简单使用vfw开闭摄像头

MSDN 参考：

http://msdn.microsoft.com/en-us/library/windows/desktop/dd407331(v=vs.85).aspx

 

#include <Windows.h>
#include <cassert>
#include <Vfw.h>
#pragma comment(lib, "vfw32")

LRESULT CALLBACK IndexWndProc(HWND, UINT, WPARAM, LPARAM);
LRESULT CALLBACK viewWndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam);

void initializeClass();
bool myRegisterClass();
void myCreateWindow();
void myUpdateWindow();
void myShowWindow();
void myMessageRoute();

// 全局实例
HINSTANCE g_hInst;

// 窗口名
TCHAR indexClassName[] = TEXT("index");
TCHAR viewClassName[] = TEXT("view");

// 窗口类
WNDCLASS indexWndClass;
WNDCLASS viewWndClass;

// 窗口对象
HWND indexHWnd;
HWND viewHWnd;

// 应用名字
const TCHAR appName[] = TEXT("使用vfw");

// 按钮ID
const INT BTN_BEGIN = 100;
const INT BTN_END = 101;

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpszCmdLine, int nCmdShow)
{
    g_hInst = hInstance;

    initializeClass();

    // 注册
    if (!myRegisterClass())
    {
        MessageBox(NULL, TEXT("注册类失败"), TEXT("错误"), MB_ICONERROR);
        return 0;
    }

    // 创建
    myCreateWindow();

    // 显示
    myShowWindow();

    // 更新
    myUpdateWindow();

    // 消息循环
    myMessageRoute();

    return 0;
}

void initializeClass()
{
    /// 初始化indexWndClass
    memset(&indexWndClass, 0, sizeof(indexWndClass));
    indexWndClass.hbrBackground = (HBRUSH) GetStockObject(WHITE_BRUSH);
    indexWndClass.hInstance = g_hInst;
    indexWndClass.lpfnWndProc = IndexWndProc;
    indexWndClass.lpszClassName = indexClassName;
    indexWndClass.style = CS_HREDRAW | CS_VREDRAW;

    // 初始化viewWndClass
    memset(&viewWndClass, 0, sizeof(viewWndClass));
    viewWndClass.hbrBackground = (HBRUSH) GetStockObject(BLACK_BRUSH);
    viewWndClass.hInstance = g_hInst;
    viewWndClass.lpfnWndProc = viewWndProc;
    viewWndClass.lpszClassName = viewClassName;
    viewWndClass.style = CS_HREDRAW | CS_VREDRAW;
}

bool myRegisterClass()
{
    if (!RegisterClass(&indexWndClass))
    {
        return false;
    }

    if (!RegisterClass(&viewWndClass))
    {
        return false;
    }

    return true;
}

void myCreateWindow()
{
    indexHWnd = CreateWindow(indexClassName, appName, WS_OVERLAPPEDWINDOW & ~WS_MAXIMIZEBOX & ~WS_THICKFRAME, CW_USEDEFAULT, CW_USEDEFAULT, 900, 700, NULL, NULL, g_hInst, NULL);
    assert(NULL != indexHWnd);
}

void myUpdateWindow()
{
    UpdateWindow(indexHWnd);
}

void myShowWindow()
{
    ShowWindow(indexHWnd, SW_NORMAL);
}

void myMessageRoute()
{
    MSG msg;
    while (GetMessage(&msg, NULL, 0, 0))
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }
}

LRESULT CALLBACK IndexWndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    INT id;
    switch(message)
    {
    case WM_COMMAND:
        id = LOWORD(wParam);
        switch (id)
        {
        case BTN_BEGIN:
            assert(NULL != viewHWnd);
            capDriverConnect(viewHWnd, 0);
            capPreviewRate(viewHWnd, 60);
            capPreview(viewHWnd, TRUE);
            break;
        case BTN_END:
            assert(NULL != viewHWnd);
            capPreview(viewHWnd, FALSE);
            capDriverDisconnect(viewHWnd);
            break;
        }
        break;
    case WM_CREATE:
        CreateWindow(TEXT("button"), TEXT("打开摄像头"), WS_VISIBLE | WS_CHILD | BS_PUSHBUTTON, 650 + 20, 10, 200, 50, hWnd, (HMENU)BTN_BEGIN, ((LPCREATESTRUCT)lParam)->hInstance, NULL);
        CreateWindow(TEXT("button"), TEXT("关闭摄像头"), WS_VISIBLE | WS_CHILD | BS_PUSHBUTTON, 650 + 20, 70, 200, 50, hWnd, (HMENU)BTN_END, ((LPCREATESTRUCT)lParam)->hInstance, NULL);
        viewHWnd = capCreateCaptureWindow(viewClassName, WS_VISIBLE | WS_CHILD | WS_BORDER, 10, 10, 640, 480, hWnd, 1);
        break;
    case WM_DESTROY:
        PostQuitMessage(0);
        break;
    }
    return DefWindowProc(hWnd, message, wParam, lParam);
}

LRESULT CALLBACK viewWndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{ 
    PAINTSTRUCT ps;
    HDC hdc;
    RECT re;
    
    HGDIOBJ old;
    switch(message)
    {
    case WM_PAINT:
        GetClientRect(hWnd, &re);

        hdc = BeginPaint(hWnd, &ps);
        old = SelectObject(hdc, GetStockObject(BLACK_BRUSH));
        Rectangle(hdc, re.left, re.top, re.right, re.bottom);
        SelectObject(hdc, old);

        EndPaint(hWnd, &ps);
        break;
    }
    return DefWindowProc(hWnd, message, wParam, lParam);
}

 

效果图：