *2) ;}
					else	{ d2 = (int)max(*(base_col+2),(*(col+2)-128)*2) ;}

				// 不透明度を入れた計算
				// Ca = 1-(1-Fa)*(1-Ba)
				//=( Fa *Ba * func(Bc,Fc) + Fa *(1-Ba) * Fc + (1-Fa)*Ba * Bc ) / Ca
				//http://www.greenwood.co.jp/~k-aki/article/pixel_composite.html

				double ca = 1 - (1- a1/255.0) * (1-a0/255.0) ;

					*dst = (a1/255.0 *(a0/255.0) * d + (a1/255.0) *(1-a0/255.0) * *col + (1-a1/255.0)*(a0/255.0) * *base_col ) / ca +0.5;
					*(dst + 1) = (a1/255.0 *(a0/255.0) * d1 + (a1/255.0) *(1-a0/255.0) * *(col+1) + (1-a1/255.0)*(a0/255.0) * *(base_col+1) ) / ca +0.5;
					*(dst + 2) = (a1/255.0 *(a0/255.0) * d2 + (a1/255.0) *(1-a0/255.0) * *(col+2) + (1-a1/255.0)*(a0/255.0) * *(base_col+2) ) / ca +0.5;

					*(dst + 3) = n_byte(((a0 + a1) * 255 - a0 * a1) / 255);	
				}
				else {
					*dst = *base_col;
					*(dst + 1) = *(base_col + 1);
					*(dst + 2) = *(base_col + 2);
					*(dst + 3) = *base_alpha;
				}

				dst += 4;
				col += col_step;
				base_col += col_step;
				alpha += alpha_step;
				base_alpha += base_alpha_step;
			}
		}
	}
	
}




}
BOOL APIENTRY DllMain( HMODULE hModule,
                       DWORD  ul_reason_for_call,
                       LPVOID lpReserved
					 )
{
    return TRUE;
}

#ifdef _MANAGED
#pragma managed(pop)
#endif