在我心中有一個夢

最近實驗室要我們研究，兩隻手機透過wifi傳影像，我想說先試試用電腦跟平板對傳影像，所以就先處理電腦這端WebCam的程式，沒想到還蠻簡單的。主要是要熟悉C語言跟呼叫dll的部分，還有剪貼簿的操作。
程式碼如下：
#include<windows.h>
#define ID_MYTIMER 100
LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
ATOM InitApp(HINSTANCE);
BOOL InitInstance(HINSTANCE hInst, int);
BOOL LoadWebCamAPI(void);


TCHAR szClassName[] = TEXT("WebCam");
INT_PTR (*CapturePicture)(LPSTR, int, int, int, int, int, INT_PTR, int);
INT_PTR intDeviceHandle;
LPSTR baDeviceName;

const int WM_CAP_DRIVER_CONNECT = 0x40a;
const int WM_CAP_DRIVER_DISCONNECT = 0x40b;
const int WM_CAP_EDIT_COPY = 0x41e;

const int WM_CAP_GRAB_FRAME = 0x43c;

int WINAPI WinMain(HINSTANCE hCurInst, HINSTANCE hPrevInst, LPSTR lpszCmdLine, int nCmdShow)
{
MSG msg;
BOOL bRet;

if (!InitApp(hCurInst))
return FALSE;
if (!InitInstance(hCurInst, nCmdShow))
return FALSE;

while ((bRet = GetMessage(&msg, NULL, 0, 0)) != 0)
{
if (bRet == -1)
break;
else {
TranslateMessage(&msg);
DispatchMessage(&msg);
}

}
return 0;
}

ATOM InitApp(HINSTANCE hInst)
{
WNDCLASSEX wc;

wc.style = CS_VREDRAW | CS_HREDRAW;

wc.cbSize = sizeof(WNDCLASSEX);
wc.cbWndExtra = 0;
wc.cbClsExtra = 0;

wc.lpfnWndProc = WndProc;
wc.lpszClassName = szClassName;
wc.lpszMenuName = NULL;

wc.hInstance = hInst;
wc.hIcon = (HICON)LoadImage(NULL,
MAKEINTRESOURCE(IDI_APPLICATION),
IMAGE_ICON,
0,
0,
LR_DEFAULTSIZE | LR_SHARED);
wc.hIconSm = NULL;
wc.hCursor = (HCURSOR)LoadImage(NULL,
MAKEINTRESOURCE(IDC_ARROW),
IMAGE_CURSOR,
0,
0,
LR_DEFAULTSIZE | LR_SHARED);
wc.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);

return (RegisterClassEx(&wc));
}

BOOL InitInstance(HINSTANCE hInst, int nCmdShow)
{
HWND hWnd = CreateWindow(szClassName,
TEXT("WebCam"),
WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT,
CW_USEDEFAULT,
CW_USEDEFAULT,
CW_USEDEFAULT,
NULL,
NULL,
hInst,
NULL);
if (!hWnd)
return FALSE;
ShowWindow(hWnd, nCmdShow);
UpdateWindow(hWnd);
return TRUE;
}

LRESULT CALLBACK WndProc(HWND hWnd, UINT msg, WPARAM wp, LPARAM lp)
{
PAINTSTRUCT ps;
HDC hdc, mdc;
HGLOBAL hmem;
RECT rc;
HBITMAP hbmp;
switch (msg) {
case WM_CREATE:
SetTimer(hWnd, ID_MYTIMER, 1, NULL);
if (!LoadWebCamAPI())
{
MessageBox(hWnd, TEXT("Error!"), TEXT("AVIcap32.dll加載失敗!"), MB_YESNO | MB_ICONQUESTION);
PostQuitMessage(0);
} else {
intDeviceHandle = (CapturePicture)(baDeviceName, WS_VISIBLE | WS_CHILD, 0, 0, 0, 0, (INT_PTR)hWnd, 0);
SendMessage(intDeviceHandle, WM_CAP_DRIVER_CONNECT, 0, 0);
MessageBox( hWnd, TEXT("Success!"), TEXT("AVIcap32.dll加載成功!"), MB_OK);
}
break;
case WM_TIMER:

InvalidateRect(hWnd, NULL, FALSE);
break;
case WM_PAINT:
hdc = BeginPaint(hWnd, &ps);
mdc = CreateCompatibleDC(hdc);
if (SendMessage(intDeviceHandle, WM_CAP_GRAB_FRAME, 0, 0) > 0) //如果有截取到畫面
{
if (SendMessage(intDeviceHandle, WM_CAP_EDIT_COPY, 0, 0) > 0) //如果有Copy到剪貼簿
{
OpenClipboard (hWnd) ;
hbmp = GetClipboardData(CF_BITMAP);
SelectObject(mdc, hbmp);
GetClipBox(mdc, &rc);
BitBlt(hdc, 0, 0, rc.right, rc.bottom, mdc,0, 0, SRCCOPY);
CloseClipboard();
}
}


EndPaint(hWnd, &ps);
DeleteObject(hbmp);
DeleteDC(mdc);
break;
case WM_DESTROY:
KillTimer(hWnd, ID_MYTIMER);
PostQuitMessage(0);
break;
default:
return DefWindowProc(hWnd, msg, wp, lp);
}

return 0;
}

BOOL LoadWebCamAPI(void)
{
HMODULE hInst;

hInst = LoadLibrary("AVIcap32.dll");
if (hInst == NULL)
return FALSE;
CapturePicture = GetProcAddress(hInst, "capCreateCaptureWindowA");
if (CapturePicture == NULL)
return FALSE;
return TRUE;
}

事實上索貝爾運算子我之前就有想說要研究，但看到維基百科上的解釋，讓我打退堂鼓。最近有開始研究他，也多虧同學的講義讓我終 於了解，其中要了解的是捲積的概念，還有邊界判定的問題，其他應該都小Case。
程式碼如下：
Sobel.rc