wm_erasebkgnd.cpp File Reference

#include <windows.h>

Include dependency graph for wm_erasebkgnd.cpp:

Go to the source code of this file.

Functions
LRESULT CALLBACK	MainWndProc (HWND HWnd, UINT Msg, WPARAM WParam, LPARAM LParam)
int APIENTRY	WinMain (HINSTANCE HInstance, HINSTANCE HPrevInstance, LPTSTR lpCmdLine, int nCmdShow)

Variables
HINSTANCE	HInst
HINSTANCE	HPrevInst
TCHAR *	cmdline
const char *	WndClassName = "GMainWnd"
HWND	HStatic
HDC	HMemDC
HBITMAP	HBmp
HBITMAP	HOldBmp
const char *	filename = "BACKBITMAP.BMP"

Function Documentation

MainWndProc()

LRESULT CALLBACK MainWndProc	(	HWND	HWnd,
		UINT	Msg,
		WPARAM	WParam,
		LPARAM	LParam
	)

Definition at line 90 of file wm_erasebkgnd.cpp.

{
   switch (Msg)
   {
      case WM_CREATE:
      {
         HStatic =
            CreateWindow(TEXT("STATIC"), TEXT("Static Text"),
                         WS_CHILD | WS_VISIBLE | SS_CENTER,
                         10, 20, 175, 30,
                         HWnd, NULL, HInst, NULL);
 
         // create a memory DC compatible with the screen
         HMemDC = CreateCompatibleDC(NULL);
         if (HMemDC)
         {
            // load a DDB from file
            HBmp = static_cast<HBITMAP>(
               LoadImage(HInst, filename, IMAGE_BITMAP,
                         0, 0, LR_LOADFROMFILE)
               );
            if (HBmp)
            {
               // associate the DDB with the memory DC
               HOldBmp = static_cast<HBITMAP>(
                  SelectObject(HMemDC, HBmp)
                  );
            }
         }
      }
      case WM_CTLCOLORSTATIC:
      {
         if (reinterpret_cast<HWND>(LParam) == HStatic)
         {
            HDC HStaticDC = reinterpret_cast<HDC>(WParam);
            SetBkMode(HStaticDC, TRANSPARENT);
 
            return reinterpret_cast<LRESULT>(
               GetStockObject(NULL_BRUSH)
               );
         }
         break;
      }
      case WM_ERASEBKGND:
      {
         BITMAP bmp;
         if (GetObject(HBmp, sizeof(BITMAP), &bmp))
         {
            RECT RClient;
            GetClientRect(HWnd, &RClient);
 
            HDC Hdc = reinterpret_cast<HDC>(WParam);
            SetStretchBltMode(Hdc, COLORONCOLOR);
 
            //
            // TODO: add palette handling code for
            // palettized displays (see Chapter 9)...
            //
 
            // render the background image
            StretchBlt(Hdc, 0, 0,
                       RClient.right - RClient.left,
                       RClient.bottom - RClient.top,
                       HMemDC, 0, 0, bmp.bmWidth, bmp.bmHeight,
                       SRCCOPY);
            return TRUE;
         }
         break;
      }
      case WM_DESTROY:
      {
         if (HBmp)
         {
            // free the bitmap
            DeleteObject(SelectObject(HMemDC, HOldBmp));
         }
         // free the memory DC
         DeleteDC(HMemDC);
 
         PostQuitMessage(0);
         return 0;
      }
   }
   return DefWindowProc(HWnd, Msg, WParam, LParam);
}

Referenced by WinMain().

WinMain()

int APIENTRY WinMain	(	HINSTANCE	HInstance,
		HINSTANCE	HPrevInstance,
		LPTSTR	lpCmdLine,
		int	nCmdShow
	)

Definition at line 38 of file wm_erasebkgnd.cpp.

{
   HInst = HInstance;
   HPrevInst = HPrevInstance;
   cmdline = lpCmdLine;
 
   WNDCLASS wc;
   memset(&wc, 0, sizeof(WNDCLASS));
 
   wc.style = CS_VREDRAW | CS_HREDRAW | CS_DBLCLKS;
   wc.lpfnWndProc = MainWndProc;
   wc.hInstance = HInstance;
   wc.hCursor = LoadCursor(NULL, IDC_ARROW);
   wc.hbrBackground =
      reinterpret_cast<HBRUSH>(COLOR_BTNFACE + 1);
   wc.lpszClassName = WndClassName;
 
   if (RegisterClass(&wc))
   {
      HWND HWnd =
         CreateWindow(WndClassName,
                      TEXT("WM_ERASEBKGND Demo"),
                      WS_OVERLAPPEDWINDOW | WS_CAPTION |
                      WS_VISIBLE | WS_CLIPSIBLINGS,
                      CW_USEDEFAULT, CW_USEDEFAULT, 205, 85,
                      NULL, NULL, HInstance, NULL);
 
      if (HWnd)
      {
         ShowWindow(HWnd, nCmdShow);
         UpdateWindow(HWnd);
 
         MSG msg;
         while (GetMessage(&msg, NULL, 0, 0))
         {
             TranslateMessage(&msg);
             DispatchMessage(&msg);
         }
      }
    }
    return 0;
}

Variable Documentation

cmdline

TCHAR* cmdline

Definition at line 32 of file wm_erasebkgnd.cpp.

Referenced by WinMain().

filename

const char* filename = "BACKBITMAP.BMP"

Definition at line 88 of file wm_erasebkgnd.cpp.

HBmp

HBITMAP HBmp

Definition at line 87 of file wm_erasebkgnd.cpp.

Referenced by MainWndProc().

HInst

HINSTANCE HInst

Definition at line 30 of file wm_erasebkgnd.cpp.

Referenced by MainWndProc(), and WinMain().

HMemDC

HDC HMemDC

Definition at line 86 of file wm_erasebkgnd.cpp.

Referenced by MainWndProc().

HOldBmp

HBITMAP HOldBmp

Definition at line 87 of file wm_erasebkgnd.cpp.

Referenced by MainWndProc().

HPrevInst

HINSTANCE HPrevInst

Definition at line 31 of file wm_erasebkgnd.cpp.

Referenced by WinMain().

HStatic

HWND HStatic

Definition at line 85 of file wm_erasebkgnd.cpp.

Referenced by MainWndProc().

WndClassName

const char* WndClassName = "GMainWnd"

Definition at line 33 of file wm_erasebkgnd.cpp.

Referenced by WinMain().