77 lines
1.7 KiB
C++
77 lines
1.7 KiB
C++
#include "dither.h"
|
|
|
|
using namespace std;
|
|
using namespace cv;
|
|
|
|
uint8_t saturated_add(uint8_t val1, int8_t val2);
|
|
|
|
Mat dither_image(Mat rawImg){
|
|
Mat dithImg;
|
|
int imgWidth;
|
|
int imgHeight;
|
|
|
|
//Load the image and convert to grayscale first
|
|
cvtColor(rawImg, dithImg, CV_BGR2GRAY);
|
|
|
|
|
|
//Get the size info
|
|
imgWidth = dithImg.cols;
|
|
imgHeight = dithImg.rows;
|
|
|
|
//Run the 'Floyd-Steinberg' dithering algorithm
|
|
int err;
|
|
int8_t a,b,c,d;
|
|
|
|
for(int i=0; i<imgHeight; i++)
|
|
{
|
|
for(int j=0; j<imgWidth; j++)
|
|
{
|
|
if(dithImg.at<uint8_t>(i,j) > 127)
|
|
{
|
|
err = dithImg.at<uint8_t>(i,j) - 255;
|
|
dithImg.at<uint8_t>(i,j) = 255;
|
|
}
|
|
else
|
|
{
|
|
err = dithImg.at<uint8_t>(i,j) - 0;
|
|
dithImg.at<uint8_t>(i,j) = 0;
|
|
}
|
|
|
|
a = (err * 7) / 16;
|
|
b = (err * 1) / 16;
|
|
c = (err * 5) / 16;
|
|
d = (err * 3) / 16;
|
|
|
|
if((i != (imgHeight-1)) && (j != 0) && (j != (imgWidth - 1)))
|
|
{
|
|
dithImg.at<uint8_t>(i+0,j+1) = saturated_add(dithImg.at<uint8_t>(i+0,j+1),a);
|
|
dithImg.at<uint8_t>(i+1,j+1) = saturated_add(dithImg.at<uint8_t>(i+1,j+1),b);
|
|
dithImg.at<uint8_t>(i+1,j+0) = saturated_add(dithImg.at<uint8_t>(i+1,j+0),c);
|
|
dithImg.at<uint8_t>(i+1,j-1) = saturated_add(dithImg.at<uint8_t>(i+1,j-1),d);
|
|
}
|
|
}
|
|
}
|
|
|
|
return dithImg;
|
|
}
|
|
|
|
uint8_t saturated_add(uint8_t val1, int8_t val2)
|
|
{
|
|
int16_t val1_int = val1;
|
|
int16_t val2_int = val2;
|
|
int16_t tmp = val1_int + val2_int;
|
|
|
|
if(tmp > 255)
|
|
{
|
|
return 255;
|
|
}
|
|
else if(tmp < 0)
|
|
{
|
|
return 0;
|
|
}
|
|
else
|
|
{
|
|
return tmp;
|
|
}
|
|
}
|