rectangle（）函数与rect类详解

rectangle（）函数

rectangle（）函数：
在给定的图片上画出一个矩形框；有两个定义：
定义1：

@param img Image.
@param pt1 Vertex of the rectangle.矩形的顶点
@param pt2 Vertex of the rectangle opposite to pt1 .与p1相反的矩形的顶点
@param color Rectangle color or brightness (grayscale image).
@param thickness Thickness of lines that make up the rectangle. Negative values, like #FILLED,
mean that the function has to draw a filled rectangle.
@param lineType Type of the line. See #LineTypes
@param shift Number of fractional bits in the point coordinates.
 */
CV_EXPORTS_W void rectangle(InputOutputArray img, Point pt1, Point pt2,
                          const Scalar& color, int thickness = 1,
                          int lineType = LINE_8, int shift = 0);

#include
#include
#include
using namespace cv;
using namespace std;
int main(int argc,char *agrv[])
{
	Mat imag = imread("C:\\Users\\Desktop\\picture.jpg");
	if (!imag.data)
	{
		cout << "Open error!" << endl;
		return -1;
	}
	rectangle(imag, Point(1000, 400), Point(imag.rows, imag.cols*0.55), Scalar(0, 255, 0), 2, 8);
	imshow("【创建矩形框】", imag);
	waitKey(0);
	return 0;
}

定义2：此方法需要借助Rect类；

CV_EXPORTS_W void rectangle(InputOutputArray img, Rect rec,
                          const Scalar& color, int thickness = 1,
                          int lineType = LINE_8, int shift = 0);

Rect的一个最常用的重载函数：

 Rect_(_Tp _x, _Tp _y, _Tp _width, _Tp _height);
 _Tp x; //!< x coordinate of the top-left corner,左上角y的坐标
    _Tp y; //!< y coordinate of the top-left corner，左上角y的坐标
    _Tp width; //!< width of the rectangle，矩形的宽度
    _Tp height; //!< height of the rectangle，矩形的高度；
    x,y是确定矩形框在输入图片的位置；

#include
#include
#include
using namespace cv;
using namespace std;
int main(int argc,char *agrv[])
{
	Mat imag = imread("C:\\Users\\Desktop\\picture.jpg");
	if (!imag.data)
	{
		cout << "Open error!" << endl;
		return -1;
	}
	/*rectangle(imag, Point(1000, 400), Point(imag.rows, imag.cols*0.55), Scalar(0, 255, 0), 2, 8);*/
	Rect rec(750, 400, 280,250);
	rectangle(imag, rec, Scalar(0,255, 0), 2, 8, 0);
	imshow("【创建矩形框】", imag);
	waitKey(0);
	return 0;
}