OpenCV实现给图片添加边框功能

/** * @file copyMakeBorder_demo.cpp * @brief Sample code that shows the functionality of copyMakeBorder * @author OpenCV team */ #include "opencv2/imgproc.hpp"#include "opencv2/imgcodecs.hpp"#include "opencv2/highgui.hpp" using namespace cv; //![variables]Mat src, dst;int top, bottom, left, right;int borderType;const char* window_name = "copyMakeBorder Demo";RNG rng(12345);//![variables] /** * @function main */int main( int, char** argv ){  int c;  //![load] src = imread( argv[1], IMREAD_COLOR ); // Load an image  if( src.empty() ) {  printf(" No data entered, please enter the path to an image file /n");  return -1; } //![load]  /// Brief how-to for this program printf( "/n /t copyMakeBorder Demo: /n" ); printf( "/t -------------------- /n" ); printf( " ** Press 'c' to set the border to a random constant value /n"); printf( " ** Press 'r' to set the border to be replicated /n"); printf( " ** Press 'ESC' to exit the program /n");  //![create_window] namedWindow( window_name, WINDOW_AUTOSIZE ); //![create_window]  //![init_arguments] /// Initialize arguments for the filter top = (int) (0.05*src.rows); bottom = (int) (0.05*src.rows); left = (int) (0.05*src.cols); right = (int) (0.05*src.cols); //![init_arguments]  dst = src; imshow( window_name, dst );  for(;;)  {   //![check_keypress]   c = waitKey(500);    if( (char)c == 27 )   { break; }   else if( (char)c == 'c' )   { borderType = BORDER_CONSTANT; }   else if( (char)c == 'r' )   { borderType = BORDER_REPLICATE; }   //![check_keypress]    //![update_value]   Scalar value( rng.uniform(0, 255), rng.uniform(0, 255), rng.uniform(0, 255) );   //![update_value]    //![copymakeborder]   copyMakeBorder( src, dst, top, bottom, left, right, borderType, value );   //![copymakeborder]    //![display]   imshow( window_name, dst );   //![display]  }  return 0;}