samples/cpp/create_mask.cpp

此程序演示了如何使用鼠标事件以及如何创建和使用遮罩图像（黑白图像）。

/*
* create_mask.cpp
*
* 作者
* Siddharth Kherada <siddharthkherada27[at]gmail[dot]com>
*
* 本教程演示了如何创建遮罩图像（黑白图像）。
* 该程序以源图像作为输入，并输出其对应的
* 遮罩图像。
*/
 
#include "opencv2/imgproc.hpp"
#include "opencv2/imgcodecs.hpp"
#include "opencv2/highgui.hpp"
#include <iostream>
 
using namespace std;
using namespace cv;
 
Mat src, img1, mask, final;
 
Point point;
vector<Point> pts;
int drag = 0;
int var = 0;
int flag = 0;
 
void mouseHandler(int, int, int, int, void*);
 
void mouseHandler(int event, int x, int y, int, void*)
{
 
    if (event == EVENT_LBUTTONDOWN && !drag)
    {
        if (flag == 0)
        {
            if (var == 0)
img1 = src.clone();
point = Point(x, y);
circle(img1, point, 2, Scalar(0, 0, 255), -1, 8, 0);
pts.push_back(point);
var++;
drag = 1;
 
            if (var > 1)
line(img1,pts[var-2], point, Scalar(0, 0, 255), 2, 8, 0);
 
imshow("Source", img1);
        }
    }
 
    if (event == EVENT_LBUTTONUP && drag)
    {
        imshow("Source", img1);
drag = 0;
    }
 
    if (event == EVENT_RBUTTONDOWN)
    {
flag = 1;
img1 = src.clone();
 
        if (var != 0)
        {
            polylines( img1, pts, 1, Scalar(0,0,0), 2, 8, 0);
        }
 
        imshow("Source", img1);
    }
 
    if (event == EVENT_RBUTTONUP)
    {
flag = var;
        final = Mat::zeros(src.size(), CV_8UC3);
        mask = Mat::zeros(src.size(), CV_8UC1);
 
        fillPoly(mask, pts, Scalar(255, 255, 255), 8, 0);
        bitwise_and(src, src, final, mask);
        imshow("Mask", mask);
        imshow("Result", final);
        imshow("Source", img1);
    }
 
    if (event == EVENT_MBUTTONDOWN)
    {
pts.clear();
var = 0;
drag = 0;
flag = 0;
        imshow("Source", src);
    }
}
 
int main(int argc, char **argv)
{
    CommandLineParser parser(argc, argv, "{@input | lena.jpg | input image}");
parser.about("此程序演示了如何使用鼠标事件\n");
parser.printMessage();
cout << "\n\tleft mouse button - set a point to create mask shape\n"
        "\tright mouse button - create mask from points\n"
        "\tmiddle mouse button - reset\n";
    String input_image = parser.get<String>("@input");
 
src = imread(samples::findFile(input_image));
 
    if (src.empty())
    {
printf("Error opening image: %s\n", input_image.c_str());
        return 0;
    }
 
    namedWindow("Source", WINDOW_AUTOSIZE);
    setMouseCallback("Source", mouseHandler, NULL);
    imshow("Source", src);
    waitKey(0);
 
    return 0;
}