qtabbar.cpp

奇趣公司比较新的qt/emd版本

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#include "private/qlayoutengine_p.h"
#include "qabstractitemdelegate.h"
#include "qapplication.h"
#include "qbitmap.h"
#include "qcursor.h"
#include "qevent.h"
#include "qpainter.h"
#include "qstyle.h"
#include "qstyleoption.h"
#include "qstylepainter.h"
#include "qtabwidget.h"
#include "qtooltip.h"
#include "qwhatsthis.h"
#include "private/qtextengine_p.h"
#ifndef QT_NO_ACCESSIBILITY
#include "qaccessible.h"
#endif

#include "qdebug.h"
#include "private/qtabbar_p.h"

#ifndef QT_NO_TABBAR

inline static bool verticalTabs(QTabBar::Shape shape)
{
    return shape == QTabBar::RoundedWest
           || shape == QTabBar::RoundedEast
           || shape == QTabBar::TriangularWest
           || shape == QTabBar::TriangularEast;
}

/*!
    Initialize \a option with the values from the tab at \a tabIndex. This method
    is useful for subclasses when they need a QStyleOptionTab or QStyleOptionTabV2, but don't want
    to fill in all the information themselves. This function will check the version
    of the QStyleOptionTab and fill in the additional values for a
    QStyleOptionTabV2.

    \sa QStyleOption::initFrom() QTabWidget::initStyleOption()
*/
void QTabBar::initStyleOption(QStyleOptionTab *option, int tabIndex) const
{
    Q_D(const QTabBar);
    int totalTabs = d->tabList.size();

    if (!option || (tabIndex < 0 || tabIndex >= totalTabs))
        return;

    const QTabBarPrivate::Tab &tab = d->tabList.at(tabIndex);
    option->initFrom(this);
    option->state &= ~(QStyle::State_HasFocus | QStyle::State_MouseOver);
    option->rect = tabRect(tabIndex);
    bool isCurrent = tabIndex == d->currentIndex;
    option->row = 0;
    if (tabIndex == d->pressedIndex)
        option->state |= QStyle::State_Sunken;
    if (isCurrent)
        option->state |= QStyle::State_Selected;
    if (isCurrent && hasFocus())
        option->state |= QStyle::State_HasFocus;
    if (!tab.enabled)
        option->state &= ~QStyle::State_Enabled;
    if (isActiveWindow())
        option->state |= QStyle::State_Active;
    if (option->rect == d->hoverRect)
        option->state |= QStyle::State_MouseOver;
    option->shape = d->shape;
    option->text = tab.text;

    if (tab.textColor.isValid())
        option->palette.setColor(foregroundRole(), tab.textColor);

    option->icon = tab.icon;
    if (QStyleOptionTabV2 *optionV2 = qstyleoption_cast<QStyleOptionTabV2 *>(option))
        optionV2->iconSize = iconSize();  // Will get the default value then.


    if (tabIndex > 0 && tabIndex - 1 == d->currentIndex)
        option->selectedPosition = QStyleOptionTab::PreviousIsSelected;
    else if (tabIndex < totalTabs - 1 && tabIndex + 1 == d->currentIndex)
        option->selectedPosition = QStyleOptionTab::NextIsSelected;
    else
        option->selectedPosition = QStyleOptionTab::NotAdjacent;

    if (tabIndex == 0) {
        if (totalTabs > 1)
            option->position = QStyleOptionTab::Beginning;
        else
            option->position = QStyleOptionTab::OnlyOneTab;
    } else if (tabIndex == totalTabs - 1) {
        option->position = QStyleOptionTab::End;
    } else {
        option->position = QStyleOptionTab::Middle;
    }
#ifndef QT_NO_TABWIDGET
    if (const QTabWidget *tw = qobject_cast<const QTabWidget *>(parentWidget())) {
        if (tw->cornerWidget(Qt::TopLeftCorner) || tw->cornerWidget(Qt::BottomLeftCorner))
            option->cornerWidgets |= QStyleOptionTab::LeftCornerWidget;
        if (tw->cornerWidget(Qt::TopRightCorner) || tw->cornerWidget(Qt::BottomRightCorner))
            option->cornerWidgets |= QStyleOptionTab::RightCornerWidget;
    }
    int hframe  = style()->pixelMetric(QStyle::PM_TabBarTabHSpace, option, this);

    option->text = fontMetrics().elidedText(option->text, d->elideMode,
                        1 + (verticalTabs(d->shape) ? tab.rect.height() : tab.rect.width()) - hframe,
                        Qt::TextShowMnemonic);
#endif
}

/*!
    \class QTabBar
    \brief The QTabBar class provides a tab bar, e.g. for use in tabbed dialogs.

    \ingroup advanced
    \mainclass

    QTabBar is straightforward to use; it draws the tabs using one of
    the predefined \link QTabBar::Shape shapes\endlink, and emits a
    signal when a tab is selected. It can be subclassed to tailor the
    look and feel. Qt also provides a ready-made \l{QTabWidget}.

    Each tab has a tabText(), an optional tabIcon(), an optional
    tabToolTip(), optional tabWhatsThis() and optional tabData().
    The tabs's attributes can be changed with setTabText(), setTabIcon(),
    setTabToolTip(), setTabWhatsThis and setTabData(). Each tabs can be
    enabled or disabled individually with setTabEnabled().

    Each tab can display text in a distinct color. The current text color
    for a tab can be found with the tabTextColor() function. Set the text
    color for a particular tab with setTabTextColor().

    Tabs are added using addTab(), or inserted at particular positions
    using insertTab(). The total number of tabs is given by
    count(). Tabs can be removed from the tab bar with
    removeTab(). Combining removeTab() and insertTab() allows you to
    move tabs to different positions.

    The \l shape property defines the tabs' appearance. The choice of
    shape is a matter of taste, although tab dialogs (for preferences
    and similar) invariably use \l RoundedNorth.
    Tab controls in windows other than dialogs almost
    always use either \l RoundedSouth or \l TriangularSouth. Many
    spreadsheets and other tab controls in which all the pages are
    essentially similar use \l TriangularSouth, whereas \l
    RoundedSouth is used mostly when the pages are different (e.g. a
    multi-page tool palette). The default in QTabBar is \l
    RoundedNorth.

    The most important part of QTabBar's API is the currentChanged()
    signal.  This is emitted whenever the current tab changes (even at
    startup, when the current tab changes from 'none'). There is also
    a slot, setCurrentIndex(), which can be used to select a tab
    programmatically. The function currentIndex() returns the index of
    the current tab, \l count holds the number of tabs.

    QTabBar creates automatic mnemonic keys in the manner of QAbstractButton;
    e.g. if a tab's label is "\&Graphics", Alt+G becomes a shortcut
    key for switching to that tab.

    The following virtual functions may need to be reimplemented in
    order to tailor the look and feel or store extra data with each
    tab:

    \list
    \i tabSizeHint() calcuates the size of a tab.
    \i tabInserted() notifies that a new tab was added.
    \i tabRemoved() notifies that a tab was removed.
    \i tabLayoutChange() notifies that the tabs have been re-laid out.
    \i paintEvent() paints all tabs.
    \endlist

    For subclasses, you might also need the tabRect() functions which
    returns the visual geometry of a single tab.

    \table 100%
    \row \o \inlineimage plastique-tabbar.png Screenshot of a Plastique style tab bar
         \o A tab bar shown in the Plastique widget style.
    \row \o \inlineimage plastique-tabbar-truncated.png Screenshot of a truncated Plastique tab bar
         \o A truncated tab bar shown in the Plastique widget style.
    \endtable

    \sa QTabWidget
*/

/*!
    \enum QTabBar::Shape

    This enum type lists the built-in shapes supported by QTabBar. Treat these
    as hints as some styles may not render some of the shapes. However,
    position should be honored.

    \value RoundedNorth  The normal rounded look above the pages

    \value RoundedSouth  The normal rounded look below the pages

    \value RoundedWest  The normal rounded look on the left side of the pages

    \value RoundedEast  The normal rounded look on the right side the pages

    \value TriangularNorth  Triangular tabs above the pages.

    \value TriangularSouth  Triangular tabs similar to those used in
    the Excel spreadsheet, for example

    \value TriangularWest  Triangular tabs on the left of the pages.

    \value TriangularEast  Triangular tabs on the right of the pages.
    \omitvalue RoundedAbove
    \omitvalue RoundedBelow
    \omitvalue TriangularAbove
    \omitvalue TriangularBelow
*/

/*!
    \fn void QTabBar::currentChanged(int index)

    This signal is emitted when the tab bar's current tab changes. The
    new current has the given \a index.
*/

int QTabBarPrivate::extraWidth() const
{
    Q_Q(const QTabBar);
    return 2 * qMax(q->style()->pixelMetric(QStyle::PM_TabBarScrollButtonWidth, 0, q),
                    QApplication::globalStrut().width());
}

void QTabBarPrivate::init()
{
    Q_Q(QTabBar);
    leftB = new QToolButton(q);
    leftB->setAutoRepeat(true);
    QObject::connect(leftB, SIGNAL(clicked()), q, SLOT(_q_scrollTabs()));
    leftB->hide();
    rightB = new QToolButton(q);
    rightB->setAutoRepeat(true);
    QObject::connect(rightB, SIGNAL(clicked()), q, SLOT(_q_scrollTabs()));
    rightB->hide();
#ifdef QT_KEYPAD_NAVIGATION
    if (QApplication::keypadNavigationEnabled()) {
        leftB->setFocusPolicy(Qt::NoFocus);
        rightB->setFocusPolicy(Qt::NoFocus);
        q->setFocusPolicy(Qt::NoFocus);
    } else
#endif
    q->setFocusPolicy(Qt::TabFocus);
    q->setSizePolicy(QSizePolicy::Preferred, QSizePolicy::Fixed);
    elideMode = Qt::TextElideMode(q->style()->styleHint(QStyle::SH_TabBar_ElideMode, 0, q));
    useScrollButtons = !q->style()->styleHint(QStyle::SH_TabBar_PreferNoArrows, 0, q);
}

QTabBarPrivate::Tab *QTabBarPrivate::at(int index)
{
    return validIndex(index)?&tabList[index]:0;
}

const QTabBarPrivate::Tab *QTabBarPrivate::at(int index) const
{
    return validIndex(index)?&tabList[index]:0;
}

int QTabBarPrivate::indexAtPos(const QPoint &p) const
{
    Q_Q(const QTabBar);
    if (q->tabRect(currentIndex).contains(p))
        return currentIndex;
    for (int i = 0; i < tabList.count(); ++i)
        if (tabList.at(i).enabled && q->tabRect(i).contains(p))
            return i;
    return -1;
}

void QTabBarPrivate::layoutTabs()
{
    Q_Q(QTabBar);
    scrollOffset = 0;
    layoutDirty = false;
    QSize size = q->size();
    int last, available;
    int maxExtent;
    int i;
    bool vertTabs = verticalTabs(shape);
    int tabChainIndex = 0;
    Qt::Alignment tabAlignment = Qt::Alignment(q->style()->styleHint(QStyle::SH_TabBar_Alignment, 0, q));
    QVector<QLayoutStruct> tabChain(tabList.count() + 2);

    // We put an empty item at the front and back and set its expansive attribute
    // depending on tabAlignment.
    tabChain[tabChainIndex].init();
    tabChain[tabChainIndex].expansive = tabAlignment != Qt::AlignLeft;
    tabChain[tabChainIndex].empty = true;
    ++tabChainIndex;

    // We now go through our list of tabs and set the minimum size and the size hint
    // This will allow us to elide text if necessary. Since we don't set
    // a maximum size, tabs will EXPAND to fill up the empty space.
    // Since tab widget is rather *ahem* strict about keeping the geometry of the
    // tab bar to its absolute minimum, this won't bleed through, but will show up
    // if you use tab bar on its own (a.k.a. not a bug, but a feature).
    // Update: if squeezeTabs is true, we DO set a maximum size to prevent the tabs
    // being wider than necessary.
    if (!vertTabs) {
        int minx = 0;
        int x = 0;
        int maxHeight = 0;
        for (i = 0; i < tabList.count(); ++i, ++tabChainIndex) {
            QSize sz = q->tabSizeHint(i);
            tabList[i].maxRect = QRect(x, 0, sz.width(), sz.height());
            x += sz.width();
            maxHeight = qMax(maxHeight, sz.height());
            sz = minimumTabSizeHint(i);
            tabList[i].minRect = QRect(minx, 0, sz.width(), sz.height());
            minx += sz.width();
            tabChain[tabChainIndex].init();
            tabChain[tabChainIndex].sizeHint = tabList.at(i).maxRect.width();
            tabChain[tabChainIndex].minimumSize = sz.width();
            tabChain[tabChainIndex].empty = false;
            tabChain[tabChainIndex].expansive = true;

            if (squeezeTabs)
                tabChain[tabChainIndex].maximumSize = tabChain[tabChainIndex].sizeHint;
        }

        last = minx;
        available = size.width();
        maxExtent = maxHeight;
    } else {
        int miny = 0;
        int y = 0;
        int maxWidth = 0;
        for (i = 0; i < tabList.count(); ++i, ++tabChainIndex) {
            QSize sz = q->tabSizeHint(i);
            tabList[i].maxRect = QRect(0, y, sz.width(), sz.height());
            y += sz.height();
            maxWidth = qMax(0, sz.width());
            sz = minimumTabSizeHint(i);
            tabList[i].minRect = QRect(0, miny, sz.width(), sz.height());
            miny += sz.height();
            tabChain[tabChainIndex].init();
            tabChain[tabChainIndex].sizeHint = tabList.at(i).maxRect.height();
            tabChain[tabChainIndex].minimumSize = sz.height();
            tabChain[tabChainIndex].empty = false;
            tabChain[tabChainIndex].expansive = true;

            if (squeezeTabs)
                tabChain[tabChainIndex].maximumSize = tabChain[tabChainIndex].sizeHint;
        }

        last = miny;
        available = size.height();
        maxExtent = maxWidth;
    }

    Q_ASSERT(tabChainIndex == tabChain.count() - 1); // add an assert just to make sure.
    // Mirror our front item.
    tabChain[tabChainIndex].init();
    tabChain[tabChainIndex].expansive = tabAlignment != Qt::AlignRight;
    tabChain[tabChainIndex].empty = true;

    // Do the calculation
    qGeomCalc(tabChain, 0, tabChain.count(), 0, qMax(available, last), 0);

    // Use the results
    for (i = 0; i < tabList.count(); ++i) {
        const QLayoutStruct &lstruct = tabChain.at(i + 1);
        if (!vertTabs)
            tabList[i].rect.setRect(lstruct.pos, 0, lstruct.size, maxExtent);
        else
            tabList[i].rect.setRect(0, lstruct.pos, maxExtent, lstruct.size);
    }

    if (useScrollButtons && tabList.count() && last > available) {
        int extra = extraWidth();
        if (!vertTabs) {
            Qt::LayoutDirection ld = q->layoutDirection();
            QRect arrows = QStyle::visualRect(ld, q->rect(),
                                              QRect(available - extra, 0, extra, size.height()));
            if (ld == Qt::LeftToRight) {
                leftB->setGeometry(arrows.left(), arrows.top(), extra/2, arrows.height());
                rightB->setGeometry(arrows.right() - extra/2 + 1, arrows.top(),
                                    extra/2, arrows.height());
                leftB->setArrowType(Qt::LeftArrow);
                rightB->setArrowType(Qt::RightArrow);
            } else {
                rightB->setGeometry(arrows.left(), arrows.top(), extra/2, arrows.height());
                leftB->setGeometry(arrows.right() - extra/2 + 1, arrows.top(),
                                    extra/2, arrows.height());
                rightB->setArrowType(Qt::LeftArrow);
                leftB->setArrowType(Qt::RightArrow);
            }
        } else {
            QRect arrows = QRect(0, available - extra, size.width(), extra );
            leftB->setGeometry(arrows.left(), arrows.top(), arrows.width(), extra/2);
            leftB->setArrowType(Qt::UpArrow);
            rightB->setGeometry(arrows.left(), arrows.bottom() - extra/2 + 1,
                                arrows.width(), extra/2);
            rightB->setArrowType(Qt::DownArrow);
        }
        leftB->setEnabled(scrollOffset > 0);
        rightB->setEnabled(last - scrollOffset >= available - extra);
        leftB->show();
        rightB->show();
    } else {
        rightB->hide();
        leftB->hide();
    }

    q->tabLayoutChange();
}

void QTabBarPrivate::makeVisible(int index)
{
    Q_Q(QTabBar);
    if (!validIndex(index) || leftB->isHidden())
        return;
    const QRect tabRect = tabList.at(index).rect;

    const int oldScrollOffset = scrollOffset;
    const bool horiz = !verticalTabs(shape);
    const int available = (horiz ? q->width() : q->height()) - extraWidth();
    const int start = horiz ? tabRect.left() : tabRect.top();
    const int end = horiz ? tabRect.right() : tabRect.bottom();
    if (start < scrollOffset) // too far left
        scrollOffset = start - (index?8:0);
    else if (end > scrollOffset + available) // too far right
        scrollOffset = end - available + 1;

    leftB->setEnabled(scrollOffset > 0);
    const int last = horiz ? tabList.last().rect.right() : tabList.last().rect.bottom();
    rightB->setEnabled(last - scrollOffset >= available);
    if (oldScrollOffset != scrollOffset)
        q->update();
}

void QTabBarPrivate::_q_scrollTabs()
{
    Q_Q(QTabBar);
    const QObject *sender = q->sender();
    int i = -1;
    if (!verticalTabs(shape)) {
        if (sender == leftB) {
            for (i = tabList.count() - 1; i >= 0; --i) {
                if (tabList.at(i).rect.left() - scrollOffset < 0) {
                    makeVisible(i);
                    return;
                }
            }