cv::_InputArray Class Reference

This is the proxy class for passing read-only input arrays into OpenCV functions. More...

#include <opencv2/core/mat.hpp>

Collaboration diagram for cv::_InputArray:

Public Types
enum	KindFlag {   KIND_SHIFT = 16 ,   FIXED_TYPE = 0x8000 << KIND_SHIFT ,   FIXED_SIZE = 0x4000 << KIND_SHIFT ,   KIND_MASK = 31 << KIND_SHIFT ,   NONE = 0 << KIND_SHIFT ,   MAT = 1 << KIND_SHIFT ,   MATX = 2 << KIND_SHIFT ,   STD_VECTOR = 3 << KIND_SHIFT ,   STD_VECTOR_VECTOR = 4 << KIND_SHIFT ,   STD_VECTOR_MAT = 5 << KIND_SHIFT ,   EXPR = 6 << KIND_SHIFT ,   OPENGL_BUFFER = 7 << KIND_SHIFT ,   CUDA_HOST_MEM = 8 << KIND_SHIFT ,   CUDA_GPU_MAT = 9 << KIND_SHIFT ,   UMAT =10 << KIND_SHIFT ,   STD_VECTOR_UMAT =11 << KIND_SHIFT ,   STD_BOOL_VECTOR =12 << KIND_SHIFT ,   STD_VECTOR_CUDA_GPU_MAT = 13 << KIND_SHIFT ,   STD_ARRAY =14 << KIND_SHIFT ,   STD_ARRAY_MAT =15 << KIND_SHIFT }

Public Member Functions
	_InputArray ()
template<typename _Tp >
	_InputArray (const _Tp *vec, int n)
	_InputArray (const cuda::GpuMat &d_mat)
	_InputArray (const cuda::HostMem &cuda_mem)
template<typename _Tp >
	_InputArray (const cudev::GpuMat_< _Tp > &m)
	_InputArray (const double &val)
	_InputArray (const Mat &m)
template<typename _Tp >
	_InputArray (const Mat_< _Tp > &m)
	_InputArray (const MatExpr &expr)
template<typename _Tp , int m, int n>
	_InputArray (const Matx< _Tp, m, n > &matx)
	_InputArray (const ogl::Buffer &buf)
template<typename _Tp , std::size_t _Nm>
	_InputArray (const std::array< _Tp, _Nm > &arr)
template<std::size_t _Nm>
	_InputArray (const std::array< Mat, _Nm > &arr)
template<typename _Tp >
	_InputArray (const std::vector< _Tp > &vec)
	_InputArray (const std::vector< bool > &vec)
	_InputArray (const std::vector< cuda::GpuMat > &d_mat_array)
	_InputArray (const std::vector< Mat > &vec)
template<typename _Tp >
	_InputArray (const std::vector< Mat_< _Tp > > &vec)
template<typename _Tp >
	_InputArray (const std::vector< std::vector< _Tp > > &vec)
	_InputArray (const std::vector< std::vector< bool > > &)=delete
	_InputArray (const std::vector< UMat > &umv)
	_InputArray (const UMat &um)
	_InputArray (int _flags, void *_obj)
	~_InputArray ()
int	channels (int i=-1) const
int	cols (int i=-1) const
void	copyTo (const _OutputArray &arr) const
void	copyTo (const _OutputArray &arr, const _InputArray &mask) const
int	depth (int i=-1) const
int	dims (int i=-1) const
bool	empty () const
int	getFlags () const
cuda::GpuMat	getGpuMat () const
void	getGpuMatVector (std::vector< cuda::GpuMat > &gpumv) const
Mat	getMat (int idx=-1) const
Mat	getMat_ (int idx=-1) const
void	getMatVector (std::vector< Mat > &mv) const
void *	getObj () const
ogl::Buffer	getOGlBuffer () const
Size	getSz () const
UMat	getUMat (int idx=-1) const
void	getUMatVector (std::vector< UMat > &umv) const
bool	isContinuous (int i=-1) const
bool	isGpuMat () const
bool	isGpuMatVector () const
bool	isMat () const
bool	isMatVector () const
bool	isMatx () const
bool	isSubmatrix (int i=-1) const
bool	isUMat () const
bool	isUMatVector () const
bool	isVector () const
_InputArray::KindFlag	kind () const
size_t	offset (int i=-1) const
int	rows (int i=-1) const
bool	sameSize (const _InputArray &arr) const
Size	size (int i=-1) const
int	sizend (int *sz, int i=-1) const
size_t	step (int i=-1) const
size_t	total (int i=-1) const
int	type (int i=-1) const

Static Public Member Functions
template<typename _Tp , std::size_t _Nm>
static _InputArray	rawIn (const std::array< _Tp, _Nm > &arr)
template<typename _Tp >
static _InputArray	rawIn (const std::vector< _Tp > &vec)

Protected Member Functions
void	init (int _flags, const void *_obj)
void	init (int _flags, const void *_obj, Size _sz)

Protected Attributes
int	flags
void *	obj
Size	sz

Detailed Description

This is the proxy class for passing read-only input arrays into OpenCV functions.

It is defined as:

typedef const _InputArray& InputArray;

where cv::_InputArray is a class that can be constructed from cv::Mat, cv::Mat_<T>, cv::Matx<T, m, n>, std::vector<T>, std::vector<std::vector<T>>, std::vector<Mat>, std::vector<Mat_<T>>, cv::UMat, std::vector<UMat> or double. It can also be constructed from a matrix expression.

Since this is mostly implementation-level class, and its interface may change in future versions, we do not describe it in details. There are a few key things, though, that should be kept in mind:

• When you see in the reference manual or in OpenCV source code a function that takes InputArray, it means that you can actually pass Mat, Matx, vector<T> etc. (see above the complete list).
• Optional input arguments: If some of the input arrays may be empty, pass cv::noArray() (or simply cv::Mat() as you probably did before).
• The class is designed solely for passing parameters. That is, normally you should not declare class members, local and global variables of this type.
• If you want to design your own function or a class method that can operate of arrays of multiple types, you can use InputArray (or OutputArray) for the respective parameters. Inside a function you should use _InputArray::getMat() method to construct a matrix header for the array (without copying data). _InputArray::kind() can be used to distinguish Mat from vector<> etc., but normally it is not needed.

Here is how you can use a function that takes InputArray :

std::vector<Point2f> vec;
// points or a circle
for( int i = 0; i < 30; i++ )
    vec.push_back(Point2f((float)(100 + 30*cos(i*CV_PI*2/5)),
                          (float)(100 - 30*sin(i*CV_PI*2/5))));
cv::transform(vec, vec, cv::Matx23f(0.707, -0.707, 10, 0.707, 0.707, 20));

That is, we form an STL vector containing points, and apply in-place affine transformation to the vector using the 2x3 matrix created inline as Matx<float, 2, 3> instance.

Here is how such a function can be implemented (for simplicity, we implement a very specific case of it, according to the assertion statement inside) :

void myAffineTransform(InputArray _src, OutputArray _dst, InputArray _m)
{
    // get Mat headers for input arrays. This is O(1) operation,
    // unless _src and/or _m are matrix expressions.
    Mat src = _src.getMat(), m = _m.getMat();
    CV_Assert( src.type() == CV_32FC2 && m.type() == CV_32F && m.size() == Size(3, 2) );
 
    // [re]create the output array so that it has the proper size and type.
    // In case of Mat it calls Mat::create, in case of STL vector it calls vector::resize.
    _dst.create(src.size(), src.type());
    Mat dst = _dst.getMat();
 
    for( int i = 0; i < src.rows; i++ )
        for( int j = 0; j < src.cols; j++ )
        {
            Point2f pt = src.at<Point2f>(i, j);
            dst.at<Point2f>(i, j) = Point2f(m.at<float>(0, 0)*pt.x +
                                            m.at<float>(0, 1)*pt.y +
                                            m.at<float>(0, 2),
                                            m.at<float>(1, 0)*pt.x +
                                            m.at<float>(1, 1)*pt.y +
                                            m.at<float>(1, 2));
        }
}

There is another related type, InputArrayOfArrays, which is currently defined as a synonym for InputArray:

typedef InputArray InputArrayOfArrays;

It denotes function arguments that are either vectors of vectors or vectors of matrices. A separate synonym is needed to generate Python/Java etc. wrappers properly. At the function implementation level their use is similar, but _InputArray::getMat(idx) should be used to get header for the idx-th component of the outer vector and _InputArray::size().area() should be used to find the number of components (vectors/matrices) of the outer vector.

In general, type support is limited to cv::Mat types. Other types are forbidden. But in some cases we need to support passing of custom non-general Mat types, like arrays of cv::KeyPoint, cv::DMatch, etc. This data is not intended to be interpreted as an image data, or processed somehow like regular cv::Mat. To pass such custom type use rawIn() / rawOut() / rawInOut() wrappers. Custom type is wrapped as Mat-compatible CV_8UC<N> values (N = sizeof(T), N <= CV_CN_MAX).

Examples

samples/cpp/pca.cpp, and samples/cpp/peopledetect.cpp.

Member Enumeration Documentation

KindFlag

enum cv::_InputArray::KindFlag

Enumerator
KIND_SHIFT
FIXED_TYPE
FIXED_SIZE
KIND_MASK
NONE
MAT
MATX
STD_VECTOR
STD_VECTOR_VECTOR
STD_VECTOR_MAT
EXPR	removed: https://github.com/opencv/opencv/pull/17046
OPENGL_BUFFER
CUDA_HOST_MEM
CUDA_GPU_MAT
UMAT
STD_VECTOR_UMAT
STD_BOOL_VECTOR
STD_VECTOR_CUDA_GPU_MAT
STD_ARRAY	removed: https://github.com/opencv/opencv/issues/18897
STD_ARRAY_MAT

Constructor & Destructor Documentation

_InputArray() [1/23]

cv::_InputArray::_InputArray

(

)

_InputArray() [2/23]

cv::_InputArray::_InputArray	(	int	_flags,
		void *	_obj )

_InputArray() [3/23]

cv::_InputArray::_InputArray

(

const Mat &

m

)

_InputArray() [4/23]

cv::_InputArray::_InputArray

(

const MatExpr &

expr

)

_InputArray() [5/23]

cv::_InputArray::_InputArray

(

const std::vector< Mat > &

vec

)

_InputArray() [6/23]

template<typename _Tp >

cv::_InputArray::_InputArray

(

const Mat_< _Tp > &

m

)

_InputArray() [7/23]

template<typename _Tp >

cv::_InputArray::_InputArray

(

const std::vector< _Tp > &

vec

)

_InputArray() [8/23]

cv::_InputArray::_InputArray

(

const std::vector< bool > &

vec

)

_InputArray() [9/23]

template<typename _Tp >

cv::_InputArray::_InputArray

(

const std::vector< std::vector< _Tp > > &

vec

)

_InputArray() [10/23]

cv::_InputArray::_InputArray ( const std::vector< std::vector< bool > > & )

delete

_InputArray() [11/23]

template<typename _Tp >

cv::_InputArray::_InputArray

(

const std::vector< Mat_< _Tp > > &

vec

)

_InputArray() [12/23]

template<typename _Tp >

cv::_InputArray::_InputArray	(	const _Tp *	vec,
		int	n )

_InputArray() [13/23]

template<typename _Tp , int m, int n>

cv::_InputArray::_InputArray

(

const Matx< _Tp, m, n > &

matx

)

_InputArray() [14/23]

cv::_InputArray::_InputArray

(

const double &

val

)

_InputArray() [15/23]

cv::_InputArray::_InputArray

(

const cuda::GpuMat &

d_mat

)

_InputArray() [16/23]

cv::_InputArray::_InputArray

(

const std::vector< cuda::GpuMat > &

d_mat_array

)

_InputArray() [17/23]

cv::_InputArray::_InputArray

(

const ogl::Buffer &

buf

)

_InputArray() [18/23]

cv::_InputArray::_InputArray

(

const cuda::HostMem &

cuda_mem

)

_InputArray() [19/23]

template<typename _Tp >

cv::_InputArray::_InputArray

(

const cudev::GpuMat_< _Tp > &

m

)

_InputArray() [20/23]

cv::_InputArray::_InputArray

(

const UMat &

um

)

_InputArray() [21/23]

cv::_InputArray::_InputArray

(

const std::vector< UMat > &

umv

)

_InputArray() [22/23]

template<typename _Tp , std::size_t _Nm>

cv::_InputArray::_InputArray

(

const std::array< _Tp, _Nm > &

arr

)

_InputArray() [23/23]

template<std::size_t _Nm>

cv::_InputArray::_InputArray

(

const std::array< Mat, _Nm > &

arr

)

~_InputArray()

cv::_InputArray::~_InputArray

(

)

Member Function Documentation

channels()

int cv::_InputArray::channels

(

int

i = -1

)

const

cols()

int cv::_InputArray::cols

(

int

i = -1

)

const

copyTo() [1/2]

void cv::_InputArray::copyTo

(

const _OutputArray &

arr

)

const

copyTo() [2/2]

void cv::_InputArray::copyTo	(	const _OutputArray &	arr,
		const _InputArray &	mask ) const

depth()

int cv::_InputArray::depth

(

int

i = -1

)

const

dims()

int cv::_InputArray::dims

(

int

i = -1

)

const

empty()

bool cv::_InputArray::empty

(

)

const

getFlags()

int cv::_InputArray::getFlags

(

)

const

getGpuMat()

cuda::GpuMat cv::_InputArray::getGpuMat

(

)

const

getGpuMatVector()

void cv::_InputArray::getGpuMatVector

(

std::vector< cuda::GpuMat > &

gpumv

)

const

getMat()

Mat cv::_InputArray::getMat

(

int

idx = -1

)

const

Examples

samples/cpp/pca.cpp.

getMat_()

Mat cv::_InputArray::getMat_

(

int

idx = -1

)

const

getMatVector()

void cv::_InputArray::getMatVector

(

std::vector< Mat > &

mv

)

const

getObj()

void * cv::_InputArray::getObj

(

)

const

getOGlBuffer()

ogl::Buffer cv::_InputArray::getOGlBuffer

(

)

const

getSz()

Size cv::_InputArray::getSz

(

)

const

getUMat()

UMat cv::_InputArray::getUMat

(

int

idx = -1

)

const

getUMatVector()

void cv::_InputArray::getUMatVector

(

std::vector< UMat > &

umv

)

const

init() [1/2]

void cv::_InputArray::init ( int _flags, const void * _obj )

protected

init() [2/2]

void cv::_InputArray::init ( int _flags, const void * _obj, Size _sz )

protected

isContinuous()

bool cv::_InputArray::isContinuous

(

int

i = -1

)

const

isGpuMat()

bool cv::_InputArray::isGpuMat

(

)

const

isGpuMatVector()

bool cv::_InputArray::isGpuMatVector

(

)

const

isMat()

bool cv::_InputArray::isMat

(

)

const

isMatVector()

bool cv::_InputArray::isMatVector

(

)

const

isMatx()

bool cv::_InputArray::isMatx

(

)

const

isSubmatrix()

bool cv::_InputArray::isSubmatrix

(

int

i = -1

)

const

isUMat()

bool cv::_InputArray::isUMat

(

)

const

isUMatVector()

bool cv::_InputArray::isUMatVector

(

)

const

isVector()

bool cv::_InputArray::isVector

(

)

const

kind()

_InputArray::KindFlag cv::_InputArray::kind

(

)

const

offset()

size_t cv::_InputArray::offset

(

int

i = -1

)

const

rawIn() [1/2]

template<typename _Tp , std::size_t _Nm>

static _InputArray cv::_InputArray::rawIn ( const std::array< _Tp, _Nm > & arr )

static

rawIn() [2/2]

template<typename _Tp >

static _InputArray cv::_InputArray::rawIn ( const std::vector< _Tp > & vec )

static

rows()

int cv::_InputArray::rows

(

int

i = -1

)

const

sameSize()

bool cv::_InputArray::sameSize

(

const _InputArray &

arr

)

const

size()

Size cv::_InputArray::size

(

int

i = -1

)

const

sizend()

int cv::_InputArray::sizend	(	int *	sz,
		int	i = -1 ) const

step()

size_t cv::_InputArray::step

(

int

i = -1

)

const

total()

size_t cv::_InputArray::total

(

int

i = -1

)

const

type()

int cv::_InputArray::type

(

int

i = -1

)

const

Member Data Documentation

flags

int cv::_InputArray::flags

protected

obj

void* cv::_InputArray::obj

protected

sz

Size cv::_InputArray::sz

protected

---

The documentation for this class was generated from the following file:

• opencv2/core/mat.hpp