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

/****************************************************************************
**
** Copyright (C) 2011 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation ([email protected])
**
** This file is part of the QtGui module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
** Commercial Usage
** Licensees holding valid Qt Commercial licenses may use this file in
** accordance with the Qt Commercial License Agreement provided with the
** Software or, alternatively, in accordance with the terms contained in
** a written agreement between you and Nokia.
**
** GNU Lesser General Public License Usage
** Alternatively, this file may be used under the terms of the GNU Lesser
** General Public License version 2.1 as published by the Free Software
** Foundation and appearing in the file LICENSE.LGPL included in the
** packaging of this file.  Please review the following information to
** ensure the GNU Lesser General Public License version 2.1 requirements
** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
**
** In addition, as a special exception, Nokia gives you certain additional
** rights.  These rights are described in the Nokia Qt LGPL Exception
** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
**
** GNU General Public License Usage
** Alternatively, this file may be used under the terms of the GNU
** General Public License version 3.0 as published by the Free Software
** Foundation and appearing in the file LICENSE.GPL included in the
** packaging of this file.  Please review the following information to
** ensure the GNU General Public License version 3.0 requirements will be
** met: http://www.gnu.org/copyleft/gpl.html.
**
** If you have questions regarding the use of this file, please contact
** Nokia at [email protected].
** $QT_END_LICENSE$
**
****************************************************************************/

#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.

  Ownership of \a style is transferred to QProxyStyle.
*/
QProxyStyle::QProxyStyle(QStyle *style) :
    QCommonStyle(*new QProxyStylePrivate())
{
    Q_D(QProxyStyle);
    if (style) {
        style->setProxy(this);
        style->setParent(this); // Take ownership
        d->baseStyle = style;
    }
}

/*!
    Destroys the QProxyStyle object.
*/
QProxyStyle::~QProxyStyle()
{
}

/*!
    Returns the proxy base style object. If no base style
    is set on the proxy style, QProxyStyle will create
    an instance of the application style instead.

    \sa setBaseStyle(), QStyle
*/
QStyle *QProxyStyle::baseStyle() const
{
    Q_D (const QProxyStyle);
    d->ensureBaseStyle();
    return d->baseStyle;
}

/*!
    Sets the base style that should be proxied.

    Ownership of \a style is transferred to QProxyStyle.

    If style is zero, a desktop-dependant style will be
    assigned automatically.
*/
void QProxyStyle::setBaseStyle(QStyle *style)
{
    Q_D (QProxyStyle);

    if (d->baseStyle && d->baseStyle->parent() == this)
        d->baseStyle->deleteLater();

    d->baseStyle = style;

    if (d->baseStyle) {
        d->baseStyle->setProxy(this);
        d->baseStyle->setParent(this);
    }
}

/*! \reimp
 */
void QProxyStyle::drawPrimitive(PrimitiveElement element, const QStyleOption *option, QPainter *painter, const QWidget *widget) const
{
    Q_D (const QProxyStyle);
    d->ensureBaseStyle();
    d->baseStyle->drawPrimitive(element, option, painter, widget);
}

/*!
  \reimp
 */
void QProxyStyle::drawControl(ControlElement element, const QStyleOption *option, QPainter *painter, const QWidget *widget) const
{
    Q_D (const QProxyStyle);
    d->ensureBaseStyle();
    d->baseStyle->drawControl(element, option, painter, widget);
}

/*! \reimp
 */
void QProxyStyle::drawComplexControl(ComplexControl control, const QStyleOptionComplex *option, QPainter *painter, const QWidget *widget) const
{
    Q_D (const QProxyStyle);
    d->ensureBaseStyle();
    d->baseStyle->drawComplexControl(control, option, painter, widget);
}

/*! \reimp
 */
void QProxyStyle::drawItemText(QPainter *painter, const QRect &rect, int flags, const QPalette &pal, bool enabled,
                               const QString &text, QPalette::ColorRole textRole) const
{
    Q_D (const QProxyStyle);
    d->ensureBaseStyle();
    d->baseStyle->drawItemText(painter, rect, flags, pal, enabled, text, textRole);
}

/*! \reimp
 */
void QProxyStyle::drawItemPixmap(QPainter *painter, const QRect &rect, int alignment, const QPixmap &pixmap) const
{
    Q_D (const QProxyStyle);
    d->ensureBaseStyle();
    d->baseStyle->drawItemPixmap(painter, rect, alignment, pixmap);
}

/*! \reimp
 */
QSize QProxyStyle::sizeFromContents(ContentsType type, const QStyleOption *option, const QSize &size, const QWidget *widget) const
{
    Q_D (const QProxyStyle);
    d->ensureBaseStyle();
    return d->baseStyle->sizeFromContents(type, option, size, widget);
}

/*! \reimp
 */
QRect QProxyStyle::subElementRect(SubElement element, const QStyleOption *option, const QWidget *widget) const
{
    Q_D (const QProxyStyle);
    d->ensureBaseStyle();
    return d->baseStyle->subElementRect(element, option, widget);
}

/*! \reimp
 */
QRect QProxyStyle::subControlRect(ComplexControl cc, const QStyleOptionComplex *option, SubControl sc, const QWidget *widget) const
{
    Q_D (const QProxyStyle);
    d->ensureBaseStyle();
    return d->baseStyle->subControlRect(cc, option, sc, widget);
}

/*! \reimp
 */
QRect QProxyStyle::itemTextRect(const QFontMetrics &fm, const QRect &r, int flags, bool enabled, const QString &text) const
{
    Q_D (const QProxyStyle);
    d->ensureBaseStyle();
    return d->baseStyle->itemTextRect(fm, r, flags, enabled, text);
}

/*! \reimp
 */
QRect QProxyStyle::itemPixmapRect(const QRect &r, int flags, const QPixmap &pixmap) const
{
    Q_D (const QProxyStyle);
    d->ensureBaseStyle();
    return d->baseStyle->itemPixmapRect(r, flags, pixmap);
}

/*! \reimp
 */
QStyle::SubControl QProxyStyle::hitTestComplexControl(ComplexControl control, const QStyleOptionComplex *option, const QPoint &pos, const QWidget *widget) const
{
    Q_D (const QProxyStyle);
    d->ensureBaseStyle();
    return d->baseStyle->hitTestComplexControl(control, option, pos, widget);
}

/*! \reimp
 */
int QProxyStyle::styleHint(StyleHint hint, const QStyleOption *option, const QWidget *widget, QStyleHintReturn *returnData) const
{
    Q_D (const QProxyStyle);
    d->ensureBaseStyle();
    return d->baseStyle->styleHint(hint, option, widget, returnData);
}

/*! \reimp
 */
int QProxyStyle::pixelMetric(PixelMetric metric, const QStyleOption *option, const QWidget *widget) const
{
    Q_D (const QProxyStyle);
    d->ensureBaseStyle();
    return d->baseStyle->pixelMetric(metric, option, widget);
}

/*! \reimp
 */
QPixmap QProxyStyle::standardPixmap(StandardPixmap standardPixmap, const QStyleOption *opt, const QWidget *widget) const
{
    Q_D (const QProxyStyle);
    d->ensureBaseStyle();
    return d->baseStyle->standardPixmap(standardPixmap, opt, widget);
}

/*! \reimp
 */
QPixmap QProxyStyle::generatedIconPixmap(QIcon::Mode iconMode, const QPixmap &pixmap, const QStyleOption *opt) const
{
    Q_D (const QProxyStyle);
    d->ensureBaseStyle();
    return d->baseStyle->generatedIconPixmap(iconMode, pixmap, opt);
}

/*! \reimp
 */
QPalette QProxyStyle::standardPalette() const
{
    Q_D (const QProxyStyle);
    d->ensureBaseStyle();
    return d->baseStyle->standardPalette();
}

/*! \reimp
 */
void QProxyStyle::polish(QWidget *widget)
{
    Q_D (QProxyStyle);
    d->ensureBaseStyle();
    d->baseStyle->polish(widget);
}

/*! \reimp
 */
void QProxyStyle::polish(QPalette &pal)
{
    Q_D (QProxyStyle);
    d->ensureBaseStyle();
    d->baseStyle->polish(pal);
}

/*! \reimp
 */
void QProxyStyle::polish(QApplication *app)
{
    Q_D (QProxyStyle);
    d->ensureBaseStyle();
    d->baseStyle->polish(app);
}

/*! \reimp
 */
void QProxyStyle::unpolish(QWidget *widget)
{
    Q_D (QProxyStyle);
    d->ensureBaseStyle();
    d->baseStyle->unpolish(widget);
}

/*! \reimp
 */
void QProxyStyle::unpolish(QApplication *app)
{
    Q_D (QProxyStyle);
    d->ensureBaseStyle();
    d->baseStyle->unpolish(app);
}

/*! \reimp
 */
bool QProxyStyle::event(QEvent *e)
{
    Q_D (QProxyStyle);
    d->ensureBaseStyle();
    return d->baseStyle->event(e);
}

/*!
  Returns an icon for the given \a standardIcon.

  Reimplement this slot to provide your own icons in a QStyle
  subclass. The \a option argument can be used to pass extra
  information required to find the appropriate icon. The \a widget
  argument is optional and can also be used to help find the icon.

  \note Because of binary compatibility constraints, standardIcon()
  introduced in Qt 4.1 is not virtual. Therefore it must dynamically
  detect and call \e this slot.  This default implementation simply
  calls standardIcon() with the given parameters.

  \sa standardIcon()
 */
QIcon QProxyStyle::standardIconImplementation(StandardPixmap standardIcon,
                                              const QStyleOption *option,
                                              const QWidget *widget) const
{
    Q_D (const QProxyStyle);
    d->ensureBaseStyle();
    return d->baseStyle->standardIcon(standardIcon, option, widget);
}

/*!
  This slot is called by layoutSpacing() to determine the spacing that
  should be used between \a control1 and \a control2 in a layout. \a
  orientation specifies whether the controls are laid out side by side
  or stacked vertically. The \a option parameter can be used to pass
  extra information about the parent widget.  The \a widget parameter
  is optional and can also be used if \a option is 0.

  The default implementation returns -1.

  \sa layoutSpacing(), combinedLayoutSpacing()
 */
int QProxyStyle::layoutSpacingImplementation(QSizePolicy::ControlType control1,
                                             QSizePolicy::ControlType control2,
                                             Qt::Orientation orientation,
                                             const QStyleOption *option,
                                             const QWidget *widget) const
{
    Q_D (const QProxyStyle);
    d->ensureBaseStyle();
    return d->baseStyle->layoutSpacing(control1, control2, orientation, option, widget);
}

QT_END_NAMESPACE

#endif // QT_NO_STYLE_PROXY