OpenCV畫橢圓、實心圓、凹多邊形、線段、矩形

OpenCV畫橢圓、實心圓、凹多邊形、線段、矩形

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author@jason_ql
http://blog.csdn.net/lql0716

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1、 實例代碼

#include <QCoreApplication>
#include <opencv2/core/core.hpp>
#include <opencv2/highgui/highgui.hpp>
#include <opencv2/imgproc/imgproc.hpp>
#include <opencv2/opencv.hpp>

using namespace cv;
using namespace std;

#define WINDOW_WIDTH 600 //定義窗口大小的宏
#define WINDOW_NAME1 "【繪製圖1】" //爲窗口標題定義的宏
#define WINDOW_NAME2 "【繪製圖2】" //爲窗口標題定義的宏

//-------------------------------------------------------------
//         OpenCV畫橢圓、實心圓、凹多邊形、線段、矩形
//-------------------------------------------------------------

//畫橢圓
void drawEllipse(cv::Mat img, double angle){
    int thickness = 2;
    int lineType = 8;

    cv::ellipse(img,
                cv::Point(WINDOW_WIDTH/2, WINDOW_WIDTH/2),
                cv::Size(WINDOW_WIDTH/4, WINDOW_WIDTH/16),
                angle,
                0,
                360,
                cv::Scalar(255,129,0),
                thickness,
                lineType);
}

//畫實心圓
void drawFilledCircle(cv::Mat img, cv::Point center){
    int thickness = -1;
    int lineType = 8;

    cv::circle(img,
               center,
               WINDOW_WIDTH/32,
               cv::Scalar(0,0,255),
               thickness,
               lineType);
}

//畫凹多邊形
void drawPolygon(cv::Mat img){
    int lineType = 8;

    //創建一些點
    cv::Point rookPoints[1][20];
    rookPoints[0][0] = cv::Point(WINDOW_WIDTH / 4, 7 * WINDOW_WIDTH / 8);
    rookPoints[0][1] = cv::Point(3 * WINDOW_WIDTH / 4, 7 * WINDOW_WIDTH / 8);
    rookPoints[0][2] = cv::Point(3 * WINDOW_WIDTH / 4, 13 * WINDOW_WIDTH / 16);
    rookPoints[0][3] = cv::Point(11 * WINDOW_WIDTH / 16, 13 * WINDOW_WIDTH / 16);
    rookPoints[0][4] = cv::Point(19 * WINDOW_WIDTH / 32, 3 * WINDOW_WIDTH / 8);
    rookPoints[0][5] = cv::Point(3 * WINDOW_WIDTH / 4, 3 * WINDOW_WIDTH / 8);
    rookPoints[0][6] = cv::Point(3 * WINDOW_WIDTH / 4, WINDOW_WIDTH / 8);
    rookPoints[0][7] = cv::Point(26 * WINDOW_WIDTH / 40, WINDOW_WIDTH / 8);
    rookPoints[0][8] = cv::Point(26 * WINDOW_WIDTH / 40, WINDOW_WIDTH / 4);
    rookPoints[0][9] = cv::Point(22 * WINDOW_WIDTH / 40, WINDOW_WIDTH / 4);
    rookPoints[0][10] = cv::Point(22 * WINDOW_WIDTH / 40, WINDOW_WIDTH / 8);
    rookPoints[0][11] = cv::Point(18 * WINDOW_WIDTH / 40, WINDOW_WIDTH / 8);
    rookPoints[0][12] = cv::Point(18 * WINDOW_WIDTH / 40, WINDOW_WIDTH / 4);
    rookPoints[0][13] = cv::Point(14 * WINDOW_WIDTH / 40, WINDOW_WIDTH / 4);
    rookPoints[0][14] = cv::Point(14 * WINDOW_WIDTH / 40, WINDOW_WIDTH / 8);
    rookPoints[0][15] = cv::Point(WINDOW_WIDTH / 4, WINDOW_WIDTH / 8);
    rookPoints[0][16] = cv::Point(WINDOW_WIDTH / 4, 3 * WINDOW_WIDTH / 8);
    rookPoints[0][17] = cv::Point(13 * WINDOW_WIDTH / 32, 3 * WINDOW_WIDTH / 8);
    rookPoints[0][18] = cv::Point(5 * WINDOW_WIDTH / 16, 13 * WINDOW_WIDTH / 16);
    rookPoints[0][19] = cv::Point(WINDOW_WIDTH / 4, 13 * WINDOW_WIDTH / 16);

    const cv::Point* ppt[1] = {rookPoints[0]};
    int npt[] = {20};

    cv::fillPoly(img,
                 ppt,
                 npt,
                 1,
                 cv::Scalar(255, 255, 255),
                 lineType);

}

//畫線
void drawLine(cv::Mat img, cv::Point start, cv::Point end){
    int thickness = 2;
    int lineType = 8;

    cv::line(img,
             start,
             end,
             cv::Scalar(0,0,0),
             thickness,
             lineType);
}

int main(void){
    //創建空白的Mat圖像
    cv::Mat atomImage = cv::Mat::zeros(WINDOW_WIDTH, WINDOW_WIDTH, CV_8UC3);
    cv::Mat rookImage = cv::Mat::zeros(WINDOW_WIDTH, WINDOW_WIDTH, CV_8UC3);

    //繪製橢圓
    drawEllipse(atomImage, 90);
    drawEllipse(atomImage, 0);
    drawEllipse(atomImage, 45);
    drawEllipse(atomImage, -45);

    //繪製圓心
    drawFilledCircle(atomImage, cv::Point(WINDOW_WIDTH / 2, WINDOW_WIDTH / 2));

    //繪製橢圓
    drawPolygon(rookImage);

    //繪製矩形
    cv::rectangle(rookImage,
                  cv::Point(0, 7 * WINDOW_WIDTH / 8),
                  cv::Point(WINDOW_WIDTH, WINDOW_WIDTH),
                  cv::Scalar(0, 255, 255),
                  -1,
                  8);

    //繪製一些線段
    drawLine(rookImage, cv::Point(0, 15 * WINDOW_WIDTH / 16), cv::Point(WINDOW_WIDTH, 15 * WINDOW_WIDTH / 16));
    drawLine(rookImage, cv::Point(WINDOW_WIDTH / 4, 7 * WINDOW_WIDTH / 8), cv::Point(WINDOW_WIDTH / 4, WINDOW_WIDTH));
    drawLine(rookImage, cv::Point(WINDOW_WIDTH / 2, 7 * WINDOW_WIDTH / 8), cv::Point(WINDOW_WIDTH / 2, WINDOW_WIDTH));
    drawLine(rookImage, cv::Point(3 * WINDOW_WIDTH / 4, 7 * WINDOW_WIDTH / 8), cv::Point(3 * WINDOW_WIDTH / 4, WINDOW_WIDTH));

    //顯示繪製出的圖像
    cv::imshow(WINDOW_NAME1, atomImage);
    cv::moveWindow(WINDOW_NAME1, 0, 200);
    cv::imshow(WINDOW_NAME2, rookImage);
    cv::moveWindow(WINDOW_NAME2, WINDOW_WIDTH, 200);

    cv::waitKey(0);

    return(0);

}

2、 ellipse()畫橢圓

Draws a simple or thick elliptic arc or fills an ellipse sector.

C++: void ellipse(Mat& img, Point center, Size axes, double angle, double startAngle, double endAngle, const Scalar& color, int thickness=1, int lineType=8, int shift=0)

C++:void ellipse(Mat& img, const RotatedRect& box, const Scalar& color, int thickness=1, int lineType=8)

Python:cv2.ellipse(img, center, axes, angle, startAngle, endAngle, color[, thickness[, lineType[, shift]]]) → None

Python:cv2.ellipse(img, box, color[, thickness[, lineType]]) → None

C:void cvEllipse(CvArr* img, CvPoint center, CvSize axes, double angle, double start_angle, double end_angle, CvScalar color, int thickness=1, int line_type=8, int shift=0 )

Python: cv.Ellipse(img, center, axes, angle, start_angle, end_angle, color, thickness=1, lineType=8, shift=0) → None

C:void cvEllipseBox(CvArr* img, CvBox2D box, CvScalar color, int thickness=1, int line_type=8, int shift=0 )

Python:cv.EllipseBox(img, box, color, thickness=1, lineType=8, shift=0) → None
Parameters:

    img – Image.
    center – Center of the ellipse.
    axes – Half of the size of the ellipse main axes.
    angle – Ellipse rotation angle in degrees.
    startAngle – Starting angle of the elliptic arc in degrees.
    endAngle – Ending angle of the elliptic arc in degrees.
    box – Alternative ellipse representation via RotatedRect or CvBox2D. This means that the function draws an ellipse inscribed in the rotated rectangle.
    color – Ellipse color.
    thickness – Thickness of the ellipse arc outline, if positive. Otherwise, this indicates that a filled ellipse sector is to be drawn.
    lineType – Type of the ellipse boundary. See the line() description.
    shift – Number of fractional bits in the coordinates of the center and values of axes.

The functions ellipse with less parameters draw an ellipse outline, a filled ellipse, an elliptic arc, or a filled ellipse sector. A piecewise-linear curve is used to approximate the elliptic arc boundary. If you need more control of the ellipse rendering, you can retrieve the curve using ellipse2Poly() and then render it with polylines() or fill it with fillPoly() . If you use the first variant of the function and want to draw the whole ellipse, not an arc, pass startAngle=0 and endAngle=360 . The figure below explains the meaning of the parameters.

3、 circle()畫實心圓

Draws a circle.

C++:void circle(Mat& img, Point center, int radius, const Scalar& color, int thickness=1, int lineType=8, int shift=0)

Python: cv2.circle(img, center, radius, color[, thickness[, lineType[, shift]]]) → None

C:void cvCircle(CvArr* img, CvPoint center, int radius, CvScalar color, int thickness=1, int line_type=8, int shift=0 )

Python: cv.Circle(img, center, radius, color, thickness=1, lineType=8, shift=0) → None

Parameters: 

    img – Image where the circle is drawn.
    center – Center of the circle.
    radius – Radius of the circle.
    color – Circle color.
    thickness – Thickness of the circle outline, if positive. Negative thickness means that a filled circle is to be drawn.
    lineType – Type of the circle boundary. See the line() description.
    shift – Number of fractional bits in the coordinates of the center and in the radius value.

The function circle draws a simple or filled circle with a given center and radius.

4、 fillpoly()畫凹多邊形

Fills the area bounded by one or more polygons.

C++:void fillPoly(Mat& img, const Point** pts, const int* npts, int ncontours, const Scalar& color, int lineType=8, int shift=0, Point offset=Point() )

Python:cv2.fillPoly(img, pts, color[, lineType[, shift[, offset]]]) → None

C:void cvFillPoly(CvArr* img, CvPoint** pts, const int* npts, int contours, CvScalar color, int line_type=8, int shift=0 )

Python: cv.FillPoly(img, polys, color, lineType=8, shift=0) → None

Parameters: 

    img – Image.
    pts – Array of polygons where each polygon is represented as an array of points.
    npts – Array of polygon vertex counters.
    ncontours – Number of contours that bind the filled region.
    color – Polygon color.
    lineType – Type of the polygon boundaries. See the line() description.
    shift – Number of fractional bits in the vertex coordinates.
    offset – Optional offset of all points of the contours.

The function fillPoly fills an area bounded by several polygonal contours. The function can fill complex areas, for example, areas with holes, contours with self-intersections (some of their parts), and so forth.

5、 line()畫線

Draws a line segment connecting two points.

C++:void line(Mat& img, Point pt1, Point pt2, const Scalar& color, int thickness=1, int lineType=8, int shift=0)

Python:cv2.line(img, pt1, pt2, color[, thickness[, lineType[, shift]]]) → None

C:void cvLine(CvArr* img, CvPoint pt1, CvPoint pt2, CvScalar color, int thickness=1, int line_type=8, int shift=0 )

Python:cv.Line(img, pt1, pt2, color, thickness=1, lineType=8, shift=0) → None

Parameters: 

    img – Image.
    pt1 – First point of the line segment.
    pt2 – Second point of the line segment.
    color – Line color.
    thickness – Line thickness.
    lineType –

    Type of the line:
        8 (or omitted) - 8-connected line.
        4 - 4-connected line.
        CV_AA - antialiased line.
    shift – Number of fractional bits in the point coordinates.

The function line draws the line segment between pt1 and pt2 points in the image. The line is clipped by the image boundaries. For non-antialiased lines with integer coordinates, the 8-connected or 4-connected Bresenham algorithm is used. Thick lines are drawn with rounding endings. Antialiased lines are drawn using Gaussian filtering. To specify the line color, you may use the macro CV_RGB(r, g, b) .

6、 rectangle()畫矩形

Draws a simple, thick, or filled up-right rectangle.

C++:void rectangle(Mat& img, Point pt1, Point pt2, const Scalar& color, int thickness=1, int lineType=8, int shift=0)

C++:void rectangle(Mat& img, Rect rec, const Scalar& color, int thickness=1, int lineType=8, int shift=0 )

Python:cv2.rectangle(img, pt1, pt2, color[, thickness[, lineType[, shift]]]) → None

C:void cvRectangle(CvArr* img, CvPoint pt1, CvPoint pt2, CvScalar color, int thickness=1, int line_type=8, int shift=0 )

Python:cv.Rectangle(img, pt1, pt2, color, thickness=1, lineType=8, shift=0) → None

Parameters: 

    img – Image.
    pt1 – Vertex of the rectangle.
    pt2 – Vertex of the rectangle opposite to pt1 .
    rec – Alternative specification of the drawn rectangle.
    color – Rectangle color or brightness (grayscale image).
    thickness – Thickness of lines that make up the rectangle. Negative values, like CV_FILLED , mean that the function has to draw a filled rectangle.
    lineType – Type of the line. See the line() description.
    shift – Number of fractional bits in the point coordinates.

The function rectangle draws a rectangle outline or a filled rectangle whose two opposite corners are pt1 and pt2, or r.tl() and r.br()-Point(1,1).

7、 更多相關函數見官方文檔

Drawing Functions