答え
#include <cv.h>
#include <highgui.h>
#include <iostream>
using namespace std;
int main( int argc, char **argv)
{
IplImage *imgA = cvLoadImage( "test2.jpg", CV_LOAD_IMAGE_ANYDEPTH | CV_LOAD_IMAGE_ANYCOLOR);
if(imgA ==NULL)
{
cout<<"Can't Load Image ." << endl;
std::exit(0);
}
for(int j = 0; j < imgA->height;j++)
for( int i = 0; i < imgA->widthStep;i+=3)
{
imgA->imageData[j*imgA->widthStep + i]=(char(255) - imgA->imageData[j*imgA->widthStep+i]);
imgA->imageData[j*imgA->widthStep +i+1]=(char(255) - imgA->imageData[j*imgA->widthStep +i+1]);
imgA->imageData[j*imgA->widthStep +i+2]=(char(255) - imgA->imageData[j*imgA->widthStep +i+2]);
}
cvNamedWindow("window",CV_WINDOW_AUTOSIZE);
cvShowImage("window",imgA);
cvWaitKey(0); // 0秒待つ => ずっと入力待ち
cvReleaseImage( &imgA );
cvDestroyWindow("window");
return 0;
}