OpenCV 그리기 함수

직선 그리기

/* Draws 4-connected, 8-connected or antialiased line segment connecting two points */

CVAPI(void)  cvLine( CvArr* img, CvPoint pt1, CvPoint pt2,

                     CvScalar color, int thickness CV_DEFAULT(1),

                     int line_type CV_DEFAULT(8), int shift CV_DEFAULT(0) );

통상적인 image 의 입력, CvPoint 타입의 점 두개를 입력받는다. 다음으로 색상값을 CvScalar로 입력받는다.

두께, anti-aliasing 방법 등을 추가로 선택 할 수 있다.

사각형 그리기

/* Draws a rectangle given two opposite corners of the rectangle (pt1 & pt2), if thickness<0 (e.g. thickness == CV_FILLED), the filled box is drawn */

CVAPI(void)  cvRectangle( CvArr* img, CvPoint pt1, CvPoint pt2,

                          CvScalar color, int thickness CV_DEFAULT(1),

                          int line_type CV_DEFAULT(8),

                          int shift CV_DEFAULT(0));

위의 cvLine과 유사하다. 두 점을 대각 방향의 모서리점으로 간주하여 사각형을 그린다.

/* Draws a rectangle specified by a CvRect structure */

CVAPI(void)  cvRectangleR( CvArr* img, CvRect r,

                           CvScalar color, int thickness CV_DEFAULT(1),

                           int line_type CV_DEFAULT(8),

                           int shift CV_DEFAULT(0));

원 그리기

/* Draws a circle with specified center and radius. Thickness works in the same way as with cvRectangle */

CVAPI(void)  cvCircle( CvArr* img, CvPoint center, int radius,

                       CvScalar color, int thickness CV_DEFAULT(1),

                       int line_type CV_DEFAULT(8), int shift CV_DEFAULT(0));

타원 그리기

/* Draws ellipse outline, filled ellipse, elliptic arc or filled elliptic sector,

   depending on <thickness>, <start_angle> and <end_angle> parameters. The resultant figure

   is rotated by <angle>. All the angles are in degrees */

CVAPI(void)  cvEllipse( CvArr* img, CvPoint center, CvSize axes,

                        double angle, double start_angle, double end_angle,

                        CvScalar color, int thickness CV_DEFAULT(1),

                        int line_type CV_DEFAULT(8), int shift CV_DEFAULT(0));

angle을 지정하여 호를 그릴 수 있다.

다각형 그리기

/* Fills convex or monotonous polygon. */

CVAPI(void)  cvFillConvexPoly( CvArr* img, const CvPoint* pts, int npts, CvScalar color,

                               int line_type CV_DEFAULT(8), int shift CV_DEFAULT(0));

/* Fills an area bounded by one or more arbitrary polygons */

CVAPI(void)  cvFillPoly( CvArr* img, CvPoint** pts, const int* npts,

                         int contours, CvScalar color,

                         int line_type CV_DEFAULT(8), int shift CV_DEFAULT(0) );

/* Draws one or more polygonal curves */

CVAPI(void)  cvPolyLine( CvArr* img, CvPoint** pts, const int* npts, int contours,

                         int is_closed, CvScalar color, int thickness CV_DEFAULT(1),

                         int line_type CV_DEFAULT(8), int shift CV_DEFAULT(0) );

CvPoint 구조체의 배열로 전달이 된다.

글자 그리기

/* Renders text stroke with specified font and color at specified location.

   CvFont should be initialized with cvInitFont */

CVAPI(void)  cvPutText( CvArr* img, const char* text, CvPoint org,

                        const CvFont* font, CvScalar color );

org을 좌하단으로 두는 사각의 영역에 color 색상과 font의 글꼴로 문자열이 출력된다.

다음 cvInitFont 를 사용하여 font를 생성한다.

/* Initializes font structure used further in cvPutText */

CVAPI(void)  cvInitFont( CvFont* font, int font_face,

                         double hscale, double vscale,

                         double shear CV_DEFAULT(0),

                         int thickness CV_DEFAULT(1),

                         int line_type CV_DEFAULT(8));