about2.c

Windows Programming source code

/*------------------------------------------
   ABOUT2.C -- About Box Demo Program No. 2
               (c) Charles Petzold, 1998
  ------------------------------------------*/

#include <windows.h>
#include "resource.h"

LRESULT CALLBACK WndProc      (HWND, UINT, WPARAM, LPARAM) ;
BOOL    CALLBACK AboutDlgProc (HWND, UINT, WPARAM, LPARAM) ;
     
int iCurrentColor  = IDC_BLACK,
    iCurrentFigure = IDC_RECT ;

int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,
                    PSTR szCmdLine, int iCmdShow)
{
     static TCHAR szAppName[] = TEXT ("About2") ;
     MSG          msg ;
     HWND         hwnd ;
     WNDCLASS     wndclass ;
     
     wndclass.style         = CS_HREDRAW | CS_VREDRAW ;
     wndclass.lpfnWndProc   = WndProc ;
     wndclass.cbClsExtra    = 0 ;
     wndclass.cbWndExtra    = 0 ;
     wndclass.hInstance     = hInstance ;
     wndclass.hIcon         = LoadIcon (hInstance, szAppName) ;
     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 ("About Box Demo Program"),
                          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 PaintWindow (HWND hwnd, int iColor, int iFigure)
{
     static COLORREF crColor[8] = { RGB (  0,   0, 0), RGB (  0,   0, 255),
                                    RGB (  0, 255, 0), RGB (  0, 255, 255),
                                    RGB (255,   0, 0), RGB (255,   0, 255),
                                    RGB (255, 255, 0), RGB (255, 255, 255) } ;

     HBRUSH          hBrush ;
     HDC             hdc ;
     RECT            rect ;
     
     hdc = GetDC (hwnd) ;
     GetClientRect (hwnd, &rect) ;
     hBrush = CreateSolidBrush (crColor[iColor - IDC_BLACK]) ;
     hBrush = (HBRUSH) SelectObject (hdc, hBrush) ;
     
     if (iFigure == IDC_RECT)
          Rectangle (hdc, rect.left, rect.top, rect.right, rect.bottom) ;
     else
          Ellipse   (hdc, rect.left, rect.top, rect.right, rect.bottom) ;
     
     DeleteObject (SelectObject (hdc, hBrush)) ;
     ReleaseDC (hwnd, hdc) ;
}

void PaintTheBlock (HWND hCtrl, int iColor, int iFigure)
{
     InvalidateRect (hCtrl, NULL, TRUE) ;
     UpdateWindow (hCtrl) ;
     PaintWindow (hCtrl, iColor, iFigure) ;
}

LRESULT CALLBACK WndProc (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
     static HINSTANCE hInstance ;
     PAINTSTRUCT      ps ;
     
     switch (message)
     {
     case WM_CREATE:
          hInstance = ((LPCREATESTRUCT) lParam)->hInstance ;
          return 0 ;
          
     case WM_COMMAND:
          switch (LOWORD (wParam))
          {
          case IDM_APP_ABOUT:
               if (DialogBox (hInstance, TEXT ("AboutBox"), hwnd, AboutDlgProc))
                    InvalidateRect (hwnd, NULL, TRUE) ;
               return 0 ;
          }
          break ;
          
     case WM_PAINT:
          BeginPaint (hwnd, &ps) ;
          EndPaint (hwnd, &ps) ;
               
          PaintWindow (hwnd, iCurrentColor, iCurrentFigure) ;
          return 0 ;
               
     case WM_DESTROY:
          PostQuitMessage (0) ;
          return 0 ;
     }
     return DefWindowProc (hwnd, message, wParam, lParam) ;
}

BOOL CALLBACK AboutDlgProc (HWND hDlg, UINT message, 
                            WPARAM wParam, LPARAM lParam)
{
     static HWND hCtrlBlock ;
     static int  iColor, iFigure ;
     
     switch (message)
     {
     case WM_INITDIALOG:
          iColor  = iCurrentColor ;
          iFigure = iCurrentFigure ;
          
          CheckRadioButton (hDlg, IDC_BLACK, IDC_WHITE,   iColor) ;
          CheckRadioButton (hDlg, IDC_RECT,  IDC_ELLIPSE, iFigure) ;
          
          hCtrlBlock = GetDlgItem (hDlg, IDC_PAINT) ;
          
          SetFocus (GetDlgItem (hDlg, iColor)) ;
          return FALSE ;
          
     case WM_COMMAND:
          switch (LOWORD (wParam))
          {
          case IDOK:
               iCurrentColor  = iColor ;
               iCurrentFigure = iFigure ;
               EndDialog (hDlg, TRUE) ;
               return TRUE ;
               
          case IDCANCEL:
               EndDialog (hDlg, FALSE) ;
               return TRUE ;
               
          case IDC_BLACK:
          case IDC_RED:
          case IDC_GREEN:
          case IDC_YELLOW:
          case IDC_BLUE:
          case IDC_MAGENTA:
          case IDC_CYAN:
          case IDC_WHITE:
               iColor = LOWORD (wParam) ;
               CheckRadioButton (hDlg, IDC_BLACK, IDC_WHITE, LOWORD (wParam)) ;
               PaintTheBlock (hCtrlBlock, iColor, iFigure) ;
               return TRUE ;
               
          case IDC_RECT:
          case IDC_ELLIPSE:
               iFigure = LOWORD (wParam) ;
               CheckRadioButton (hDlg, IDC_RECT, IDC_ELLIPSE, LOWORD (wParam)) ;
               PaintTheBlock (hCtrlBlock, iColor, iFigure) ;
               return TRUE ;
          }
          break ;
          
     case WM_PAINT:
          PaintTheBlock (hCtrlBlock, iColor, iFigure) ;
          break ;
     }
     return FALSE ;
}