比较VC和Delphi的WinTest工程

HWND hwndButton;
int cx, cy;

LRESULT CALLBACK MainWndProc (HWND hWindow, UINT nMsg, WPARAM wPrm, LPARAM lPrm)
{

HDC dc;
 PAINTSTRUCT ps;
 RECT rc;
 switch (nMsg)
 {
  case WM_CREATE:
  {
TEXTMETRIC tm;

dc = GetDC (hWindow);
SelectObject (dc, GetStockObject (SYSTEM_FIXED_FONT));
GetTextMetrics (dc, &tm);
cx = tm.tmAveCharWidth * 30;
cy = (tm.tmHeight + tm.tmExternalLeading) * 2;
ReleaseDC (hWindow, dc);

hwndButton = CreateWindow (
  "button",
  "Click Here",
  WS_CHILD | WS_VISIBLE | BS_PUSHBUTTON,
  0, 0, cx, cy,
  hWindow,
  (HMENU) 1,
  ((LPCREATESTRUCT) lPrm)->hInstance,
  NULL
  );

return 0;
break;
  }

case WM_DESTROY:
  {
PostQuitMessage (0);
return 0;
break;
  }

case WM_PAINT:
  {
dc = BeginPaint (hWindow, &ps);
GetClientRect (hWindow, &rc);

rc.bottom = rc.bottom / 2;
DrawText (dc, "Hello, World!", -1, &rc,
DT_SINGLELINE | DT_CENTER | DT_VCENTER);

EndPaint (hWindow, &ps);
return 0;
break;
  }

case WM_SIZE:
  {
if (hwndButton && (wPrm == SIZEFULLSCREEN ||wPrm == SIZENORMAL))
{
 rc.left = (LOWORD(lPrm) - cx) / 2;
 rc.top = HIWORD(lPrm) * 3 / 4 - cy / 2;
 MoveWindow (hwndButton,rc.left, rc.top, cx, cy, TRUE);
}
return 0;
break;
  }

case WM_COMMAND:
  {
if (LOWORD(wPrm) == 1 && HIWORD(wPrm) == BN_CLICKED &&
 (HWND) lPrm == hwndButton)
{
 DestroyWindow (hWindow);
}
return 0;
break;
  }
 }

return DefWindowProc (hWindow, nMsg, wPrm, lPrm);
}

//winmain
int __stdcall WinMain (HINSTANCE hInst, HINSTANCE hPrev, LPSTR lpCmd, int nShow)
{
 HWND hWindowMain;
 MSG MyMsg;

WNDCLASSEX wcex;

wcex.cbSize = sizeof(WNDCLASSEX);
 wcex.style= CS_HREDRAW | CS_VREDRAW;
 wcex.lpfnWndProc = (WNDPROC)MainWndProc;
 wcex.cbClsExtra  = 0;
 wcex.cbWndExtra  = 0;
 wcex.hInstance  = hInst;
 wcex.hIcon= LoadIcon (NULL, IDI_APPLICATION);
 wcex.hCursor  = LoadCursor (NULL, IDC_ARROW);
 wcex.hbrBackground = (HBRUSH)(COLOR_WINDOW+1);
 wcex.lpszClassName = "WinTestWin";
 wcex.hIconSm  = LoadIcon (NULL, IDI_APPLICATION);

RegisterClassEx (&wcex);

hWindowMain = CreateWindow (
  "WinTestWin",
  "Hello",
  WS_OVERLAPPEDWINDOW,
  CW_USEDEFAULT,
  CW_USEDEFAULT,
  CW_USEDEFAULT,
  CW_USEDEFAULT,
  0,
  0,
  hInst,
  NULL
 );

ShowWindow (hWindowMain, nShow);
 UpdateWindow (hWindowMain);

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

其中选择Release方式编译，打开VC6的最小代码优化，编译生成的执行码为36.0KB，
然后将其翻译成Delphi代码，如下：

program WinTest;

uses
  Windows,Messages;

var
  hwndButton:HWND;
  cx,cy:Integer;

function MainWndProc (hWindow:HWND;nMsg:UINT;wPrm:WPARAM;lPrm:LPARAM):LRESULT;stdcall;
var
  dc:HDC;
 ps:PAINTSTRUCT;
 rc:TRect;
  tm:TEXTMETRIC;
  pctst:PCREATESTRUCT;
begin
  case nMsg of
WM_CREATE:
begin
   dc := GetDC (hWindow);
SelectObject (dc, GetStockObject (SYSTEM_FIXED_FONT));
GetTextMetrics (dc, tm);
cx := tm.tmAveCharWidth * 30;
cy := (tm.tmHeight + tm.tmExternalLeading) * 2;
ReleaseDC (hWindow, dc);
   pctst:= PCREATESTRUCT(lPrm);
   hwndButton := CreateWindow(
  'button',
  'Click Here',
  WS_CHILD or WS_VISIBLE or BS_PUSHBUTTON,
  0, 0, cx, cy,
  hWindow,
  HMENU(1),
  pctst^.hInstance,
  nil
  );
   Result:=0;
   Exit;
end;

WM_DESTROY:
begin
   PostQuitMessage(0);
   Result:=0;
   Exit;
end;

WM_PAINT:
begin
dc := BeginPaint (hWindow, ps);
GetClientRect (hWindow, rc);

rc.bottom := Round(rc.bottom / 2);
DrawText (dc, 'Hello, World!', -1, rc,
DT_SINGLELINE or DT_CENTER or DT_VCENTER);

EndPaint (hWindow, ps);
Result:= 0;
Exit;
end;

WM_SIZE:
begin
if (hwndButton<>0) and (wPrm = SIZEFULLSCREEN)  or (wPrm = SIZENORMAL) then
begin
 rc.left := Round((LOWORD(lPrm) - cx) / 2);
 rc.top := Round(HIWORD(lPrm) * 3 / 4 - cy / 2);
 MoveWindow (hwndButton,rc.left, rc.top, cx, cy, True);
end;
Result:= 0;
Exit;
end;

WM_COMMAND:
begin
if (LOWORD(wPrm) = 1) and (HIWORD(wPrm) = BN_CLICKED) and
 (HWND(lPrm) = hwndButton) then
begin
 DestroyWindow (hWindow);
end;
Result:= 0;
Exit;
end;

end;

Result:=DefWindowProc (hWindow, nMsg, wPrm, lPrm);

end;

//winmain
var
 hWindowMain:HWND;
 MyMsg:MSG;
 wcex:WNDCLASSEX;
begin
 wcex.cbSize := SizeOf(WNDCLASSEX);
 wcex.style := CS_HREDRAW or CS_VREDRAW;
 wcex.lpfnWndProc := @MainWndProc;
 wcex.cbClsExtra := 0;
 wcex.cbWndExtra := 0;
 wcex.hInstance := MainInstance;
 wcex.hIcon := LoadIcon (0, IDI_APPLICATION);
 wcex.hCursor := LoadCursor (0, IDC_ARROW);
 wcex.hbrBackground := HBRUSH(COLOR_WINDOW+1);
 wcex.lpszClassName := 'WinTestWin';
 wcex.hIconSm := LoadIcon (0, IDI_APPLICATION);

RegisterClassEx (wcex);

hWindowMain := CreateWindow (
  'WinTestWin',
  'Hello',
  WS_OVERLAPPEDWINDOW,
  CW_USEDEFAULT,
  CW_USEDEFAULT,
  CW_USEDEFAULT,
  CW_USEDEFAULT,
  0,
  0,
  MainInstance,
  nil
 );

ShowWindow (hWindowMain, CmdShow);
 UpdateWindow (hWindowMain);

while GetMessage (MyMsg, 0, 0, 0)=True do
 begin
  TranslateMessage (MyMsg);
  DispatchMessage (MyMsg);
 end;
 
end.