cv::LineIterator クラス

Line iterator [詳解]

#include <imgproc.hpp>

公開メンバ関数
	LineIterator (const Mat &img, Point pt1, Point pt2, int connectivity=8, bool leftToRight=false)
	initializes the iterator [詳解]
	LineIterator (Point pt1, Point pt2, int connectivity=8, bool leftToRight=false)
	LineIterator (Size boundingAreaSize, Point pt1, Point pt2, int connectivity=8, bool leftToRight=false)
	LineIterator (Rect boundingAreaRect, Point pt1, Point pt2, int connectivity=8, bool leftToRight=false)
void	init (const Mat *img, Rect boundingAreaRect, Point pt1, Point pt2, int connectivity, bool leftToRight)
uchar *	operator* ()
	returns pointer to the current pixel
LineIterator &	operator++ ()
	prefix increment operator (++it). shifts iterator to the next pixel
LineIterator	operator++ (int)
	postfix increment operator (it++). shifts iterator to the next pixel
Point	pos () const
	returns coordinates of the current pixel

公開変数類
uchar *	ptr
const uchar *	ptr0
int	step
int	elemSize
int	err
int	count
int	minusDelta
int	plusDelta
int	minusStep
int	plusStep
int	minusShift
int	plusShift
Point	p
bool	ptmode

詳解

Line iterator

The class is used to iterate over all the pixels on the raster line segment connecting two specified points.

The class LineIterator is used to get each pixel of a raster line. It can be treated as versatile implementation of the Bresenham algorithm where you can stop at each pixel and do some extra processing, for example, grab pixel values along the line or draw a line with an effect (for example, with XOR operation).

The number of pixels along the line is stored in LineIterator::count. The method LineIterator::pos returns the current position in the image:

// grabs pixels along the line (pt1, pt2)
// from 8-bit 3-channel image to the buffer
LineIterator it(img, pt1, pt2, 8);
LineIterator it2 = it;
vector<Vec3b> buf(it.count);
 
for(int i = 0; i < it.count; i++, ++it)
    buf[i] = *(const Vec3b*)*it;
 
// alternative way of iterating through the line
for(int i = 0; i < it2.count; i++, ++it2)
{
    Vec3b val = img.at<Vec3b>(it2.pos());
    CV_Assert(buf[i] == val);
}

構築子と解体子

LineIterator()

cv::LineIterator::LineIterator ( const Mat &  img, Point  pt1, Point  pt2, int  connectivity = 8, bool  leftToRight = false  )

inline

initializes the iterator

creates iterators for the line connecting pt1 and pt2 the line will be clipped on the image boundaries the line is 8-connected or 4-connected If leftToRight=true, then the iteration is always done from the left-most point to the right most, not to depend on the ordering of pt1 and pt2 parameters;

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このクラス詳解は次のファイルから抽出されました:

• imgproc.hpp