#include <opencv2/highgui/highgui.hpp>
#include <opencv2/imgproc/imgproc.hpp>
#include <opencv2/core/core.hpp>
#include <opencv2/calib3d/calib3d.hpp>
#include <iostream>
using namespace cv;
using namespace std;
#define PATH "/Users/mac/ClionProjects/opencv_test/"

/**
 仿射變換矩陣是一個2*3矩陣，採用齊次座標時，第三行的前兩個元素為0（表示投影變換的）
 仿射變換不改變形狀（三角形還是三角形），但是如果是投影變換可能會變成四邊形
 使用warpAffine
 使用getrotaton由旋轉中心縮放係數旋轉角度得到旋轉放縮變換矩陣
 static_cast<type>(expression)  相當於強制轉換 (type)expression
 */
int main()
{

    //
    Mat srcImg = imread(PATH"home.jpg");
    //cvtColor(srcImg,srcImg, CV_BGR2GRAY);

    Mat rotMat(2, 3, CV_32FC1);
    Mat warpMat(2, 3, CV_32FC1);
    Mat dstImgWarp, dstImgWarpRot;
    dstImgWarp = Mat::zeros(srcImg.rows, srcImg.cols, srcImg.type());
    Point2f srcTriangle[3]; //三角形，包含了三個點
    Point2f dstTriangle[3];
    srcTriangle[0] = Point2f(0, 0);
    srcTriangle[1] = Point2f(static_cast<float>(srcImg.cols-1), 0);
    srcTriangle[2] = Point2f(0, static_cast<float>(srcImg.rows-1));
    dstTriangle[0] = Point2f(static_cast<float>(srcImg.cols*0), (float)(srcImg.rows*0.33));
    dstTriangle[0] = Point2f(static_cast<float>(srcImg.cols*0.65), (float)(srcImg.rows*0.35));
    dstTriangle[0] = Point2f(static_cast<float>(srcImg.cols*0.15), (float)(srcImg.rows*0.6));
    //由兩個三角形座標對應關係解出變換矩陣
    warpMat = getAffineTransform(srcTriangle, dstTriangle);

    warpAffine(srcImg, dstImgWarp, warpMat, dstImgWarp.size());

    //旋轉放縮
    Point center = Point(dstImgWarp.cols/2, dstImgWarp.rows/2);
    double angle = -30;
    double scale = 0.8;
    rotMat = getRotationMatrix2D(center, angle, scale);
    warpAffine(srcImg, dstImgWarpRot, rotMat, dstImgWarpRot.size());
    imshow("origial", srcImg);
    imshow("warp", dstImgWarp);
    imshow("warp_rot", dstImgWarpRot);

    waitKey(0);
    return 0;

}