Opencv实现画笔的功能

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

using namespace std;
using namespace cv;

Rect g_rectangle;
bool g_bDrawing = false;
RNG g_rng(12345);
Point g_nCurrPoint;
int g_nThick = 0, g_nBlue = 255, g_nGreen = 255, g_nRed = 0;

/*注意：不能在毁掉函数中写入未初始化的矩阵类，所以需要用时，需要写一个标志位，然后再在while(1)循环内使用*/
void onMouse(int event, int x, int y, int flag, void *param)
{
	Mat &img = *(cv::Mat*)param;

	switch (event)
	{
		//移动鼠标的时候
	case CV_EVENT_MOUSEMOVE:
	{
							   g_nCurrPoint = Point(x, y);
	}
		break;
		//点击鼠标左键时
	case CV_EVENT_LBUTTONDOWN:
	{
								 g_bDrawing = true;
								 g_nCurrPoint = Point(x, y);
	}
		break;
		//松开鼠标左键时
	case CV_EVENT_LBUTTONUP:
	{
							   g_bDrawing = false;
	}
		break;
	}
}

int main()
{
	Mat srcImage(600, 800, CV_8UC3);
	Mat tempImage;

	srcImage.copyTo(tempImage);
	srcImage = Scalar::all(0);

	namedWindow("【鼠标事件窗口】", 0);
	setMouseCallback("【鼠标事件窗口】", onMouse, (void *)&srcImage);

	namedWindow("【滚动条窗口】", 0);
	createTrackbar("thick", "【滚动条窗口】", &g_nThick, 100, 0);
	createTrackbar("Blue", "【滚动条窗口】", &g_nBlue, 255, 0);
	createTrackbar("Green", "【滚动条窗口】", &g_nGreen, 255, 0);
	createTrackbar("Red", "【滚动条窗口】", &g_nRed, 255, 0);

	char key;
	while (1)
	{
		if (g_bDrawing)
		{
			circle(srcImage, g_nCurrPoint, 0, Scalar(g_nBlue, g_nGreen, g_nRed), g_nThick + 1);
		}

		imshow("【鼠标事件窗口】", srcImage);

		key = waitKey(1);
		if (key == 27)
			break;

		if (key == '1')
			srcImage = Scalar::all(0);

		/*DrawRectangle(srcImage, g_rectangle);
		imshow(WINDOW_NAME, srcImage);
		if (waitKey(10) == 27)
		break;*/
	}

	return 0;
}