source: trunk/src/gui/styles/qproxystyle.cpp@ 938

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#include <qstyle.h>
#include <private/qproxystyle_p.h>
#include <private/qapplication_p.h>
#include "qproxystyle.h"
#include "qstylefactory.h"
#include <private/qstyle_p.h>

#if !defined(QT_NO_STYLE_PROXY) || defined(QT_PLUGIN)

QT_BEGIN_NAMESPACE

/*!
    \class QProxyStyle

    \brief The QProxyStyle class is a convenience class that simplifies
    dynamically overriding QStyle elements.

    \since 4.6

    A QProxyStyle wraps a QStyle (usually the default system style) for the
    purpose of dynamically overriding painting or other specific style behavior.

    The following example shows how to override the shortcut underline
    behavior on any platform:

    \snippet doc/src/snippets/code/src_gui_qproxystyle.cpp 1

    Warning: The \l {QCommonStyle} {common styles} provided by Qt will
    respect this hint, because they call QStyle::proxy(), but there is
    no guarantee that QStyle::proxy() will be called for user defined
    or system controlled styles. It would not work on a Mac, for
    example, where menus are handled by the operating system.

    \sa QStyle
*/

void QProxyStylePrivate::ensureBaseStyle() const
{
    Q_Q(const QProxyStyle);

    if (baseStyle)
        return;

    if (!baseStyle && !QApplicationPrivate::styleOverride.isEmpty()) {
        baseStyle = QStyleFactory::create(QApplicationPrivate::styleOverride);
        if (baseStyle) {
            // If baseStyle is an instance of the same proxyStyle
            // we destroy it and fall back to the desktop style
            if (qstrcmp(baseStyle->metaObject()->className(),
                        q->metaObject()->className()) == 0) {
                delete baseStyle;
                baseStyle = 0;
            }
        }
    }

    if (!baseStyle) // Use application desktop style
        baseStyle = QStyleFactory::create(QApplicationPrivate::desktopStyleKey());

    if (!baseStyle) // Fallback to windows style
        baseStyle = QStyleFactory::create(QLatin1String("windows"));

    baseStyle->setProxy(const_cast<QProxyStyle*>(q));
    baseStyle->setParent(const_cast<QProxyStyle*>(q)); // Take ownership
}

/*!
  Constructs a QProxyStyle object for overriding behavior in \a style
  or in the current application \l{QStyle}{style} if \a style is 0
  (default). Normally \a style is 0, because you want to override
  behavior in the system style.