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katie/src/gui/widgets/qabstractscrollarea.cpp
Ivailo Monev bfbc380756 initial import 
Signed-off-by: Ivailo Monev <xakepa10@gmail.com>
2015-12-10 05:06:13 +02:00

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/****************************************************************************
**
** Copyright (C) 2015 The Qt Company Ltd.
** Contact: http://www.qt.io/licensing/
**
** This file is part of the QtGui module of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:LGPL$
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****************************************************************************/
#include "qabstractscrollarea.h"
#ifndef QT_NO_SCROLLAREA
#include "qscrollbar.h"
#include "qapplication.h"
#include "qstyle.h"
#include "qstyleoption.h"
#include "qevent.h"
#include "qdebug.h"
#include "qboxlayout.h"
#include "qpainter.h"
#include "qmargins.h"
#include "qabstractscrollarea_p.h"
#include <qwidget.h>
#include <qapplication_p.h>
#ifdef Q_WS_MAC
#include <qt_mac_p.h>
#include <qt_cocoa_helpers_mac_p.h>
#endif
QT_BEGIN_NAMESPACE
/*!
\class QAbstractScrollArea
\brief The QAbstractScrollArea widget provides a scrolling area with
on-demand scroll bars.
\ingroup abstractwidgets
QAbstractScrollArea is a low-level abstraction of a scrolling
area. The area provides a central widget called the viewport, in
which the contents of the area is to be scrolled (i.e, the
visible parts of the contents are rendered in the viewport).
Next to the viewport is a vertical scroll bar, and below is a
horizontal scroll bar. When all of the area contents fits in the
viewport, each scroll bar can be either visible or hidden
depending on the scroll bar's Qt::ScrollBarPolicy. When a scroll
bar is hidden, the viewport expands in order to cover all
available space. When a scroll bar becomes visible again, the
viewport shrinks in order to make room for the scroll bar.
It is possible to reserve a margin area around the viewport, see
setViewportMargins(). The feature is mostly used to place a
QHeaderView widget above or beside the scrolling area. Subclasses
of QAbstractScrollArea should implement margins.
When inheriting QAbstractScrollArea, you need to do the
following:
\list
\o Control the scroll bars by setting their
range, value, page step, and tracking their
movements.
\o Draw the contents of the area in the viewport according
to the values of the scroll bars.
\o Handle events received by the viewport in
viewportEvent() - notably resize events.
\o Use \c{viewport->update()} to update the contents of the
viewport instead of \l{QWidget::update()}{update()}
as all painting operations take place on the viewport.
\endlist
With a scroll bar policy of Qt::ScrollBarAsNeeded (the default),
QAbstractScrollArea shows scroll bars when they provide a non-zero
scrolling range, and hides them otherwise.
The scroll bars and viewport should be updated whenever the viewport
receives a resize event or the size of the contents changes.
The viewport also needs to be updated when the scroll bars
values change. The initial values of the scroll bars are often
set when the area receives new contents.
We give a simple example, in which we have implemented a scroll area
that can scroll any QWidget. We make the widget a child of the
viewport; this way, we do not have to calculate which part of
the widget to draw but can simply move the widget with
QWidget::move(). When the area contents or the viewport size
changes, we do the following:
\snippet doc/src/snippets/myscrollarea.cpp 1
When the scroll bars change value, we need to update the widget
position, i.e., find the part of the widget that is to be drawn in
the viewport:
\snippet doc/src/snippets/myscrollarea.cpp 0
In order to track scroll bar movements, reimplement the virtual
function scrollContentsBy(). In order to fine-tune scrolling
behavior, connect to a scroll bar's
QAbstractSlider::actionTriggered() signal and adjust the \l
QAbstractSlider::sliderPosition as you wish.
For convenience, QAbstractScrollArea makes all viewport events
available in the virtual viewportEvent() handler. QWidget's
specialized handlers are remapped to viewport events in the cases
where this makes sense. The remapped specialized handlers are:
paintEvent(), mousePressEvent(), mouseReleaseEvent(),
mouseDoubleClickEvent(), mouseMoveEvent(), wheelEvent(),
dragEnterEvent(), dragMoveEvent(), dragLeaveEvent(), dropEvent(),
contextMenuEvent(), and resizeEvent().
QScrollArea, which inherits QAbstractScrollArea, provides smooth
scrolling for any QWidget (i.e., the widget is scrolled pixel by
pixel). You only need to subclass QAbstractScrollArea if you need
more specialized behavior. This is, for instance, true if the
entire contents of the area is not suitable for being drawn on a
QWidget or if you do not want smooth scrolling.
\sa QScrollArea
*/
QAbstractScrollAreaPrivate::QAbstractScrollAreaPrivate()
:hbar(0), vbar(0), vbarpolicy(Qt::ScrollBarAsNeeded), hbarpolicy(Qt::ScrollBarAsNeeded),
viewport(0), cornerWidget(0), left(0), top(0), right(0), bottom(0),
xoffset(0), yoffset(0), viewportFilter(0)
#ifdef Q_WS_WIN
, singleFingerPanEnabled(false)
#endif
{
}
QAbstractScrollAreaScrollBarContainer::QAbstractScrollAreaScrollBarContainer(Qt::Orientation orientation, QWidget *parent)
:QWidget(parent), scrollBar(new QScrollBar(orientation, this)),
layout(new QBoxLayout(orientation == Qt::Horizontal ? QBoxLayout::LeftToRight : QBoxLayout::TopToBottom)),
orientation(orientation)
{
setLayout(layout);
layout->setMargin(0);
layout->setSpacing(0);
layout->addWidget(scrollBar);
}
/*! \internal
Adds a widget to the scroll bar container.
*/
void QAbstractScrollAreaScrollBarContainer::addWidget(QWidget *widget, LogicalPosition position)
{
QSizePolicy policy = widget->sizePolicy();
if (orientation == Qt::Vertical)
policy.setHorizontalPolicy(QSizePolicy::Ignored);
else
policy.setVerticalPolicy(QSizePolicy::Ignored);
widget->setSizePolicy(policy);
widget->setParent(this);
const int insertIndex = (position & LogicalLeft) ? 0 : scrollBarLayoutIndex() + 1;
layout->insertWidget(insertIndex, widget);
}
/*! \internal
Retuns a list of scroll bar widgets for the given position. The scroll bar
itself is not returned.
*/
QWidgetList QAbstractScrollAreaScrollBarContainer::widgets(LogicalPosition position)
{
QWidgetList list;
const int scrollBarIndex = scrollBarLayoutIndex();
if (position == LogicalLeft) {
for (int i = 0; i < scrollBarIndex; ++i)
list.append(layout->itemAt(i)->widget());
} else if (position == LogicalRight) {
const int layoutItemCount = layout->count();
for (int i = scrollBarIndex + 1; i < layoutItemCount; ++i)
list.append(layout->itemAt(i)->widget());
}
return list;
}
/*! \internal
Returns the layout index for the scroll bar. This needs to be
recalculated by a linear search for each use, since items in
the layout can be removed at any time (i.e. when a widget is
deleted or re-parented).
*/
int QAbstractScrollAreaScrollBarContainer::scrollBarLayoutIndex() const
{
const int layoutItemCount = layout->count();
for (int i = 0; i < layoutItemCount; ++i) {
if (qobject_cast<QScrollBar *>(layout->itemAt(i)->widget()))
return i;
}
return -1;
}
/*! \internal
*/
void QAbstractScrollAreaPrivate::replaceScrollBar(QScrollBar *scrollBar,
Qt::Orientation orientation)
{
Q_Q(QAbstractScrollArea);
QAbstractScrollAreaScrollBarContainer *container = scrollBarContainers[orientation];
bool horizontal = (orientation == Qt::Horizontal);
QScrollBar *oldBar = horizontal ? hbar : vbar;
if (horizontal)
hbar = scrollBar;
else
vbar = scrollBar;
scrollBar->setParent(container);
container->scrollBar = scrollBar;
container->layout->removeWidget(oldBar);
container->layout->insertWidget(0, scrollBar);
scrollBar->setVisible(oldBar->isVisibleTo(container));
scrollBar->setInvertedAppearance(oldBar->invertedAppearance());
scrollBar->setInvertedControls(oldBar->invertedControls());
scrollBar->setRange(oldBar->minimum(), oldBar->maximum());
scrollBar->setOrientation(oldBar->orientation());
scrollBar->setPageStep(oldBar->pageStep());
scrollBar->setSingleStep(oldBar->singleStep());
scrollBar->setSliderDown(oldBar->isSliderDown());
scrollBar->setSliderPosition(oldBar->sliderPosition());
scrollBar->setTracking(oldBar->hasTracking());
scrollBar->setValue(oldBar->value());
delete oldBar;
QObject::connect(scrollBar, SIGNAL(valueChanged(int)),
q, horizontal ? SLOT(_q_hslide(int)) : SLOT(_q_vslide(int)));
QObject::connect(scrollBar, SIGNAL(rangeChanged(int,int)),
q, SLOT(_q_showOrHideScrollBars()), Qt::QueuedConnection);
}
void QAbstractScrollAreaPrivate::init()
{
Q_Q(QAbstractScrollArea);
viewport = new QWidget(q);
viewport->setObjectName(QLatin1String("qt_scrollarea_viewport"));
viewport->setBackgroundRole(QPalette::Base);
viewport->setAutoFillBackground(true);
scrollBarContainers[Qt::Horizontal] = new QAbstractScrollAreaScrollBarContainer(Qt::Horizontal, q);
scrollBarContainers[Qt::Horizontal]->setObjectName(QLatin1String("qt_scrollarea_hcontainer"));
hbar = scrollBarContainers[Qt::Horizontal]->scrollBar;
hbar->setRange(0,0);
scrollBarContainers[Qt::Horizontal]->setVisible(false);
QObject::connect(hbar, SIGNAL(valueChanged(int)), q, SLOT(_q_hslide(int)));
QObject::connect(hbar, SIGNAL(rangeChanged(int,int)), q, SLOT(_q_showOrHideScrollBars()), Qt::QueuedConnection);
scrollBarContainers[Qt::Vertical] = new QAbstractScrollAreaScrollBarContainer(Qt::Vertical, q);
scrollBarContainers[Qt::Vertical]->setObjectName(QLatin1String("qt_scrollarea_vcontainer"));
vbar = scrollBarContainers[Qt::Vertical]->scrollBar;
vbar->setRange(0,0);
scrollBarContainers[Qt::Vertical]->setVisible(false);
QObject::connect(vbar, SIGNAL(valueChanged(int)), q, SLOT(_q_vslide(int)));
QObject::connect(vbar, SIGNAL(rangeChanged(int,int)), q, SLOT(_q_showOrHideScrollBars()), Qt::QueuedConnection);
viewportFilter.reset(new QAbstractScrollAreaFilter(this));
viewport->installEventFilter(viewportFilter.data());
viewport->setFocusProxy(q);
q->setFocusPolicy(Qt::WheelFocus);
q->setFrameStyle(QFrame::StyledPanel | QFrame::Sunken);
q->setSizePolicy(QSizePolicy::Expanding, QSizePolicy::Expanding);
layoutChildren();
#ifndef Q_WS_MAC
#ifndef QT_NO_GESTURES
viewport->grabGesture(Qt::PanGesture);
#endif
#endif
}
#ifdef Q_WS_WIN
void QAbstractScrollAreaPrivate::setSingleFingerPanEnabled(bool on)
{
singleFingerPanEnabled = on;
QWidgetPrivate *dd = static_cast<QWidgetPrivate *>(QObjectPrivate::get(viewport));
if (dd)
dd->winSetupGestures();
}
#endif // Q_WS_WIN
void QAbstractScrollAreaPrivate::layoutChildren()
{
Q_Q(QAbstractScrollArea);
bool needh = (hbarpolicy == Qt::ScrollBarAlwaysOn
|| (hbarpolicy == Qt::ScrollBarAsNeeded && hbar->minimum() < hbar->maximum()));
bool needv = (vbarpolicy == Qt::ScrollBarAlwaysOn
|| (vbarpolicy == Qt::ScrollBarAsNeeded && vbar->minimum() < vbar->maximum()));
#ifdef Q_WS_MAC
QWidget * const window = q->window();
// Use small scroll bars for tool windows, to match the native size grip.
bool hbarIsSmall = hbar->testAttribute(Qt::WA_MacSmallSize);
bool vbarIsSmall = vbar->testAttribute(Qt::WA_MacSmallSize);
const Qt::WindowType windowType = window->windowType();
if (windowType == Qt::Tool) {
if (!hbarIsSmall) {
hbar->setAttribute(Qt::WA_MacMiniSize, false);
hbar->setAttribute(Qt::WA_MacNormalSize, false);
hbar->setAttribute(Qt::WA_MacSmallSize, true);
}
if (!vbarIsSmall) {
vbar->setAttribute(Qt::WA_MacMiniSize, false);
vbar->setAttribute(Qt::WA_MacNormalSize, false);
vbar->setAttribute(Qt::WA_MacSmallSize, true);
}
} else {
if (hbarIsSmall) {
hbar->setAttribute(Qt::WA_MacMiniSize, false);
hbar->setAttribute(Qt::WA_MacNormalSize, false);
hbar->setAttribute(Qt::WA_MacSmallSize, false);
}
if (vbarIsSmall) {
vbar->setAttribute(Qt::WA_MacMiniSize, false);
vbar->setAttribute(Qt::WA_MacNormalSize, false);
vbar->setAttribute(Qt::WA_MacSmallSize, false);
}
}
#endif
const int hsbExt = hbar->sizeHint().height();
const int vsbExt = vbar->sizeHint().width();
const QPoint extPoint(vsbExt, hsbExt);
const QSize extSize(vsbExt, hsbExt);
const QRect widgetRect = q->rect();
QStyleOption opt(0);
opt.init(q);
const bool hasCornerWidget = (cornerWidget != 0);
// If the scroll bars are at the very right and bottom of the window we
// move their positions to be aligned with the size grip.
#ifdef Q_WS_MAC
// Check if a native sizegrip is present.
bool hasMacReverseSizeGrip = false;
bool hasMacSizeGrip = false;
bool nativeGripPresent = false;
if (q->testAttribute(Qt::WA_WState_Created))
nativeGripPresent = qt_mac_checkForNativeSizeGrip(q);
if (nativeGripPresent) {
// Look for a native size grip at the visual window bottom right and at the
// absolute window bottom right. In reverse mode, the native size grip does not
// swich side, so we need to check if it is on the "wrong side".
const QPoint scrollAreaBottomRight = q->mapTo(window, widgetRect.bottomRight() - QPoint(frameWidth, frameWidth));
const QPoint windowBottomRight = window->rect().bottomRight();
const QPoint visualWindowBottomRight = QStyle::visualPos(opt.direction, opt.rect, windowBottomRight);
const QPoint offset = windowBottomRight - scrollAreaBottomRight;
const QPoint visualOffset = visualWindowBottomRight - scrollAreaBottomRight;
hasMacSizeGrip = (visualOffset.manhattanLength() < vsbExt);
hasMacReverseSizeGrip = (hasMacSizeGrip == false && (offset.manhattanLength() < hsbExt));
}
#endif
QPoint cornerOffset(needv ? vsbExt : 0, needh ? hsbExt : 0);
QRect controlsRect;
QRect viewportRect;
// In FrameOnlyAroundContents mode the frame is drawn between the controls and
// the viewport, else the frame rect is equal to the widget rect.
if ((frameStyle != QFrame::NoFrame) &&
q->style()->styleHint(QStyle::SH_ScrollView_FrameOnlyAroundContents, &opt, q)) {
controlsRect = widgetRect;
const int extra = q->style()->pixelMetric(QStyle::PM_ScrollView_ScrollBarSpacing, &opt, q);
const QPoint cornerExtra(needv ? extra : 0, needh ? extra : 0);
QRect frameRect = widgetRect;
frameRect.adjust(0, 0, -cornerOffset.x() - cornerExtra.x(), -cornerOffset.y() - cornerExtra.y());
q->setFrameRect(QStyle::visualRect(opt.direction, opt.rect, frameRect));
// The frame rect needs to be in logical coords, however we need to flip
// the contentsRect back before passing it on to the viewportRect
// since the viewportRect has its logical coords calculated later.
viewportRect = QStyle::visualRect(opt.direction, opt.rect, q->contentsRect());
} else {
q->setFrameRect(QStyle::visualRect(opt.direction, opt.rect, widgetRect));
controlsRect = q->contentsRect();
viewportRect = QRect(controlsRect.topLeft(), controlsRect.bottomRight() - cornerOffset);
}
// If we have a corner widget and are only showing one scroll bar, we need to move it
// to make room for the corner widget.
if (hasCornerWidget && (needv || needh))
cornerOffset = extPoint;
#ifdef Q_WS_MAC
// Also move the scroll bars if they are covered by the native Mac size grip.
if (hasMacSizeGrip)
cornerOffset = extPoint;
#endif
// The corner point is where the scroll bar rects, the corner widget rect and the
// viewport rect meets.
const QPoint cornerPoint(controlsRect.bottomRight() + QPoint(1, 1) - cornerOffset);
// Some styles paints the corner if both scorllbars are showing and there is
// no corner widget. Also, on the Mac we paint if there is a native
// (transparent) sizegrip in the area where a corner widget would be.
if ((needv && needh && hasCornerWidget == false)
|| ((needv || needh)
#ifdef Q_WS_MAC
&& hasMacSizeGrip
#endif
)
) {
cornerPaintingRect = QStyle::visualRect(opt.direction, opt.rect, QRect(cornerPoint, extSize));
} else {
cornerPaintingRect = QRect();
}
#ifdef Q_WS_MAC
if (hasMacReverseSizeGrip)
reverseCornerPaintingRect = QRect(controlsRect.bottomRight() + QPoint(1, 1) - extPoint, extSize);
else
reverseCornerPaintingRect = QRect();
#endif
if (needh) {
QRect horizontalScrollBarRect(QPoint(controlsRect.left(), cornerPoint.y()), QPoint(cornerPoint.x() - 1, controlsRect.bottom()));
#ifdef Q_WS_MAC
if (hasMacReverseSizeGrip)
horizontalScrollBarRect.adjust(vsbExt, 0, 0, 0);
#endif
scrollBarContainers[Qt::Horizontal]->setGeometry(QStyle::visualRect(opt.direction, opt.rect, horizontalScrollBarRect));
scrollBarContainers[Qt::Horizontal]->raise();
}
if (needv) {
const QRect verticalScrollBarRect (QPoint(cornerPoint.x(), controlsRect.top()), QPoint(controlsRect.right(), cornerPoint.y() - 1));
scrollBarContainers[Qt::Vertical]->setGeometry(QStyle::visualRect(opt.direction, opt.rect, verticalScrollBarRect));
scrollBarContainers[Qt::Vertical]->raise();
}
if (cornerWidget) {
const QRect cornerWidgetRect(cornerPoint, controlsRect.bottomRight());
cornerWidget->setGeometry(QStyle::visualRect(opt.direction, opt.rect, cornerWidgetRect));
}
scrollBarContainers[Qt::Horizontal]->setVisible(needh);
scrollBarContainers[Qt::Vertical]->setVisible(needv);
if (q->isRightToLeft())
viewportRect.adjust(right, top, -left, -bottom);
else
viewportRect.adjust(left, top, -right, -bottom);
viewport->setGeometry(QStyle::visualRect(opt.direction, opt.rect, viewportRect)); // resize the viewport last
}
/*!
\internal
Creates a new QAbstractScrollAreaPrivate, \a dd with the given \a parent.
*/
QAbstractScrollArea::QAbstractScrollArea(QAbstractScrollAreaPrivate &dd, QWidget *parent)
:QFrame(dd, parent)
{
Q_D(QAbstractScrollArea);
QT_TRY {
d->init();
} QT_CATCH(...) {
d->viewportFilter.reset();
QT_RETHROW;
}
}
/*!
Constructs a viewport.
The \a parent argument is sent to the QWidget constructor.
*/
QAbstractScrollArea::QAbstractScrollArea(QWidget *parent)
:QFrame(*new QAbstractScrollAreaPrivate, parent)
{
Q_D(QAbstractScrollArea);
QT_TRY {
d->init();
} QT_CATCH(...) {
d->viewportFilter.reset();
QT_RETHROW;
}
}
/*!
Destroys the viewport.
*/
QAbstractScrollArea::~QAbstractScrollArea()
{
Q_D(QAbstractScrollArea);
// reset it here, otherwise we'll have a dangling pointer in ~QWidget
d->viewportFilter.reset();
}
/*!
\since 4.2
Sets the viewport to be the given \a widget.
The QAbstractScrollArea will take ownership of the given \a widget.
If \a widget is 0, QAbstractScrollArea will assign a new QWidget instance
for the viewport.
\sa viewport()
*/
void QAbstractScrollArea::setViewport(QWidget *widget)
{
Q_D(QAbstractScrollArea);
if (widget != d->viewport) {
QWidget *oldViewport = d->viewport;
if (!widget)
widget = new QWidget;
d->viewport = widget;
d->viewport->setParent(this);
d->viewport->setFocusProxy(this);
d->viewport->installEventFilter(d->viewportFilter.data());
#ifndef Q_WS_MAC
#ifndef QT_NO_GESTURES
d->viewport->grabGesture(Qt::PanGesture);
#endif
#endif
d->layoutChildren();
if (isVisible())
d->viewport->show();
QMetaObject::invokeMethod(this, "setupViewport", Q_ARG(QWidget *, widget));
delete oldViewport;
}
}
/*!
Returns the viewport widget.
Use the QScrollArea::widget() function to retrieve the contents of
the viewport widget.
\sa QScrollArea::widget()
*/
QWidget *QAbstractScrollArea::viewport() const
{
Q_D(const QAbstractScrollArea);
return d->viewport;
}
/*!
Returns the size of the viewport as if the scroll bars had no valid
scrolling range.
*/
// ### still thinking about the name
QSize QAbstractScrollArea::maximumViewportSize() const
{
Q_D(const QAbstractScrollArea);
int hsbExt = d->hbar->sizeHint().height();
int vsbExt = d->vbar->sizeHint().width();
int f = 2 * d->frameWidth;
QSize max = size() - QSize(f + d->left + d->right, f + d->top + d->bottom);
if (d->vbarpolicy == Qt::ScrollBarAlwaysOn)
max.rwidth() -= vsbExt;
if (d->hbarpolicy == Qt::ScrollBarAlwaysOn)
max.rheight() -= hsbExt;
return max;
}
/*!
\property QAbstractScrollArea::verticalScrollBarPolicy
\brief the policy for the vertical scroll bar
The default policy is Qt::ScrollBarAsNeeded.
\sa horizontalScrollBarPolicy
*/
Qt::ScrollBarPolicy QAbstractScrollArea::verticalScrollBarPolicy() const
{
Q_D(const QAbstractScrollArea);
return d->vbarpolicy;
}
void QAbstractScrollArea::setVerticalScrollBarPolicy(Qt::ScrollBarPolicy policy)
{
Q_D(QAbstractScrollArea);
const Qt::ScrollBarPolicy oldPolicy = d->vbarpolicy;
d->vbarpolicy = policy;
if (isVisible())
d->layoutChildren();
if (oldPolicy != d->vbarpolicy)
d->scrollBarPolicyChanged(Qt::Vertical, d->vbarpolicy);
}
/*!
Returns the vertical scroll bar.
\sa verticalScrollBarPolicy, horizontalScrollBar()
*/
QScrollBar *QAbstractScrollArea::verticalScrollBar() const
{
Q_D(const QAbstractScrollArea);
return d->vbar;
}
/*!
\since 4.2
Replaces the existing vertical scroll bar with \a scrollBar, and sets all
the former scroll bar's slider properties on the new scroll bar. The former
scroll bar is then deleted.
QAbstractScrollArea already provides vertical and horizontal scroll bars by
default. You can call this function to replace the default vertical
scroll bar with your own custom scroll bar.
\sa verticalScrollBar(), setHorizontalScrollBar()
*/
void QAbstractScrollArea::setVerticalScrollBar(QScrollBar *scrollBar)
{
Q_D(QAbstractScrollArea);
if (!scrollBar) {
qWarning("QAbstractScrollArea::setVerticalScrollBar: Cannot set a null scroll bar");
return;
}
d->replaceScrollBar(scrollBar, Qt::Vertical);
}
/*!
\property QAbstractScrollArea::horizontalScrollBarPolicy
\brief the policy for the horizontal scroll bar
The default policy is Qt::ScrollBarAsNeeded.
\sa verticalScrollBarPolicy
*/
Qt::ScrollBarPolicy QAbstractScrollArea::horizontalScrollBarPolicy() const
{
Q_D(const QAbstractScrollArea);
return d->hbarpolicy;
}
void QAbstractScrollArea::setHorizontalScrollBarPolicy(Qt::ScrollBarPolicy policy)
{
Q_D(QAbstractScrollArea);
const Qt::ScrollBarPolicy oldPolicy = d->hbarpolicy;
d->hbarpolicy = policy;
if (isVisible())
d->layoutChildren();
if (oldPolicy != d->hbarpolicy)
d->scrollBarPolicyChanged(Qt::Horizontal, d->hbarpolicy);
}
/*!
Returns the horizontal scroll bar.
\sa horizontalScrollBarPolicy, verticalScrollBar()
*/
QScrollBar *QAbstractScrollArea::horizontalScrollBar() const
{
Q_D(const QAbstractScrollArea);
return d->hbar;
}
/*!
\since 4.2
Replaces the existing horizontal scroll bar with \a scrollBar, and sets all
the former scroll bar's slider properties on the new scroll bar. The former
scroll bar is then deleted.
QAbstractScrollArea already provides horizontal and vertical scroll bars by
default. You can call this function to replace the default horizontal
scroll bar with your own custom scroll bar.
\sa horizontalScrollBar(), setVerticalScrollBar()
*/
void QAbstractScrollArea::setHorizontalScrollBar(QScrollBar *scrollBar)
{
Q_D(QAbstractScrollArea);
if (!scrollBar) {
qWarning("QAbstractScrollArea::setHorizontalScrollBar: Cannot set a null scroll bar");
return;
}
d->replaceScrollBar(scrollBar, Qt::Horizontal);
}
/*!
\since 4.2
Returns the widget in the corner between the two scroll bars.
By default, no corner widget is present.
*/
QWidget *QAbstractScrollArea::cornerWidget() const
{
Q_D(const QAbstractScrollArea);
return d->cornerWidget;
}
/*!
\since 4.2
Sets the widget in the corner between the two scroll bars to be
\a widget.
You will probably also want to set at least one of the scroll bar
modes to \c AlwaysOn.
Passing 0 shows no widget in the corner.
Any previous corner widget is hidden.
You may call setCornerWidget() with the same widget at different
times.
All widgets set here will be deleted by the scroll area when it is
destroyed unless you separately reparent the widget after setting
some other corner widget (or 0).
Any \e newly set widget should have no current parent.
By default, no corner widget is present.
\sa horizontalScrollBarPolicy, horizontalScrollBarPolicy
*/
void QAbstractScrollArea::setCornerWidget(QWidget *widget)
{
Q_D(QAbstractScrollArea);
QWidget* oldWidget = d->cornerWidget;
if (oldWidget != widget) {
if (oldWidget)
oldWidget->hide();
d->cornerWidget = widget;
if (widget && widget->parentWidget() != this)
widget->setParent(this);
d->layoutChildren();
if (widget)
widget->show();
} else {
d->cornerWidget = widget;
d->layoutChildren();
}
}
/*!
\since 4.2
Adds \a widget as a scroll bar widget in the location specified
by \a alignment.
Scroll bar widgets are shown next to the horizontal or vertical
scroll bar, and can be placed on either side of it. If you want
the scroll bar widgets to be always visible, set the
scrollBarPolicy for the corresponding scroll bar to \c AlwaysOn.
\a alignment must be one of Qt::Alignleft and Qt::AlignRight,
which maps to the horizontal scroll bar, or Qt::AlignTop and
Qt::AlignBottom, which maps to the vertical scroll bar.
A scroll bar widget can be removed by either re-parenting the
widget or deleting it. It's also possible to hide a widget with
QWidget::hide()
The scroll bar widget will be resized to fit the scroll bar
geometry for the current style. The following describes the case
for scroll bar widgets on the horizontal scroll bar:
The height of the widget will be set to match the height of the
scroll bar. To control the width of the widget, use
QWidget::setMinimumWidth and QWidget::setMaximumWidth, or
implement QWidget::sizeHint() and set a horizontal size policy.
If you want a square widget, call
QStyle::pixelMetric(QStyle::PM_ScrollBarExtent) and set the
width to this value.
\sa scrollBarWidgets()
*/
void QAbstractScrollArea::addScrollBarWidget(QWidget *widget, Qt::Alignment alignment)
{
Q_D(QAbstractScrollArea);
if (widget == 0)
return;
const Qt::Orientation scrollBarOrientation
= ((alignment & Qt::AlignLeft) || (alignment & Qt::AlignRight)) ? Qt::Horizontal : Qt::Vertical;
const QAbstractScrollAreaScrollBarContainer::LogicalPosition position
= ((alignment & Qt::AlignRight) || (alignment & Qt::AlignBottom))
? QAbstractScrollAreaScrollBarContainer::LogicalRight : QAbstractScrollAreaScrollBarContainer::LogicalLeft;
d->scrollBarContainers[scrollBarOrientation]->addWidget(widget, position);
d->layoutChildren();
if (isHidden() == false)
widget->show();
}
/*!
\since 4.2
Returns a list of the currently set scroll bar widgets. \a alignment
can be any combination of the four location flags.
\sa addScrollBarWidget()
*/
QWidgetList QAbstractScrollArea::scrollBarWidgets(Qt::Alignment alignment)
{
Q_D(QAbstractScrollArea);
QWidgetList list;
if (alignment & Qt::AlignLeft)
list += d->scrollBarContainers[Qt::Horizontal]->widgets(QAbstractScrollAreaScrollBarContainer::LogicalLeft);
if (alignment & Qt::AlignRight)
list += d->scrollBarContainers[Qt::Horizontal]->widgets(QAbstractScrollAreaScrollBarContainer::LogicalRight);
if (alignment & Qt::AlignTop)
list += d->scrollBarContainers[Qt::Vertical]->widgets(QAbstractScrollAreaScrollBarContainer::LogicalLeft);
if (alignment & Qt::AlignBottom)
list += d->scrollBarContainers[Qt::Vertical]->widgets(QAbstractScrollAreaScrollBarContainer::LogicalRight);
return list;
}
/*!
Sets the margins around the scrolling area to \a left, \a top, \a
right and \a bottom. This is useful for applications such as
spreadsheets with "locked" rows and columns. The marginal space is
is left blank; put widgets in the unused area.
Note that this function is frequently called by QTreeView and
QTableView, so margins must be implemented by QAbstractScrollArea
subclasses. Also, if the subclasses are to be used in item views,
they should not call this function.
By default all margins are zero.
*/
void QAbstractScrollArea::setViewportMargins(int left, int top, int right, int bottom)
{
Q_D(QAbstractScrollArea);
d->left = left;
d->top = top;
d->right = right;
d->bottom = bottom;
d->layoutChildren();
}
/*!
\since 4.6
Sets \a margins around the scrolling area. This is useful for
applications such as spreadsheets with "locked" rows and columns.
The marginal space is is left blank; put widgets in the unused
area.
By default all margins are zero.
*/
void QAbstractScrollArea::setViewportMargins(const QMargins &margins)
{
setViewportMargins(margins.left(), margins.top(),
margins.right(), margins.bottom());
}
/*!
\fn bool QAbstractScrollArea::event(QEvent *event)
\reimp
This is the main event handler for the QAbstractScrollArea widget (\e not
the scrolling area viewport()). The specified \a event is a general event
object that may need to be cast to the appropriate class depending on its
type.
\sa QEvent::type()
*/
bool QAbstractScrollArea::event(QEvent *e)
{
Q_D(QAbstractScrollArea);
switch (e->type()) {
case QEvent::AcceptDropsChange:
// There was a chance that with accessibility client we get an
// event before the viewport was created.
// Also, in some cases we might get here from QWidget::event() virtual function which is (indirectly) called
// from the viewport constructor at the time when the d->viewport is not yet initialized even without any
// accessibility client. See qabstractscrollarea autotest for a test case.
if (d->viewport)
d->viewport->setAcceptDrops(acceptDrops());
break;
case QEvent::MouseTrackingChange:
d->viewport->setMouseTracking(hasMouseTracking());
break;
case QEvent::Resize:
d->layoutChildren();
break;
case QEvent::Paint: {
QStyleOption option;
option.initFrom(this);
if (d->cornerPaintingRect.isValid()) {
option.rect = d->cornerPaintingRect;
QPainter p(this);
style()->drawPrimitive(QStyle::PE_PanelScrollAreaCorner, &option, &p, this);
}
#ifdef Q_WS_MAC
if (d->reverseCornerPaintingRect.isValid()) {
option.rect = d->reverseCornerPaintingRect;
QPainter p(this);
style()->drawPrimitive(QStyle::PE_PanelScrollAreaCorner, &option, &p, this);
}
#endif
}
QFrame::paintEvent((QPaintEvent*)e);
break;
#ifndef QT_NO_CONTEXTMENU
case QEvent::ContextMenu:
if (static_cast<QContextMenuEvent *>(e)->reason() == QContextMenuEvent::Keyboard)
return QFrame::event(e);
e->ignore();
break;
#endif // QT_NO_CONTEXTMENU
case QEvent::MouseButtonPress:
case QEvent::MouseButtonRelease:
case QEvent::MouseButtonDblClick:
case QEvent::MouseMove:
case QEvent::Wheel:
#ifndef QT_NO_DRAGANDDROP
case QEvent::Drop:
case QEvent::DragEnter:
case QEvent::DragMove:
case QEvent::DragLeave:
#endif
// ignore touch events in case they have been propagated from the viewport
case QEvent::TouchBegin:
case QEvent::TouchUpdate:
case QEvent::TouchEnd:
return false;
#ifndef QT_NO_GESTURES
case QEvent::Gesture:
{
QGestureEvent *ge = static_cast<QGestureEvent *>(e);
QPanGesture *g = static_cast<QPanGesture *>(ge->gesture(Qt::PanGesture));
if (g) {
QScrollBar *hBar = horizontalScrollBar();
QScrollBar *vBar = verticalScrollBar();
QPointF delta = g->delta();
if (!delta.isNull()) {
if (QApplication::isRightToLeft())
delta.rx() *= -1;
int newX = hBar->value() - delta.x();
int newY = vBar->value() - delta.y();
hBar->setValue(newX);
vBar->setValue(newY);
}
return true;
}
return false;
}
#endif // QT_NO_GESTURES
case QEvent::StyleChange:
case QEvent::LayoutDirectionChange:
case QEvent::ApplicationLayoutDirectionChange:
case QEvent::LayoutRequest:
d->layoutChildren();
// fall through
default:
return QFrame::event(e);
}
return true;
}
/*!
\fn bool QAbstractScrollArea::viewportEvent(QEvent *event)
The main event handler for the scrolling area (the viewport() widget).
It handles the \a event specified, and can be called by subclasses to
provide reasonable default behavior.
Returns true to indicate to the event system that the event has been
handled, and needs no further processing; otherwise returns false to
indicate that the event should be propagated further.
You can reimplement this function in a subclass, but we recommend
using one of the specialized event handlers instead.
Specialized handlers for viewport events are: paintEvent(),
mousePressEvent(), mouseReleaseEvent(), mouseDoubleClickEvent(),
mouseMoveEvent(), wheelEvent(), dragEnterEvent(), dragMoveEvent(),
dragLeaveEvent(), dropEvent(), contextMenuEvent(), and
resizeEvent().
*/
bool QAbstractScrollArea::viewportEvent(QEvent *e)
{
switch (e->type()) {
case QEvent::Resize:
case QEvent::Paint:
case QEvent::MouseButtonPress:
case QEvent::MouseButtonRelease:
case QEvent::MouseButtonDblClick:
case QEvent::TouchBegin:
case QEvent::TouchUpdate:
case QEvent::TouchEnd:
case QEvent::MouseMove:
case QEvent::ContextMenu:
#ifndef QT_NO_WHEELEVENT
case QEvent::Wheel:
#endif
#ifndef QT_NO_DRAGANDDROP
case QEvent::Drop:
case QEvent::DragEnter:
case QEvent::DragMove:
case QEvent::DragLeave:
#endif
return QFrame::event(e);
case QEvent::LayoutRequest:
#ifndef QT_NO_GESTURES
case QEvent::Gesture:
case QEvent::GestureOverride:
return event(e);
#endif
default:
break;
}
return false; // let the viewport widget handle the event
}
/*!
\fn void QAbstractScrollArea::resizeEvent(QResizeEvent *event)
This event handler can be reimplemented in a subclass to receive
resize events (passed in \a event), for the viewport() widget.
When resizeEvent() is called, the viewport already has its new
geometry: Its new size is accessible through the
QResizeEvent::size() function, and the old size through
QResizeEvent::oldSize().
\sa QWidget::resizeEvent()
*/
void QAbstractScrollArea::resizeEvent(QResizeEvent *)
{
}
/*!
\fn void QAbstractScrollArea::paintEvent(QPaintEvent *event)
This event handler can be reimplemented in a subclass to receive
paint events (passed in \a event), for the viewport() widget.
\note If you open a painter, make sure to open it on the viewport().
\sa QWidget::paintEvent()
*/
void QAbstractScrollArea::paintEvent(QPaintEvent*)
{
}
/*!
This event handler can be reimplemented in a subclass to receive
mouse press events for the viewport() widget. The event is passed
in \a e.
\sa QWidget::mousePressEvent()
*/
void QAbstractScrollArea::mousePressEvent(QMouseEvent *e)
{
e->ignore();
}
/*!
This event handler can be reimplemented in a subclass to receive
mouse release events for the viewport() widget. The event is
passed in \a e.
\sa QWidget::mouseReleaseEvent()
*/
void QAbstractScrollArea::mouseReleaseEvent(QMouseEvent *e)
{
e->ignore();
}
/*!
This event handler can be reimplemented in a subclass to receive
mouse double click events for the viewport() widget. The event is
passed in \a e.
\sa QWidget::mouseDoubleClickEvent()
*/
void QAbstractScrollArea::mouseDoubleClickEvent(QMouseEvent *e)
{
e->ignore();
}
/*!
This event handler can be reimplemented in a subclass to receive
mouse move events for the viewport() widget. The event is passed
in \a e.
\sa QWidget::mouseMoveEvent()
*/
void QAbstractScrollArea::mouseMoveEvent(QMouseEvent *e)
{
e->ignore();
}
/*!
This event handler can be reimplemented in a subclass to receive
wheel events for the viewport() widget. The event is passed in \a
e.
\sa QWidget::wheelEvent()
*/
#ifndef QT_NO_WHEELEVENT
void QAbstractScrollArea::wheelEvent(QWheelEvent *e)
{
Q_D(QAbstractScrollArea);
if (static_cast<QWheelEvent*>(e)->orientation() == Qt::Horizontal)
QApplication::sendEvent(d->hbar, e);
else
QApplication::sendEvent(d->vbar, e);
}
#endif
#ifndef QT_NO_CONTEXTMENU
/*!
This event handler can be reimplemented in a subclass to receive
context menu events for the viewport() widget. The event is passed
in \a e.
\sa QWidget::contextMenuEvent()
*/
void QAbstractScrollArea::contextMenuEvent(QContextMenuEvent *e)
{
e->ignore();
}
#endif // QT_NO_CONTEXTMENU
/*!
This function is called with key event \a e when key presses
occur. It handles PageUp, PageDown, Up, Down, Left, and Right, and
ignores all other key presses.
*/
void QAbstractScrollArea::keyPressEvent(QKeyEvent * e)
{
Q_D(QAbstractScrollArea);
if (false){
#ifndef QT_NO_SHORTCUT
} else if (e == QKeySequence::MoveToPreviousPage) {
d->vbar->triggerAction(QScrollBar::SliderPageStepSub);
} else if (e == QKeySequence::MoveToNextPage) {
d->vbar->triggerAction(QScrollBar::SliderPageStepAdd);
#endif
} else {
#ifdef QT_KEYPAD_NAVIGATION
if (QApplication::keypadNavigationEnabled() && !hasEditFocus()) {
e->ignore();
return;
}
#endif
switch (e->key()) {
case Qt::Key_Up:
d->vbar->triggerAction(QScrollBar::SliderSingleStepSub);
break;
case Qt::Key_Down:
d->vbar->triggerAction(QScrollBar::SliderSingleStepAdd);
break;
case Qt::Key_Left:
#ifdef QT_KEYPAD_NAVIGATION
if (QApplication::keypadNavigationEnabled() && hasEditFocus()
&& (!d->hbar->isVisible() || d->hbar->value() == d->hbar->minimum())) {
//if we aren't using the hbar or we are already at the leftmost point ignore
e->ignore();
return;
}
#endif
d->hbar->triggerAction(
layoutDirection() == Qt::LeftToRight
? QScrollBar::SliderSingleStepSub : QScrollBar::SliderSingleStepAdd);
break;
case Qt::Key_Right:
#ifdef QT_KEYPAD_NAVIGATION
if (QApplication::keypadNavigationEnabled() && hasEditFocus()
&& (!d->hbar->isVisible() || d->hbar->value() == d->hbar->maximum())) {
//if we aren't using the hbar or we are already at the rightmost point ignore
e->ignore();
return;
}
#endif
d->hbar->triggerAction(
layoutDirection() == Qt::LeftToRight
? QScrollBar::SliderSingleStepAdd : QScrollBar::SliderSingleStepSub);
break;
default:
e->ignore();
return;
}
}
e->accept();
}
#ifndef QT_NO_DRAGANDDROP
/*!
\fn void QAbstractScrollArea::dragEnterEvent(QDragEnterEvent *event)
This event handler can be reimplemented in a subclass to receive
drag enter events (passed in \a event), for the viewport() widget.
\sa QWidget::dragEnterEvent()
*/
void QAbstractScrollArea::dragEnterEvent(QDragEnterEvent *)
{
}
/*!
\fn void QAbstractScrollArea::dragMoveEvent(QDragMoveEvent *event)
This event handler can be reimplemented in a subclass to receive
drag move events (passed in \a event), for the viewport() widget.
\sa QWidget::dragMoveEvent()
*/
void QAbstractScrollArea::dragMoveEvent(QDragMoveEvent *)
{
}
/*!
\fn void QAbstractScrollArea::dragLeaveEvent(QDragLeaveEvent *event)
This event handler can be reimplemented in a subclass to receive
drag leave events (passed in \a event), for the viewport() widget.
\sa QWidget::dragLeaveEvent()
*/
void QAbstractScrollArea::dragLeaveEvent(QDragLeaveEvent *)
{
}
/*!
\fn void QAbstractScrollArea::dropEvent(QDropEvent *event)
This event handler can be reimplemented in a subclass to receive
drop events (passed in \a event), for the viewport() widget.
\sa QWidget::dropEvent()
*/
void QAbstractScrollArea::dropEvent(QDropEvent *)
{
}
#endif
/*!
This virtual handler is called when the scroll bars are moved by
\a dx, \a dy, and consequently the viewport's contents should be
scrolled accordingly.
The default implementation simply calls update() on the entire
viewport(), subclasses can reimplement this handler for
optimization purposes, or - like QScrollArea - to move a contents
widget. The parameters \a dx and \a dy are there for convenience,
so that the class knows how much should be scrolled (useful
e.g. when doing pixel-shifts). You may just as well ignore these
values and scroll directly to the position the scroll bars
indicate.
Calling this function in order to scroll programmatically is an
error, use the scroll bars instead (e.g. by calling
QScrollBar::setValue() directly).
*/
void QAbstractScrollArea::scrollContentsBy(int, int)
{
viewport()->update();
}
void QAbstractScrollAreaPrivate::_q_hslide(int x)
{
Q_Q(QAbstractScrollArea);
int dx = xoffset - x;
xoffset = x;
q->scrollContentsBy(dx, 0);
}
void QAbstractScrollAreaPrivate::_q_vslide(int y)
{
Q_Q(QAbstractScrollArea);
int dy = yoffset - y;
yoffset = y;
q->scrollContentsBy(0, dy);
}
void QAbstractScrollAreaPrivate::_q_showOrHideScrollBars()
{
layoutChildren();
#ifdef Q_WS_WIN
// Need to re-subscribe to gestures as the content changes to make sure we
// enable/disable panning when needed.
QWidgetPrivate *dd = static_cast<QWidgetPrivate *>(QObjectPrivate::get(viewport));
if (dd)
dd->winSetupGestures();
#endif // Q_WS_WIN
}
QPoint QAbstractScrollAreaPrivate::contentsOffset() const
{
Q_Q(const QAbstractScrollArea);
QPoint offset;
if (vbar->isVisible())
offset.setY(vbar->value());
if (hbar->isVisible()) {
if (q->isRightToLeft())
offset.setX(hbar->maximum() - hbar->value());
else
offset.setX(hbar->value());
}
return offset;
}
/*!
\reimp
*/
QSize QAbstractScrollArea::minimumSizeHint() const
{
Q_D(const QAbstractScrollArea);
int hsbExt = d->hbar->sizeHint().height();
int vsbExt = d->vbar->sizeHint().width();
int extra = 2 * d->frameWidth;
QStyleOption opt;
opt.initFrom(this);
if ((d->frameStyle != QFrame::NoFrame)
&& style()->styleHint(QStyle::SH_ScrollView_FrameOnlyAroundContents, &opt, this)) {
extra += style()->pixelMetric(QStyle::PM_ScrollView_ScrollBarSpacing, &opt, this);
}
return QSize(d->scrollBarContainers[Qt::Horizontal]->sizeHint().width() + vsbExt + extra,
d->scrollBarContainers[Qt::Vertical]->sizeHint().height() + hsbExt + extra);
}
/*!
\reimp
*/
QSize QAbstractScrollArea::sizeHint() const
{
return QSize(256, 192);
#if 0
Q_D(const QAbstractScrollArea);
int h = qMax(10, fontMetrics().height());
int f = 2 * d->frameWidth;
return QSize((6 * h) + f, (4 * h) + f);
#endif
}
/*!
This slot is called by QAbstractScrollArea after setViewport(\a
viewport) has been called. Reimplement this function in a
subclass of QAbstractScrollArea to initialize the new \a viewport
before it is used.
\sa setViewport()
*/
void QAbstractScrollArea::setupViewport(QWidget *viewport)
{
Q_UNUSED(viewport);
}
QT_END_NAMESPACE
#include "moc_qabstractscrollarea.h"
#include "moc_qabstractscrollarea_p.h"
#endif // QT_NO_SCROLLAREA
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