图像饱和度调整

package chapter4;

import java.awt.image.BufferedImage;
import java.nio.Buffer;

/**
* Created by LENOVO on 18-1-29.
*/
public class SaturationFilter extends AbstractBufferedImageOp{
public static final double clo60 = 1.0/60.0;
public static final double clo255 = 1.0/255.0;
private double ratio =0.25;//饱和度调整系数
public SaturationFilter(){}
public double getRatio() {
return ratio;
}
public void setRatio(double ratio) {
this.ratio = ratio;
}
public BufferedImage filter(BufferedImage src,BufferedImage dest){
int width = src.getWidth();
int height = src.getHeight();
if(dest == null){//目标图像为空的话
dest = creatCompatibleDestImage(src,null);
}
double sat =127.0d*ratio;//sat为调整值，计算公式为sat=127*ratio
int[] inpixels = new int[width*height];
int[] outpixels = new int[width*height];

getRGB(src,0,0,width,height,inpixels);
double min,max,dif,sum;
double f1,f2;
int index = 0;
double h,s,l;//HSL色彩空间的三个分量
double v1,v2,v3,h1;
for(int row=0;row<height;row++){
int ta=0,tr=0,tg=0,tb=0;
for(int col=0;col<width;col++){
index = row*width+col;
ta = (inpixels[index] >> 24 ) & 0xff;
tr = (inpixels[index] >> 16 ) & 0xff;
tg = (inpixels[index] >> 8 ) & 0xff;
tb = (inpixels[index]) & 0xff;

//RGB 转换为 HSL
min = tr;
if(tg<min)
min = tg;
if(tb<min)
min = tb;
max = tr;
f1 = 0.0;
f2 = tg-tb;
if(tg>max){
max = tg;
f1 = 120.0;
f2 = tb-tr;
}
if(tb >max){
max = tb;
f1 = 240.0;
f2 = tr-tg;
}
dif = max-min;
sum = max+min;
l =0.5*sum;//亮度仅与图像的最多颜色成分和最少的颜色成分的总量有关。亮度越小，图像越趋于黑色。亮度越高图像越趋于明亮的白色。
if(dif == 0){//最大值与最小值相同，则表示为灰色，那么s定义为0，h未定义通常也写为0
h = 0.0;
s = 0.0;
} else if(l<127.5){//根据亮度l计算饱和度
s = 255.0*dif/sum;
} else{
s = 255.0*dif/(510.0-sum);
}
h = (f1 +60.0*f2)/dif;//计算色调h
if(h<0.0){
h+=360.0;
}
if(h>360.0){
h-=360.0;
}

//饱和度调整
s = s+sat;
if(s<0.0){
s = 0.0;
}
if(s>255.0){
s = 255.0;
}

//HSL 转换为 RGB
if(s == 0){//表示灰色，R，G，B定义为0
tr = (int)l;
tg = (int)l;
tb = (int)l;
}else{
if(l<127.5){
v2 = clo255 *l*(255+s);
}else{
v2 = l+s-clo255*s*l;
}
v1 = 2*l-v2;
v3 = v2-v1;
h1 = h+120.0;
if(h1>=360.0)
h1 -=360.0;
//计算tr
if(h1<60){
tr = (int)(v1 +v3 *h1 *clo60);
}else if(h1<180.0){
tr = (int)v2;
}else if(h1<240.0){
tr = (int)(v1+v3*(4-h1*clo60));
}else{
tr = (int)v1;
}
//计算tg
h1 = h;
if(h1<60.0){
tg = (int)(v1 +v3 *h1 *clo60);
}else if(h1 <180.0){
tg = (int)v2;
}else if(h1<240.0){
tg = (int)(v1+v3*(4-h1*clo60));
}else {
tg = (int)v1;
}
//计算tb
h1 = h-120.0;
if(h1 <0.0){
h1 += 360.0;
}
if(h1<60.0){
tb = (int)(v1 +v3 *h1 *clo60);
}else if(h1<180.0){
tb = (int)v2;
}else if(h1<240.0){
tb = (int)(v1+v3*(4-h1*clo60));
}else{
tb = (int)v1;
}
}
outpixels[index] = (ta <<24) | (clamp(tr) << 16) | (clamp(tg) << 8) | clamp(tb);
}
}
setRGB(dest,0,0,width,height,outpixels);
return dest;
}
public static int clamp(int c){
return c>255 ? 255:((c<0) ? 0:c);
}
}

测试代码同上面老照片特效！！