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qt'QProgressData (./qt-2.1.0/src/dialogs/qprogressdialog.cpp:46)

struct QProgressData
{
    QProgressData( QProgressDialog* that, QWidget* parent,
		   const QString& labelText,
		   int totalSteps ) :
	creator( parent ),
	label( new QLabel(labelText,that,"label") ),
	cancel( 0 ),
	bar( new QProgressBar(totalSteps,that,"bar") ),
	shown_once( FALSE ),
	cancellation_flag( FALSE ),
	showTime( defaultShowTime )
    {
	label->setAlignment( that->style() != Qt::WindowsStyle
			     ? Qt::AlignCenter
			     : Qt::AlignLeft|Qt::AlignVCenter );
    }

    QWidget	 *creator;
    QLabel	 *label;
    QPushButton	 *cancel;
    QProgressBar *bar;
    bool	  shown_once;
    bool	  cancellation_flag;
    QTime	  starttime;
    QCursor	  parentCursor;
    int		  showTime;
    bool autoClose;
    bool autoReset;
    bool forceHide;
};


// REVISED: paul
/*!
  \class QProgressDialog qprogressdialog.h
  \brief Provides feedback on the progress of a slow operation.
  \ingroup dialogs

  A progress dialog is used to give the user an indication of how long
  an operation is going to take to perform, and to reassure them that
  the application has not frozen. It also gives the user an
  opportunity to abort the operation.

  A potential problem with progress dialogs is that it is difficult to know
  when to use them, as operations take different amounts of time on different
  computer hardware.  QProgressDialog offers a solution to this problem:
  it estimates the time the operation will take (based on time for
  steps), and only shows itself if that estimate is beyond minimumDuration()
  (4 seconds by default).

  Use setTotalSteps() (or the constructor) to set the number of
  "steps" in the operation and call setProgress() as the operation
  progresses. The step value can be chosen arbitrarily. It can be
  eg. the number of files copied, the number of bytes received, or the
  number of iterations through the main loop of your algorithm.
  You must call setProgress() with parameter 0 initially, and with
  parameter totalSteps() at the end.

  The dialog will automatically be reset and hidden at the end of the
  operation, Use setAutoReset() and setAutoClose() to change this
  behavior.

  There are two ways of using QProgressDialog, modal and non-modal.

  Using a modal QProgressDialog is simpler for the programmer, but it
  freezes the application, making it inaccessible to the user for the
  duration of the operation.  Do the operation in a loop, calling
  \l setProgress() at intervals, and checking for cancellation with
  wasCancelled().

  Example:
  \code
    QProgressDialog progress( "Copying files...", "Abort Copy", numFiles,
				this, "progress", TRUE );
    for (int i=0; i<numFiles; i++) {
	progress.setProgress( i );
	if ( progress.wasCancelled() )
	    break;
	... // copy one file
    }
    progress.setProgress( numFiles );
  \endcode

  A non-modal progress dialog is suitable for operations that take
  place in the background, where the user is able to interact with the
  application. Such operations are typically based on QTimer (or
  QObject::timerEvent()), QSocketNotifier, or QUrlOperator; or performed
  in a separate thread. A QProgressBar in the status bar of your main window
  is often an alternative to a non-modal progress dialog.

  You need an event loop to be running. Connect the cancelled()
  signal to a slot that stops the operation, and call \l setProgress() at
  intervals.

  Example:
  \code
  Operation::Operation( QObject *parent = 0 )
      : QObject( parent ), steps(0)
  {
      pd = new QProgressDialog( "Operation in progress.", "Cancel", 100 );
      connect( pd, SIGNAL(cancelled()), this, SLOT(cancel()) );
      t = new QTimer( this );
      connect( t, SIGNAL(timeout()), this, SLOT(perform()) );
      t->start(0);
  }

  void Operation::perform()
  {
      pd->setProgress( steps );
      ...	//perform one percent of the operation
      steps++;
      if ( steps > pd->totalSteps() )
		t->stop();
  }

  void Operation::cancel()
  {
      t->stop();
      ...	//cleanup
  }
  \endcode


  In both modes, the progress dialog may be customized by
  replacing the child widgets with custom widgets, using setLabel(),
  setBar() and setCancelButton().
  The functions setLabelText() and setCancelButtonText()
  sets the texts shown.

  <img src=qprogdlg-m.png> <img src=qprogdlg-w.png>

  \sa QDialog QProgressBar
  <a href="guibooks.html#fowler">GUI Design Handbook: Progress Indicator</a>
*/


/*!
  Returns the QLabel currently being displayed above the progress bar.
  Note that this QLabel remains owned by the QProgressDialog.

  \sa setLabel()
*/