Schnittrahmen proportional - WM_SysCommand

[DeddyH]

Ich habe mir mal erlaubt, den Code leicht zu modifizieren:

Delphi-Quellcode:

procedure TMainForm.OnMessageHandlingHook(var Msg: TMsg; var Handled: Boolean);
var
  Direction: Integer;
begin
  Handled := False;
  if (Msg.message = WM_NCLBUTTONDOWN) then
    if (Msg.hwnd = Handle) then
      begin
        if Msg.wParam in [HTMINBUTTON, HTMAXBUTTON, HTCLOSE] then
          Handled := true
        else
          begin
            Direction := -1;
            case Msg.wParam of
              HTLEFT:
                Direction := WMSZ_LEFT;
              HTRIGHT:
                Direction := WMSZ_RIGHT;
              HTTOP:
                Direction := WMSZ_TOP;
              HTBOTTOM:
                Direction := WMSZ_BOTTOM;
              HTTOPLEFT:
                Direction := WMSZ_TOPLEFT;
              HTTOPRIGHT:
                Direction := WMSZ_TOPRIGHT;
              HTBOTTOMLEFT:
                Direction := WMSZ_BOTTOMLEFT;
              HTBOTTOMRIGHT:
                Direction := WMSZ_BOTTOMRIGHT;
            end;
            if Direction <> -1 then
              begin
                ReleaseCapture;
                DefWindowProc(Handle, WM_SYSCOMMAND, SC_SIZE or Direction, 0);
                Handled := true;
              end;
          end;
      end;
end;