CODEWITHSUNDEEP
javaopencvoperator-overloading
AndreKR
AndreKR

Reputation: 33678

Union two rectangles in Java OpenCV

This documentation page states:

In addition to the class members, the following operations on rectangles are implemented: [...]

  • rect = rect1 | rect2 (minimum area rectangle containing rect2 and rect3)

However, this code:

Rect box1 = new Rect();
Rect box2 = new Rect();
Rect unionBox = new Rect();

unionBox = box1 | box2;

leads to this error:

Operator '|' cannot be applied to 'org.opencv.core.Rect', 'org.opencv.core.Rect'

How do I correctly union two (or better: many) Rects?

Upvotes: 3

Views: 789

Answers (1)

sturkmen
sturkmen

Reputation: 3550

AFAIK using operators is not supported on JAVA.

i suggest using boundingRect but you should to know there is one pixel difference as seen C++ code below

#include "opencv2/imgproc/imgproc.hpp"
#include "opencv2/highgui/highgui.hpp"

#include <iostream>

using namespace cv;
using namespace std;

int main(int argc, char** argv)
{
    Rect a(10,10,20,20);
    Rect b(11,11,20,20);

    vector<Point> pts;

    pts.push_back(a.tl());
    pts.push_back(a.br());

    pts.push_back(b.tl());
    pts.push_back(b.br());

    Rect boundingRect_result = boundingRect( pts );
    Rect operator_result = a | b;

    cout << "Rect a: " << a << endl;
    cout << "Rect b: " << b << endl;

    cout << "\nRect Points a b:\n" << pts << endl;

    cout << "\nboundingRect result : " << boundingRect_result << endl;
    cout << "result a | b        : " << operator_result << endl;

    return 0;
}

output :

Rect a: [20 x 20 from (10, 10)]
Rect b: [20 x 20 from (11, 11)]

Rect Points a b:
[10, 10;
 30, 30;
 11, 11;
 31, 31]

boundingRect result : [22 x 22 from (10, 10)]
result a | b        : [21 x 21 from (10, 10)]

(i am not familiar with JAVA but tried to write the code below to test)

Rect r1 = new Rect(10,10,20,20);
Rect r2 = new Rect(11,11,20,20);

Point[] rects_pts = new Point[4];
rects_pts[0] =  r1.tl();
rects_pts[1] =  r1.br();
rects_pts[2] =  r2.tl();
rects_pts[3] =  r2.br();

MatOfPoint mof = new MatOfPoint();
mof.fromArray(rects_pts);

Rect union = Imgproc.boundingRect(mof);
System.out.print( union);

result is like {10, 10, 22x22}

another option is writing your own function in JAVA. here is OpenCV source that can be converted to JAVA

Upvotes: 2

Related Questions