在实现鼠标绘图时，使用cvSet2D来画轨迹，为什么在边缘处出界。求指点。

Question

下面是代码，

/*
创建白色图像，通过鼠标左键绘图，右键实现橡皮擦功能
*/



#include <iostream>
#include <opencv2/opencv.hpp>
#include <opencv2/highgui/highgui.hpp>

using namespace std;
using namespace cv;

bool LFlag = false;
bool RFlag = false;
Point point ;


void onMouseCallback(int event, int x , int y , int flags, void *param)
{
    IplImage *img = (IplImage *)param;
    Point point1, point2;
    switch (event)
    {
        //鼠标左键按下获取当前位置，设置标记
    case CV_EVENT_LBUTTONDOWN:
        LFlag = true;
        point = cvPoint(x, y);
        break;
    case CV_EVENT_LBUTTONUP:
        LFlag = false;

        break;
    case CV_EVENT_RBUTTONDOWN:
        RFlag = true;
        point = Point(x, y);
        cvCircle(img,point,5,CV_RGB(255,255,255),-1);
        break;
    case CV_EVENT_RBUTTONUP:
        RFlag = false;

        break;
    case CV_EVENT_MOUSEMOVE:
        point = Point(x, y);    
        break;
    }
    if (LFlag)
    {

        cvSet2D(img,point.y,point.x,CV_RGB(255,0,0));
    }else if (RFlag)
    {
        cvCircle(img, point, 5, CV_RGB(255,255,255),-1);
    }
}

int main()
{
    IplImage *pImage = cvCreateImage(cvSize(500,500), 8, 3);
    cvRectangle(pImage, cvPoint(0,0), cvPoint(500,500), CV_RGB(255,255,255),-1);
    IplImage *temp = cvCloneImage(pImage);

    namedWindow("简易画板");
    cvSetMouseCallback("简易画板", onMouseCallback, (void *)pImage);

    while (1)
    {
        cvCopy(pImage, temp);

        cvShowImage("简易画板", temp);
        if(waitKey(1)==27)
        {
            break;
        }
    }

    return 0;
}

Answer 1

数组越界了，下面那个函数应该是画出来了但是没有显示，具体函数实现得查查文档