绘制功能 图像处理


class cv::LineIterator
行迭代器。 更多...

#define CV_RGB (r, g, b) cv::Scalar ((b), (g), (r), 0)

枚举

enum cv::HersheyFonts {
cv::FONT_HERSHEY_SIMPLEX = 0,
cv::FONT_HERSHEY_PLAIN = 1,
cv::FONT_HERSHEY_DUPLEX = 2,
cv::FONT_HERSHEY_COMPLEX = 3,
cv::FONT_HERSHEY_TRIPLEX = 4,
cv::FONT_HERSHEY_COMPLEX_SMALL = 5,
cv::FONT_HERSHEY_SCRIPT_SIMPLEX = 6,
cv::FONT_HERSHEY_SCRIPT_COMPLEX = 7,
cv::FONT_ITALIC = 16
}
enum cv::LineTypes {
cv::FILLED = -1,
cv::LINE_4 = 4,
cv::LINE_8 = 8,
cv::LINE_AA = 16
}
enum cv::MarkerTypes {
cv::MARKER_CROSS = 0,
cv::MARKER_TILTED_CROSS = 1,
cv::MARKER_STAR = 2,
cv::MARKER_DIAMOND = 3,
cv::MARKER_SQUARE = 4,
cv::MARKER_TRIANGLE_UP = 5,
cv::MARKER_TRIANGLE_DOWN = 6
}

函数

void cv::arrowedLine ( InputOutputArray img, Point pt1, Point pt2, const Scalar &color, int thickness=1, int line_type=8, int shift=0, double tipLength=0.1)
Draws a arrow segment pointing from the first point to the second one. 更多...
void cv::circle ( InputOutputArray img, Point center, int radius, const Scalar &color, int thickness=1, int lineType= LINE_8 , int shift=0)
Draws a circle. 更多...
bool cv::clipLine ( Size imgSize, Point &pt1, Point &pt2)
Clips the line against the image rectangle. 更多...
bool cv::clipLine ( Size2l imgSize, Point2l &pt1, Point2l &pt2)
bool cv::clipLine ( Rect imgRect, Point &pt1, Point &pt2)
void cv::drawContours ( InputOutputArray image, InputArrayOfArrays contours, int contourIdx, const Scalar &color, int thickness=1, int lineType= LINE_8 , InputArray hierarchy= noArray (), int maxLevel=INT_MAX, Point offset= Point ())
Draws contours outlines or filled contours. 更多...
void cv::drawMarker ( InputOutputArray img, Point position, const Scalar &color, int markerType= MARKER_CROSS , int markerSize=20, int thickness=1, int line_type=8)
Draws a marker on a predefined position in an image. 更多...
void cv::ellipse ( InputOutputArray img, Point center, Size axes, double angle, double startAngle, double endAngle, const Scalar &color, int thickness=1, int lineType= LINE_8 , int shift=0)
Draws a simple or thick elliptic arc or fills an ellipse sector. 更多...
void cv::ellipse ( InputOutputArray img, const RotatedRect &box, const Scalar &color, int thickness=1, int lineType= LINE_8 )
void cv::ellipse2Poly ( Point center, Size axes, int angle, int arcStart, int arcEnd, int delta, std::vector< Point > &pts)
Approximates an elliptic arc with a polyline. 更多...
void cv::ellipse2Poly ( Point2d center, Size2d axes, int angle, int arcStart, int arcEnd, int delta, std::vector< Point2d > &pts)
void cv::fillConvexPoly ( InputOutputArray img, const Point *pts, int npts, const Scalar &color, int lineType= LINE_8 , int shift=0)
void cv::fillConvexPoly ( InputOutputArray img, InputArray points, const Scalar &color, int lineType= LINE_8 , int shift=0)
Fills a convex polygon. 更多...
void cv::fillPoly ( InputOutputArray img, const Point **pts, const int *npts, int ncontours, const Scalar &color, int lineType= LINE_8 , int shift=0, Point offset= Point ())
void cv::fillPoly ( InputOutputArray img, InputArrayOfArrays pts, const Scalar &color, int lineType= LINE_8 , int shift=0, Point offset= Point ())
Fills the area bounded by one or more polygons. 更多...
double cv::getFontScaleFromHeight (const int fontFace, const int pixelHeight, const int thickness=1)
Calculates the font-specific size to use to achieve a given height in pixels. 更多...
Size cv::getTextSize (const 字符串 &text, int fontFace, double fontScale, int thickness, int *baseLine)
Calculates the width and height of a text string. 更多...
void cv::line ( InputOutputArray img, Point pt1, Point pt2, const Scalar &color, int thickness=1, int lineType= LINE_8 , int shift=0)
Draws a line segment connecting two points. 更多...
void cv::polylines ( InputOutputArray img, const Point *const *pts, const int *npts, int ncontours, bool isClosed, const Scalar &color, int thickness=1, int lineType= LINE_8 , int shift=0)
void cv::polylines ( InputOutputArray img, InputArrayOfArrays pts, bool isClosed, const Scalar &color, int thickness=1, int lineType= LINE_8 , int shift=0)
Draws several polygonal curves. 更多...
void cv::putText ( InputOutputArray img, const 字符串 &text, Point org, int fontFace, double fontScale, Scalar color, int thickness=1, int lineType= LINE_8 , bool bottomLeftOrigin=false)
Draws a text string. 更多...
void cv::rectangle ( InputOutputArray img, Point pt1, Point pt2, const Scalar &color, int thickness=1, int lineType= LINE_8 , int shift=0)
Draws a simple, thick, or filled up-right rectangle. 更多...
void cv::rectangle ( InputOutputArray img, Rect rec, const Scalar &color, int thickness=1, int lineType= LINE_8 , int shift=0)

详细描述

Drawing functions work with matrices/images of arbitrary depth. The boundaries of the shapes can be rendered with antialiasing (implemented only for 8-bit images for now). All the functions include the parameter color that uses an RGB value (that may be constructed with the Scalar constructor ) for color images and brightness for grayscale images. For color images, the channel ordering is normally Blue, Green, Red . This is what imshow, imread, and imwrite expect. So, if you form a color using the Scalar constructor, it should look like:

\[\texttt{Scalar} (blue \_ component, green \_ component, red \_ component[, alpha \_ component])\]

If you are using your own image rendering and I/O functions, you can use any channel ordering. The drawing functions process each channel independently and do not depend on the channel order or even on the used color space. The whole image can be converted from BGR to RGB or to a different color space using cvtColor .

If a drawn figure is partially or completely outside the image, the drawing functions clip it. Also, many drawing functions can handle pixel coordinates specified with sub-pixel accuracy. This means that the coordinates can be passed as fixed-point numbers encoded as integers. The number of fractional bits is specified by the shift parameter and the real point coordinates are calculated as \(\texttt{Point}(x,y)\rightarrow\texttt{Point2f}(x*2^{-shift},y*2^{-shift})\) . This feature is especially effective when rendering antialiased shapes.

注意
The functions do not support alpha-transparency when the target image is 4-channel. In this case, the color[3] is simply copied to the repainted pixels. Thus, if you want to paint semi-transparent shapes, you can paint them in a separate buffer and then blend it with the main image.

宏定义文档编制

CV_RGB

#define CV_RGB ( r,
g,
b
) cv::Scalar ((b), (g), (r), 0)

#include < opencv2/imgproc.hpp >

OpenCV color channel order is BGR[A]

枚举类型文档编制

HersheyFonts

#include < opencv2/imgproc.hpp >

Only a subset of Hershey fonts https://en.wikipedia.org/wiki/Hershey_fonts are supported

枚举器
FONT_HERSHEY_SIMPLEX
Python: cv.FONT_HERSHEY_SIMPLEX

normal size sans-serif font

FONT_HERSHEY_PLAIN
Python: cv.FONT_HERSHEY_PLAIN

small size sans-serif font

FONT_HERSHEY_DUPLEX
Python: cv.FONT_HERSHEY_DUPLEX

normal size sans-serif font (more complex than FONT_HERSHEY_SIMPLEX)

FONT_HERSHEY_COMPLEX
Python: cv.FONT_HERSHEY_COMPLEX

normal size serif font

FONT_HERSHEY_TRIPLEX
Python: cv.FONT_HERSHEY_TRIPLEX

normal size serif font (more complex than FONT_HERSHEY_COMPLEX)

FONT_HERSHEY_COMPLEX_SMALL
Python: cv.FONT_HERSHEY_COMPLEX_SMALL

smaller version of FONT_HERSHEY_COMPLEX

FONT_HERSHEY_SCRIPT_SIMPLEX
Python: cv.FONT_HERSHEY_SCRIPT_SIMPLEX

hand-writing style font

FONT_HERSHEY_SCRIPT_COMPLEX
Python: cv.FONT_HERSHEY_SCRIPT_COMPLEX

more complex variant of FONT_HERSHEY_SCRIPT_SIMPLEX

FONT_ITALIC
Python: cv.FONT_ITALIC

flag for italic font

LineTypes

#include < opencv2/imgproc.hpp >

types of line

枚举器
FILLED
Python: cv.FILLED
LINE_4
Python: cv.LINE_4

4-connected line

LINE_8
Python: cv.LINE_8

8-connected line

LINE_AA
Python: cv.LINE_AA

antialiased line

MarkerTypes

#include < opencv2/imgproc.hpp >

Possible set of marker types used for the cv::drawMarker function

枚举器
MARKER_CROSS
Python: cv.MARKER_CROSS

A crosshair marker shape.

MARKER_TILTED_CROSS
Python: cv.MARKER_TILTED_CROSS

A 45 degree tilted crosshair marker shape.

MARKER_STAR
Python: cv.MARKER_STAR

A star marker shape, combination of cross and tilted cross.

MARKER_DIAMOND
Python: cv.MARKER_DIAMOND

A diamond marker shape.

MARKER_SQUARE
Python: cv.MARKER_SQUARE

A square marker shape.

MARKER_TRIANGLE_UP
Python: cv.MARKER_TRIANGLE_UP

An upwards pointing triangle marker shape.

MARKER_TRIANGLE_DOWN
Python: cv.MARKER_TRIANGLE_DOWN

A downwards pointing triangle marker shape.

函数文档编制

arrowedLine()

void cv::arrowedLine ( InputOutputArray img ,
Point pt1 ,
Point pt2 ,
const Scalar & color ,
int thickness = 1 ,
int line_type = 8 ,
int shift = 0 ,
double tipLength = 0.1
)
Python:
img = cv.arrowedLine( img, pt1, pt2, color[, thickness[, line_type[, shift[, tipLength]]]] )

#include < opencv2/imgproc.hpp >

Draws a arrow segment pointing from the first point to the second one.

函数 cv::arrowedLine draws an arrow between pt1 and pt2 points in the image. See also line .

参数
img Image.
pt1 The point the arrow starts from.
pt2 The point the arrow points to.
color Line color.
thickness Line thickness.
line_type Type of the line. See LineTypes
shift Number of fractional bits in the point coordinates.
tipLength The length of the arrow tip in relation to the arrow length

circle()

void cv::circle ( InputOutputArray img ,
Point center ,
int radius ,
const Scalar & color ,
int thickness = 1 ,
int lineType = LINE_8 ,
int shift = 0
)
Python:
img = cv.circle( img, center, radius, color[, thickness[, lineType[, shift]]] )

#include < opencv2/imgproc.hpp >

Draws a circle.

函数 cv::circle draws a simple or filled circle with a given center and radius.

参数
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 values, like FILLED , mean that a filled circle is to be drawn.
lineType Type of the circle boundary. See LineTypes
shift Number of fractional bits in the coordinates of the center and in the radius value.
范例:
samples/cpp/convexhull.cpp , samples/cpp/falsecolor.cpp , samples/cpp/kmeans.cpp , samples/cpp/lkdemo.cpp , samples/cpp/minarea.cpp , samples/cpp/tutorial_code/ImgProc/basic_drawing/Drawing_1.cpp , samples/cpp/tutorial_code/ImgProc/basic_drawing/Drawing_2.cpp , samples/cpp/tutorial_code/ImgTrans/houghcircles.cpp ,和 samples/dnn/openpose.cpp .

clipLine() [1/3]

bool cv::clipLine ( Size imgSize ,
Point & pt1 ,
Point & pt2
)
Python:
retval, pt1, pt2 = cv.clipLine( imgRect, pt1, pt2 )

#include < opencv2/imgproc.hpp >

Clips the line against the image rectangle.

函数 cv::clipLine calculates a part of the line segment that is entirely within the specified rectangle. it returns false if the line segment is completely outside the rectangle. Otherwise, it returns true .

参数
imgSize Image size. The image rectangle is Rect(0, 0, imgSize.width, imgSize.height) .
pt1 First line point.
pt2 Second line point.

clipLine() [2/3]

bool cv::clipLine ( Size2l imgSize ,
Point2l & pt1 ,
Point2l & pt2
)
Python:
retval, pt1, pt2 = cv.clipLine( imgRect, pt1, pt2 )

#include < opencv2/imgproc.hpp >

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

参数
imgSize Image size. The image rectangle is Rect(0, 0, imgSize.width, imgSize.height) .
pt1 First line point.
pt2 Second line point.

clipLine() [3/3]

bool cv::clipLine ( Rect imgRect ,
Point & pt1 ,
Point & pt2
)
Python:
retval, pt1, pt2 = cv.clipLine( imgRect, pt1, pt2 )

#include < opencv2/imgproc.hpp >

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

参数
imgRect Image rectangle.
pt1 First line point.
pt2 Second line point.

drawContours()

void cv::drawContours ( InputOutputArray image ,
InputArrayOfArrays contours ,
int contourIdx ,
const Scalar & color ,
int thickness = 1 ,
int lineType = LINE_8 ,
InputArray hierarchy = noArray () ,
int maxLevel = INT_MAX ,
Point offset = Point ()
)
Python:
image = cv.drawContours( image, contours, contourIdx, color[, thickness[, lineType[, hierarchy[, maxLevel[, offset]]]]] )

#include < opencv2/imgproc.hpp >

Draws contours outlines or filled contours.

The function draws contour outlines in the image if \(\texttt{thickness} \ge 0\) or fills the area bounded by the contours if \(\texttt{thickness}<0\) . The example below shows how to retrieve connected components from the binary image and label them: :

using namespace cv ;
using namespace std ;
int main( int argc, char ** argv )
{
Mat src;
// the first command-line parameter must be a filename of the binary
// (black-n-white) image
if ( argc != 2 || !(src= imread (argv[1], 0)).data)
return -1;
src = src > 1;
namedWindow ( "Source" , 1 );
imshow ( "Source" , src );
vector<vector<Point> > contours;
vector<Vec4i> hierarchy;
findContours ( src, contours, hierarchy,
// iterate through all the top-level contours,
// draw each connected component with its own random color
int idx = 0;
for ( ; idx >= 0; idx = hierarchy[idx][0] )
{
Scalar color( rand()&255, rand()&255, rand()&255 );
drawContours ( dst, contours, idx, color, FILLED , 8, hierarchy );
}
namedWindow ( "Components" , 1 );
imshow ( "Components" , dst );
}
参数
image Destination image.
contours All the input contours. Each contour is stored as a point vector.
contourIdx Parameter indicating a contour to draw. If it is negative, all the contours are drawn.
color Color of the contours.
thickness Thickness of lines the contours are drawn with. If it is negative (for example, thickness= FILLED ), the contour interiors are drawn.
lineType Line connectivity. See LineTypes
hierarchy Optional information about hierarchy. It is only needed if you want to draw only some of the contours (see maxLevel ).
maxLevel Maximal level for drawn contours. If it is 0, only the specified contour is drawn. If it is 1, the function draws the contour(s) and all the nested contours. If it is 2, the function draws the contours, all the nested contours, all the nested-to-nested contours, and so on. This parameter is only taken into account when there is hierarchy available.
offset Optional contour shift parameter. Shift all the drawn contours by the specified \(\texttt{offset}=(dx,dy)\) .
注意
When thickness= FILLED , the function is designed to handle connected components with holes correctly even when no hierarchy date is provided. This is done by analyzing all the outlines together using even-odd rule. This may give incorrect results if you have a joint collection of separately retrieved contours. In order to solve this problem, you need to call drawContours separately for each sub-group of contours, or iterate over the collection using contourIdx parameter.
范例:
samples/cpp/contours2.cpp , samples/cpp/segment_objects.cpp , samples/cpp/tutorial_code/ml/introduction_to_pca/introduction_to_pca.cpp ,和 samples/cpp/watershed.cpp .

drawMarker()

void cv::drawMarker ( InputOutputArray img ,
Point position ,
const Scalar & color ,
int markerType = MARKER_CROSS ,
int markerSize = 20 ,
int thickness = 1 ,
int line_type = 8
)
Python:
img = cv.drawMarker( img, position, color[, markerType[, markerSize[, thickness[, line_type]]]] )

#include < opencv2/imgproc.hpp >

Draws a marker on a predefined position in an image.

函数 cv::drawMarker draws a marker on a given position in the image. For the moment several marker types are supported, see MarkerTypes 了解更多信息。

参数
img Image.
position The point where the crosshair is positioned.
color Line color.
markerType The specific type of marker you want to use, see MarkerTypes
thickness Line thickness.
line_type Type of the line, See LineTypes
markerSize The length of the marker axis [default = 20 pixels]
范例:
samples/cpp/polar_transforms.cpp .

ellipse() [1/2]

void cv::ellipse ( InputOutputArray img ,
Point center ,
Size axes ,
double angle ,
double startAngle ,
double endAngle ,
const Scalar & color ,
int thickness = 1 ,
int lineType = LINE_8 ,
int shift = 0
)
Python:
img = cv.ellipse( img, center, axes, angle, startAngle, endAngle, color[, thickness[, lineType[, shift]]] )
img = cv.ellipse( img, box, color[, thickness[, lineType]] )

#include < opencv2/imgproc.hpp >

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

函数 cv::ellipse with more parameters draws an ellipse outline, a filled ellipse, an elliptic arc, or a filled ellipse sector. The drawing code uses general parametric form. 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 。若 startAngle 大于 endAngle , they are swapped. The figure below explains the meaning of the parameters to draw the blue arc.

ellipse.svg
Parameters of Elliptic Arc
参数
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.
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 LineTypes
shift Number of fractional bits in the coordinates of the center and values of axes.
范例:
samples/cpp/camshiftdemo.cpp , samples/cpp/contours2.cpp , samples/cpp/falsecolor.cpp , samples/cpp/fitellipse.cpp , samples/cpp/tutorial_code/ImgProc/basic_drawing/Drawing_1.cpp ,和 samples/cpp/tutorial_code/ImgProc/basic_drawing/Drawing_2.cpp .

ellipse() [2/2]

void cv::ellipse ( InputOutputArray img ,
const RotatedRect & box ,
const Scalar & color ,
int thickness = 1 ,
int lineType = LINE_8
)
Python:
img = cv.ellipse( img, center, axes, angle, startAngle, endAngle, color[, thickness[, lineType[, shift]]] )
img = cv.ellipse( img, box, color[, thickness[, lineType]] )

#include < opencv2/imgproc.hpp >

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

参数
img Image.
box Alternative ellipse representation via RotatedRect . 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 LineTypes

ellipse2Poly() [1/2]

void cv::ellipse2Poly ( Point center ,
Size axes ,
int angle ,
int arcStart ,
int arcEnd ,
int delta ,
std::vector< Point > & pts
)
Python:
pts = cv.ellipse2Poly( center, axes, angle, arcStart, arcEnd, delta )

#include < opencv2/imgproc.hpp >

Approximates an elliptic arc with a polyline.

The function ellipse2Poly computes the vertices of a polyline that approximates the specified elliptic arc. It is used by ellipse 。若 arcStart 大于 arcEnd , they are swapped.

参数
center Center of the arc.
axes Half of the size of the ellipse main axes. See ellipse 了解细节。
angle Rotation angle of the ellipse in degrees. See ellipse 了解细节。
arcStart Starting angle of the elliptic arc in degrees.
arcEnd Ending angle of the elliptic arc in degrees.
delta Angle between the subsequent polyline vertices. It defines the approximation accuracy.
pts Output vector of polyline vertices.

ellipse2Poly() [2/2]

void cv::ellipse2Poly ( Point2d center ,
Size2d axes ,
int angle ,
int arcStart ,
int arcEnd ,
int delta ,
std::vector< Point2d > & pts
)
Python:
pts = cv.ellipse2Poly( center, axes, angle, arcStart, arcEnd, delta )

#include < opencv2/imgproc.hpp >

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

参数
center Center of the arc.
axes Half of the size of the ellipse main axes. See ellipse 了解细节。
angle Rotation angle of the ellipse in degrees. See ellipse 了解细节。
arcStart Starting angle of the elliptic arc in degrees.
arcEnd Ending angle of the elliptic arc in degrees.
delta Angle between the subsequent polyline vertices. It defines the approximation accuracy.
pts Output vector of polyline vertices.

fillConvexPoly() [1/2]

void cv::fillConvexPoly ( InputOutputArray img ,
const Point * pts ,
int npts ,
const Scalar & color ,
int lineType = LINE_8 ,
int shift = 0
)
Python:
img = cv.fillConvexPoly( img, points, color[, lineType[, shift]] )

#include < opencv2/imgproc.hpp >

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

fillConvexPoly() [2/2]

void cv::fillConvexPoly ( InputOutputArray img ,
InputArray points ,
const Scalar & color ,
int lineType = LINE_8 ,
int shift = 0
)
Python:
img = cv.fillConvexPoly( img, points, color[, lineType[, shift]] )

#include < opencv2/imgproc.hpp >

Fills a convex polygon.

函数 cv::fillConvexPoly draws a filled convex polygon. This function is much faster than the function fillPoly . It can fill not only convex polygons but any monotonic polygon without self-intersections, that is, a polygon whose contour intersects every horizontal line (scan line) twice at the most (though, its top-most and/or the bottom edge could be horizontal).

参数
img Image.
points Polygon vertices.
color Polygon color.
lineType Type of the polygon boundaries. See LineTypes
shift Number of fractional bits in the vertex coordinates.

fillPoly() [1/2]

void cv::fillPoly ( InputOutputArray img ,
const Point ** pts ,
const int * npts ,
int ncontours ,
const Scalar & color ,
int lineType = LINE_8 ,
int shift = 0 ,
Point offset = Point ()
)
Python:
img = cv.fillPoly( img, pts, color[, lineType[, shift[, offset]]] )

#include < opencv2/imgproc.hpp >

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

范例:
samples/cpp/create_mask.cpp , samples/cpp/intersectExample.cpp , samples/cpp/tutorial_code/ImgProc/basic_drawing/Drawing_1.cpp ,和 samples/cpp/tutorial_code/ImgProc/basic_drawing/Drawing_2.cpp .

fillPoly() [2/2]

void cv::fillPoly ( InputOutputArray img ,
InputArrayOfArrays pts ,
const Scalar & color ,
int lineType = LINE_8 ,
int shift = 0 ,
Point offset = Point ()
)
Python:
img = cv.fillPoly( img, pts, color[, lineType[, shift[, offset]]] )

#include < opencv2/imgproc.hpp >

Fills the area bounded by one or more polygons.

函数 cv::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.

参数
img Image.
pts Array of polygons where each polygon is represented as an array of points.
color Polygon color.
lineType Type of the polygon boundaries. See LineTypes
shift Number of fractional bits in the vertex coordinates.
offset Optional offset of all points of the contours.

getFontScaleFromHeight()

double cv::getFontScaleFromHeight ( const int fontFace ,
const int pixelHeight ,
const int thickness = 1
)
Python:
retval = cv.getFontScaleFromHeight( fontFace, pixelHeight[, thickness] )

#include < opencv2/imgproc.hpp >

Calculates the font-specific size to use to achieve a given height in pixels.

参数
fontFace Font to use, see cv::HersheyFonts .
pixelHeight Pixel height to compute the fontScale for
thickness Thickness of lines used to render the text.See putText for details.
返回
The fontSize to use for cv::putText
另请参阅
cv::putText

getTextSize()

Size cv::getTextSize ( const 字符串 & text ,
int fontFace ,
double fontScale ,
int thickness ,
int * baseLine
)
Python:
retval, baseLine = cv.getTextSize( text, fontFace, fontScale, thickness )

#include < opencv2/imgproc.hpp >

Calculates the width and height of a text string.

函数 cv::getTextSize calculates and returns the size of a box that contains the specified text. That is, the following code renders some text, the tight box surrounding it, and the baseline: :

字符串 text = "Funny text inside the box" ;
double fontScale = 2;
int thickness = 3;
Mat img(600, 800, CV_8UC3 , Scalar::all (0));
int baseline=0;
Size textSize = getTextSize (text, fontFace,
fontScale, thickness, &baseline);
baseline += thickness;
// center the text
Point textOrg((img.cols - textSize.width)/2,
(img.rows + textSize.height)/2);
// draw the box
rectangle (img, textOrg + Point (0, baseline),
textOrg + Point (textSize.width, -textSize.height),
Scalar (0,0,255));
// ... and the baseline first
line (img, textOrg + Point (0, thickness),
textOrg + Point (textSize.width, thickness),
Scalar (0, 0, 255));
// then put the text itself
putText (img, text, textOrg, fontFace, fontScale,
Scalar::all (255), thickness, 8);
参数
text Input text string.
fontFace Font to use, see HersheyFonts .
fontScale Font scale factor that is multiplied by the font-specific base size.
thickness Thickness of lines used to render the text. See putText 了解细节。
[out] baseLine y-coordinate of the baseline relative to the bottom-most text point.
返回
The size of a box that contains the specified text.
另请参阅
putText
范例:
samples/cpp/fitellipse.cpp , samples/cpp/tutorial_code/ImgProc/basic_drawing/Drawing_2.cpp ,和 samples/dnn/object_detection.cpp .

line()

void cv::line ( InputOutputArray img ,
Point pt1 ,
Point pt2 ,
const Scalar & color ,
int thickness = 1 ,
int lineType = LINE_8 ,
int shift = 0
)
Python:
img = cv.line( img, pt1, pt2, color[, thickness[, lineType[, shift]]] )

#include < opencv2/imgproc.hpp >

Draws a line segment connecting two points.

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.

参数
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. See LineTypes .
shift Number of fractional bits in the point coordinates.
范例:
samples/cpp/contours2.cpp , samples/cpp/convexhull.cpp , samples/cpp/create_mask.cpp , samples/cpp/falsecolor.cpp , samples/cpp/fitellipse.cpp , samples/cpp/image_alignment.cpp , samples/cpp/kalman.cpp , samples/cpp/minarea.cpp , samples/cpp/pca.cpp , samples/cpp/tutorial_code/ImgProc/basic_drawing/Drawing_1.cpp , samples/cpp/tutorial_code/ImgProc/basic_drawing/Drawing_2.cpp , samples/cpp/tutorial_code/ImgTrans/houghlines.cpp , samples/cpp/tutorial_code/ml/introduction_to_pca/introduction_to_pca.cpp , samples/cpp/warpPerspective_demo.cpp , samples/cpp/watershed.cpp , samples/dnn/classification.cpp , samples/dnn/object_detection.cpp , samples/dnn/openpose.cpp , samples/dnn/segmentation.cpp ,和 samples/dnn/text_detection.cpp .

polylines() [1/2]

void cv::polylines ( InputOutputArray img ,
const Point *const * pts ,
const int * npts ,
int ncontours ,
bool isClosed ,
const Scalar & color ,
int thickness = 1 ,
int lineType = LINE_8 ,
int shift = 0
)
Python:
img = cv.polylines( img, pts, isClosed, color[, thickness[, lineType[, shift]]] )

#include < opencv2/imgproc.hpp >

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

范例:
samples/cpp/create_mask.cpp , samples/cpp/intersectExample.cpp , samples/cpp/squares.cpp , samples/cpp/tutorial_code/ImgProc/basic_drawing/Drawing_2.cpp ,和 samples/tapi/squares.cpp .

polylines() [2/2]

void cv::polylines ( InputOutputArray img ,
InputArrayOfArrays pts ,
bool isClosed ,
const Scalar & color ,
int thickness = 1 ,
int lineType = LINE_8 ,
int shift = 0
)
Python:
img = cv.polylines( img, pts, isClosed, color[, thickness[, lineType[, shift]]] )

#include < opencv2/imgproc.hpp >

Draws several polygonal curves.

参数
img Image.
pts Array of polygonal curves.
isClosed Flag indicating whether the drawn polylines are closed or not. If they are closed, the function draws a line from the last vertex of each curve to its first vertex.
color Polyline color.
thickness Thickness of the polyline edges.
lineType Type of the line segments. See LineTypes
shift Number of fractional bits in the vertex coordinates.

函数 cv::polylines draws one or more polygonal curves.

putText()

void cv::putText ( InputOutputArray img ,
const 字符串 & text ,
Point org ,
int fontFace ,
double fontScale ,
Scalar color ,
int thickness = 1 ,
int lineType = LINE_8 ,
bool bottomLeftOrigin = false
)
Python:
img = cv.putText( img, text, org, fontFace, fontScale, color[, thickness[, lineType[, bottomLeftOrigin]]] )

#include < opencv2/imgproc.hpp >

Draws a text string.

函数 cv::putText renders the specified text string in the image. Symbols that cannot be rendered using the specified font are replaced by question marks. See getTextSize for a text rendering code example.

参数
img Image.
text Text string to be drawn.
org Bottom-left corner of the text string in the image.
fontFace Font type, see HersheyFonts .
fontScale Font scale factor that is multiplied by the font-specific base size.
color Text color.
thickness Thickness of the lines used to draw a text.
lineType Line type. See LineTypes
bottomLeftOrigin When true, the image data origin is at the bottom-left corner. Otherwise, it is at the top-left corner.
范例:
samples/cpp/falsecolor.cpp , samples/cpp/fitellipse.cpp , samples/cpp/intersectExample.cpp , samples/cpp/peopledetect.cpp , samples/cpp/tutorial_code/ImgProc/basic_drawing/Drawing_2.cpp , samples/cpp/tutorial_code/ImgProc/Smoothing/Smoothing.cpp , samples/cpp/warpPerspective_demo.cpp , samples/dnn/classification.cpp , samples/dnn/object_detection.cpp , samples/dnn/segmentation.cpp , samples/dnn/text_detection.cpp ,和 samples/tapi/hog.cpp .

rectangle() [1/2]

void cv::rectangle ( InputOutputArray img ,
Point pt1 ,
Point pt2 ,
const Scalar & color ,
int thickness = 1 ,
int lineType = LINE_8 ,
int shift = 0
)
Python:
img = cv.rectangle( img, pt1, pt2, color[, thickness[, lineType[, shift]]] )
img = cv.rectangle( img, rec, color[, thickness[, lineType[, shift]]] )

#include < opencv2/imgproc.hpp >

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

函数 cv::rectangle draws a rectangle outline or a filled rectangle whose two opposite corners are pt1 and pt2.

参数
img Image.
pt1 Vertex of the rectangle.
pt2 Vertex of the rectangle opposite to pt1 .
color Rectangle color or brightness (grayscale image).
thickness Thickness of lines that make up the rectangle. Negative values, like FILLED , mean that the function has to draw a filled rectangle.
lineType Type of the line. See LineTypes
shift Number of fractional bits in the point coordinates.
范例:
samples/cpp/camshiftdemo.cpp , samples/cpp/demhist.cpp , samples/cpp/facedetect.cpp , samples/cpp/falsecolor.cpp , samples/cpp/grabcut.cpp , samples/cpp/intersectExample.cpp , samples/cpp/peopledetect.cpp , samples/cpp/train_HOG.cpp , samples/cpp/tutorial_code/Histograms_Matching/MatchTemplate_Demo.cpp , samples/cpp/tutorial_code/ImgProc/basic_drawing/Drawing_1.cpp , samples/cpp/tutorial_code/ImgProc/basic_drawing/Drawing_2.cpp , samples/dnn/object_detection.cpp ,和 samples/tapi/hog.cpp .

rectangle() [2/2]

void cv::rectangle ( InputOutputArray img ,
Rect rec ,
const Scalar & color ,
int thickness = 1 ,
int lineType = LINE_8 ,
int shift = 0
)
Python:
img = cv.rectangle( img, pt1, pt2, color[, thickness[, lineType[, shift]]] )
img = cv.rectangle( img, rec, color[, thickness[, lineType[, shift]]] )

#include < opencv2/imgproc.hpp >

This is an overloaded member function, provided for convenience. It differs from the above function only in what argument(s) it accepts.

use rec parameter as alternative specification of the drawn rectangle: r.tl() and r.br()-Point(1,1) are opposite corners