用opencv简单显示图像和视频（代码有注释）

#include "stdafx.h"#include "cv.h"#include "highgui.h"void displayPic(char *argv){IplImage* img = cvLoadImage( argv );//opens a window on the screen that can//contain and display an imagecvNamedWindow( "Example1", CV_WINDOW_AUTOSIZE );//Whenever we have an image in the form of an IplImage* pointer, we can display it in an//existing window with cvShowImage().//The cvShowImage() function requires that a named//window already exist (created by cvNamedWindow()).cvShowImage( "Example1", img );//The cvWaitKey() function asks the program to stop and wait for a keystrokecvWaitKey(0);//free the allocated memorycvReleaseImage( &img );cvDestroyWindow( "Example1" );}void playVideo(char *argv){cvNamedWindow( "Example1", CV_WINDOW_AUTOSIZE );//Th e function cvCreateFileCapture() takes as its argument the name of the video file to be//loaded and then returns a pointer to a CvCapture structureCvCapture* capture = cvCreateFileCapture( argv );IplImage* frame;while(1) //begin reading from the video file{//Unlike cvLoadImage(), which actually allocates memory for the//image, cvQueryFrame uses memory already allocated in the CvCapture structure//!thus no need to call cvReleaseImage()frame = cvQueryFrame( capture );if( !frame ) break;cvShowImage( "Example1", frame );//assume that it is correct to play//the video at 30 frames per second and allow user input to interrupt between each framechar c = cvWaitKey(33);if( c == 27 ) break; //Esc ASCII value == 27}cvReleaseCapture( &capture );cvDestroyWindow( "Example1" );}