GDIdemo: C/C++ Version

/****************************************************************************\
*                                                                            *
*  GDIdemo.c                                                                 *
*                                                                            *
*  This program shows how to use Windows GDI functions to write to a virtual *
*  buffer. It uses GDI functions to display a cross-hatched rectangle with a *
*  border, something that would require construction from several graphics   *
*  primitives if using Fastgraph for Windows drawing functions only.         *
*                                                                            *
\****************************************************************************/
#include <fgwin.h>
LRESULT CALLBACK WindowProc(HWND,UINT,WPARAM,LPARAM);
int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,
                    PSTR szCmdParam, int iCmdShow)
{
   static char szAppName[] = "FGgdidemo";
   HWND        hWnd;
   MSG         msg;
   WNDCLASSEX  wndclass;
   wndclass.cbSize        = sizeof(wndclass);
   wndclass.style         = CS_HREDRAW | CS_VREDRAW | CS_OWNDC;
   wndclass.lpfnWndProc   = WindowProc;
   wndclass.cbClsExtra    = 0;
   wndclass.cbWndExtra    = 0;
   wndclass.hInstance     = hInstance;
   wndclass.hIcon         = LoadIcon(NULL,IDI_APPLICATION);
   wndclass.hCursor       = LoadCursor(NULL,IDC_ARROW);
   wndclass.hbrBackground = NULL;
   wndclass.lpszMenuName  = NULL;
   wndclass.lpszClassName = szAppName;
   wndclass.hIconSm       = LoadIcon(NULL,IDI_APPLICATION);
   RegisterClassEx&wndclass);
   hWnd = CreateWindow(szAppName,     // window class name
      "Fastgraph for Windows GDI Demo", // window caption
      WS_OVERLAPPEDWINDOW,     // window style
      CW_USEDEFAULT,           // initial x position
      CW_USEDEFAULT,           // initial y position
      CW_USEDEFAULT,           // initial x size
      CW_USEDEFAULT,           // initial y size
      NULL,                    // parent window handle
      NULL,                    // window menu handle
      hInstance,               // program instance handle
      NULL);                   // creation parameters
   ShowWindow(hWnd,iCmdShow);
   UpdateWindow(hWnd);
   while (GetMessage(&msg,NULL,0,0))
   {
      TranslateMessage(&msg);
      DispatchMessage(&msg);
   }
   return msg.wParam;
}
/****************************************************************************\
*                                                                            *
*  WindowProc()                                                              *
*                                                                            *
\****************************************************************************/
HDC      hDC;
HPALETTE hPal;
int      hVB;
UINT     cxClient, cyClient;
LRESULT CALLBACK WindowProc(HWND hWnd, UINT iMsg, WPARAM wParam, LPARAM lParam)
{
   HBRUSH hBrush;
   HDC    hDIB;
   HPEN   hPen;
   PAINTSTRUCT ps;
   switch (iMsg)
   {
      case WM_CREATE:
         hDC = GetDC(hWnd);
         fg_setdc(hDC);
         hPal = fg_defpal();
         fg_realize(hPal);
         fg_vbinit();
         hVB = fg_vballoc(320,240);
         fg_vbopen(hVB);
         fg_vbcolors();
         // use FG to fill the virtual buffer with light green pixels
         fg_setcolor(20);
         fg_fillpage();
         // use Windows GDI functions to display a cross-hatched
         // rectangle with blue border in the virtual buffer
         hDIB = fg_getdc();
         hPen = CreatePen(PS_SOLID,3,RGB(0,0,255));
         hBrush = CreateHatchBrush(HS_DIAGCROSS,RGB(255,0,0));
         SelectObject(hDIB,hPen);
         SelectObject(hDIB,hBrush);
         Rectangle(hDIB,20,20,50,50);
         DeleteObject(hPen);
         DeleteObject(hBrush);
         return 0;
      case WM_PAINT:
         BeginPaint(hWnd,&ps);
         fg_vbscale(0,fg_getmaxx(),0,fg_getmaxy(),0,cxClient-1,0,cyClient-1);
         EndPaint(hWnd,&ps);
         return 0;
      case WM_SETFOCUS:
         fg_realize(hPal);
         InvalidateRect(hWnd,NULL,TRUE);
         return 0;
      case WM_SIZE:
         cxClient = LOWORD(lParam);
         cyClient = HIWORD(lParam);
         return 0;
      case WM_DESTROY:
         fg_vbclose();
         fg_vbfree(hVB);
         fg_vbfin();
         DeleteObject(hPal);
         ReleaseDC(hWnd,hDC);
         PostQuitMessage(0);
         return 0;
   }
   return DefWindowProc(hWnd,iMsg,wParam,lParam);
}