windows下攝像頭的使用

windows下提供了調用攝像頭的相關api函數，函數定義包含在vfw.h頭文件中。

http://msdn.microsoft.com/zh-cn/dd757677 這個地址提供了完整的教程。

下面貼出一個簡單的例子

頭文件：

#ifndef pvcamerasnapshoter_h
#define pvcamerasnapshoter_h

#include <QtGui/QWidget>
#include <QtGui/QPixmap>
#include <QtCore/QByteArray>
#include <Windows.h>
#include <Vfw.h>
#pragma comment(lib,"Vfw32.lib")

class pvCameraSnapshoter : public QWidget
{
    Q_OBJECT

public:
    pvCameraSnapshoter(QWidget *parent = 0);

    ~pvCameraSnapshoter(void);
    
    bool OpenCamera();            //初始化攝像頭 void CloseCamera();

    QPixmap GetCameraSnapshot();   //保持一幀圖片數據

private:
    HWND cameraScreenHwnd;

};

#endif //pvcamerasnapshoter_h

實現文件：

#include <tchar.h>
#include <QtGui/QBitmap>
#include <QtCore/QByteArray>

#include "pvCameraSnapshoter.h"
#include "../common/pvcmuserpath.h"

LRESULT PASCAL SnapshotFrameCbProc(HWND hWnd, LPVIDEOHDR lpVHdr);        //回調函數用於處理接收到的圖像數據

pvCameraSnapshoter::pvCameraSnapshoter(QWidget *parent) :
    QWidget(parent)
{

}

pvCameraSnapshoter::~pvCameraSnapshoter(void)
{
}

bool pvCameraSnapshoter::OpenCamera()
{
    LPTSTR lpszName = new TCHAR[100];
    LPTSTR lpszVer = new TCHAR[100];
    
    capGetDriverDescription(0,lpszName,100,lpszVer,100);
    cameraScreenHwnd = capCreateCaptureWindow(lpszName, WS_CHILD | WS_VISIBLE, 0, 0, width(), height(), winId(), 0); //創建一個用來顯示攝像頭視頻的窗口 if(cameraScreenHwnd == INVALID_HANDLE_VALUE)
    {
        return false;
    }
    if(capDriverConnect(cameraScreenHwnd,0))       //與鏈接攝像頭
    {
        capPreview(cameraScreenHwnd,true);         //設置娛樂模式，這樣與攝像頭關聯的窗口就可以自動顯示視頻數據了
        capPreviewRate(cameraScreenHwnd,60);       //每秒60幀 
        BITMAPINFO bitmapinfo;
        memset(&bitmapinfo,0,sizeof(BITMAPINFO));
        bitmapinfo.bmiHeader.biSize = sizeof(BITMAPINFOHEADER);
        bitmapinfo.bmiHeader.biWidth = 320;
        bitmapinfo.bmiHeader.biHeight = 240;
        bitmapinfo.bmiHeader.biPlanes = 1;
        bitmapinfo.bmiHeader.biBitCount = 32;
        bitmapinfo.bmiHeader.biCompression = BI_RGB;
        
        capSetVideoFormat(cameraScreenHwnd, &bitmapinfo, sizeof(bitmapinfo)); //設置攝像頭的視頻格式，不過這個函數好像不起作用
        capSetUserData(cameraScreenHwnd,this);   //添加用戶數據，在回調函數中可能會用到
        capSetCallbackOnFrame(cameraScreenHwnd,SnapshotFrameCbProc); //設置回調函數，攝像頭的視頻數據每一幀都會經過這個函數 return true;
    }
    return false;
}

void pvCameraSnapshoter::CloseCamera()
{
    capDriverDisconnect(cameraScreenHwnd);
}

QPixmap pvCameraSnapshoter::GetCameraSnapshot()
{
    QPixmap cameraSnapshot;
    if(cameraScreenHwnd == INVALID_HANDLE_VALUE)
    {
        return cameraSnapshot;
    }
    if(capGrabFrameNoStop(cameraScreenHwnd)) //抓取一幀圖像數據，與capGrabFrame相比，它不會停止預覽模式和重疊
    {
        pvcmUserPath userpath;
        QString strSnapshotFile = userpath.GetUserSubPath("camerasnapshot").filePath("snapshot.bmp");
        const wchar_t* wSnapshotpath = reinterpret_cast<const wchar_t*>(strSnapshotFile.utf16());
        if(!capFileSaveDIB(cameraScreenHwnd,wSnapshotpath))  //保持攝像頭快照
        {
            qDebug("save camerasnapshot fail");
            return cameraSnapshot;
        }
        cameraSnapshot.load(strSnapshotFile);
    }
    return cameraSnapshot;
}

LRESULT PASCAL SnapshotFrameCbProc(HWND hWnd, LPVIDEOHDR lpVHdr) 
{ 
　　//這里處理視頻數據return (LRESULT) TRUE ; 
}

#include "moc_pvcamerasnapshoter.cpp"