qquickselectionrectangle.cpp

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// Copyright (C) 2021 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR LGPL-3.0-only OR GPL-2.0-only OR GPL-3.0-only
 
#include "qquickselectionrectangle_p.h"
#include "qquickselectionrectangle_p_p.h"
 
#include <QtQml/qqmlinfo.h>
#include <QtQuick/private/qquickdraghandler_p.h>
#include <QtQuick/private/qquickhoverhandler_p.h>
 
#include <QtQuick/private/qquicktableview_p_p.h>
 
#include "qquickscrollview_p.h"
 
QT_BEGIN_NAMESPACE
 
 
QQuickSelectionRectanglePrivate::QQuickSelectionRectanglePrivate()
    : QQuickControlPrivate()
{
    m_tapHandler = new QQuickTapHandler();
    m_dragHandler = new QQuickDragHandler();
    m_dragHandler->setTarget(nullptr);
 
    QObject::connect(&m_scrollTimer, &QTimer::timeout, [&]{
        if (m_topLeftHandle && m_draggedHandle == m_topLeftHandle.data())
            m_selectable->setSelectionStartPos(m_scrollToPoint);
        else
            m_selectable->setSelectionEndPos(m_scrollToPoint);
        updateHandles();
        const QSizeF dist = m_selectable->scrollTowardsSelectionPoint(m_scrollToPoint, m_scrollSpeed);
        m_scrollToPoint.rx() += dist.width() > 0 ? m_scrollSpeed.width() : -m_scrollSpeed.width();
        m_scrollToPoint.ry() += dist.height() > 0 ? m_scrollSpeed.height() : -m_scrollSpeed.height();
        m_scrollSpeed = QSizeF(qAbs(dist.width() * 0.007), qAbs(dist.height() * 0.007));
    });
 
    QObject::connect(m_tapHandler, &QQuickTapHandler::pressedChanged, [this]() {
        if (!m_tapHandler->isPressed())
            return;
        if (m_effectiveSelectionMode != QQuickSelectionRectangle::Drag)
            return;
 
        const QPointF pos = m_tapHandler->point().pressPosition();
        const auto modifiers = m_tapHandler->point().modifiers();
        if (modifiers & ~(Qt::ControlModifier | Qt::ShiftModifier))
            return;
 
        if (modifiers & Qt::ShiftModifier) {
            // Extend the selection towards the pressed cell. If there is no
            // existing selection, start a new selection from the current item
            // to the pressed item.
            if (!m_active) {
                if (!m_selectable->startSelection(pos, modifiers))
                    return;
                m_selectable->setSelectionStartPos(QPoint{-1, -1});
            }
            m_selectable->setSelectionEndPos(pos);
            updateHandles();
            updateActiveState(true);
        } else if (modifiers & Qt::ControlModifier) {
            // Select a single cell, but keep the old selection (unless
            // m_selectable->startSelection(pos. modifiers) returns false, which
            // it will if selectionMode only allows a single selection).
            if (handleUnderPos(pos) != nullptr) {
                // Don't allow press'n'hold to start a new
                // selection if it started on top of a handle.
                return;
            }
 
            if (!m_selectable->startSelection(pos, modifiers))
                return;
            m_selectable->setSelectionStartPos(pos);
            m_selectable->setSelectionEndPos(pos);
            updateHandles();
            updateActiveState(true);
        }
    });
 
    QObject::connect(m_tapHandler, &QQuickTapHandler::longPressed, [this]() {
        if (m_effectiveSelectionMode != QQuickSelectionRectangle::PressAndHold)
            return;
 
        const QPointF pos = m_tapHandler->point().pressPosition();
        const auto modifiers = m_tapHandler->point().modifiers();
        if (handleUnderPos(pos) != nullptr) {
            // Don't allow press'n'hold to start a new
            // selection if it started on top of a handle.
            return;
        }
 
        if (modifiers == Qt::ShiftModifier) {
            // Extend the selection towards the pressed cell. If there is no
            // existing selection, start a new selection from the current item
            // to the pressed item.
            if (!m_active) {
                if (!m_selectable->startSelection(pos, modifiers))
                    return;
                m_selectable->setSelectionStartPos(QPoint{-1, -1});
            }
            m_selectable->setSelectionEndPos(pos);
            updateHandles();
            updateActiveState(true);
        } else if (modifiers == Qt::ControlModifier) {
            // Select a single cell, but keep the old selection (unless
            // m_selectable->startSelection(pos, modifiers) returns false, which
            // it will if selectionMode only allows a single selection).
            if (!m_selectable->startSelection(pos, modifiers))
                return;
            m_selectable->setSelectionStartPos(pos);
            m_selectable->setSelectionEndPos(pos);
            updateHandles();
            updateActiveState(true);
        } else if (modifiers == Qt::NoModifier) {
            // Select a single cell
            m_selectable->clearSelection();
            if (!m_selectable->startSelection(pos, modifiers))
                return;
            m_selectable->setSelectionStartPos(pos);
            m_selectable->setSelectionEndPos(pos);
            updateHandles();
            updateActiveState(true);
        }
    });
 
    QObject::connect(m_dragHandler, &QQuickDragHandler::activeChanged, [this]() {
        Q_ASSERT(m_effectiveSelectionMode == QQuickSelectionRectangle::Drag);
        const QPointF startPos = m_dragHandler->centroid().pressPosition();
        const QPointF dragPos = m_dragHandler->centroid().position();
        const auto modifiers = m_dragHandler->centroid().modifiers();
        if (modifiers & ~(Qt::ControlModifier | Qt::ShiftModifier))
            return;
 
        if (m_dragHandler->active()) {
            // Start a new selection unless there is an active selection
            // already, and one of the relevant modifiers are being held.
            // In that case we continue to extend the active selection instead.
            const bool modifiersHeld = modifiers & (Qt::ControlModifier | Qt::ShiftModifier);
            if (!m_active || !modifiersHeld) {
                if (!m_selectable->startSelection(startPos, modifiers))
                    return;
                m_selectable->setSelectionStartPos(startPos);
            }
            m_selectable->setSelectionEndPos(dragPos);
            m_draggedHandle = nullptr;
            updateHandles();
            updateActiveState(true);
            updateDraggingState(true);
        } else {
            m_scrollTimer.stop();
            m_selectable->normalizeSelection();
            updateDraggingState(false);
        }
    });
 
    QObject::connect(m_dragHandler, &QQuickDragHandler::centroidChanged, [this]() {
        if (!m_dragging)
            return;
        const QPointF pos = m_dragHandler->centroid().position();
        m_selectable->setSelectionEndPos(pos);
        updateHandles();
        scrollTowardsPos(pos);
    });
}
 
void QQuickSelectionRectanglePrivate::scrollTowardsPos(const QPointF &pos)
{
    m_scrollToPoint = pos;
    if (m_scrollTimer.isActive())
        return;
 
    const QSizeF dist = m_selectable->scrollTowardsSelectionPoint(m_scrollToPoint, m_scrollSpeed);
    if (!dist.isNull())
        m_scrollTimer.start(1);
}
 
QQuickItem *QQuickSelectionRectanglePrivate::handleUnderPos(const QPointF &pos)
{
    const auto handlerTarget = m_selectable->selectionPointerHandlerTarget();
    if (m_topLeftHandle) {
        const QPointF localPos = m_topLeftHandle->mapFromItem(handlerTarget, pos);
        if (m_topLeftHandle->contains(localPos))
            return m_topLeftHandle.data();
    }
 
    if (m_bottomRightHandle) {
        const QPointF localPos = m_bottomRightHandle->mapFromItem(handlerTarget, pos);
        if (m_bottomRightHandle->contains(localPos))
            return m_bottomRightHandle.data();
    }
 
    return nullptr;
}
 
void QQuickSelectionRectanglePrivate::updateDraggingState(bool dragging)
{
    if (dragging != m_dragging) {
        m_dragging = dragging;
        emit q_func()->draggingChanged();
    }
 
    if (auto attached = getAttachedObject(m_draggedHandle))
        attached->setDragging(dragging);
}
 
void QQuickSelectionRectanglePrivate::updateActiveState(bool active)
{
    if (active == m_active)
        return;
 
    m_active = active;
 
    if (const auto tableview = qobject_cast<QQuickTableView *>(m_target)) {
        if (active) {
            // If the position of rows and columns changes, we'll need to reposition the handles
            connect(tableview, &QQuickTableView::layoutChanged, this, &QQuickSelectionRectanglePrivate::updateHandles);
        } else {
            disconnect(tableview, &QQuickTableView::layoutChanged, this, &QQuickSelectionRectanglePrivate::updateHandles);
        }
    }
 
    emit q_func()->activeChanged();
}
 
QQuickItem *QQuickSelectionRectanglePrivate::createHandle(QQmlComponent *delegate, Qt::Corner corner)
{
    Q_Q(QQuickSelectionRectangle);
 
    // Incubate the handle
    QObject *obj = delegate->beginCreate(QQmlEngine::contextForObject(q));
    QQuickItem *handleItem = qobject_cast<QQuickItem*>(obj);
    const auto handlerTarget = m_selectable->selectionPointerHandlerTarget();
    handleItem->setParentItem(handlerTarget);
    if (auto attached = getAttachedObject(handleItem))
        attached->setControl(q);
    delegate->completeCreate();
    if (handleItem->z() == 0)
        handleItem->setZ(100);
 
    // Add pointer handlers to it
    QQuickDragHandler *dragHandler = new QQuickDragHandler();
    dragHandler->setTarget(nullptr);
    dragHandler->setParentItem(handleItem);
    dragHandler->setGrabPermissions(QQuickPointerHandler::CanTakeOverFromAnything);
 
    QQuickHoverHandler *hoverHandler = new QQuickHoverHandler();
    hoverHandler->setTarget(nullptr);
    hoverHandler->setParentItem(handleItem);
#if QT_CONFIG(cursor)
    hoverHandler->setCursorShape(Qt::SizeFDiagCursor);
#endif
    hoverHandler->setBlocking(true);
 
    // Add a dummy TapHandler that blocks the user from being
    // able to tap on a tap handler underneath the handle.
    QQuickTapHandler *tapHandler = new QQuickTapHandler();
    tapHandler->setTarget(nullptr);
    tapHandler->setParentItem(handleItem);
    // Set a dummy gesture policy so that the tap handler
    // will get an exclusive grab already on press
    tapHandler->setGesturePolicy(QQuickTapHandler::DragWithinBounds);
 
    QObject::connect(dragHandler, &QQuickDragHandler::activeChanged, [this, corner, handleItem, dragHandler]() {
        if (dragHandler->active()) {
            const QPointF localPos = dragHandler->centroid().position();
            const QPointF pos = handleItem->mapToItem(handleItem->parentItem(), localPos);
            if (corner == Qt::TopLeftCorner)
                m_selectable->setSelectionStartPos(pos);
            else
                m_selectable->setSelectionEndPos(pos);
 
            m_draggedHandle = handleItem;
            updateHandles();
            updateDraggingState(true);
#if QT_CONFIG(cursor)
            QGuiApplication::setOverrideCursor(Qt::SizeFDiagCursor);
#endif
        } else {
            m_scrollTimer.stop();
            m_selectable->normalizeSelection();
            updateDraggingState(false);
#if QT_CONFIG(cursor)
            QGuiApplication::restoreOverrideCursor();
#endif
        }
    });
 
    QObject::connect(dragHandler, &QQuickDragHandler::centroidChanged, [this, corner, handleItem, dragHandler]() {
        if (!m_dragging)
            return;
 
        const QPointF localPos = dragHandler->centroid().position();
        const QPointF pos = handleItem->mapToItem(handleItem->parentItem(), localPos);
        if (corner == Qt::TopLeftCorner)
            m_selectable->setSelectionStartPos(pos);
        else
            m_selectable->setSelectionEndPos(pos);
 
        updateHandles();
        scrollTowardsPos(pos);
    });
 
    return handleItem;
}
 
void QQuickSelectionRectanglePrivate::updateHandles()
{
    const QRectF rect = m_selectable->selectionRectangle().normalized();
 
    if (!m_topLeftHandle && m_topLeftHandleDelegate)
        m_topLeftHandle.reset(createHandle(m_topLeftHandleDelegate, Qt::TopLeftCorner));
 
    if (!m_bottomRightHandle && m_bottomRightHandleDelegate)
        m_bottomRightHandle.reset(createHandle(m_bottomRightHandleDelegate, Qt::BottomRightCorner));
 
    if (m_topLeftHandle) {
        m_topLeftHandle->setX(rect.x() - (m_topLeftHandle->width() / 2));
        m_topLeftHandle->setY(rect.y() - (m_topLeftHandle->height() / 2));
    }
 
    if (m_bottomRightHandle) {
        m_bottomRightHandle->setX(rect.x() + rect.width() - (m_bottomRightHandle->width() / 2));
        m_bottomRightHandle->setY(rect.y() + rect.height() - (m_bottomRightHandle->height() / 2));
    }
}
 
void QQuickSelectionRectanglePrivate::connectToTarget()
{
    // To support QuickSelectionRectangle::Auto, we need to listen for changes to the target
    if (const auto flickable = qobject_cast<QQuickFlickable *>(m_target)) {
        connect(flickable, &QQuickFlickable::interactiveChanged, this, &QQuickSelectionRectanglePrivate::updateSelectionMode);
    }
 
    // Add a callback function that tells if the selection was
    // modified outside of the actions taken by SelectionRectangle.
    m_selectable->setCallback([this](QQuickSelectable::CallBackFlag flag){
        switch (flag) {
        case QQuickSelectable::CallBackFlag::CancelSelection:
            // The selection is either cleared, or can no longer be
            // represented as a rectangle with two selection handles.
            updateActiveState(false);
            break;
        case QQuickSelectable::CallBackFlag::SelectionRectangleChanged:
            // The selection has changed, but the selection is still
            // rectangular and without holes.
            updateHandles();
            break;
        default:
            Q_UNREACHABLE();
        }
    });
}
 
void QQuickSelectionRectanglePrivate::updateSelectionMode()
{
    Q_Q(QQuickSelectionRectangle);
 
    const bool enabled = q->isEnabled();
    m_tapHandler->setEnabled(enabled);
 
    if (m_selectionMode == QQuickSelectionRectangle::Auto) {
        if (m_target && qobject_cast<QQuickScrollView *>(m_target->parentItem())) {
            // ScrollView allows flicking with touch, but not with mouse. So we do
            // the same here: you can drag to select with a mouse, but not with touch.
            m_effectiveSelectionMode = QQuickSelectionRectangle::Drag;
            m_dragHandler->setAcceptedDevices(QInputDevice::DeviceType::Mouse);
            m_dragHandler->setEnabled(enabled);
        } else if (const auto flickable = qobject_cast<QQuickFlickable *>(m_target)) {
            if (enabled && !flickable->isInteractive()) {
                m_effectiveSelectionMode = QQuickSelectionRectangle::Drag;
                m_dragHandler->setEnabled(true);
            } else {
                m_effectiveSelectionMode = QQuickSelectionRectangle::PressAndHold;
                m_dragHandler->setEnabled(false);
            }
        } else {
            m_effectiveSelectionMode = QQuickSelectionRectangle::Drag;
            m_dragHandler->setAcceptedDevices(QInputDevice::DeviceType::Mouse);
            m_dragHandler->setEnabled(enabled);
        }
    } else if (m_selectionMode == QQuickSelectionRectangle::Drag) {
        m_effectiveSelectionMode = QQuickSelectionRectangle::Drag;
        m_dragHandler->setAcceptedDevices(QInputDevice::DeviceType::AllDevices);
        m_dragHandler->setEnabled(enabled);
    } else {
        m_effectiveSelectionMode = QQuickSelectionRectangle::PressAndHold;
        m_dragHandler->setEnabled(false);
    }
}
 
QQuickSelectionRectangleAttached *QQuickSelectionRectanglePrivate::getAttachedObject(const QObject *object) const
{
    QObject *attachedObject = qmlAttachedPropertiesObject<QQuickSelectionRectangle>(object);
    return static_cast<QQuickSelectionRectangleAttached *>(attachedObject);
}
 
// --------------------------------------------------------
 
QQuickSelectionRectangle::QQuickSelectionRectangle(QQuickItem *parent)
    : QQuickControl(*(new QQuickSelectionRectanglePrivate), parent)
{
    Q_D(QQuickSelectionRectangle);
    d->m_tapHandler->setParent(this);
    d->m_dragHandler->setParent(this);
 
    QObject::connect(this, &QQuickItem::enabledChanged, [=]() {
        d->m_scrollTimer.stop();
        d->updateSelectionMode();
        d->updateDraggingState(false);
        d->updateActiveState(false);
    });
}
 
QQuickItem *QQuickSelectionRectangle::target() const
{
    return d_func()->m_target;
}
 
void QQuickSelectionRectangle::setTarget(QQuickItem *target)
{
    Q_D(QQuickSelectionRectangle);
    if (d->m_target == target)
        return;
 
    if (d->m_selectable) {
        d->m_scrollTimer.stop();
        d->m_tapHandler->setParent(this);
        d->m_dragHandler->setParent(this);
        d->m_target->disconnect(this);
        d->m_selectable->setCallback(nullptr);
    }
 
    d->m_target = target;
    d->m_selectable = nullptr;
 
    if (d->m_target) {
        d->m_selectable = dynamic_cast<QQuickSelectable *>(QObjectPrivate::get(d->m_target.data()));
        if (!d->m_selectable)
            qmlWarning(this) << "the assigned target is not supported by the control";
    }
 
    if (d->m_selectable) {
        const auto handlerTarget = d->m_selectable->selectionPointerHandlerTarget();
        d->m_dragHandler->setParentItem(handlerTarget);
        d->m_tapHandler->setParentItem(handlerTarget);
        d->connectToTarget();
        d->updateSelectionMode();
    }
 
    emit targetChanged();
}
 
bool QQuickSelectionRectangle::active()
{
    return d_func()->m_active;
}
 
bool QQuickSelectionRectangle::dragging()
{
    return d_func()->m_dragging;
}
 
QQuickSelectionRectangle::SelectionMode QQuickSelectionRectangle::selectionMode() const
{
    return d_func()->m_selectionMode;
}
 
void QQuickSelectionRectangle::setSelectionMode(QQuickSelectionRectangle::SelectionMode selectionMode)
{
    Q_D(QQuickSelectionRectangle);
    if (d->m_selectionMode == selectionMode)
        return;
 
    d->m_selectionMode = selectionMode;
 
    if (d->m_target)
        d->updateSelectionMode();
 
    emit selectionModeChanged();
}
 
QQmlComponent *QQuickSelectionRectangle::topLeftHandle() const
{
    return d_func()->m_topLeftHandleDelegate;
}
 
void QQuickSelectionRectangle::setTopLeftHandle(QQmlComponent *topLeftHandle)
{
    Q_D(QQuickSelectionRectangle);
    if (d->m_topLeftHandleDelegate == topLeftHandle)
        return;
 
    d->m_topLeftHandleDelegate = topLeftHandle;
    emit topLeftHandleChanged();
}
 
QQmlComponent *QQuickSelectionRectangle::bottomRightHandle() const
{
    return d_func()->m_bottomRightHandleDelegate;
}
 
void QQuickSelectionRectangle::setBottomRightHandle(QQmlComponent *bottomRightHandle)
{
    Q_D(QQuickSelectionRectangle);
    if (d->m_bottomRightHandleDelegate == bottomRightHandle)
        return;
 
    d->m_bottomRightHandleDelegate = bottomRightHandle;
    emit bottomRightHandleChanged();
}
 
QQuickSelectionRectangleAttached *QQuickSelectionRectangle::qmlAttachedProperties(QObject *obj)
{
    return new QQuickSelectionRectangleAttached(obj);
}
 
QQuickSelectionRectangleAttached::QQuickSelectionRectangleAttached(QObject *parent)
    : QObject(parent)
{
}
 
QQuickSelectionRectangle *QQuickSelectionRectangleAttached::control() const
{
    return m_control;
}
 
void QQuickSelectionRectangleAttached::setControl(QQuickSelectionRectangle *control)
{
    if (m_control == control)
        return;
 
    m_control = control;
    emit controlChanged();
}
 
bool QQuickSelectionRectangleAttached::dragging() const
{
    return m_dragging;
}
 
void QQuickSelectionRectangleAttached::setDragging(bool dragging)
{
    if (m_dragging == dragging)
        return;
 
    m_dragging = dragging;
    emit draggingChanged();
}
 
QT_END_NAMESPACE
 
#include "moc_qquickselectionrectangle_p.cpp"