一个简单的win32截图例子

#include "SaveBitmapToFile.cpp"
#include <windows.h>
#define  IDC_S***E 1
#define  IDC_FILEPATH 2

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

void InitWindow(HWND hWnd, LPARAM lParam);

int WINAPI WinMain( HINSTANCE hInstance, HINSTANCE hPrevInstance,
	PSTR szCmdLine, int iCmdShow)
{
	static TCHAR szAppName[] = TEXT ("test") ;

	HWND         hWnd ;
	MSG          msg ;
	WNDCLASS     wndclass ;

	wndclass.style         = CS_HREDRAW | CS_VREDRAW ;
	wndclass.lpfnWndProc   = WndProc ;
	wndclass.cbClsExtra    = 0 ;
	wndclass.cbWndExtra    = 0 ;
	wndclass.hInstance     = hInstance ;
	wndclass.hIcon         = LoadIcon (NULL, IDI_APPLICATION) ;
	wndclass.hCursor       = LoadCursor (NULL, IDC_ARROW) ;
	wndclass.hbrBackground = (HBRUSH) GetStockObject (WHITE_BRUSH) ;
	wndclass.lpszMenuName  = NULL ;
	wndclass.lpszClassName = szAppName ;

	if (!RegisterClass (&wndclass))
	{
		MessageBox (NULL, TEXT ("注册窗口类失败！"), szAppName, MB_ICONERROR) ;
		return 0 ;
	}

	hWnd = CreateWindow (szAppName,
						TEXT ("test"),
						WS_OVERLAPPEDWINDOW,
						100,
						100,
						350,
						100,
						NULL,
						NULL,
						hInstance,
						NULL) ;

	ShowWindow (hWnd, iCmdShow) ;
	UpdateWindow (hWnd) ;

	while (GetMessage(&msg, NULL, 0, 0))
	{
		TranslateMessage (&msg) ;
		DispatchMessage (&msg) ;
	}
	return msg.wParam ;
}

LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
	HDC         hdc ;
	PAINTSTRUCT ps;
	HBITMAP		hBitmap;
	HDC			hdcMem;
	static int screenx, screeny;
	static char filePath[MAXPNAMELEN];

	switch (message)
	{
	case WM_PAINT:
		hdc = BeginPaint(hWnd, &ps);
		EndPaint(hWnd,&ps);
		return 0;
			
	case WM_CREATE:
		InitWindow(hWnd, lParam);
		screenx = GetSystemMetrics(SM_CXSCREEN);
		screeny = GetSystemMetrics(SM_CYSCREEN);
		return 0;

	case WM_COMMAND:

		switch (LOWORD(wParam))
		{
		case IDC_S***E:
			GetDlgItemText(hWnd, IDC_FILEPATH, (LPWSTR)filePath, sizeof(filePath));

			ShowWindow(hWnd, SW_HIDE);
			Sleep(500);

			hdc = GetDC(NULL);

			hBitmap = CreateCompatibleBitmap(hdc, screenx, screeny);
			hdcMem = CreateCompatibleDC(hdc);
			
			SelectObject(hdcMem, hBitmap);
			BitBlt(hdcMem, 0, 0, screenx, screeny, hdc, 0, 0, SRCCOPY);
			SaveBitmapToFile((LPCTSTR)filePath, hdc, hBitmap);
			
			ReleaseDC(hWnd, hdcMem);
			ReleaseDC(hWnd, hdc);

			ShowWindow(hWnd, SW_SHOW);

			MessageBox(hWnd, TEXT("截图完成"), TEXT("提示"), MB_OK);
			return 0;
		}

		return 0;

	case WM_DESTROY:
		PostQuitMessage (0) ;
		return 0 ;
	}

	return DefWindowProc (hWnd, message, wParam, lParam) ;
}

void InitWindow(HWND hWnd, LPARAM lParam)
{
	HWND btnSave, txtFilePath;

	btnSave = CreateWindow(TEXT("BUTTON"),
						TEXT("Save"),
						WS_CHILD | BS_PUSHBUTTON,
						20,
						30,
						100,
						25,
						hWnd,
						(HMENU)IDC_S***E,
						((LPCREATESTRUCT) lParam)->hInstance,
						NULL);

	txtFilePath = CreateWindow(TEXT("EDIT"),
								TEXT("d:\\test.bmp"),
								WS_CHILD | WS_BORDER,
								20,
								1,
								300,
								25,
								hWnd,
								(HMENU)IDC_FILEPATH,
								((LPCREATESTRUCT) lParam)->hInstance,
								NULL);

	ShowWindow(btnSave, SW_SHOW);
	ShowWindow(txtFilePath, SW_SHOW);
}