owndraw.cpp

C++中编辑之后的窗口缩放,以及放大.无论是缩小还是放大缩小、放大按钮都会保持在窗口中间

#include <windows.h>
#define ID_SMALLER      					1
#define ID_LARGER       					2
#define BTN_WIDTH        			 	(	8 * cxChar)
#define BTN_HEIGHT       			 	(	4 * cyChar)

LRESULT CALLBACK WndProc (HWND, UINT, WPARAM, LPARAM) ;
HINSTANCE hInst ;
int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,
						PSTR szCmdLine, int iCmdShow)
{
     	static TCHAR 	szAppName[] = TEXT ("OwnDraw") ;
     	MSG          				msg ;
     	HWND         				hwnd ;
     	WNDCLASS     			wndclass ;
     
     	hInst = hInstance ;
     	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  		= szAppName ;
     	wndclass.lpszClassName 		= szAppName ;
     
     	if (!RegisterClass (&wndclass))
	{
          		MessageBox (	NULL, TEXT ("This program requires Windows NT!"),
                      							szAppName, MB_ICONERROR) ;
          		return 0 ;
     	}

     	hwnd = CreateWindow (	szAppName, TEXT ("Owner-Draw Button Demo"),
                         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 ;
}

void Triangle (HDC hdc, POINT pt[])
{
     	SelectObject (hdc, GetStockObject (BLACK_BRUSH)) ;
     	Polygon (hdc, pt, 3) ;
     	SelectObject (hdc, GetStockObject (WHITE_BRUSH)) ;
}

LRESULT CALLBACK WndProc (	HWND hwnd, UINT message, WPARAM wParam,LPARAM lParam)
{
     	static HWND   			hwndSmaller, hwndLarger ;
     	static int   				cxClient, cyClient, cxChar, cyChar ;
     	int       						cx, cy ;
     	LPDRAWITEMSTRUCT pdis ;
     	POINT    						pt[3] ;
     	RECT             						rc ;
     
     	switch (message)
     	{
     	case 	WM_CREATE :
          		cxChar = LOWORD (GetDialogBaseUnits ()) ;
          		cyChar = HIWORD (GetDialogBaseUnits ()) ;
          
               			// Create the owner-draw pushbuttons
          
          		hwndSmaller = CreateWindow (TEXT ("button"), TEXT (""),
                              WS_CHILD | WS_VISIBLE | BS_OWNERDRAW,
                               0, 0, BTN_WIDTH, BTN_HEIGHT,
                               hwnd, (HMENU) ID_SMALLER, hInst, NULL) ;
          
          		hwndLarger  = CreateWindow (TEXT ("button"), TEXT (""),
                              WS_CHILD | WS_VISIBLE | BS_OWNERDRAW,
                               0, 0, BTN_WIDTH, BTN_HEIGHT,
                               hwnd, (HMENU) ID_LARGER, hInst, NULL) ;
          		return 0 ;
          
     	case 	WM_SIZE :
          		cxClient = LOWORD (lParam) ;
          		cyClient = HIWORD (lParam) ;
               			// Move the buttons to the new center
          
          	MoveWindow	(	hwndSmaller, 	cxClient / 2 - 3 * 	BTN_WIDTH  / 2,
                                cyClient / 2 -  	BTN_HEIGHT / 2,
                      			BTN_WIDTH, BTN_HEIGHT, TRUE) ;
          		MoveWindow (	hwndLarger,	cxClient / 2 + 	BTN_WIDTH  / 2,cyClient / 2 -  BTN_HEIGHT / 2,
							BTN_WIDTH, BTN_HEIGHT, TRUE) ;
          		return 0 ;
          
     	case 	WM_COMMAND :
          		GetWindowRect (hwnd, &rc) ;
          
               				// Make the window 10% smaller or larger
          
          		switch (wParam)
          		{
          		case 	ID_SMALLER :
               				rc.left 	+= cxClient / 20 ;
               				rc.right	-= cxClient / 20 ;
               				rc.top 		+= cyClient / 20 ;
               				rc.bottom	-= cyClient / 20 ;
               				break ;
               
          		case 	ID_LARGER :
               				rc.left 	-= cxClient / 20 ;
               				rc.right	+= cxClient / 20 ;
               				rc.top 		-= cyClient / 20 ;
               				rc.bottom	+= cyClient / 20 ;
               				break ;
          	}
          
          		MoveWindow (	hwnd, rc.left, rc.top, rc.right  - rc.left,
                            							rc.bottom - rc.top, TRUE) ;
          		return 0 ;
          
     	case 	WM_DRAWITEM :
          		pdis = (LPDRAWITEMSTRUCT) lParam ;
               
               				// Fill area with white and frame it black
               
          		FillRect 		(pdis->hDC, &pdis->rcItem,
                    			(HBRUSH) GetStockObject (WHITE_BRUSH)) ;
               
          		FrameRect (	pdis->hDC, &pdis->rcItem,
                     			(	HBRUSH) GetStockObject (BLACK_BRUSH)) ;
               				// 			Draw inward and outward black triangles
          		cx = 		pdis->rcItem.right  - pdis->rcItem.left ;
          		cy = 		pdis->rcItem.bottom - pdis->rcItem.top  ;

          		switch (pdis->CtlID)
          		{
          		case 	ID_SMALLER :
               				pt[0].x = 3 * cx / 8 ;  pt[0].y = 1 * cy / 8 ;
               				pt[1].x = 5 * cx / 8 ;  pt[1].y = 1 * cy / 8 ;
               				pt[2].x = 4 * cx / 8 ;  pt[2].y = 3 * cy / 8 ;
                    
               				Triangle (pdis->hDC, pt) ;
                    
               				pt[0].x = 7 * cx / 8 ;  pt[0].y = 3 * cy / 8 ;
               				pt[1].x = 7 * cx / 8 ;  pt[1].y = 5 * cy / 8 ;
               				pt[2].x = 5 * cx / 8 ;  pt[2].y = 4 * cy / 8 ;
                    
               				Triangle (pdis->hDC, pt) ;
                    
               				pt[0].x = 5 * cx / 8 ;  pt[0].y = 7 * cy / 8 ;
               				pt[1].x = 3 * cx / 8 ;  pt[1].y = 7 * cy / 8 ;
               				pt[2].x = 4 * cx / 8 ;  pt[2].y = 5 * cy / 8 ;
                    
               				Triangle (pdis->hDC, pt) ;
                    
               				pt[0].x = 1 * cx / 8 ;  pt[0].y = 5 * cy / 8 ;
               				pt[1].x = 1 * cx / 8 ;  pt[1].y = 3 * cy / 8 ;
               				pt[2].x = 3 * cx / 8 ;  pt[2].y = 4 * cy / 8 ;
                    
               			Triangle (pdis->hDC, pt) ;
               			break ;
                    
          			case ID_LARGER :
               			pt[0].x = 5 * cx / 8 ;  pt[0].y = 3 * cy / 8 ;
               			pt[1].x = 3 * cx / 8 ;  pt[1].y = 3 * cy / 8 ;
               			pt[2].x = 4 * cx / 8 ;  pt[2].y = 1 * cy / 8 ;
                    
               			Triangle (pdis->hDC, pt) ;
                    
               			pt[0].x = 5 * cx / 8 ;  pt[0].y = 5 * cy / 8 ;
               			pt[1].x = 5 * cx / 8 ;  pt[1].y = 3 * cy / 8 ;
               			pt[2].x = 7 * cx / 8 ;  pt[2].y = 4 * cy / 8 ;
                    
               			Triangle (pdis->hDC, pt) ;
               			pt[0].x = 3 * cx / 8 ;  pt[0].y = 5 * cy / 8 ;
               			pt[1].x = 5 * cx / 8 ;  pt[1].y = 5 * cy / 8 ;
               			pt[2].x = 4 * cx / 8 ;  pt[2].y = 7 * cy / 8 ;
                    
               			Triangle (pdis->hDC, pt) ;
               			pt[0].x = 3 * cx / 8 ;  pt[0].y = 3 * cy / 8 ;
               			pt[1].x = 3 * cx / 8 ;  pt[1].y = 5 * cy / 8 ;
               			pt[2].x = 1 * cx / 8 ;  pt[2].y = 4 * cy / 8 ;
                    
               			Triangle (pdis->hDC, pt) ;
               			break ;
         		 }
               
               			// Invert the rectangle if the button is selected
               
          		if (pdis->itemState & ODS_SELECTED)
               				InvertRect (pdis->hDC, &pdis->rcItem) ;
               
               			// Draw a focus rectangle if the button has the focus
               
          		if (pdis->itemState & ODS_FOCUS)
          		{
               				pdis->rcItem.left  += cx / 16 ;
               				pdis->rcItem.top   += cy / 16 ;
               				pdis->rcItem.right -= cx / 16 ;
               				pdis->rcItem.bottom-= cy / 16 ;
                    
               				DrawFocusRect (pdis->hDC, &pdis->rcItem) ;
          		}
          		return 0 ;
               
   	case 	WM_DESTROY :
          		PostQuitMessage (0) ;
          		return 0 ;
     	}
     	return DefWindowProc (hwnd, message, wParam, lParam) ;
}