whatsize.c

图形基础 GDI 的例子

/*-----------------------------------------
   WHATSIZE.C -- What Size is the Window?
                 (c) Charles Petzold, 1996
  -----------------------------------------*/

#include <windows.h>
#include <stdio.h>

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

int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,
                    PSTR szCmdLine, int iCmdShow)
     {
     static char szAppName[] = "WhatSize" ;
     HWND        hwnd ;
     MSG         msg ;
     WNDCLASSEX  wndclass ;

     wndclass.cbSize        = sizeof (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 ;
     wndclass.hIconSm       = LoadIcon (NULL, IDI_APPLICATION) ;

     RegisterClassEx (&wndclass) ;

     hwnd = CreateWindow (szAppName, "What Size is the Window?",
                          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 Show (HWND hwnd, HDC hdc, int xText, int yText, int iMapMode,
           char *szMapMode)
     {
     char szBuffer [60] ;
     RECT rect ;

     SaveDC (hdc) ;

     SetMapMode (hdc, iMapMode) ;
     GetClientRect (hwnd, &rect) ;
     DPtoLP (hdc, (PPOINT) &rect, 2) ;

     RestoreDC (hdc, -1) ;

     TextOut (hdc, xText, yText, szBuffer,
               sprintf (szBuffer, "%-20s %7d %7d %7d %7d", szMapMode,
                    rect.left, rect.right, rect.top, rect.bottom)) ;
     }  

LRESULT CALLBACK WndProc (HWND hwnd, UINT iMsg, WPARAM wParam, LPARAM lParam)
     {
     static char  szHeading [] =
                    "Mapping Mode            Left   Right     Top  Bottom" ;
     static char  szUndLine [] = 
                    "------------            ----   -----     ---  ------" ;
     static int   cxChar, cyChar ;
     HDC          hdc ;
     PAINTSTRUCT  ps ;
     TEXTMETRIC   tm ;

     switch (iMsg)
          {
          case WM_CREATE:
               hdc = GetDC (hwnd) ;
               SelectObject (hdc, GetStockObject (SYSTEM_FIXED_FONT)) ;

               GetTextMetrics (hdc, &tm) ;
               cxChar = tm.tmAveCharWidth ;
               cyChar = tm.tmHeight + tm.tmExternalLeading ;

               ReleaseDC (hwnd, hdc) ;
               return 0 ;

          case WM_PAINT:
               hdc = BeginPaint (hwnd, &ps) ;
               SelectObject (hdc, GetStockObject (SYSTEM_FIXED_FONT)) ;

               SetMapMode (hdc, MM_ANISOTROPIC) ;
               SetWindowExtEx (hdc, 1, 1, NULL) ;
               SetViewportExtEx (hdc, cxChar, cyChar, NULL) ;

               TextOut (hdc, 1, 1, szHeading, sizeof szHeading - 1) ;
               TextOut (hdc, 1, 2, szUndLine, sizeof szUndLine - 1) ;

               Show (hwnd, hdc, 1, 3, MM_TEXT,      "TEXT (pixels)") ;
               Show (hwnd, hdc, 1, 4, MM_LOMETRIC,  "LOMETRIC (.1 mm)") ;
               Show (hwnd, hdc, 1, 5, MM_HIMETRIC,  "HIMETRIC (.01 mm)") ;
               Show (hwnd, hdc, 1, 6, MM_LOENGLISH, "LOENGLISH (.01 in)") ;
               Show (hwnd, hdc, 1, 7, MM_HIENGLISH, "HIENGLISH (.001 in)") ;
               Show (hwnd, hdc, 1, 8, MM_TWIPS,     "TWIPS (1/1440 in)") ;

               EndPaint (hwnd, &ps) ;
               return 0 ;

          case WM_DESTROY:
               PostQuitMessage (0) ;
               return 0 ;
          }
     return DefWindowProc (hwnd, iMsg, wParam, lParam) ;
     }