qlabel.cpp

qt-x11-opensource-src-4.1.4.tar.gz源码

/****************************************************************************
**
** Copyright (C) 1992-2006 Trolltech ASA. All rights reserved.
**
** This file is part of the QtGui module of the Qt Toolkit.
**
** This file may be used under the terms of the GNU General Public
** License version 2.0 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 GNU
** General Public Licensing requirements will be met:
** http://www.trolltech.com/products/qt/opensource.html
**
** If you are unsure which license is appropriate for your use, please
** review the following information:
** http://www.trolltech.com/products/qt/licensing.html or contact the
** sales department at [e-mail].
**
** This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
** WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
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****************************************************************************/

#include "qlabel.h"
#include "qpainter.h"
#include "qevent.h"
#include "qdrawutil.h"
#include "qmovie.h"
#include "qimage.h"
#include "qbitmap.h"
#include "qpicture.h"
#include "qapplication.h"
#include "qtextdocument.h"
#include "qabstractbutton.h"
#include "qstyle.h"
#include "qstyleoption.h"
#include "qframe_p.h"
#include <limits.h>
#include "../text/qtextdocumentlayout_p.h"

class QLabelPrivate : public QFramePrivate
{
    Q_DECLARE_PUBLIC(QLabel)
public:
    QLabelPrivate()
        : img(0), pix(0), valid_hints(false), margin(0)
    {}

    void init();
    void clearContents();
    void updateLabel();
    QSize sizeForWidth(int w) const;

    QImage* img; // for scaled contents
    QPixmap* pix; // for scaled contents
    mutable QSize sh;
    mutable QSize msh;
    mutable bool valid_hints;
    int margin;
    QString ltext;
    QPixmap *lpixmap;
#ifndef QT_NO_PICTURE
    QPicture *lpicture;
#endif
#ifndef QT_NO_MOVIE
    QMovie *lmovie;
    void _q_movieUpdated(const QRect&);
    void _q_movieResized(const QSize&);
#endif
    QPointer<QWidget> lbuddy;
    int shortcutId;
    ushort align;
    short extraMargin;
    uint scaledcontents :1;
    Qt::TextFormat textformat;
    QTextDocument* doc;
};

/*!
    \class QLabel
    \brief The QLabel widget provides a text or image display.

    \ingroup basic
    \ingroup text
    \mainclass

    QLabel is used for displaying text or an image. No user
    interaction functionality is provided. The visual appearance of
    the label can be configured in various ways, and it can be used
    for specifying a focus mnemonic key for another widget.

    A QLabel can contain any of the following content types:

    \table
    \header \o Content \o Setting
    \row \o Plain text
         \o Pass a QString to setText().
    \row \o Rich text
         \o Pass a QString that contains rich text to setText().
    \row \o A pixmap
         \o Pass a QPixmap to setPixmap().
    \row \o A movie
         \o Pass a QMovie to setMovie().
    \row \o A number
         \o Pass an \e int or a \e double to setNum(), which converts
            the number to plain text.
    \row \o Nothing
         \o The same as an empty plain text. This is the default. Set
            by clear().
    \endtable

    When the content is changed using any of these functions, any
    previous content is cleared.

    The look of a QLabel can be tuned in several ways. All the
    settings of QFrame are available for specifying a widget frame.
    The positioning of the content within the QLabel widget area can
    be tuned with setAlignment() and setIndent(). Text content can
    also wrap lines along word bounderies with setWordWrap(). For
    example, this code sets up a sunken panel with a two-line text in
    the bottom right corner (both lines being flush with the right
    side of the label):

    \code
    QLabel *label = new QLabel(this);
    label->setFrameStyle(QFrame::Panel | QFrame::Sunken);
    label->setText("first line\nsecond line");
    label->setAlignment(Qt::AlignBottom | Qt::AlignRight);
    \endcode

    A QLabel is often used as a label for an interactive widget. For
    this use QLabel provides a useful mechanism for adding an
    mnemonic (see QKeysequence) that will set the keyboard focus to
    the other widget (called the QLabel's "buddy"). For example:
    \code
    QLineEdit* phoneEdit = new QLineEdit(this);
    QLabel* phoneLabel = new QLabel("&Phone:", this);
    phoneLabel->setBuddy(phoneEdit);
    \endcode

    In this example, keyboard focus is transferred to the label's
    buddy (the QLineEdit) when the user presses Alt+P. If the buddy
    was a button (inheriting from QAbstractButton), triggering the
    mnemonic would emulate a button click.

    \table 100%
    \row
    \o \inlineimage macintosh-label.png Screenshot of a Macintosh style label
    \o A label shown in the \l{Macintosh Style Widget Gallery}{Macintosh widget style}.
    \row
    \o \inlineimage plastique-label.png Screenshot of a Plastique style label
    \o A label shown in the \l{Plastique Style Widget Gallery}{Plastique widget style}.
    \row
    \o \inlineimage windowsxp-label.png Screenshot of a Windows XP style label
    \o A label shown in the \l{Windows XP Style Widget Gallery}{Windows XP widget style}.
    \endtable

    \sa QLineEdit, QTextEdit, QPixmap, QMovie,
        {fowler}{GUI Design Handbook: Label}
*/

#ifndef QT_NO_PICTURE
/*!
    Returns the label's picture or 0 if the label doesn't have a
    picture.
*/

const QPicture *QLabel::picture() const
{
    Q_D(const QLabel);
    return d->lpicture;
}
#endif


/*!
    Constructs an empty label.

    The \a parent and widget flag \a f, arguments are passed
    to the QFrame constructor.

    \sa setAlignment(), setFrameStyle(), setIndent()
*/
QLabel::QLabel(QWidget *parent, Qt::WFlags f)
    : QFrame(*new QLabelPrivate(), parent, f)
{
    Q_D(QLabel);
    d->init();
}

/*!
    Constructs a label that displays the text, \a text.

    The \a parent and widget flag \a f, arguments are passed
    to the QFrame constructor.

    \sa setText(), setAlignment(), setFrameStyle(), setIndent()
*/
QLabel::QLabel(const QString &text, QWidget *parent, Qt::WFlags f)
        : QFrame(*new QLabelPrivate(), parent, f)
{
    Q_D(QLabel);
    d->init();
    setText(text);
}


#ifdef QT3_SUPPORT
/*! \obsolete
    Constructs an empty label.

    The \a parent, \a name and widget flag \a f, arguments are passed
    to the QFrame constructor.

    \sa setAlignment(), setFrameStyle(), setIndent()
*/

QLabel::QLabel(QWidget *parent, const char *name, Qt::WFlags f)
    : QFrame(*new QLabelPrivate(), parent, f)
{
    Q_D(QLabel);
    if (name)
        setObjectName(QString::fromAscii(name));
    d->init();
}


/*! \obsolete
    Constructs a label that displays the text, \a text.

    The \a parent, \a name and widget flag \a f, arguments are passed
    to the QFrame constructor.

    \sa setText(), setAlignment(), setFrameStyle(), setIndent()
*/

QLabel::QLabel(const QString &text, QWidget *parent, const char *name,
                Qt::WFlags f)
        : QFrame(*new QLabelPrivate(), parent, f)
{
    Q_D(QLabel);
    if (name)
        setObjectName(QString::fromAscii(name));
    d->init();
    setText(text);
}


/*! \obsolete
    Constructs a label that displays the text \a text. The label has a
    buddy widget, \a buddy.

    If the \a text contains an underlined letter (a letter preceded by
    an ampersand, \&), and the text is in plain text format, when the
    user presses Alt+ the underlined letter, focus is passed to the
    buddy widget.

    The \a parent, \a name and widget flag, \a f, arguments are passed
    to the QFrame constructor.

    \sa setText(), setBuddy(), setAlignment(), setFrameStyle(),
    setIndent()
*/
QLabel::QLabel(QWidget *buddy, const QString &text,
                QWidget *parent, const char *name, Qt::WFlags f)
    : QFrame(*new QLabelPrivate(), parent, f)
{
    Q_D(QLabel);
    if (name)
        setObjectName(QString::fromAscii(name));
    d->init();
    setBuddy(buddy);
    setText(text);
}
#endif //QT3_SUPPORT

/*!
    Destroys the label.
*/

QLabel::~QLabel()
{
    Q_D(QLabel);
    d->clearContents();
}


void QLabelPrivate::init()
{
    Q_Q(QLabel);
    lpixmap = 0;
#ifndef QT_NO_MOVIE
    lmovie = 0;
#endif
    shortcutId = 0;
    lpixmap = 0;
#ifndef QT_NO_PICTURE
    lpicture = 0;
#endif
    align = Qt::AlignLeft | Qt::AlignVCenter | Qt::TextExpandTabs;
    extraMargin = -1;
    scaledcontents = false;
    textformat = Qt::AutoText;
    doc = 0;

    q->setSizePolicy(QSizePolicy(QSizePolicy::Preferred, QSizePolicy::Preferred));
}


/*!
    \property QLabel::text
    \brief the label's text

    If no text has been set this will return an empty string. Setting
    the text clears any previous content.

    The text will be interpreted either as plain text or as rich
    text, depending on the text format setting; see setTextFormat().
    The default setting is Qt::AutoText; i.e. QLabel will try to
    auto-detect the format of the text set.

    If the text is interpreted as a plain text and a buddy has been
    set, the buddy mnemonic key is updated from the new text.

    The label resizes itself if auto-resizing is enabled.

    Note that QLabel is well-suited to display small rich text
    documents, such as small documents that get their document
    specific settings (font, text color, link color) from the label's
    palette and font properties. For large documents, use QTextEdit
    in read-only mode instead. QTextEdit can also provide a scrollbar
    when necessary.

    \sa setTextFormat(), setBuddy(), alignment
*/

void QLabel::setText(const QString &text)
{
    Q_D(QLabel);
    if (d->ltext == text)
        return;
    d->clearContents();
    d->ltext = text;
    if (d->textformat == Qt::RichText
        || ((d->textformat == Qt::AutoText) && Qt::mightBeRichText(d->ltext))) {
        if (!d->doc)
            d->doc = new QTextDocument();
        d->doc->setUndoRedoEnabled(false);
        d->doc->setDefaultFont(font());
        d->doc->setHtml(d->ltext);
    }

    d->updateLabel();
}

QString QLabel::text() const
{
    Q_D(const QLabel);
    return d->ltext;
}

/*!
    Clears any label contents.
*/

void QLabel::clear()
{
    Q_D(QLabel);
    d->clearContents();
    d->updateLabel();
}

/*!
    \property QLabel::pixmap
    \brief the label's pixmap

    If no pixmap has been set this will return an invalid pixmap.

    Setting the pixmap clears any previous content. The buddy
    shortcut, if any, is disabled.
*/
void QLabel::setPixmap(const QPixmap &pixmap)
{
    Q_D(QLabel);
    if (!d->lpixmap || d->lpixmap->serialNumber() != pixmap.serialNumber()) {
        d->clearContents();
        d->lpixmap = new QPixmap(pixmap);
    }

    if (d->lpixmap->depth() == 1 && !d->lpixmap->mask())
        d->lpixmap->setMask(*((QBitmap *)d->lpixmap));

    d->updateLabel();
}

const QPixmap *QLabel::pixmap() const
{
    Q_D(const QLabel);
    return d->lpixmap;
}