16. 调色盘管理器.txt

本书介绍了在Microsoft Windows 98、Microsoft Windows NT 4.0和Windows NT 5.0下程序写作的方法

        
                   MessageBox (  NULL, TEXT ("This program requires Windows NT!"),
        
                                                 szAppName, MB_ICONERROR) ;
        
                          return 0 ;
        
           }
        
   
        
           hwnd = CreateWindow ( szAppName, TEXT ("System Palette #1"),
        
                        WS_OVERLAPPEDWINDOW,
        
                         CW_USEDEFAULT, CW_USEDEFAULT,
        
                         CW_USEDEFAULT, CW_USEDEFAULT,
        
                         NULL, NULL, hInstance, NULL) ;
        

           if (!hwnd)
        
                          return 0 ;
        
         ShowWindow (hwnd, iCmdShow) ;
        
           UpdateWindow (hwnd) ;
        

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

BOOL CheckDisplay (HWND hwnd)
        
{
        
           HDC    hdc ;
        
           int    iPalSize ;
        

           hdc = GetDC (hwnd) ;
        
           iPalSize = GetDeviceCaps (hdc, SIZEPALETTE) ;
        
           ReleaseDC (hwnd, hdc) ;
        

           if (iPalSize != 256)
        
  {
        
            MessageBox (hwnd,TEXT ("This program requires that the video ")
        
                        TEXT ("display mode have a 256-color palette."),
        
                                szAppName, MB_ICONERROR) ;
        
                  return FALSE ;
        
           }
        
           return TRUE ;
        
}
        

LRESULT CALLBACK WndProc ( HWND hwnd, UINT message, WPARAM wParam,LPARAM lParam)
        
{
        
           static int            cxClient, cyClient ;
        
           static SIZE           sizeChar ;
        
           HDC                   hdc ;
        
           HPALETTE              hPalette ;
        
           int                   i, x, y ;
        
           PAINTSTRUCT           ps ;
        
           PALETTEENTRY          pe [256] ;
        
           TCHAR                                        szBuffer [16] ;
        

           switch (message)
        
         {
        
           case WM_CREATE:
        
                          if (!CheckDisplay (hwnd))
        
                                                 return -1 ;
        
                          hdc = GetDC (hwnd) ;
        
                          SelectObject (hdc, GetStockObject (SYSTEM_FIXED_FONT)) ;
        
                          GetTextExtentPoint32 (hdc, TEXT ("FF-FF-FF"), 10, &sizeChar) ;
        
                          ReleaseDC (hwnd, hdc) ;
        
                          return 0 ;
        
   
        
           case   WM_DISPLAYCHANGE:
        
                          if (!CheckDisplay (hwnd))
        
                                                 DestroyWindow (hwnd) ;
        

                          return 0 ;
        

           case   WM_SIZE:
        
                         cxClient = LOWORD (lParam) ;
        
                          cyClient = HIWORD (lParam) ;
        
                          return 0 ;
        

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

                          GetSystemPaletteEntries (hdc, 0, 256, pe) ;
        

                          for (i = 0, x = 0, y = 0 ; i < 256 ; i++)
        
                          {
        
                          wsprintf (    szBuffer, TEXT ("%02X-%02X-%02X"),
        
                   pe[i].peRed, pe[i].peGreen, pe[i].peBlue) ;
        

                         TextOut (hdc, x, y, szBuffer, lstrlen (szBuffer)) ;
        

                          if ((  x += sizeChar.cx) + sizeChar.cx > cxClient)
        
                                                 {
        
                                                 x = 0 ;
        
        
        
                                                 if ((  y += sizeChar.cy) > cyClient)
        
                                                               break ;
        
                                                 }
        
                         }
        
                          EndPaint (hwnd, &ps) ;
        
                          return 0 ;
        

           case   WM_PALETTECHANGED:
        
                          InvalidateRect (hwnd, NULL, FALSE) ;
        
                          return 0 ;
        

           case   WM_DESTROY:
        
                         PostQuitMessage (0) ;
        
                          return 0 ;
        
           }
        
           return DefWindowProc (hwnd, message, wParam, lParam) ;
        
}
        
与SYSPAL系列中的其它程序一样，除非带有SIZEPALETTE参数的GetDeviceCaps传回值为256，否则SYSPAL1不会执行。

注意无论SYSPAL1的显示区域什么时候收到WM_PALETTECHANGED消息，它都是无效的。在合并WM_PAINT消息处理期间，SYSPAL1呼叫GetSystemPaletteEntries，并用一个含256个PALETTEENTRY结构的数组作为参数。RGB值作为文字字符串显示在显示区域。程序执行时，注意20种保留颜色是RGB值列表中的前10个和后10个，这与表16-1所示相同。

当SYSPAL1显示有用的信息时，它与实际看到的256种颜色不同。那就是SYSPAL2的作业，如程序16-5所示。

程序16-5 SYSPAL2 
        
SYSPAL2.C
        
/*---------------------------------------------------------------------------
        
  SYSPAL2.C --    Displays system palette
        
                                                 (c) Charles Petzold, 1998
        
----------------------------------------------------------------------------*/
        
#include <windows.h>
        

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

TCHAR szAppName [] = TEXT ("SysPal2") ;
        

int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,
        
                          PSTR szCmdLine, int iCmdShow)
        
{
        
           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 ("System Palette #2"),
        
                                  WS_OVERLAPPEDWINDOW,
        
                                 CW_USEDEFAULT, CW_USEDEFAULT,
        
                                  CW_USEDEFAULT, CW_USEDEFAULT,
        
                                  NULL, NULL, hInstance, NULL) ;
        
           if (!hwnd)
        
                          return 0 ;
        
           ShowWindow (hwnd, iCmdShow) ;
        
           UpdateWindow (hwnd) ;
        

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

BOOL CheckDisplay (HWND hwnd)
        
{
        
           HDC hdc ;
        
           int iPalSize ;
        

           hdc = GetDC (hwnd) ;
        
           iPalSize = GetDeviceCaps (hdc, SIZEPALETTE) ;
        
           ReleaseDC (hwnd, hdc) ;
        

    if (iPalSize != 256)
        
           {
        
   MessageBox (hwnd, TEXT("This program requires that the video ")
        
                     TEXT ("display mode have a 256-color palette."),
        
                                 szAppName, MB_ICONERROR) ;
        
                  return FALSE ;
        
           }
        
           return TRUE ;
        
}
        

LRESULT CALLBACK WndProc ( HWND hwnd, UINT message, WPARAM wParam,LPARAM lParam)
        
{
        
           static HPALETTE               hPalette ;
        
           static int                    cxClient, cyClient ;
        
           HBRUSH                        hBrush ;
        
           HDC                           hdc ;
        
           int                           i, x, y ;
        
           LOGPALETTE                    *      plp ;