相關函數介紹

Point

該數據結構表示了由其圖像坐標 和 指定的2D點。可定義為：

Point pt;

pt.x = 10;

pt.y = 8;

或者

Point pt =?Point(10, 8);

Scalar

表示了具有4個元素的數組。次類型在OpenCV中被大量用于傳遞像素值。

本節中，我們將進一步用它來表示RGB顏色值（三個參數）。如果用不到第四個參數，則無需定義。

我們來看個例子，如果給出以下顏色參數表達式：

Scalar( a, b, c )

那么定義的RGB顏色值為：Red = c,?Green = b?and?Blue= a

Rectangle

C++:?void rectangle(Mat&?img,Point?pt1, Pointpt2, const Scalar&color, intthickness=1,intlineType=8, intshift=0)

C++:?void rectangle(Mat&?img,Rect?rec, const Scalar&color, intthickness=1, intlineType=8,intshift=0 )

Parameters:

img?– 畫矩形的對象 pt1?– 矩形的一個頂點，左上角的. pt2?– 另一個頂點，右下角的. rec?– 確定矩形的另一種方式，給左上角坐標和長寬 color?– 指定矩形的顏色或亮度(灰度圖像)，scalar(255,0,255)既可指定. thickness?– 矩形邊框的粗細. 負值（like CV_FILLED）表示要畫一個填充的矩形 lineType?– 邊框線型. （??? 8 (or 0) - 8-connected line（8鄰接)連接 線。 4 - 4-connected line(4鄰接)連接線。 CV_AA - antialiased 線條。） shift?–坐標點的小數點位數

Line

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

Parameters:

img – 圖像. pt1 – 線條起點. pt2 – 線條終點. color – 線條顏色. thickness – 線條寬度. lineType – 線型 Type of the line: 8 (or omitted) - 8-connected line. 4 - 4-connected line. CV_AA - antialiased line. shift – 坐標點小數點位數.

Circle

C++:?void circle(Mat&img, Point?center, intradius, const Scalar&color,intthickness=1, intlineType=8, intshift=0)

Parameters:

img?– 要畫圓的那個矩形. center?– 圓心坐標. radius?– 半徑. color?– 圓邊框顏色，scalar類型的 thickness?– 正值表示圓邊框寬度. 負值表示畫一個填充圓形 lineType?– 圓邊框線型 shift?– 圓心坐標和半徑的小數點位數

Ellipse

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, constRotatedRect& box, const Scalar& color, int thickness=1, int lineType=8)

Parameters:

img?– 橢圓所在圖像. center?– 橢圓中心. axes?– 橢圓主軸一半的長度 angle?– 橢圓旋轉角度 startAngle?– 橢圓弧起始角度 endAngle?–橢圓弧終止角度 box?– 指定橢圓中心和旋轉角度的信息，通過?RotatedRect?或 CvBox2D. 這表示橢圓畫在旋轉矩形上（矩形是不可見的，只是指定了一個框而已） color?– 橢圓邊框顏色. thickness?– 正值代表橢圓邊框寬度，負值代表填充的橢圓 lineType?– 線型 shift?– 橢圓中心坐標和坐標軸的小數點位數

PolyLine

C++: void polylines(Mat& img, const Point** pts, const int* npts, int ncontours, bool isClosed, const Scalar& color, int thickness=1, int lineType=8, int shift=0 )

C++: void polylines(InputOutputArray img, InputArrayOfArrays pts, bool isClosed, const Scalar& color, int thickness=1, int lineType=8, int shift=0 )

Parameters:

img?– 折線所在圖像. pts?– 折線中拐點坐標指針. npts?– 折線拐點個數指針. ncontours?– 折線線段數量. isClosed?– 折線是否閉合. color?– 折線顏色. thickness?– 折線寬度. lineType?– 線型. shift?– 頂點坐標小數點位數.

PutText

C++: void putText(Mat& img, const string& text, Point org, int fontFace, double fontScale, Scalar color, int thickness=1, int lineType=8, bool bottomLeftOrigin=false )

Parameters:

img?– 顯示文字所在圖像. text?– 待顯示的文字. org?– 文字在圖像中的左下角 坐標. font?–?字體結構體. fontFace?– 字體類型， 可選擇字體：FONT_HERSHEY_SIMPLEX,?FONT_HERSHEY_PLAIN,?FONT_HERSHEY_DUPLEX,FONT_HERSHEY_COMPLEX,?FONT_HERSHEY_TRIPLEX,?FONT_HERSHEY_COMPLEX_SMALL,?FONT_HERSHEY_SCRIPT_SIMPLEX, orFONT_HERSHEY_SCRIPT_COMPLEX,以上所有類型都可以配合?FONT_HERSHEY_ITALIC使用，產生斜體效果。 fontScale?– 字體大小，該值和字體內置大小相乘得到字體大小 color?– 文本顏色 thickness?– ?寫字的線的粗細，類似于0.38的筆尖和0.5的筆尖 lineType?– 線性. bottomLeftOrigin?– true,?圖像數據原點在左下角. Otherwise,?圖像數據原點在左上角.

示例代碼

[cpp]?view plaincopyprint?

/**?

?*?@file?Drawing_1.cpp?

?*?@brief?Simple?sample?code?

?*/??

??

#include?<opencv2/core/core.hpp>??

#include?<opencv2/highgui/highgui.hpp>??

??

#define?w?400??

??

using?namespace?cv;??

??

///?Function?headers??

void?MyEllipse(?Mat?img,?double?angle?);??

void?MyFilledCircle(?Mat?img,?Point?center?);??

void?MyPolygon(?Mat?img?);??

void?MyLine(?Mat?img,?Point?start,?Point?end?);??

??

/**?

?*?@function?main?

?*?@brief?Main?function?

?*/??

int?main(?void?){??

??

??///?Windows?names??

??char?atom_window[]?=?"Drawing?1:?Atom";??

??char?rook_window[]?=?"Drawing?2:?Rook";??

??

??///?Create?black?empty?images??

??Mat?atom_image?=?Mat::zeros(?w,?w,?CV_8UC3?);??

??Mat?rook_image?=?Mat::zeros(?w,?w,?CV_8UC3?);??

??

??///?1.?Draw?a?simple?atom:??

??///?-----------------------??

??

??///?1.a.?Creating?ellipses??

??MyEllipse(?atom_image,?90?);??

??MyEllipse(?atom_image,?0?);??

??MyEllipse(?atom_image,?45?);??

??MyEllipse(?atom_image,?-45?);??

??

??///?1.b.?Creating?circles??

??MyFilledCircle(?atom_image,?Point(?w/2,?w/2)?);??

??

??///?2.?Draw?a?rook??

??///?------------------??

??

??///?2.a.?Create?a?convex?polygon??

??MyPolygon(?rook_image?);??

??

??///?2.b.?Creating?rectangles??

??rectangle(?rook_image,??

?????????Point(?0,?7*w/8?),??

?????????Point(?w,?w),??

?????????Scalar(?0,?255,?255?),??

?????????-1,??

?????????8?);??

??

??RotatedRect?rRect?=?RotatedRect(Point2f(100,100),?Size2f(100,50),?30);??

??ellipse(rook_image,?rRect,?Scalar(255,255,0));??

??

??///?2.c.?Create?a?few?lines??

??MyLine(?rook_image,?Point(?0,?15*w/16?),?Point(?w,?15*w/16?)?);??

??MyLine(?rook_image,?Point(?w/4,?7*w/8?),?Point(?w/4,?w?)?);??

??MyLine(?rook_image,?Point(?w/2,?7*w/8?),?Point(?w/2,?w?)?);??

??MyLine(?rook_image,?Point(?3*w/4,?7*w/8?),?Point(?3*w/4,?w?)?);??

??

??///?3.?Display?your?stuff!??

??imshow(?atom_window,?atom_image?);??

??moveWindow(?atom_window,?0,?200?);??

??imshow(?rook_window,?rook_image?);??

??moveWindow(?rook_window,?w,?200?);??

??

??waitKey(?0?);??

??return(0);??

}??

??

///?Function?Declaration??

??

/**?

?*?@function?MyEllipse?

?*?@brief?Draw?a?fixed-size?ellipse?with?different?angles?

?*/??

void?MyEllipse(?Mat?img,?double?angle?)??

{??

??int?thickness?=?2;??

??int?lineType?=?8;??

??

??ellipse(?img,??

???????Point(?w/2,?w/2?),??

???????Size(?w/4,?w/16?),??

???????angle,??

???????0,??

???????360,??

???????Scalar(?255,?0,?0?),??

???????thickness,??

???????lineType?);??

}??

??

/**?

?*?@function?MyFilledCircle?

?*?@brief?Draw?a?fixed-size?filled?circle?

?*/??

void?MyFilledCircle(?Mat?img,?Point?center?)??

{??

??int?thickness?=?-1;??

??int?lineType?=?8;??

??

??circle(?img,??

??????center,??

??????w/32,??

??????Scalar(?0,?0,?255?),??

??????thickness,??

??????lineType?);??

}??

??

/**?

?*?@function?MyPolygon?

?*?@function?Draw?a?simple?concave?polygon?(rook)?

?*/??

void?MyPolygon(?Mat?img?)??

{??

??int?lineType?=?8;??

??

??/**?Create?some?points?*/??

??Point?rook_points[1][20];??

??rook_points[0][0]??=?Point(????w/4,???7*w/8?);??

??rook_points[0][1]??=?Point(??3*w/4,???7*w/8?);??

??rook_points[0][2]??=?Point(??3*w/4,??13*w/16?);??

??rook_points[0][3]??=?Point(?11*w/16,?13*w/16?);??

??rook_points[0][4]??=?Point(?19*w/32,??3*w/8?);??

??rook_points[0][5]??=?Point(??3*w/4,???3*w/8?);??

??rook_points[0][6]??=?Point(??3*w/4,?????w/8?);??

??rook_points[0][7]??=?Point(?26*w/40,????w/8?);??

??rook_points[0][8]??=?Point(?26*w/40,????w/4?);??

??rook_points[0][9]??=?Point(?22*w/40,????w/4?);??

??rook_points[0][10]?=?Point(?22*w/40,????w/8?);??

??rook_points[0][11]?=?Point(?18*w/40,????w/8?);??

??rook_points[0][12]?=?Point(?18*w/40,????w/4?);??

??rook_points[0][13]?=?Point(?14*w/40,????w/4?);??

??rook_points[0][14]?=?Point(?14*w/40,????w/8?);??

??rook_points[0][15]?=?Point(????w/4,?????w/8?);??

??rook_points[0][16]?=?Point(????w/4,???3*w/8?);??

??rook_points[0][17]?=?Point(?13*w/32,??3*w/8?);??

??rook_points[0][18]?=?Point(??5*w/16,?13*w/16?);??

??rook_points[0][19]?=?Point(????w/4,??13*w/16?);??

??

??const?Point*?ppt[1]?=?{?rook_points[0]?};??

??int?npt[]?=?{?20?};??

??

??fillPoly(?img,??

????????ppt,??

????????npt,??

????????????1,??

????????Scalar(?255,?255,?255?),??

????????lineType?);??

}??

??

/**?

?*?@function?MyLine?

?*?@brief?Draw?a?simple?line?

?*/??

void?MyLine(?Mat?img,?Point?start,?Point?end?)??

{??

??int?thickness?=?2;??

??int?lineType?=?8;??

??line(?img,??

????start,??

????end,??

????Scalar(?0,?0,?0?),??

????thickness,??

????lineType?);??

}??

實驗結果

總結

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