《学习OpenCV》练习题第三章第三题

#include <highgui.h>
#include <cv.h>
#include <stdio.h>

#pragma comment (lib,"opencv_calib3d231d.lib")
#pragma comment (lib,"opencv_contrib231d.lib")
#pragma comment (lib,"opencv_core231d.lib")
#pragma comment (lib,"opencv_features2d231d.lib")
#pragma comment (lib,"opencv_flann231d.lib")
#pragma comment (lib,"opencv_gpu231d.lib")
#pragma comment (lib,"opencv_haartraining_engined.lib")
#pragma comment (lib,"opencv_highgui231d.lib")
#pragma comment (lib,"opencv_imgproc231d.lib")
#pragma comment (lib,"opencv_legacy231d.lib")
#pragma comment (lib,"opencv_ml231d.lib")
#pragma comment (lib,"opencv_objdetect231d.lib")
#pragma comment (lib,"opencv_ts231d.lib")
#pragma comment (lib,"opencv_video231d.lib")

/*
 *《学习OpenCV》第三章第三题
 * 完成时间：1:34 3/2 星期六 2013
 */

#define ROWS 400  // 矩阵行数
#define COLS 400  // 矩阵列数

// 定义绿色长方形的两个顶点
CvPoint point1 = cvPoint(80, 20);
CvPoint point2 = cvPoint(160, 80);

// Help function
// 检查当前点是否在要画的长方形区域内
bool isThePointInRectangle(int x, int y)
{
    if( (x <= point2.x) && (y <= point2.y) 
        & (x >= point1.x) && (y >= point1.y))
        return true;
    else 
        return false;
}

int main()
{
    // 三通道的二维字节类型矩阵
    CvMat* mat = cvCreateMat(ROWS, COLS, CV_8UC3);

    // 将所有数值初始化为零 
    cvZero(mat);
    // 获得矩阵元素(0,0)的指针
    uchar *p = (uchar*)cvPtr2D(mat, 0, 0);
    // 为矩阵赋值，画长方形
    for(int i = 0; i < mat->cols; i++)
    {
        for(int j = 0; j < mat->rows; j++)
        {
            p = (uchar*)cvPtr2D(mat, i, j);
            // 使其指向中间的通道
            p++;
            if(isThePointInRectangle(i, j) == true)
            {
                *p = 255;
            }
            p++;
        }
    }

    cvShowImage("img", mat);
    cvWaitKey(0);

    cvReleaseMat(&mat);
    cvDestroyAllWindows(); 

    return 0;
}

运行结果：