opencv c 小练习9-1

/*

用鼠标读取图像颜色值。

编写程序读取并显示一张图片。

当用户鼠标点击图片时，读取当前鼠标对应位置的像素值（注意像素存储顺序是BGR），

以文本的形式在鼠标所在位置的左上角显示出来（显示当前坐标值和像素值）。当鼠标移动时，旧的文本框消失。

本代码：不能做到当鼠标移动时，旧的文本框消失。

*/

#include <iostream>
#include <opencv.hpp>
#include <opencv2/imgproc/types_c.h>

#pragma comment(lib, "opencv_world420d.lib")
using namespace cv;

Mat img, temp;
int move;

//鼠标的callback定义
void my_mouse_callback(int event, int x, int y, int flags, void* param)
{
	Mat& img = *(Mat*)param;
	int B, G, R, X, Y;
	String s;
	switch (event)
	{
		case EVENT_LBUTTONDOWN:
		{
			move = 0;
			CvPoint pt = cvPoint(x, y);
			X = pt.x;
			Y = pt.y;
			B = img.at<Vec3b>(x, y)[0];
			G = img.at<Vec3b>(x, y)[1];
			R = img.at<Vec3b>(x, y)[2];
			s = std::to_string(X) + "  " + std::to_string(Y) + ";" + std::to_string(B) + "  " + std::to_string(G) + "  " + std::to_string(R);
			int font_face = FONT_HERSHEY_COMPLEX;
			double font_scale = 0.5;
			int thickness = 0.5;
			int baseline;
			Size s_size = getTextSize(s, font_face, font_scale, thickness, &baseline);
			Point origin;
			origin.x = pt.x - s_size.width;
			origin.y = pt.y;
			putText(img, s, origin, FONT_HERSHEY_DUPLEX, 0.5, Scalar(0, 0, 0));
		}
		break;
		case EVENT_MOUSEMOVE:
		{
			move = 1;
		}
		break;
	}
}

int main()
{
	img = imread("D:\\opencvcx\\work1\\fruits.png");
	img.copyTo(temp);	 
	move = 0;
	while (1) {

		if (move != 1)
		{
			setMouseCallback("fruit", my_mouse_callback, (void*)&temp);
			imshow("fruit", temp);
		}
		else img.copyTo(temp);
		if (waitKey(100) == 27)
			break;
	}
	return 0;
}