qtextbrowser.cpp

奇趣公司比较新的qt/emd版本

            focusedPos = scrollYOffset;
            focusIt = true;
        } else {
            // This is the "normal" case - no scroll bar adjustments, no large anchors,
            // and no wrapping.
            foundNextAnchor = control->findNextPrevAnchor(prevFocus, next, anchorToFocus);
        }
    }

    // If not found yet, see if we need to wrap
    if (!focusIt && !foundNextAnchor) {
        if (next) {
            if (yOffset == vbar->maximum()) {
                prevFocus.movePosition(QTextCursor::Start);
                yOffset = scrollYOffset = 0;

                // Refresh the rectangles
                viewRect = QRectF(0, yOffset, control->size().width(), height);
                newViewRect = QRectF(0, scrollYOffset, control->size().width(), height);
                bothViewRects = viewRect.united(newViewRect);
            }
        } else {
            if (yOffset == 0) {
                prevFocus.movePosition(QTextCursor::End);
                yOffset = scrollYOffset = vbar->maximum();

                // Refresh the rectangles
                viewRect = QRectF(0, yOffset, control->size().width(), height);
                newViewRect = QRectF(0, scrollYOffset, control->size().width(), height);
                bothViewRects = viewRect.united(newViewRect);
            }
        }

        // Try looking now
        foundNextAnchor = control->findNextPrevAnchor(prevFocus, next, anchorToFocus);
    }

    // If we did actually find an anchor to use...
    if (foundNextAnchor) {
        QRectF desiredRect = control->selectionRect(anchorToFocus);

        // XXX This is an arbitrary heuristic
        // Decide to focus an anchor if it will be at least be
        // in the middle region of the screen after a scroll.
        // This can result in partial anchors with focus, but
        // insisting on links being completely visible before
        // selecting them causes disparities between links that
        // take up 90% of the screen height and those that take
        // up e.g. 110%
        // Obviously if a link is entirely visible, we still
        // focus it.
        if(bothViewRects.contains(desiredRect)
                || bothViewRects.adjusted(0, visibleLinkAmount, 0, -visibleLinkAmount).intersects(desiredRect)) {
            focusIt = true;

            // We aim to put the new link in the middle of the screen,
            // unless the link is larger than the screen (we just move to
            // display the first page of the link)
            if (desiredRect.height() > height) {
                if (next)
                    focusedPos = (int) desiredRect.top();
                else
                    focusedPos = (int) desiredRect.bottom() - height;
            } else
                focusedPos = (int) ((desiredRect.top() + desiredRect.bottom()) / 2 - (height / 2));

            // and clamp it to make sure we don't skip content.
            if (next)
                focusedPos = qBound(yOffset, focusedPos, scrollYOffset);
            else
                focusedPos = qBound(scrollYOffset, focusedPos, yOffset);
        }
    }

    // If we didn't get a new anchor, check if the old one is still on screen when we scroll
    // Note that big (larger than screen height) anchors also have some handling at the
    // start of this function.
    if (!focusIt && prevFocus.hasSelection()) {
        QRectF desiredRect = control->selectionRect(prevFocus);
        // XXX this may be better off also using the visibleLinkAmount value
        if(newViewRect.intersects(desiredRect)) {
            focusedPos = scrollYOffset;
            focusIt = true;
            anchorToFocus = prevFocus;
        }
    }

    // setTextCursor ensures that the cursor is visible. save & restore
    // the scroll bar values therefore
    const int savedXOffset = hbar->value();

    // Now actually process our decision
    if (focusIt && control->setFocusToAnchor(anchorToFocus)) {
        // Save the focus for next time
        prevFocus = control->textCursor();

        // Scroll
        vbar->setValue(focusedPos);
        lastKeypadScrollValue = focusedPos;
        hbar->setValue(savedXOffset);

        // Ensure that the new selection is highlighted.
        const QString href = control->anchorAtCursor();
        QUrl url = resolveUrl(href);
        emit q->highlighted(url);
        emit q->highlighted(url.toString());
    } else {
        // Scroll
        vbar->setValue(scrollYOffset);
        lastKeypadScrollValue = scrollYOffset;

        // now make sure we don't have a focused anchor
        QTextCursor cursor = control->textCursor();
        cursor.clearSelection();

        control->setTextCursor(cursor);

        hbar->setValue(savedXOffset);
        vbar->setValue(scrollYOffset);

        emit q->highlighted(QUrl());
        emit q->highlighted(QString());
    }
}
#endif

QTextBrowserPrivate::HistoryEntry QTextBrowserPrivate::createHistoryEntry() const
{
    HistoryEntry entry;
    entry.url = q_func()->source();
    entry.hpos = hbar->value();
    entry.vpos = vbar->value();

    const QTextCursor cursor = control->textCursor();
    if (control->cursorIsFocusIndicator()
        && cursor.hasSelection()) {

        entry.focusIndicatorPosition = cursor.position();
        entry.focusIndicatorAnchor = cursor.anchor();
    }
    return entry;
}

void QTextBrowserPrivate::restoreHistoryEntry(const HistoryEntry entry)
{
    setSource(entry.url);
    hbar->setValue(entry.hpos);
    vbar->setValue(entry.vpos);
    if (entry.focusIndicatorAnchor != -1 && entry.focusIndicatorPosition != -1) {
        QTextCursor cursor(control->document());
        cursor.setPosition(entry.focusIndicatorAnchor);
        cursor.setPosition(entry.focusIndicatorPosition, QTextCursor::KeepAnchor);
        control->setCursorIsFocusIndicator(true);
        control->setTextCursor(cursor);
    }
#ifdef QT_KEYPAD_NAVIGATION 
    lastKeypadScrollValue = vbar->value(); 
    prevFocus = control->textCursor(); 
#endif 
}

/*!
    \class QTextBrowser qtextbrowser.h
    \brief The QTextBrowser class provides a rich text browser with hypertext navigation.

    \ingroup text

    This class extends QTextEdit (in read-only mode), adding some navigation
    functionality so that users can follow links in hypertext documents.

    If you want to provide your users with an editable rich text editor,
    use QTextEdit. If you want a text browser without hypertext navigation
    use QTextEdit, and use QTextEdit::setReadOnly() to disable
    editing. If you just need to display a small piece of rich text
    use QLabel.

    \section1 Document Source and Contents

    The contents of QTextEdit are set with setHtml() or setPlainText(),
    but QTextBrowser also implements the setSource() function, making it
    possible to use a named document as the source text. The name is looked
    up in a list of search paths and in the directory of the current document
    factory.

    If a document name ends with
    an anchor (for example, "\c #anchor"), the text browser automatically
    scrolls to that position (using scrollToAnchor()). When the user clicks
    on a hyperlink, the browser will call setSource() itself with the link's
    \c href value as argument. You can track the current source by connecting
    to the sourceChanged() signal.

    \section1 Navigation

    QTextBrowser provides backward() and forward() slots which you can
    use to implement Back and Forward buttons. The home() slot sets
    the text to the very first document displayed. The anchorClicked()
    signal is emitted when the user clicks an anchor. To override the
    default navigation behavior of the browser, call the setSource()
    function to supply new document text in a slot connected to this
    signal.

    If you want to load documents stored in the Qt resource system use
    \c{qrc} as the scheme in the URL to load. For example, for the document
    resource path \c{:/docs/index.html} use \c{qrc:/docs/index.html} as
    the URL with setSource().

    \sa QTextEdit, QTextDocument
*/

/*!
    \property QTextBrowser::modified
    \brief whether the contents of the text browser have been modified
*/

/*!
    \property QTextBrowser::readOnly
    \brief whether the text browser is read-only
*/

/*!
    \property QTextBrowser::undoRedoEnabled
    \brief whether the text browser supports undo/redo operations
*/

void QTextBrowserPrivate::init()
{
    Q_Q(QTextBrowser);
    control->setTextInteractionFlags(Qt::TextBrowserInteraction);
#ifndef QT_NO_CURSOR
    viewport->setCursor(oldCursor);
#endif
    q->setUndoRedoEnabled(false);
    viewport->setMouseTracking(true);
    QObject::connect(q->document(), SIGNAL(contentsChanged()), q, SLOT(_q_documentModified()));
    QObject::connect(control, SIGNAL(linkActivated(QString)),
                     q, SLOT(_q_activateAnchor(QString)));
    QObject::connect(control, SIGNAL(linkHovered(QString)),
                     q, SLOT(_q_highlightLink(QString)));
}

/*!
    Constructs an empty QTextBrowser with parent \a parent.
*/
QTextBrowser::QTextBrowser(QWidget *parent)
    : QTextEdit(*new QTextBrowserPrivate, parent)
{
    Q_D(QTextBrowser);
    d->init();
}

#ifdef QT3_SUPPORT
/*!
    Use one of the constructors that doesn't take the \a name
    argument and then use setObjectName() instead.
*/
QTextBrowser::QTextBrowser(QWidget *parent, const char *name)
    : QTextEdit(*new QTextBrowserPrivate, parent)
{
    setObjectName(QString::fromAscii(name));
    Q_D(QTextBrowser);
    d->init();
}
#endif

/*!
    \internal
*/
QTextBrowser::~QTextBrowser()
{
}

/*!
    \property QTextBrowser::source
    \brief the name of the displayed document.

    This is a an invalid url if no document is displayed or if the
    source is unknown.

    When setting this property QTextBrowser tries to find a document
    with the specified name in the paths of the searchPaths property
    and directory of the current source, unless the value is an absolute
    file path. It also checks for optional anchors and scrolls the document
    accordingly

    If the first tag in the document is \c{<qt type=detail>}, the
    document is displayed as a popup rather than as new document in
    the browser window itself. Otherwise, the document is displayed
    normally in the text browser with the text set to the contents of
    the named document with setHtml().
*/
QUrl QTextBrowser::source() const
{
    Q_D(const QTextBrowser);
    if (d->stack.isEmpty())
        return QUrl();
    else
        return d->stack.top().url;
}

/*!
    \property QTextBrowser::searchPaths
    \brief the search paths used by the text browser to find supporting
    content

    QTextBrowser uses this list to locate images and documents.
*/

QStringList QTextBrowser::searchPaths() const
{
    Q_D(const QTextBrowser);
    return d->searchPaths;
}

void QTextBrowser::setSearchPaths(const QStringList &paths)
{
    Q_D(QTextBrowser);
    d->searchPaths = paths;
}

/*!
    Reloads the current set source.
*/
void QTextBrowser::reload()
{
    Q_D(QTextBrowser);
    QUrl s = d->currentURL;
    d->currentURL = QUrl();
    setSource(s);
}

void QTextBrowser::setSource(const QUrl &url)
{
    Q_D(QTextBrowser);

    const QTextBrowserPrivate::HistoryEntry historyEntry = d->createHistoryEntry();

    d->setSource(url);

    if (!url.isValid())
        return;

    // the same url you are already watching?
    if (!d->stack.isEmpty() && d->stack.top().url == url)
        return;

    if (!d->stack.isEmpty())
        d->stack.top() = historyEntry;

    QTextBrowserPrivate::HistoryEntry entry;
    entry.url = url;
    entry.hpos = 0;
    entry.vpos = 0;
    d->stack.push(entry);

    emit backwardAvailable(d->stack.count() > 1);

    if (!d->forwardStack.isEmpty() && d->forwardStack.top().url == url) {
        d->forwardStack.pop();
        emit forwardAvailable(d->forwardStack.count() > 0);
    } else {
        d->forwardStack.clear();
        emit forwardAvailable(false);
    }
}

/*!
    \fn void QTextBrowser::backwardAvailable(bool available)

    This signal is emitted when the availability of backward()
    changes. \a available is false when the user is at home();
    otherwise it is true.
*/

/*!
    \fn void QTextBrowser::forwardAvailable(bool available)

    This signal is emitted when the availability of forward() changes.
    \a available is true after the user navigates backward() and false
    when the user navigates or goes forward().
*/

/*!
    \fn void QTextBrowser::sourceChanged(const QUrl &src)