File indexing completed on 2024-04-28 05:45:06

 /*
  * SPDX-FileCopyrightText: 2011 Peter Penz <peter.penz19@gmail.com>
  *
  * Based on the Itemviews NG project from Trolltech Labs
  *
  * SPDX-License-Identifier: GPL-2.0-or-later
  */
 
 #include "kitemlistcontainer.h"
 
 #include "kitemlistcontroller.h"
 #include "kitemlistview.h"
 #include "private/kitemlistsmoothscroller.h"
 
 #include <QApplication>
 #include <QFontMetrics>
 #include <QGraphicsScene>
 #include <QGraphicsView>
 #include <QScrollBar>
 #include <QScroller>
 #include <QStyleOption>
 
 /**
  * Replaces the default viewport of KItemListContainer by a
  * non-scrollable viewport. The scrolling is done in an optimized
  * way by KItemListView internally.
  */
 class KItemListContainerViewport : public QGraphicsView
 {
     Q_OBJECT
 
 public:
     KItemListContainerViewport(QGraphicsScene *scene, QWidget *parent);
 
 protected:
     void wheelEvent(QWheelEvent *event) override;
 };
 
 KItemListContainerViewport::KItemListContainerViewport(QGraphicsScene *scene, QWidget *parent)
     : QGraphicsView(scene, parent)
 {
     setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
     setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
     setViewportMargins(0, 0, 0, 0);
     setFrameShape(QFrame::NoFrame);
 }
 
 void KItemListContainerViewport::wheelEvent(QWheelEvent *event)
 {
     // Assure that the wheel-event gets forwarded to the parent
     // and not handled at all by QGraphicsView.
     event->ignore();
 }
 
 KItemListContainer::KItemListContainer(KItemListController *controller, QWidget *parent)
     : QAbstractScrollArea(parent)
     , m_controller(controller)
     , m_horizontalSmoothScroller(nullptr)
     , m_verticalSmoothScroller(nullptr)
     , m_scroller(nullptr)
 {
     Q_ASSERT(controller);
     controller->setParent(this);
 
     QGraphicsView *graphicsView = new KItemListContainerViewport(new QGraphicsScene(this), this);
     setViewport(graphicsView);
 
     m_horizontalSmoothScroller = new KItemListSmoothScroller(horizontalScrollBar(), this);
     m_verticalSmoothScroller = new KItemListSmoothScroller(verticalScrollBar(), this);
 
     if (controller->model()) {
         slotModelChanged(controller->model(), nullptr);
     }
     if (controller->view()) {
         slotViewChanged(controller->view(), nullptr);
     }
 
     connect(controller, &KItemListController::modelChanged, this, &KItemListContainer::slotModelChanged);
     connect(controller, &KItemListController::viewChanged, this, &KItemListContainer::slotViewChanged);
 
     m_scroller = QScroller::scroller(viewport());
     m_scroller->grabGesture(viewport());
     connect(controller, &KItemListController::scrollerStop, this, &KItemListContainer::stopScroller);
     connect(m_scroller, &QScroller::stateChanged, controller, &KItemListController::slotStateChanged);
 }
 
 KItemListContainer::~KItemListContainer()
 {
     // Don't rely on the QObject-order to delete the controller, otherwise
     // the QGraphicsScene might get deleted before the view.
     delete m_controller;
     m_controller = nullptr;
 }
 
 KItemListController *KItemListContainer::controller() const
 {
     return m_controller;
 }
 
 void KItemListContainer::setEnabledFrame(bool enable)
 {
     QGraphicsView *graphicsView = qobject_cast<QGraphicsView *>(viewport());
     if (enable) {
         setFrameShape(QFrame::StyledPanel);
         graphicsView->setPalette(palette());
         graphicsView->viewport()->setAutoFillBackground(true);
     } else {
         setFrameShape(QFrame::NoFrame);
         // Make the background of the container transparent and apply the window-text color
         // to the text color, so that enough contrast is given for all color
         // schemes
         QPalette p = graphicsView->palette();
         p.setColor(QPalette::Active, QPalette::Text, p.color(QPalette::Active, QPalette::WindowText));
         p.setColor(QPalette::Inactive, QPalette::Text, p.color(QPalette::Inactive, QPalette::WindowText));
         p.setColor(QPalette::Disabled, QPalette::Text, p.color(QPalette::Disabled, QPalette::WindowText));
         graphicsView->setPalette(p);
         graphicsView->viewport()->setAutoFillBackground(false);
     }
 }
 
 bool KItemListContainer::enabledFrame() const
 {
     const QGraphicsView *graphicsView = qobject_cast<QGraphicsView *>(viewport());
     return graphicsView->autoFillBackground();
 }
 
 void KItemListContainer::keyPressEvent(QKeyEvent *event)
 {
     // TODO: We should find a better way to handle the key press events in the view.
     // The reasons why we need this hack are:
     // 1. Without reimplementing keyPressEvent() here, the event would not reach the QGraphicsView.
     // 2. By default, the KItemListView does not have the keyboard focus in the QGraphicsScene, so
     //    simply sending the event to the QGraphicsView which is the KItemListContainer's viewport
     //    does not work.
     KItemListView *view = m_controller->view();
     if (view) {
         QApplication::sendEvent(view, event);
     }
 }
 
 void KItemListContainer::contextMenuEvent(QContextMenuEvent *event)
 {
     // Note copied from the keyPressEvent() method above because the same reasons probably also apply here.
     // TODO: We should find a better way to handle the context menu events in the view.
     // The reasons why we need this hack are:
     // 1. Without reimplementing contextMenuEvent() here, the event would not reach the QGraphicsView.
     // 2. By default, the KItemListView does not have the keyboard focus in the QGraphicsScene, so
     //    simply sending the event to the QGraphicsView which is the KItemListContainer's viewport
     //    does not work.
     KItemListView *view = m_controller->view();
     if (view) {
         QApplication::sendEvent(view, event);
     }
 }
 
 void KItemListContainer::showEvent(QShowEvent *event)
 {
     QAbstractScrollArea::showEvent(event);
     updateGeometries();
 }
 
 void KItemListContainer::resizeEvent(QResizeEvent *event)
 {
     QAbstractScrollArea::resizeEvent(event);
     updateGeometries();
 }
 
 void KItemListContainer::scrollContentsBy(int dx, int dy)
 {
     m_horizontalSmoothScroller->scrollContentsBy(dx);
     m_verticalSmoothScroller->scrollContentsBy(dy);
 }
 
 void KItemListContainer::wheelEvent(QWheelEvent *event)
 {
     if (event->modifiers().testFlag(Qt::ControlModifier)) {
         event->ignore();
         return;
     }
 
     KItemListView *view = m_controller->view();
     if (!view) {
         event->ignore();
         return;
     }
 
     const bool scrollHorizontally = (qAbs(event->angleDelta().y()) < qAbs(event->angleDelta().x())) || (!verticalScrollBar()->isVisible());
     KItemListSmoothScroller *smoothScroller = scrollHorizontally ? m_horizontalSmoothScroller : m_verticalSmoothScroller;
 
     smoothScroller->handleWheelEvent(event);
 }
 
 void KItemListContainer::focusInEvent(QFocusEvent *event)
 {
     KItemListView *view = m_controller->view();
     if (view) {
         QApplication::sendEvent(view, event);
     }
 }
 
 void KItemListContainer::focusOutEvent(QFocusEvent *event)
 {
     KItemListView *view = m_controller->view();
     if (view) {
         QApplication::sendEvent(view, event);
     }
 }
 
 void KItemListContainer::slotScrollOrientationChanged(Qt::Orientation current, Qt::Orientation previous)
 {
     Q_UNUSED(previous)
     updateSmoothScrollers(current);
 }
 
 void KItemListContainer::slotModelChanged(KItemModelBase *current, KItemModelBase *previous)
 {
     Q_UNUSED(current)
     Q_UNUSED(previous)
 }
 
 void KItemListContainer::slotViewChanged(KItemListView *current, KItemListView *previous)
 {
     QGraphicsScene *scene = static_cast<QGraphicsView *>(viewport())->scene();
     if (previous) {
         scene->removeItem(previous);
         disconnect(previous, &KItemListView::scrollOrientationChanged, this, &KItemListContainer::slotScrollOrientationChanged);
         disconnect(previous, &KItemListView::scrollOffsetChanged, this, &KItemListContainer::updateScrollOffsetScrollBar);
         disconnect(previous, &KItemListView::maximumScrollOffsetChanged, this, &KItemListContainer::updateScrollOffsetScrollBar);
         disconnect(previous, &KItemListView::itemOffsetChanged, this, &KItemListContainer::updateItemOffsetScrollBar);
         disconnect(previous, &KItemListView::maximumItemOffsetChanged, this, &KItemListContainer::updateItemOffsetScrollBar);
         disconnect(previous, &KItemListView::scrollTo, this, &KItemListContainer::scrollTo);
         disconnect(m_horizontalSmoothScroller, &KItemListSmoothScroller::scrollingStopped, previous, &KItemListView::scrollingStopped);
         disconnect(m_verticalSmoothScroller, &KItemListSmoothScroller::scrollingStopped, previous, &KItemListView::scrollingStopped);
         m_horizontalSmoothScroller->setTargetObject(nullptr);
         m_verticalSmoothScroller->setTargetObject(nullptr);
     }
     if (current) {
         scene->addItem(current);
         connect(current, &KItemListView::scrollOrientationChanged, this, &KItemListContainer::slotScrollOrientationChanged);
         connect(current, &KItemListView::scrollOffsetChanged, this, &KItemListContainer::updateScrollOffsetScrollBar);
         connect(current, &KItemListView::maximumScrollOffsetChanged, this, &KItemListContainer::updateScrollOffsetScrollBar);
         connect(current, &KItemListView::itemOffsetChanged, this, &KItemListContainer::updateItemOffsetScrollBar);
         connect(current, &KItemListView::maximumItemOffsetChanged, this, &KItemListContainer::updateItemOffsetScrollBar);
         connect(current, &KItemListView::scrollTo, this, &KItemListContainer::scrollTo);
         connect(m_horizontalSmoothScroller, &KItemListSmoothScroller::scrollingStopped, current, &KItemListView::scrollingStopped);
         connect(m_verticalSmoothScroller, &KItemListSmoothScroller::scrollingStopped, current, &KItemListView::scrollingStopped);
 
         m_horizontalSmoothScroller->setTargetObject(current);
         m_verticalSmoothScroller->setTargetObject(current);
         updateSmoothScrollers(current->scrollOrientation());
     }
 }
 
 void KItemListContainer::scrollTo(qreal offset)
 {
     const KItemListView *view = m_controller->view();
     if (view) {
         if (view->scrollOrientation() == Qt::Vertical) {
             m_verticalSmoothScroller->scrollTo(offset);
         } else {
             m_horizontalSmoothScroller->scrollTo(offset);
         }
     }
 }
 
 void KItemListContainer::updateScrollOffsetScrollBar()
 {
     const KItemListView *view = m_controller->view();
     if (!view) {
         return;
     }
 
     KItemListSmoothScroller *smoothScroller = nullptr;
     QScrollBar *scrollOffsetScrollBar = nullptr;
     int singleStep = 0;
     int pageStep = 0;
     int maximum = 0;
     if (view->scrollOrientation() == Qt::Vertical) {
         smoothScroller = m_verticalSmoothScroller;
         scrollOffsetScrollBar = verticalScrollBar();
 
         // Don't scroll super fast when using a wheel mouse:
         // We want to consider one "line" to be the text label which has a
         // roughly fixed height rather than using the height of the icon which
         // may be very tall
         const QFontMetrics metrics(font());
         singleStep = metrics.height() * QApplication::wheelScrollLines();
 
         // We cannot use view->size().height() because this height might
         // include the header widget, which is not part of the scrolled area.
         pageStep = view->verticalPageStep();
 
         // However, the total height of the view must be considered for the
         // maximum value of the scroll bar. Note that the view's scrollOffset()
         // refers to the offset of the top part of the view, which might be
         // hidden behind the header.
         maximum = qMax(0, int(view->maximumScrollOffset() - view->size().height()));
     } else {
         smoothScroller = m_horizontalSmoothScroller;
         scrollOffsetScrollBar = horizontalScrollBar();
         singleStep = view->itemSize().width();
         pageStep = view->size().width();
         maximum = qMax(0, int(view->maximumScrollOffset() - view->size().width()));
     }
 
     const int value = view->scrollOffset();
     if (smoothScroller->requestScrollBarUpdate(maximum)) {
         const bool updatePolicy = (scrollOffsetScrollBar->maximum() > 0 && maximum == 0) || horizontalScrollBarPolicy() == Qt::ScrollBarAlwaysOn;
 
         scrollOffsetScrollBar->setSingleStep(singleStep);
         scrollOffsetScrollBar->setPageStep(pageStep);
         scrollOffsetScrollBar->setMinimum(0);
         scrollOffsetScrollBar->setMaximum(maximum);
         scrollOffsetScrollBar->setValue(value);
 
         if (updatePolicy) {
             // Prevent a potential endless layout loop (see bug #293318).
             updateScrollOffsetScrollBarPolicy();
         }
     }
 }
 
 void KItemListContainer::updateItemOffsetScrollBar()
 {
     const KItemListView *view = m_controller->view();
     if (!view) {
         return;
     }
 
     KItemListSmoothScroller *smoothScroller = nullptr;
     QScrollBar *itemOffsetScrollBar = nullptr;
     int singleStep = 0;
     int pageStep = 0;
     if (view->scrollOrientation() == Qt::Vertical) {
         smoothScroller = m_horizontalSmoothScroller;
         itemOffsetScrollBar = horizontalScrollBar();
         singleStep = view->size().width() / 10;
         pageStep = view->size().width();
     } else {
         smoothScroller = m_verticalSmoothScroller;
         itemOffsetScrollBar = verticalScrollBar();
         singleStep = view->size().height() / 10;
         pageStep = view->size().height();
     }
 
     const int value = view->itemOffset();
     const int maximum = qMax(0, int(view->maximumItemOffset()) - pageStep);
     if (smoothScroller->requestScrollBarUpdate(maximum)) {
         itemOffsetScrollBar->setSingleStep(singleStep);
         itemOffsetScrollBar->setPageStep(pageStep);
         itemOffsetScrollBar->setMinimum(0);
         itemOffsetScrollBar->setMaximum(maximum);
         itemOffsetScrollBar->setValue(value);
     }
 }
 
 void KItemListContainer::stopScroller()
 {
     m_scroller->stop();
 }
 
 void KItemListContainer::updateGeometries()
 {
     QRect rect = geometry();
 
     int extra = frameWidth() * 2;
     QStyleOption option;
     option.initFrom(this);
     int scrollbarSpacing = 0;
     if (style()->styleHint(QStyle::SH_ScrollView_FrameOnlyAroundContents, &option, this)) {
         scrollbarSpacing = style()->pixelMetric(QStyle::PM_ScrollView_ScrollBarSpacing, &option, this);
     }
 
     const int widthDec = verticalScrollBar()->isVisible() ? extra + scrollbarSpacing + style()->pixelMetric(QStyle::PM_ScrollBarExtent, &option, this) : extra;
 
     const int heightDec =
         horizontalScrollBar()->isVisible() ? extra + scrollbarSpacing + style()->pixelMetric(QStyle::PM_ScrollBarExtent, &option, this) : extra;
 
     const QRectF newGeometry(0, 0, rect.width() - widthDec, rect.height() - heightDec);
     if (m_controller->view()->geometry() != newGeometry) {
         m_controller->view()->setGeometry(newGeometry);
 
         // Get the real geometry of the view again since the scrollbars
         // visibilities and the view geometry may have changed in re-layout.
         static_cast<KItemListContainerViewport *>(viewport())->scene()->setSceneRect(m_controller->view()->geometry());
         static_cast<KItemListContainerViewport *>(viewport())->viewport()->setGeometry(m_controller->view()->geometry().toRect());
 
         updateScrollOffsetScrollBar();
         updateItemOffsetScrollBar();
     }
 }
 
 void KItemListContainer::updateSmoothScrollers(Qt::Orientation orientation)
 {
     if (orientation == Qt::Vertical) {
         m_verticalSmoothScroller->setPropertyName("scrollOffset");
         m_horizontalSmoothScroller->setPropertyName("itemOffset");
     } else {
         m_horizontalSmoothScroller->setPropertyName("scrollOffset");
         m_verticalSmoothScroller->setPropertyName("itemOffset");
     }
 }
 
 void KItemListContainer::updateScrollOffsetScrollBarPolicy()
 {
     const KItemListView *view = m_controller->view();
     Q_ASSERT(view);
     const bool vertical = (view->scrollOrientation() == Qt::Vertical);
 
     QStyleOption option;
     option.initFrom(this);
     const int scrollBarInc = style()->pixelMetric(QStyle::PM_ScrollBarExtent, &option, this);
 
     QSizeF newViewSize = m_controller->view()->size();
     if (vertical) {
         newViewSize.rwidth() += scrollBarInc;
     } else {
         newViewSize.rheight() += scrollBarInc;
     }
 
     const Qt::ScrollBarPolicy policy = view->scrollBarRequired(newViewSize) ? Qt::ScrollBarAlwaysOn : Qt::ScrollBarAsNeeded;
     if (vertical) {
         setVerticalScrollBarPolicy(policy);
     } else {
         setHorizontalScrollBarPolicy(policy);
     }
 }
 
 #include "kitemlistcontainer.moc"
 #include "moc_kitemlistcontainer.cpp"