qicon.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 "qicon.h"
#include "qiconengine.h"
#include "qiconengineplugin.h"
#include "private/qfactoryloader_p.h"
#include "qapplication.h"
#include "qstyleoption.h"
#include "qpainter.h"
#include "qfileinfo.h"
#include "qstyle.h"
#include "qpixmapcache.h"
#include "qvariant.h"
#include "qdebug.h"

/*!
    \enum QIcon::Mode

    This enum type describes the mode for which a pixmap is intended
    to be used. The currently defined modes are:

    \value Normal
         Display the pixmap when the user is
        not interacting with the icon, but the
        functionality represented by the icon is available.
    \value Disabled
         Display the pixmap when the
        functionality represented by the icon is not available.
    \value Active
         Display the pixmap when the
        functionality represented by the icon is available and
        the user is interacting with the icon, for example, moving the
        mouse over it or clicking it.
*/

/*!
  \enum QIcon::State

  This enum describes the state for which a pixmap is intended to be
  used. The \e state can be:

  \value Off  Display the pixmap when the widget is in an "off" state
  \value On  Display the pixmap when the widget is in an "on" state
*/

static int serialNumCounter = 0;

class QIconPrivate
{
public:
    QIconPrivate():ref(1),engine(0),serialNum(++serialNumCounter){}
    ~QIconPrivate() { delete engine; }
    QAtomic ref;
    QIconEngine *engine;
    int serialNum;
};


struct QPixmapIconEngineEntry
{
    QPixmapIconEngineEntry():mode(QIcon::Normal), state(QIcon::Off){}
    QPixmapIconEngineEntry(const QPixmap &pm, QIcon::Mode m = QIcon::Normal, QIcon::State s = QIcon::Off)
        :pixmap(pm), size(pm.size()), mode(m), state(s){}
    QPixmapIconEngineEntry(const QString &file, const QSize &sz = QSize(), QIcon::Mode m = QIcon::Normal, QIcon::State s = QIcon::Off)
        :fileName(file), size(sz), mode(m), state(s){}
    QPixmap pixmap;
    QString fileName;
    QSize size;
    QIcon::Mode mode;
    QIcon::State state;
    bool isNull() const {return (fileName.isEmpty() && pixmap.isNull()); }
};

class QPixmapIconEngine : public QIconEngine{
public:
    QPixmapIconEngine();
    ~QPixmapIconEngine();
    void paint(QPainter *painter, const QRect &rect, QIcon::Mode mode, QIcon::State state);
    QPixmap pixmap(const QSize &size, QIcon::Mode mode, QIcon::State state);
    QPixmapIconEngineEntry *bestMatch(const QSize &size, QIcon::Mode mode, QIcon::State state, bool sizeOnly);
    QSize actualSize(const QSize &size, QIcon::Mode mode, QIcon::State state);
    void addPixmap(const QPixmap &pixmap, QIcon::Mode mode, QIcon::State state);
    void addFile(const QString &fileName, const QSize &size, QIcon::Mode mode, QIcon::State state);
private:
    QPixmapIconEngineEntry *tryMatch(const QSize &size, QIcon::Mode mode, QIcon::State state);
    QVector<QPixmapIconEngineEntry> pixmaps;
};

QPixmapIconEngine::QPixmapIconEngine()
{
}

QPixmapIconEngine::~QPixmapIconEngine()
{
}

void QPixmapIconEngine::paint(QPainter *painter, const QRect &rect, QIcon::Mode mode, QIcon::State state)
{
    painter->drawPixmap(rect, pixmap(rect.size(), mode, state));
}

static inline int area(const QSize &s) { return s.width() * s.height(); }

// returns the smallest of the two that is still larger than or equal to size.
static QPixmapIconEngineEntry *bestSizeMatch( const QSize &size, QPixmapIconEngineEntry *pa, QPixmapIconEngineEntry *pb)
{
    int s = area(size);
    if (pa->size == QSize() && pa->pixmap.isNull()) {
        pa->pixmap = QPixmap(pa->fileName);
        pa->size = pa->pixmap.size();
    }
    int a = area(pa->size);
    if (pb->size == QSize() && pb->pixmap.isNull()) {
        pb->pixmap = QPixmap(pb->fileName);
        pb->size = pb->pixmap.size();
    }
    int b = area(pb->size);
    int res = a;
    if (qMin(a,b) >= s)
        res = qMin(a,b);
    else
        res = qMax(a,b);
    if (res == a)
        return pa;
    return pb;
}

QPixmapIconEngineEntry *QPixmapIconEngine::tryMatch(const QSize &size, QIcon::Mode mode, QIcon::State state)
{
    QPixmapIconEngineEntry *pe = 0;
    for (int i = 0; i < pixmaps.count(); ++i)
        if (pixmaps.at(i).mode == mode && pixmaps.at(i).state == state) {
            if (pe)
                pe = bestSizeMatch(size, &pixmaps[i], pe);
            else
                pe = &pixmaps[i];
        }
    return pe;
}


QPixmapIconEngineEntry *QPixmapIconEngine::bestMatch(const QSize &size, QIcon::Mode mode, QIcon::State state, bool sizeOnly)
{
    QPixmapIconEngineEntry *pe = tryMatch(size, mode, state);
    while (!pe){
        QIcon::State oppositeState = (state == QIcon::On) ? QIcon::Off : QIcon::On;
        if (mode == QIcon::Disabled) {
            if ((pe = tryMatch(size, QIcon::Normal, state)))
                break;
            if ((pe = tryMatch(size, QIcon::Active, state)))
                break;
            if ((pe = tryMatch(size, QIcon::Disabled, oppositeState)))
                break;
            if ((pe = tryMatch(size, QIcon::Normal, oppositeState)))
                break;
            if ((pe = tryMatch(size, QIcon::Active, oppositeState)))
                break;
        } else {
            QIcon::Mode oppositeMode = (mode == QIcon::Normal) ? QIcon::Active : QIcon::Normal;
            if ((pe = tryMatch(size, oppositeMode, state)))
                break;
            if ((pe = tryMatch(size, mode, oppositeState)))
                break;
            if ((pe = tryMatch(size, oppositeMode, oppositeState)))
                break;
            if ((pe = tryMatch(size, QIcon::Disabled, state)))
                break;
            if ((pe = tryMatch(size, QIcon::Disabled, oppositeState)))
                break;
        }

        if (!pe)
            return pe;
    }

    if (sizeOnly ? (pe->size.isNull() || !pe->size.isValid()) : pe->pixmap.isNull()) {
        pe->pixmap = QPixmap(pe->fileName);
        if (!pe->pixmap.isNull())
            pe->size = pe->pixmap.size();
    }

    return pe;
}

QPixmap QPixmapIconEngine::pixmap(const QSize &size, QIcon::Mode mode, QIcon::State state)
{
    QPixmap pm;
    QPixmapIconEngineEntry *pe = bestMatch(size, mode, state, false);
    if (pe)
        pm = pe->pixmap;

    if (pm.isNull())
        return pm;

    QSize actualSize = pm.size();
    if (!actualSize.isNull() && (actualSize.width() > size.width() && actualSize.height() > size.height()))
        actualSize.scale(size, Qt::KeepAspectRatio);

    QString key = QLatin1String("$qt_icon_")
                  + QString::number(pm.serialNumber())
                  + QString::number(actualSize.width())
                  + QLatin1Char('_')
                  + QString::number(actualSize.height())
                  + QLatin1Char('_');


    if (mode == QIcon::Active) {
        if (QPixmapCache::find(key + QString::number(mode), pm))
            return pm; // horray
        if (QPixmapCache::find(key + QString::number(QIcon::Normal), pm)) {
            QStyleOption opt(0);
            opt.palette = QApplication::palette();
            QPixmap active = QApplication::style()->generatedIconPixmap(QIcon::Active, pm, &opt);
            if (pm.serialNumber() == active.serialNumber())
                return pm;
        }
    }

    if (!QPixmapCache::find(key + QString::number(mode), pm)) {
        if (pe->mode != mode && mode != QIcon::Normal && pe->mode != QIcon::Disabled) {
            QStyleOption opt(0);
            opt.palette = QApplication::palette();
            QPixmap generated = QApplication::style()->generatedIconPixmap(mode, pm, &opt);
            if (!generated.isNull())
                pm = generated;
        }
        if (pm.size() != actualSize)
            pm = pm.scaled(actualSize, Qt::IgnoreAspectRatio, Qt::SmoothTransformation);
        QPixmapCache::insert(key + QString::number(mode), pm);
    }
    return pm;
}

QSize QPixmapIconEngine::actualSize(const QSize &size, QIcon::Mode mode, QIcon::State state)
{
    QSize actualSize;
    if (QPixmapIconEngineEntry *pe = bestMatch(size, mode, state, true))
        actualSize = pe->size;

    if (actualSize.isNull())
        return actualSize;

    if (!actualSize.isNull() && (actualSize.width() > size.width() && actualSize.height() > size.height()))
        actualSize.scale(size, Qt::KeepAspectRatio);
    return actualSize;
}

void QPixmapIconEngine::addPixmap(const QPixmap &pixmap, QIcon::Mode mode, QIcon::State state)
{
    if (!pixmap.isNull())
        pixmaps += QPixmapIconEngineEntry(pixmap, mode, state);
}

void QPixmapIconEngine::addFile(const QString &fileName, const QSize &size, QIcon::Mode mode, QIcon::State state)
{
    if (!fileName.isEmpty()) {
        QString abs = fileName;
        if (fileName.at(0) != QLatin1Char(':'))
            abs = QFileInfo(fileName).absoluteFilePath();
        pixmaps += QPixmapIconEngineEntry(abs, size, mode, state);
    }
}



#ifndef QT_NO_LIBRARY
Q_GLOBAL_STATIC_WITH_ARGS(QFactoryLoader, loader,
    (QIconEngineFactoryInterface_iid, QCoreApplication::libraryPaths(), "/iconengines", Qt::CaseInsensitive))
#endif



/*!
  \class QIcon

  \brief The QIcon class provides scalable icons in different modes
  and states.

  \ingroup multimedia
  \ingroup shared
  \mainclass

  A QIcon can generate smaller, larger, active, and disabled pixmaps
  from the set of pixmaps it is given. Such pixmaps are used by Qt
  widgets to show an icon representing a particular action.

  The simplest use of QIcon is to create one from a QPixmap file or
  resource, and then use it, allowing Qt to work out all the required
  icon styles and sizes. For example:

  \code
    QToolButton *button = new QToolButton;
    button->setIcon(QIcon("open.xpm"));
  \endcode

  Use the QImageReader::supportedImageFormats() and
  QImageWriter::supportedImageFormats() functions to retrieve a
  complete list of the supported file formats.

  When you retrieve a pixmap using pixmap(QSize, Mode, State), and no
  pixmap for this given size, mode and state has been added with
  addFile() or addPixmap(), then QIcon will generate one on the
  fly. This pixmap generation happens in a QIconEngine. The default
  engine scales pixmaps down if required, but never up, and it uses
  the current style to calculate a disabled appearance. By using
  custom icon engines, you can customize every aspect of generated
  icons. With QIconEnginePlugin it is possible to register different
  icon engines for different file suffixes, so you could provide a SVG
  icon engine or any other scalable format.

  \section1 Making Classes that Use QIcon

  If you write your own widgets that have an option to set a small
  pixmap, consider allowing a QIcon to be set for that pixmap.  The
  Qt class QToolButton is an example of such a widget.

  Provide a method to set a QIcon, and when you draw the icon, choose
  whichever pixmap is appropriate for the current state of your widget.
  For example:
  \code
    void MyWidget::drawIcon(QPainter *painter, QPoint pos)
    {
        QPixmap pixmap = icon.pixmap(QSize(22, 22),
                                       isEnabled() ? QIcon::Normal
                                                   : QIcon::Disabled,
                                       isOn() ? QIcon::On
                                              : QIcon::Off);
        painter->drawPixmap(pos, pixmap);
    }
  \endcode

  You might also make use of the \c Active mode, perhaps making your
  widget \c Active when the mouse is over the widget (see \l
  QWidget::enterEvent()), while the mouse is pressed pending the
  release that will activate the function, or when it is the currently
  selected item. If the widget can be toggled, the "On" mode might be
  used to draw a different icon.

  \img icon.png QIcon