qlabel.cpp

奇趣公司比较新的qt/emd版本

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#include "qpainter.h"
#include "qevent.h"
#include "qdrawutil.h"
#include "qapplication.h"
#include "qabstractbutton.h"
#include "qstyle.h"
#include "qstyleoption.h"
#include <limits.h>
#include "qaction.h"
#include "qclipboard.h"
#include <qdebug.h>
#include <qurl.h>
#include "qlabel_p.h"

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

    \ingroup basicwidgets
    \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->picture;
}
#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::WindowFlags 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::WindowFlags 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::WindowFlags 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::WindowFlags 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, \&), 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::WindowFlags f)
    : QFrame(*new QLabelPrivate(), parent, f)
{
    Q_D(QLabel);
    if (name)
        setObjectName(QString::fromAscii(name));
    d->init();
#ifndef QT_NO_SHORTCUT
    setBuddy(buddy);
#endif
    setText(text);
}
#endif //QT3_SUPPORT

/*!
    Destroys the label.
*/

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

void QLabelPrivate::init()
{
    Q_Q(QLabel);

    valid_hints = false;
    margin = 0;
#ifndef QT_NO_MOVIE
    movie = 0;
#endif
#ifndef QT_NO_SHORTCUT
    shortcutId = 0;
#endif
    pixmap = 0;
    scaledpixmap = 0;
    cachedimage = 0;
#ifndef QT_NO_PICTURE
    picture = 0;
#endif
    align = Qt::AlignLeft | Qt::AlignVCenter | Qt::TextExpandTabs;
    indent = -1;
    scaledcontents = false;
    textLayoutDirty = false;
    textDirty = false;
    textformat = Qt::AutoText;
    control = 0;
    textInteractionFlags = Qt::LinksAccessibleByMouse;
    isRichText = false;
    isTextLabel = false;

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

#ifndef QT_NO_CURSOR
    validCursor = false;
    onAnchor = false;
#endif

    openExternalLinks = false;

    setLayoutItemMargins(QStyle::SE_LabelLayoutItem);
}


/*!
    \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 a buddy has been set, the buddy mnemonic key is updated
    from the new text.

    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 scroll bar
    when necessary.

    \note This function enables mouse tracking if \a text contains rich
    text.

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

void QLabel::setText(const QString &text)
{
    Q_D(QLabel);
    if (d->text == text)
        return;

    QTextControl *oldControl = d->control;
    d->control = 0;

    d->clearContents();
    d->text = text;
    d->isTextLabel = true;
    d->textDirty = true;
    d->isRichText = d->textformat == Qt::RichText
                    || (d->textformat == Qt::AutoText && Qt::mightBeRichText(d->text));

    d->control = oldControl;

    if (d->needTextControl()) {
        d->ensureTextControl();
    } else {
        delete d->control;
        d->control = 0;
    }

    if (d->isRichText) {
        setMouseTracking(true);
    } else {
        // Note: mouse tracking not disabled intentionally
    }

#ifndef QT_NO_SHORTCUT
    if (d->buddy)
        d->updateShortcut();
#endif

    d->updateLabel();
}

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

/*!
    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 0.

    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->pixmap || d->pixmap->cacheKey() != pixmap.cacheKey()) {
        d->clearContents();
        d->pixmap = new QPixmap(pixmap);
    }

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

    d->updateLabel();
}

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

#ifndef QT_NO_PICTURE
/*!
    Sets the label contents to \a picture. Any previous content is
    cleared.

    The buddy shortcut, if any, is disabled.

    \sa picture(), setBuddy()
*/

void QLabel::setPicture(const QPicture &picture)
{
    Q_D(QLabel);
    d->clearContents();
    d->picture = new QPicture(picture);

    d->updateLabel();
}
#endif // QT_NO_PICTURE

/*!
    Sets the label contents to plain text containing the textual
    representation of integer \a num. Any previous content is cleared.
    Does nothing if the integer's string representation is the same as
    the current contents of the label.

    The buddy shortcut, if any, is disabled.

    \sa setText(), QString::setNum(), setBuddy()
*/

void QLabel::setNum(int num)
{
    QString str;
    str.setNum(num);
    setText(str);
}

/*!
    \overload

    Sets the label contents to plain text containing the textual
    representation of double \a num. Any previous content is cleared.
    Does nothing if the double's string representation is the same as
    the current contents of the label.

    The buddy shortcut, if any, is disabled.

    \sa setText(), QString::setNum(), setBuddy()
*/

void QLabel::setNum(double num)
{
    QString str;
    str.setNum(num);
    setText(str);
}

/*!
    \property QLabel::alignment
    \brief the alignment of the label's contents

    \sa text
*/

void QLabel::setAlignment(Qt::Alignment alignment)
{
    Q_D(QLabel);
    if (alignment == (d->align & (Qt::AlignVertical_Mask|Qt::AlignHorizontal_Mask)))
        return;
    d->align = (d->align & ~(Qt::AlignVertical_Mask|Qt::AlignHorizontal_Mask))
               | (alignment & (Qt::AlignVertical_Mask|Qt::AlignHorizontal_Mask));

    d->updateLabel();
}

#ifdef QT3_SUPPORT
/*!
    Use setAlignment(Qt::Alignment) instead.

    If \a alignment specifies text flags as well, use setTextFormat()
    to set those.
*/
void QLabel::setAlignment(int alignment)
{
    Q_D(QLabel);
    d->align = alignment & ~(Qt::AlignVertical_Mask|Qt::AlignHorizontal_Mask|Qt::TextWordWrap);
    setAlignment(Qt::Alignment(QFlag(alignment)));
}
#endif

Qt::Alignment QLabel::alignment() const
{
    Q_D(const QLabel);
    return QFlag(d->align & (Qt::AlignVertical_Mask|Qt::AlignHorizontal_Mask));
}


/*!
    \property QLabel::wordWrap
    \brief the label's word-wrapping policy

    If this property is true then label text is wrapped where
    necessary at word-breaks; otherwise it is not wrapped at all.
*/
void QLabel::setWordWrap(bool on)
{
    Q_D(QLabel);
    if (on)
        d->align |= Qt::TextWordWrap;
    else
        d->align &= ~Qt::TextWordWrap;