Learning OpenCV, 2nd Edition

The function cv::line() draws a straight line from pt1 to pt2 in the image img. Lines are

automatically clipped by the image boundaries.

cv::rectangle()

void rectangle(

cv::Mat& img, // Image to be drawn on

cv::Point pt1, // First corner of rectangle

cv::Point pt2 // Opposite corner of rectangle

const cv::Scalar& color, // Color, BGR form

int lineType = 8, // Connectedness, 4 or 8

int shift = 0 // Bits of radius to treat as fraction

);

void rectangle(

cv::Mat& img, // Image to be drawn on

cv::Rect r, // Rectangle to draw

const cv::Scalar& color, // Color, BGR form

int lineType = 8, // Connectedness, 4 or 8

int shift = 0 // Bits of radius to treat as fraction

);

The function cv::rectangle() draws a rectangle with corners pt1 to pt2 in the image img. An

alternate form of cv::rectangle() allows the rectangle’s location and size to be specified by a single

cv::Rect argument r.

cv::polyLines()

void polyLines(

cv::Mat& img, // Image to be drawn on

const cv::Point* pts, // C-style array of arrays of points

int npts, // Number of points in ‘pts[i]’

int ncontours, // Number of arrays in ‘pts’

bool isClosed, // If true, connect last and first points

const cv::Scalar& color, // Color, BGR form

int lineType = 8, // Connectedness, 4 or 8

int shift = 0 // Bits of radius to treat as fraction

);

This function draws any number of unfilled ...