flip()
#include <opencv2/core.hpp>
Flips a 2D array around vertical, horizontal, or both axes.
The function cv::flip flips the array in one of three different ways (row and column indices are 0-based):
The example scenarios of using the function are the following: Vertical flipping of the image (flipCode == 0) to switch between top-left and bottom-left image origin. This is a typical operation in video processing on Microsoft Windows* OS. Horizontal flipping of the image with the subsequent horizontal shift and absolute difference calculation to check for a vertical-axis symmetry (flipCode > 0). Simultaneous horizontal and vertical flipping of the image with the subsequent shift and absolute difference calculation to check for a central symmetry (flipCode < 0). Reversing the order of point arrays (flipCode > 0 or flipCode == 0).
- Parameters
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src input array. dst output array of the same size and type as src. flipCode a flag to specify how to flip the array; 0 means flipping around the x-axis and positive value (for example, 1) means flipping around y-axis. Negative value (for example, -1) means flipping around both axes. flipcode： =0（上下翻转） / >0（左右翻转） / <0（上下左右同时翻转）