#include <stdio.h>
#include <math.h>
#include "cv.h"
#include "cxcore.h"
#include "highgui.h"
#pragma comment(lib,"cv.lib")
#pragma comment(lib,"cxcore.lib")
#pragma comment(lib,"highgui.lib")

void rotationOption(unsigned char *out, unsigned char *in, int inHeight, int inWidth, int inChannel, double theta, int centerX, int centerY);


int main(){
    IplImage *in, *out;

   in = cvLoadImage("./image640.bmp", 0);
    out = cvCreateImage(cvSize(in->width, in->height), in->depth, in->nChannels);
    
    rotationOption((unsigned char*)out->imageData, (unsigned char*)in->imageData, in->height, in->width, in->nChannels, 15.0, 0, 0);

    cvNamedWindow("in", 1);
    cvShowImage("in", in);
    cvNamedWindow("out", 1);
    cvShowImage("out", out);
    cvWaitKey(-1);
    
    cvDestroyWindow("in");
    cvDestroyWindow("out");

    cvReleaseImage( &in );
    cvReleaseImage( &out );

    return 0;
}

void rotationOption(unsigned char *out, unsigned char *in, int inHeight, int inWidth, int inChannel, double theta, int centerX, int centerY){
    int i, j;
    int index;
    int widthStep;
    int pointX, pointY;
    double radian = theta / 180.0 * 3.14159265;
    double cosRadian = cos(radian);
    double sinRadian = sin(radian);

    widthStep = inWidth * inChannel;
    if(widthStep % 4 != 0){
        widthStep = widthStep + 4 - widthStep % 4;
    }

    for(i = 0; i < inHeight; ++i){
        for(j = 0; j < inWidth; ++j){
            pointX = (int)((j - centerX) * cosRadian - (i - centerY) * sinRadian + centerX);
            pointY = (int)((j - centerX) * sinRadian + (i - centerY) * cosRadian + centerY);

            // poiuntX, pointYが入力画像の有効範囲にあれば出力画像へ代入する
            if(pointX >= 0 && pointX < inWidth && pointY >= 0 && pointY < inHeight){
                out[i * widthStep + j] = in[pointY * widthStep + pointX];
            } else {
                out[i * widthStep + j] = 0;
            }
        }
    }
}