opencv 绘图 cvLine cvRectangle cvCircle cvEllipse cvEllipseBox cvFillPoly cvConvexPoly cvPolyLine
常用宏定义：
#define CV_RGB( r, g, b ) cvScalar( (b), (g), (r), 0 ) #define CV_FILLED -1 #define CV_AA 16
#define cvDrawRect cvRectangle #define cvDrawLine cvLine #define cvDrawCircle cvCircle #define cvDrawEllipse cvEllipse #define cvDrawPolyLine cvPolyLine
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直线 cvLine()
/* 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) );
array：输入图像
pt1、pt2：直线的两点 CvPoint()结构
typedef struct CvPoint
{
int x;
int y;
}
CvPoint;
color：边的颜色 CvScalar结构
typedef struct CvScalar
{
double val[4];
}
CvScalar;
这种结构是四个双精度浮点型变量的集合，前三个分别代表红、绿、蓝通道
常用的便捷宏指令CV_RGB(r, g, b)
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矩形 cvRectagle()
/* 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));
pt1和pt2为对顶角
thickness参数可设置为CV_FILL，其值是-1，表示使用color填充内部 在圆形和矩阵等很多封闭图形函数都可用
################################################################
圆形 cvCircle()
/* 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));
center：圆中心 CvPoint()结构
radius：圆半径
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椭圆 cvEllipse() cvEllipseBox
/* 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));
axes：CvSize()结构，height和width参数分别表示椭圆的长短半轴长
typedef struct CvSize
{
int width;
int height;
}
CvSize;
angle：指偏离主轴的角度，从X轴算起，逆时针为正
start_angle和end_angle表示弧线可是和结束位置的角度。因此，一个完整的椭圆必须分别将这两个值分别设为0度和360度
CV_INLINE void cvEllipseBox( CvArr* img, CvBox2D box, CvScalar color,
int thickness CV_DEFAULT(1),
int line_type CV_DEFAULT(8), int shift CV_DEFAULT(0) )
{
CvSize axes;
axes.width = cvRound(box.size.width*0.5);
axes.height = cvRound(box.size.height*0.5);
cvEllipse( img, cvPointFrom32f( box.center ), axes, box.angle,
0, 360, color, thickness, line_type, shift );
}
box：CvBox2D结构
typedef struct CvBox2D
{
CvPoint2D32f center; /* Center of the box. */
CvSize2D32f size; /* Box width and length. */
float angle; /* Angle between the horizontal axis */
/* and the first side (i.e. length) in degrees */
}
CvBox2D;
####################################################################
void paint(void)
{
IplImage *src=cvLoadImage("lena.jpg");
if (src == NULL)
{
exit(0);
}
cvLine(src, cvPoint(3, 3), cvPoint(3, 300), CV_RGB(255, 255, 255), 1, 8);
cvRectangle(src, cvPoint(10, 10), cvPoint(100, 100), CV_RGB(255, 255, 255), 1);
cvCircle(src, cvPoint(350, 350), 50, CV_RGB(255, 255, 255), 1);
cvEllipse(src, cvPoint(200, 200), cvSize(100, 50), 90, 0, 360, CV_RGB(255, 255, 255), 1, 8);
CvSize2D32f size=cvSize2D32f(100, 50);
CvBox2D box;
box.center.x = 100;
box.center.y = 300;
box.size = size;
box.angle = 90;
cvEllipseBox(src, box, CV_RGB(255, 255, 255), 1, 8, 0);
cvNamedWindow("src");
cvShowImage("src", src);
cvWaitKey(0);
cvReleaseImage(&src);
cvDestroyWindow("src");
}
######################################################################################
/* 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));
cvFillConvexPoly()一次只能画一个多边形，而且只能画凸多边形
pts：存储点的数组
npts：存储点的数目
void convexPoly(void)
{
IplImage *Image1;
CvPoint PointArray1[6];
int PolyVertexNumber;
int Shift;
CvSize ImageSize1 = cvSize(1000,700);
Image1 = cvCreateImage(ImageSize1, IPL_DEPTH_8U, 3);
PointArray1[0]=cvPoint(200,200);
PointArray1[1]=cvPoint(400,100);
PointArray1[2]=cvPoint(650,230);
PointArray1[3]=cvPoint(800,300);
PointArray1[4]=cvPoint(900,550);
PointArray1[5]=cvPoint(100,400);
CvScalar Color=CV_RGB(255,255,255);
PolyVertexNumber=6;
Shift=0;
cvFillConvexPoly(Image1,PointArray1,PolyVertexNumber,Color,CV_AA,Shift);
cvNamedWindow("FillConvexPoly",0);
cvShowImage("FillConvexPoly",Image1);
cvWaitKey(0);
cvSaveImage("poly.jpg",Image1);
cvReleaseImage(&Image1);
}
#######################################################
/* 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) );
npts：由记数点构成的数组，与多边形对应
is_closed为true：则起点和终点连线；否则，不连线
void fillPoly(void)
{
IplImage *src=cvLoadImage("lena.jpg");
if (src == NULL)
exit(0);
CvPoint** pt=new CvPoint*[1];
pt[0]=new CvPoint[6];
pt[0][0]=cvPoint(100, 100);
pt[0][1]=cvPoint(400, 50);
pt[0][2]=cvPoint(500, 400);
pt[0][3]=cvPoint(300, 500);
pt[0][4]=cvPoint(200, 300);
pt[0][5]=cvPoint(50, 400);
int *npt=new int[1];
npt[0]=6;
int contours=1;
cvFillPoly(src, pt, npt, contours, CV_RGB(255, 255, 255), 8);
//cvPolyLine(src, pt, npt, contours, 1, CV_RGB(255, 255, 255));//is_closed为true则将起点和终点连线
//cvPolyLine(src, pt, npt, contours, 0, CV_RGB(255, 255, 255));//is_closed为false则不将起点和终点连线
cvNamedWindow("src");
cvShowImage("src", src);
cvWaitKey(0);
cvReleaseImage(&src);
cvDestroyWindow("src");
}
