图像滤镜艺术---PS图层混合模式之明度模式

#include"TRGB2YCbCr.h"
#include <stdlib.h>
#include <stdio.h>
#include "math.h"
#include <string.h>

const float YCbCrYRF = 0.299F;              // RGB转YCbCr的系数(浮点类型）
const float YCbCrYGF = 0.587F;
const float YCbCrYBF = 0.114F;
const float YCbCrCbRF = -0.168736F;
const float YCbCrCbGF = -0.331264F;
const float YCbCrCbBF = 0.500000F;
const float YCbCrCrRF = 0.500000F;
const float YCbCrCrGF = -0.418688F;
const float YCbCrCrBF = -0.081312F;

const float RGBRYF = 1.00000F;            // YCbCr转RGB的系数(浮点类型）
const float RGBRCbF = 0.0000F;
const float RGBRCrF = 1.40200F;
const float RGBGYF = 1.00000F;
const float RGBGCbF = -0.34414F;
const float RGBGCrF = -0.71414F;
const float RGBBYF = 1.00000F;
const float RGBBCbF = 1.77200F;
const float RGBBCrF = 0.00000F;

const int Shift = 20;
const int HalfShiftValue = 1 << (Shift - 1);

const int YCbCrYRI = (int)(YCbCrYRF * (1 << Shift) + 0.5);         // RGB转YCbCr的系数(整数类型）
const int YCbCrYGI = (int)(YCbCrYGF * (1 << Shift) + 0.5);
const int YCbCrYBI = (int)(YCbCrYBF * (1 << Shift) + 0.5);
const int YCbCrCbRI = (int)(YCbCrCbRF * (1 << Shift) + 0.5);
const int YCbCrCbGI = (int)(YCbCrCbGF * (1 << Shift) + 0.5);
const int YCbCrCbBI = (int)(YCbCrCbBF * (1 << Shift) + 0.5);
const int YCbCrCrRI = (int)(YCbCrCrRF * (1 << Shift) + 0.5);
const int YCbCrCrGI = (int)(YCbCrCrGF * (1 << Shift) + 0.5);
const int YCbCrCrBI = (int)(YCbCrCrBF * (1 << Shift) + 0.5);

const int RGBRYI = (int)(RGBRYF * (1 << Shift) + 0.5);              // YCbCr转RGB的系数(整数类型）
const int RGBRCbI = (int)(RGBRCbF * (1 << Shift) + 0.5);
const int RGBRCrI = (int)(RGBRCrF * (1 << Shift) + 0.5);
const int RGBGYI = (int)(RGBGYF * (1 << Shift) + 0.5);
const int RGBGCbI = (int)(RGBGCbF * (1 << Shift) + 0.5);
const int RGBGCrI = (int)(RGBGCrF * (1 << Shift) + 0.5);
const int RGBBYI = (int)(RGBBYF * (1 << Shift) + 0.5);
const int RGBBCbI = (int)(RGBBCbF * (1 << Shift) + 0.5);
const int RGBBCrI = (int)(RGBBCrF * (1 << Shift) + 0.5);

void RGBToYCbCr(int R, int G, int B, int*Y,int*Cb, int* Cr)
{
	*Y  = ((YCbCrYRI * R + YCbCrYGI * G + YCbCrYBI * B + HalfShiftValue) >> Shift);
    *Cb = (128 + ((YCbCrCbRI * R + YCbCrCbGI * G + YCbCrCbBI * B + HalfShiftValue) >> Shift));
    *Cr = (128 + ((YCbCrCrRI * R + YCbCrCrGI * G + YCbCrCrBI * B + HalfShiftValue) >> Shift));
}

void YCbCrToRGB(int Y, int Cb, int Cr, int*R,int*G, int* B)
{
    Cb = Cb - 128; Cr = Cr - 128;
    *R = Y + ((RGBRCrI * Cr + HalfShiftValue) >> Shift);
    *G = Y + ((RGBGCbI * Cb + RGBGCrI * Cr + HalfShiftValue) >> Shift);
    *B = Y + ((RGBBCbI * Cb + HalfShiftValue) >> Shift);
    if (*R > 255) *R = 255; else if (*R < 0) *R = 0;
    if (*G > 255) *G = 255; else if (*G < 0) *G = 0;   
    if (*B > 255) *B = 255; else if (*B < 0) *B = 0;
}
int ColorBlendModeBrightness(unsigned char* baseData, unsigned char* mixData, int width, int height, int stride)
{
	int i, j, pos;
	int bY, bCb, bCr, mY, mCb, mCr, br, bg, bb, mr, mg, mb;
	unsigned char* pBase = baseData;
	unsigned char* pMix = mixData;
	int offset = stride - width * 4;
	for(j = 0; j < height; j++)
	{
		for(i = 0; i < width; i++)
		{
			bb = pBase[0];
			bg = pBase[1];
			br = pBase[2];
			mb = pMix[0];
			mg = pMix[1];
			mr = pMix[2];
			RGBToYCbCr(mr,mg,mb,&mY,&mCb,&mCr);
			RGBToYCbCr(br,bg,bb,&bY,&bCb,&bCr);
			YCbCrToRGB((mY+bY)/2, bCb, bCr, &br,&bg,&bb);//(mY+bY)/2表示透明度为50%
			pBase[0] = bb;
			pBase[1] = bg;
			pBase[2] = br;
			pBase += 4;
			pMix  += 4;
		}
		pBase += offset;
		pMix  += offset;
	}
	return 0;

}


    

大家可以看到，效果图和PS的效果图几乎一致，最后，给出一个DEMO下载链接：点击打开链接