qsplashscreen.cpp

qt-x11-opensource-src-4.1.4.tar.gz源码

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**
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** This file is part of the QtGui module of the Qt Toolkit.
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#include "qsplashscreen.h"

#ifndef QT_NO_SPLASHSCREEN

#include "qapplication.h"
#include "qdesktopwidget.h"
#include "qpainter.h"
#include "qpixmap.h"
#include <private/qwidget_p.h>

class QSplashScreenPrivate : public QWidgetPrivate
{
    Q_DECLARE_PUBLIC(QSplashScreen)
public:
    QPixmap pixmap;
    QString currStatus;
    QColor currColor;
    int currAlign;
    void drawContents();
};

/*!
   \class QSplashScreen qsplashscreen.h
   \brief The QSplashScreen widget provides a splash screen that can
   be shown during application startup.

    \ingroup misc
    \mainclass

   A splash screen is a widget that is usually displayed when an
   application is being started. Splash screens are often used for
   applications that have long start up times (e.g. database or
   networking applications that take time to establish connections) to
   provide the user with feedback that the application is loading.

   The splash screen appears centered on the screen. It may be useful to add
   the Qt::WStyle_StaysOnTop if you desire to keep above all the windows in the
   GUI.

   Some X11 window managers do not support the "stays on top" flag. A
   solution is to set up a timer that periodically calls raise() on
   the splash screen to simulate the "stays on top" effect.

   The most common usage is to show a splash screen before the main
   widget is displayed on the screen. This is illustrated in the
   following code snippet.

   \code
   int main(int argc, char **argv)
   {
       QApplication app(argc, argv);
       QPixmap pixmap("splash.png");
       QSplashScreen *splash = new QSplashScreen(pixmap);
       splash->show();
       QMainWindow *mainWin = new QMainWindow;
       ...
       mainWin->show();
       splash->finish(mainWin);
       delete splash;
       return app.exec();
   }
   \endcode

   It is sometimes useful to update the splash screen with messages,
   for example, announcing connections established or modules loaded
   as the application starts up. QSplashScreen supports this with the
   showMessage() function. If you wish to do your own drawing you can
   get a pointer to the pixmap used in the splash screen with pixmap().
   Alternatively, you can subclass QSplashScreen and reimplement
   drawContents().

   The user can hide the splash screen by clicking on it with the
   mouse. Since the splash screen is typically displayed before the
   event loop has started running, it is necessary to periodically
   call QApplication::processEvents() to receive the mouse clicks.

   \code
   QSplashScreen *splash = new QSplashScreen("splash.png");
   splash->show();
   ... // Loading some items
   splash->showMessage("Loaded modules");
   qApp->processEvents();
   ... // Establishing connections
   splash->showMessage("Established connections");
   qApp->processEvents();
   \endcode

*/

/*!
    Construct a splash screen that will display the \a pixmap.

    There should be no need to set the widget flags, \a f, except
    perhaps Qt::WindowStaysOnTopHint.
*/
QSplashScreen::QSplashScreen(const QPixmap &pixmap, Qt::WFlags f)
    : QWidget(*(new QSplashScreenPrivate()), 0, Qt::SplashScreen | f)
{
    d_func()->pixmap = pixmap;
    setPixmap(d_func()->pixmap);  // Does an implicit repaint
}

/*!
    \overload

    This function allows you to specify a parent for your splashscreen. The
    typical use for this constructor is if you have a multiple screens and
    prefer to have the splash screen on a different screen than your primary
    one. In that case pass the proper desktop() as the \a parent.
*/
QSplashScreen::QSplashScreen(QWidget *parent, const QPixmap &pixmap, Qt::WFlags f)
    : QWidget(*new QSplashScreenPrivate, parent, Qt::SplashScreen | f)
{
    d_func()->pixmap = pixmap;
    setPixmap(d_func()->pixmap);  // Does an implicit repaint
}

/*!
  Destructor.
*/
QSplashScreen::~QSplashScreen()
{
}

/*!
    \reimp
*/
void QSplashScreen::mousePressEvent(QMouseEvent *)
{
    hide();
}

/*!
    This overrides QWidget::repaint(). It differs from the standard
    repaint function in that it also calls QApplication::flush() to
    ensure the updates are displayed, even when there is no event loop
    present.
*/
void QSplashScreen::repaint()
{
    d_func()->drawContents();
    QWidget::repaint();
    QApplication::flush();
}

/*!
    \fn QSplashScreen::messageChanged(const QString &message)

    This signal is emitted when the message on the splash screen
    changes. \a message is the new message and is a null-string
    when the message has been removed.

    \sa showMessage(), clearMessage()
*/



/*!
    Draws the \a message text onto the splash screen with color \a
    color and aligns the text according to the flags in \a alignment.

    \sa Qt::Alignment, clearMessage()
*/
void QSplashScreen::showMessage(const QString &message, int alignment,
                             const QColor &color)
{
    Q_D(QSplashScreen);
    d->currStatus = message;
    d->currAlign = alignment;
    d->currColor = color;
    emit messageChanged(d->currStatus);
    repaint();
}

/*!
    Removes the message being displayed on the splash screen

    \sa showMessage()
 */
void QSplashScreen::clearMessage()
{
    d_func()->currStatus.clear();
    emit messageChanged(d_func()->currStatus);
    repaint();
}

/*!
    Makes the splash screen wait until the widget \a mainWin is displayed
    before calling close() on itself.
*/
void QSplashScreen::finish(QWidget *mainWin)
{
    if (mainWin) {
#if defined(Q_WS_X11)
        extern void qt_x11_wait_for_window_manager(QWidget *mainWin);
        qt_x11_wait_for_window_manager(mainWin);
#endif
    }
    close();
}

/*!
    Sets the pixmap that will be used as the splash screen's image to
    \a pixmap.
*/
void QSplashScreen::setPixmap(const QPixmap &pixmap)
{
    Q_D(QSplashScreen);

    if (pixmap.hasAlpha()) {
        QPixmap opaque(pixmap.size());
        QPainter p(&opaque);
        p.fillRect(0, 0, pixmap.width(), pixmap.height(), palette().background());
        p.drawPixmap(0, 0, pixmap);
        p.end();
        d->pixmap = opaque;
    } else {
        d->pixmap = pixmap;
    }

    QRect r(0, 0, d->pixmap.size().width(), d->pixmap.size().height());
    resize(d->pixmap.size());
    move(QApplication::desktop()->screenGeometry().center() - r.center());
    if (!isVisible())
        d->drawContents();
    else
        repaint();
}

/*!
    Returns the pixmap that is used in the splash screen. The image
    does not have any of the text drawn by showMessage() calls.
*/
const QPixmap QSplashScreen::pixmap() const
{
    return d_func()->pixmap;
}

/*!
  \internal
*/
void QSplashScreenPrivate::drawContents()
{
    Q_Q(QSplashScreen);
    QPixmap textPix = pixmap;
    if (!textPix.isNull()) {
        QPainter painter(&textPix);
        painter.initFrom(q);
        q->drawContents(&painter);
        QPalette p = q->palette();
        p.setBrush(q->backgroundRole(), QBrush(textPix));
        q->setPalette(p);
    }
}

/*!
    Draw the contents of the splash screen using painter \a painter.
    The default implementation draws the message passed by showMessage().
    Reimplement this function if you want to do your own drawing on
    the splash screen.
*/
void QSplashScreen::drawContents(QPainter *painter)
{
    painter->setPen(d_func()->currColor);
    QRect r = rect();
    r.setRect(r.x() + 5, r.y() + 5, r.width() - 10, r.height() - 10);
    painter->drawText(r, d_func()->currAlign, d_func()->currStatus);
}

/*!
    \fn void QSplashScreen::message(const QString &message, int alignment,
                                    const QColor &color)
    \compat

    Use showMessage() instead.
*/

/*!
    \fn void QSplashScreen::clear()
    \compat

    Use clearMessage() instead.
*/

/*! \reimp */
bool QSplashScreen::event(QEvent *e)
{
    return QWidget::event(e);
}

#endif //QT_NO_SPLASHSCREEN