GetClientRect | GetClientRect

这个函数好像就是对应于视口的，获取视口的宽高
#include <windows.h>

LRESULT CALLBACK WndProc (HWND, UINT, WPARAM, LPARAM) ;

int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,

 PSTR szCmdLine, int iCmdShow)

{

	static TCHAR szAppName[] = TEXT ("坐标") ;

    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 ("This program requires Windows NT!"),

        szAppName, MB_ICONERROR) ;

        return 0 ;

	}

    hwnd = CreateWindow (szAppName, TEXT ("坐标尺寸"),

                         WS_OVERLAPPEDWINDOW,

                         CW_USEDEFAULT, CW_USEDEFAULT,

                         CW_USEDEFAULT, CW_USEDEFAULT,

                         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 ;

	RECT rect;

	switch (message)

	{

     case WM_PAINT:

		 hdc = BeginPaint (hwnd, &ps) ;

		HPEN hPen,hOldPen;

		 hPen=CreatePen(PS_SOLID,1,RGB(0,12,255));

		 hOldPen=(HPEN)SelectObject(hdc,hPen);

//1	     Ellipse(hdc,-100, -100, 100, 100);

		 GetClientRect(hwnd,&rect);

     //    MoveToEx(hdc,rect.right/2,0,NULL);

	//	 LineTo(hdc,rect.right/2,rect.bottom);

//		 MoveToEx(hdc,rect.left,rect.bottom/2,NULL);

//		 LineTo(hdc,rect.right,rect.bottom/2);

//2		 Ellipse(hdc,-50,-50,50,50);

//		 MoveToEx(hdc,0,0,NULL);

//		 LineTo(hdc,100,100);

//3		 SetViewportOrgEx(hdc,200,150,NULL);

//		 Ellipse(hdc,-50,-50,50,50);

//		 MoveToEx(hdc,0,0,NULL);

//		 LineTo(hdc,100,100);

//3.1 SetViewportOrgEx(hdc,rect.right/2,rect.bottom/2,NULL);

//		 Ellipse(hdc,-50,-50,50,50);

//		 MoveToEx(hdc,0,0,NULL);

//		 LineTo(hdc,100,100);

//3.2		SetViewportOrgEx(hdc,rect.right/2,rect.bottom/2,NULL);

//		Ellipse(hdc,-100,-100,100,100);

//		MoveToEx(hdc,rect.left,0,NULL);

//		LineTo(hdc,rect.right,0);

	//	MoveToEx(hdc,0,rect.top,NULL);

	//	LineTo(hdc,0,rect.bottom);

//4		 SetMapMode(hdc,MM_ANISOTROPIC);

//		SetViewportOrgEx(hdc,380,220,NULL);

//		Ellipse(hdc,-100,-100,100,100);

//		MoveToEx(hdc,-380,0,NULL);

//		LineTo(hdc,380,0);

//		MoveToEx(hdc,0,-220,NULL);

//		LineTo(hdc,0,220);

//		MoveToEx(hdc,0,0,NULL);

//		LineTo(hdc,120,120);

		 LOGBRUSH logbrush;

		 HBRUSH hBrush,hOldBrush;

		 logbrush.lbStyle=BS_SOLID;

		 logbrush.lbColor=RGB(128,128,128);

		 logbrush.lbHatch=HS_HORIZONTAL;

		 hBrush=CreateBrushIndirect(&logbrush);

		 hOldBrush=(HBRUSH)SelectObject(hdc,hBrush);

		 Rectangle(hdc,-100,-100,100,100);

		 MoveToEx(hdc,0,0,NULL);

		 LineTo(hdc,200,200);

		 DeleteObject(hPen);

		 DeleteObject(hBrush);

		 SelectObject(hdc,hOldPen);

		 SelectObject(hdc,hOldBrush);

        EndPaint (hwnd, &ps) ;

        break;

     case WM_DESTROY:

        PostQuitMessage (0) ;

        return 0 ;

	}

     return DefWindowProc (hwnd, message, wParam, lParam) ;

}