qdeclarativepolylinemapitem.cpp

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// Copyright (C) 2022 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 "qdeclarativepolylinemapitem_p.h"
#include "qdeclarativepolylinemapitem_p_p.h"
 
#include <QtCore/QScopedValueRollback>
#include <qnumeric.h>
#include <QPainterPath>
 
#include <QtGui/private/qtriangulatingstroker_p.h>
#include <QtPositioning/private/qlocationutils_p.h>
#include <QtPositioning/private/qdoublevector2d_p.h>
#include <QtPositioning/private/qwebmercator_p.h>
#include <QtPositioning/private/qclipperutils_p.h>
#include <QtPositioning/private/qgeopath_p.h>
#include <QtLocation/private/qgeomap_p.h>
 
#include <array>
 
QT_BEGIN_NAMESPACE
 
 
static bool get_line_intersection(const double p0_x,
                                 const double p0_y,
                                 const double p1_x,
                                 const double p1_y,
                                 const double p2_x,
                                 const double p2_y,
                                 const double p3_x,
                                 const double p3_y,
                                 double *i_x,
                                 double *i_y,
                                 double *i_t)
{
    const double s10_x = p1_x - p0_x;
    const double s10_y = p1_y - p0_y;
    const double s32_x = p3_x - p2_x;
    const double s32_y = p3_y - p2_y;
 
    const double denom = s10_x * s32_y - s32_x * s10_y;
    if (denom == 0.0)
        return false; // Collinear
    const bool denomPositive = denom > 0;
 
    const double s02_x = p0_x - p2_x;
    const double s02_y = p0_y - p2_y;
    const double s_numer = s10_x * s02_y - s10_y * s02_x;
    if ((s_numer < 0.0) == denomPositive)
        return false; // No collision
 
    const double t_numer = s32_x * s02_y - s32_y * s02_x;
    if ((t_numer < 0.0) == denomPositive)
        return false; // No collision
 
    if (((s_numer > denom) == denomPositive) || ((t_numer > denom) == denomPositive))
        return false; // No collision
    // Collision detected
    *i_t = t_numer / denom;
    *i_x = p0_x + (*i_t * s10_x);
    *i_y = p0_y + (*i_t * s10_y);
 
    return true;
}
 
enum SegmentType {
    NoIntersection,
    OneIntersection,
    TwoIntersections
};
 
static QList<QList<QDoubleVector2D> > clipLine(
        const QList<QDoubleVector2D> &l,
        const QList<QDoubleVector2D> &poly)
{
    QList<QList<QDoubleVector2D> > res;
    if (poly.size() < 2 || l.size() < 2)
        return res;
 
    // Step 1: build edges
    std::vector<std::array<double, 4> > edges;
    for (qsizetype i = 1; i < poly.size(); i++)
        edges.push_back({ { poly.at(i-1).x(), poly.at(i-1).y(), poly.at(i).x(), poly.at(i).y() } });
    edges.push_back({ { poly.at(poly.size()-1).x(), poly.at(poly.size()-1).y(), poly.at(0).x(), poly.at(0).y() } });
 
    // Step 2: check each segment against each edge
    QList<QDoubleVector2D> subLine;
    std::array<double, 4> intersections = { { 0.0, 0.0, 0.0, 0.0 } };
 
    for (qsizetype i = 0; i < l.size() - 1; ++i) {
        SegmentType type = NoIntersection;
        double t = -1; // valid values are in [0, 1]. Only written if intersects
        double previousT = t;
        double i_x, i_y;
 
        const int firstContained = QClipperUtils::pointInPolygon(l.at(i), poly);
        const int secondContained = QClipperUtils::pointInPolygon(l.at(i+1), poly);
 
        if (firstContained && secondContained) { // Second most common condition, test early and skip inner loop if possible
            if (!subLine.size())
                subLine.push_back(l.at(i)); // the initial element has to be pushed now.
            subLine.push_back(l.at(i+1));
            continue;
        }
 
        for (unsigned int j = 0; j < edges.size(); ++j) {
            const bool intersects = get_line_intersection(l.at(i).x(),
                                                         l.at(i).y(),
                                                         l.at(i+1).x(),
                                                         l.at(i+1).y(),
                                                         edges.at(j).at(0),
                                                         edges.at(j).at(1),
                                                         edges.at(j).at(2),
                                                         edges.at(j).at(3),
                                                         &i_x,
                                                         &i_y,
                                                         &t);
            if (intersects) {
                if (previousT >= 0.0) { //One intersection already hit
                    if (t < previousT) { // Reorder
                        intersections[2] = intersections[0];
                        intersections[3] = intersections[1];
                        intersections[0] = i_x;
                        intersections[1] = i_y;
                    } else {
                        intersections[2] = i_x;
                        intersections[3] = i_y;
                    }
 
                    type = TwoIntersections;
                    break; // no need to check anything else
                } else { // First intersection
                    intersections[0] = i_x;
                    intersections[1] = i_y;
                    type = OneIntersection;
                }
                previousT = t;
            }
        }
 
        if (type == NoIntersection) {
            if (!firstContained && !secondContained) { // Both outside
                subLine.clear();
            } else if (firstContained && secondContained) {
                // Handled above already.
            } else { // Mismatch between PointInPolygon and get_line_intersection. Treat it as no intersection
                if (subLine.size())
                    res.push_back(subLine);
                subLine.clear();
            }
        } else if (type == OneIntersection) { // Need to check the following cases to avoid mismatch with PointInPolygon result.
            if (firstContained <= 0 && secondContained > 0) { // subLine MUST be empty
                if (!subLine.size())
                    subLine.push_back(QDoubleVector2D(intersections[0], intersections[1]));
                subLine.push_back(l.at(i+1));
            } else if (firstContained > 0 && secondContained <= 0) { // subLine MUST NOT be empty
                if (!subLine.size())
                    subLine.push_back(l.at(i));
                subLine.push_back(QDoubleVector2D(intersections[0], intersections[1]));
                res.push_back(subLine);
                subLine.clear();
            } else {
                if (subLine.size())
                    res.push_back(subLine);
                subLine.clear();
            }
        } else { // Two
            // restart strip
            subLine.clear();
            subLine.push_back(QDoubleVector2D(intersections[0], intersections[1]));
            subLine.push_back(QDoubleVector2D(intersections[2], intersections[3]));
            res.push_back(subLine);
            subLine.clear();
        }
    }
 
    if (subLine.size())
        res.push_back(subLine);
    return res;
}
 
QDeclarativeMapLineProperties::QDeclarativeMapLineProperties(QObject *parent)
    : QObject(parent)
{
}
 
QColor QDeclarativeMapLineProperties::color() const
{
    return color_;
}
 
void QDeclarativeMapLineProperties::setColor(const QColor &color)
{
    if (color_ == color)
        return;
 
    color_ = color;
    emit colorChanged(color_);
}
 
qreal QDeclarativeMapLineProperties::width() const
{
    return width_;
}
 
void QDeclarativeMapLineProperties::setWidth(qreal width)
{
    if (width_ == width)
        return;
 
    width_ = width;
    emit widthChanged(width_);
}
 
void QGeoMapPolylineGeometry::updateSourcePoints(const QGeoMap &map,
                                                 const QList<QDoubleVector2D> &basePath)
{
    // A polygon consists of mutliple paths. This is usually a perimeter and multiple holes
    // We move all paths into a single QPainterPath. The filling rule EvenOdd will then ensure that the paths are shown correctly
    if (!sourceDirty_)
        return;
    const QGeoProjectionWebMercator &p = static_cast<const QGeoProjectionWebMercator&>(map.geoProjection());
    srcPath_ = QPainterPath();
    srcOrigin_ = p.mapProjectionToGeo(QDoubleVector2D(0, 0)); //avoid warning of NaN values if function is returned early
 
    //0 Wrap the points around the globe if the path makes more sense that way.
    //  Ultimately, this is done if it is closer to walk around the day-border than the other direction
    QVarLengthArray<QList<QDoubleVector2D>, 3> wrappedPaths;
    wrappedPaths << QList<QDoubleVector2D>({basePath[0]});
    wrappedPaths.last().reserve(basePath.size());
    for (int i = 1; i < basePath.size(); i++) {
        if (basePath[i].x() > wrappedPaths.last().last().x() + 0.5)
            wrappedPaths.last() << basePath[i] - QDoubleVector2D(1.0, 0.0);
        else if (basePath[i].x() < wrappedPaths.last().last().x() - 0.5)
            wrappedPaths.last() << basePath[i] + QDoubleVector2D(1.0, 0.0);
        else
            wrappedPaths.last() << basePath[i];
    }
 
    //1 The bounding rectangle of the polygon and camera view are compared to determine if the polygon is visible
    //  The viewport is periodic in x-direction in the interval [-1; 1].
    //  The polygon (maybe) has to be ploted periodically too by shifting it by -1 or +1;
    const QRectF cameraRect = QDeclarativeGeoMapItemUtils::boundingRectangleFromList(p.visibleGeometry());
    QRectF itemRect;
    for (const auto &path : wrappedPaths)
        itemRect |= QDeclarativeGeoMapItemUtils::boundingRectangleFromList(path).adjusted(-1e-6, -1e-6, 2e-6, 2e-6); //TODO: Maybe use linewidth?
    for (double xoffset : {-1.0, 1.0}) {
        if (!cameraRect.intersects(itemRect.translated(QPointF(xoffset,0))))
            continue;
        wrappedPaths.append(QList<QDoubleVector2D>());
        QList<QDoubleVector2D> &wP = wrappedPaths.last();
        wP.reserve(wrappedPaths.first().size());
        for (const QDoubleVector2D &coord : wrappedPaths.first())
            wP.append(coord + QDoubleVector2D(xoffset, 0.0));
    }
    if (wrappedPaths.isEmpty()) // the polygon boundary rectangle does not overlap with the viewport rectangle
        return;
 
    //2 The polygons that are at least partially in the viewport are cliped to reduce their size
    QList<QList<QDoubleVector2D>> clippedPaths;
    const QList<QDoubleVector2D> &visibleRegion = p.visibleGeometryExpanded();
    for (const auto &path : wrappedPaths) {
        if (visibleRegion.size()) {
            clippedPaths << clipLine(path, visibleRegion);
            //TODO: Replace clipping with Clipper lib, similar to QPolygonMapItem
        } else {
            clippedPaths.append(path); //Do we really need this if there are no visible regions??
        }
    }
    if (clippedPaths.isEmpty()) //the polygon is entirely outside visibleRegion
        return;
 
    QRectF bb;
    for (const auto &path: clippedPaths)
        bb |= QDeclarativeGeoMapItemUtils::boundingRectangleFromList(path);
    //Offset by origin, find the maximum coordinate
    maxCoord_ = 0.0;
    srcOrigin_ = p.mapProjectionToGeo(QDoubleVector2D(bb.left(), bb.top()));
    QDoubleVector2D origin = p.wrappedMapProjectionToItemPosition(p.geoToWrappedMapProjection(srcOrigin_)); //save way: redo all projections
    for (const auto &path: clippedPaths) {
        QDoubleVector2D lastAddedPoint;
        for (qsizetype i = 0; i < path.size(); ++i) {
            QDoubleVector2D point = p.wrappedMapProjectionToItemPosition(path.at(i));
            point = point - origin; // (0,0) if point == origin
 
            if (qMax(point.x(), point.y()) > maxCoord_)
                maxCoord_ = qMax(point.x(), point.y());
 
            if (i == 0) {
                srcPath_.moveTo(point.toPointF());
                lastAddedPoint = point;
            } else {
                if ((point - lastAddedPoint).manhattanLength() > 3 ||
                        i == path.size() - 1) {
                    srcPath_.lineTo(point.toPointF());
                    lastAddedPoint = point;
                }
            }
        }
    }
 
    sourceBounds_ = srcPath_.boundingRect();
}
 
/*
 * QDeclarativePolygonMapItem Private Implementations
 */
 
QDeclarativePolylineMapItemPrivate::~QDeclarativePolylineMapItemPrivate()
{
}
 
QDeclarativePolylineMapItemPrivateCPU::QDeclarativePolylineMapItemPrivateCPU(QDeclarativePolylineMapItem &poly)
    : QDeclarativePolylineMapItemPrivate(poly)
{
    m_shape = new QQuickShape(&m_poly);
    m_shape->setObjectName("_qt_map_item_shape");
    m_shape->setZ(-1);
    m_shape->setContainsMode(QQuickShape::FillContains);
 
    m_shapePath = new QQuickShapePath(m_shape);
    m_painterPath = new QDeclarativeGeoMapPainterPath(m_shapePath);
 
    auto pathElements = m_shapePath->pathElements();
    pathElements.append(&pathElements, m_painterPath);
 
    auto shapePaths = m_shape->data();
    shapePaths.append(&shapePaths, m_shapePath);
}
 
QDeclarativePolylineMapItemPrivateCPU::~QDeclarativePolylineMapItemPrivateCPU()
{
    delete m_shape;
}
 
void QDeclarativePolylineMapItemPrivateCPU::regenerateCache()
{
    if (!m_poly.map() || m_poly.map()->geoProjection().projectionType() != QGeoProjection::ProjectionWebMercator)
        return;
    const QGeoProjectionWebMercator &p = static_cast<const QGeoProjectionWebMercator&>(m_poly.map()->geoProjection());
    m_geopathProjected.clear();
    if (m_poly.referenceSurface() == QLocation::ReferenceSurface::Globe) {
        const QList<QGeoCoordinate> realPath = QDeclarativeGeoMapItemUtils::greaterCirclePath(m_poly.m_geopath.path());
        m_geopathProjected.reserve(realPath.size());
        for (const QGeoCoordinate &c : realPath)
            m_geopathProjected << p.geoToMapProjection(c);
    } else {
        m_geopathProjected.reserve(m_poly.m_geopath.path().size());
        const QList<QGeoCoordinate> path = m_poly.m_geopath.path();
        for (const QGeoCoordinate &c : path)
            m_geopathProjected << p.geoToMapProjection(c);
    }
}
 
void QDeclarativePolylineMapItemPrivateCPU::updateCache()
{
    if (!m_poly.map() || m_poly.map()->geoProjection().projectionType() != QGeoProjection::ProjectionWebMercator)
        return;
    const QGeoProjectionWebMercator &p = static_cast<const QGeoProjectionWebMercator&>(m_poly.map()->geoProjection());
    m_geopathProjected << p.geoToMapProjection(m_poly.m_geopath.path().last());
}
 
void QDeclarativePolylineMapItemPrivateCPU::updatePolish()
{
    if (m_poly.m_geopath.path().length() < 2) { // Possibly cleared
        m_geometry.clear();
        m_poly.setWidth(0);
        m_poly.setHeight(0);
        m_shape->setVisible(false);
        return;
    }
    QScopedValueRollback<bool> rollback(m_poly.m_updatingGeometry);
    m_poly.m_updatingGeometry = true;
 
    const QGeoMap *map = m_poly.map();
    const qreal borderWidth = m_poly.m_line.width();
 
    m_geometry.updateSourcePoints(*map, m_geopathProjected);
 
    const QRectF bb = m_geometry.sourceBoundingBox();
    m_poly.setSize(bb.size() + QSizeF(borderWidth, borderWidth));
    // it has to be shifted so that the center of the line is on the correct geocoord
    m_poly.setPositionOnMap(m_geometry.origin(), -1 * bb.topLeft() + QPointF(borderWidth, borderWidth) * 0.5);
 
 
    m_poly.setShapeTriangulationScale(m_shape, m_geometry.maxCoord_);
 
    m_shapePath->setStrokeColor(m_poly.m_line.color());
    m_shapePath->setStrokeWidth(borderWidth);
    m_shapePath->setFillColor(Qt::transparent);
 
    QPainterPath path = m_geometry.srcPath();
    path.translate(-bb.left() + borderWidth * 0.5, -bb.top() + borderWidth * 0.5);
    m_painterPath->setPath(path);
 
    m_shape->setSize(m_poly.size());
    m_shape->setOpacity(m_poly.zoomLevelOpacity());
    m_shape->setVisible(true);
}
 
QSGNode *QDeclarativePolylineMapItemPrivateCPU::updateMapItemPaintNode(QSGNode *oldNode,
                                                        QQuickItem::UpdatePaintNodeData * /*data*/)
{
    delete oldNode;
 
    if (m_geometry.isScreenDirty() || !oldNode) {
        m_geometry.markClean();
    }
    return nullptr;
}
 
bool QDeclarativePolylineMapItemPrivateCPU::contains(const QPointF &point) const
{
    // With Shapes, do not just call
    // m_shape->contains(m_poly.mapToItem(m_shape, point)) because that can
    // only do FillContains at best, whereas the polyline relies on stroking.
 
    const QPainterPath &path = m_geometry.srcPath_;
    const double &lineWidth = m_poly.m_line.width();
    const QPointF p = m_poly.mapToItem(m_shape, point) - QPointF(lineWidth, lineWidth) * 0.5;
 
    for (int i = 1; i < path.elementCount(); i++) {
        if (path.elementAt(i).type == QPainterPath::MoveToElement)
            continue;
        const double dsqr = QDeclarativeGeoMapItemUtils::distanceSqrPointLine(p.x(), p.y(),
                                path.elementAt(i - 1).x, path.elementAt(i - 1).y,
                                path.elementAt(i).x, path.elementAt(i).y);
        if (dsqr < 0.25 * lineWidth * lineWidth)
            return true;
    }
    return false;
}
 
/*
 * QDeclarativePolygonMapItem Implementation
 */
 
QDeclarativePolylineMapItem::QDeclarativePolylineMapItem(QQuickItem *parent)
    : QDeclarativeGeoMapItemBase(parent), m_line(this),
      m_d(new QDeclarativePolylineMapItemPrivateCPU(*this))
{
    m_itemType = QGeoMap::MapPolyline;
    m_geopath = QGeoPathEager();
    setFlag(ItemHasContents, true);
    QObject::connect(&m_line, &QDeclarativeMapLineProperties::colorChanged,
                     this, &QDeclarativePolylineMapItem::updateAfterLinePropertiesChanged);
    QObject::connect(&m_line, &QDeclarativeMapLineProperties::widthChanged,
                     this, &QDeclarativePolylineMapItem::updateAfterLinePropertiesChanged);
    QObject::connect(this, &QDeclarativePolylineMapItem::referenceSurfaceChanged,
                     [=]() {m_d->onGeoGeometryChanged();});
}
 
QDeclarativePolylineMapItem::~QDeclarativePolylineMapItem()
{
}
 
void QDeclarativePolylineMapItem::updateAfterLinePropertiesChanged()
{
    m_d->onLinePropertiesChanged();
}
 
void QDeclarativePolylineMapItem::setMap(QDeclarativeGeoMap *quickMap, QGeoMap *map)
{
    QDeclarativeGeoMapItemBase::setMap(quickMap,map);
    if (map)
        m_d->onMapSet();
}
 
QList<QGeoCoordinate> QDeclarativePolylineMapItem::path() const
{
    return m_geopath.path();
}
 
void QDeclarativePolylineMapItem::setPath(const QList<QGeoCoordinate> &value)
{
    setPathFromGeoList(value);
}
 
void QDeclarativePolylineMapItem::setPath(const QGeoPath &path)
{
    if (m_geopath.path() == path.path())
        return;
 
    m_geopath = QGeoPathEager(path);
    m_d->onGeoGeometryChanged();
    emit pathChanged();
}
 
void QDeclarativePolylineMapItem::setPathFromGeoList(const QList<QGeoCoordinate> &path)
{
    if (m_geopath.path() == path)
        return;
 
    m_geopath.setPath(path);
 
    m_d->onGeoGeometryChanged();
    emit pathChanged();
}
 
int QDeclarativePolylineMapItem::pathLength() const
{
    return m_geopath.path().length();
}
 
void QDeclarativePolylineMapItem::addCoordinate(const QGeoCoordinate &coordinate)
{
    if (!coordinate.isValid())
        return;
 
    m_geopath.addCoordinate(coordinate);
 
    m_d->onGeoGeometryUpdated();
    emit pathChanged();
}
 
void QDeclarativePolylineMapItem::insertCoordinate(int index, const QGeoCoordinate &coordinate)
{
    if (index < 0 || index > m_geopath.path().length())
        return;
 
    m_geopath.insertCoordinate(index, coordinate);
 
    m_d->onGeoGeometryChanged();
    emit pathChanged();
}
 
void QDeclarativePolylineMapItem::replaceCoordinate(int index, const QGeoCoordinate &coordinate)
{
    if (index < 0 || index >= m_geopath.path().length())
        return;
 
    m_geopath.replaceCoordinate(index, coordinate);
 
    m_d->onGeoGeometryChanged();
    emit pathChanged();
}
 
QGeoCoordinate QDeclarativePolylineMapItem::coordinateAt(int index) const
{
    if (index < 0 || index >= m_geopath.path().length())
        return QGeoCoordinate();
 
    return m_geopath.coordinateAt(index);
}
 
bool QDeclarativePolylineMapItem::containsCoordinate(const QGeoCoordinate &coordinate)
{
    return m_geopath.containsCoordinate(coordinate);
}
 
void QDeclarativePolylineMapItem::removeCoordinate(const QGeoCoordinate &coordinate)
{
    int length = m_geopath.path().length();
    m_geopath.removeCoordinate(coordinate);
    if (m_geopath.path().length() == length)
        return;
 
    m_d->onGeoGeometryChanged();
    emit pathChanged();
}
 
void QDeclarativePolylineMapItem::removeCoordinate(int index)
{
    if (index < 0 || index >= m_geopath.path().length())
        return;
 
    m_geopath.removeCoordinate(index);
 
    m_d->onGeoGeometryChanged();
    emit pathChanged();
}
 
QDeclarativeMapLineProperties *QDeclarativePolylineMapItem::line()
{
    return &m_line;
}
 
void QDeclarativePolylineMapItem::geometryChange(const QRectF &newGeometry, const QRectF &oldGeometry)
{
    if (newGeometry.topLeft() == oldGeometry.topLeft() || !map() || !m_geopath.isValid() || m_updatingGeometry) {
        QDeclarativeGeoMapItemBase::geometryChange(newGeometry, oldGeometry);
        return;
    }
    // TODO: change the algorithm to preserve the distances and size!
    QGeoCoordinate newCenter = map()->geoProjection().itemPositionToCoordinate(QDoubleVector2D(newGeometry.center()), false);
    QGeoCoordinate oldCenter = map()->geoProjection().itemPositionToCoordinate(QDoubleVector2D(oldGeometry.center()), false);
    if (!newCenter.isValid() || !oldCenter.isValid())
        return;
    double offsetLongi = newCenter.longitude() - oldCenter.longitude();
    double offsetLati = newCenter.latitude() - oldCenter.latitude();
    if (offsetLati == 0.0 && offsetLongi == 0.0)
        return;
 
    m_geopath.translate(offsetLati, offsetLongi);
    m_d->onGeoGeometryChanged();
    emit pathChanged();
 
    // Not calling QDeclarativeGeoMapItemBase::geometryChange() as it will be called from a nested
    // call to this function.
}
 
void QDeclarativePolylineMapItem::afterViewportChanged(const QGeoMapViewportChangeEvent &event)
{
    if (event.mapSize.isEmpty())
        return;
 
    m_d->afterViewportChanged();
}
 
void QDeclarativePolylineMapItem::updatePolish()
{
    if (!map() || map()->geoProjection().projectionType() != QGeoProjection::ProjectionWebMercator)
        return;
    m_d->updatePolish();
}
 
QSGNode *QDeclarativePolylineMapItem::updateMapItemPaintNode(QSGNode *oldNode, UpdatePaintNodeData *data)
{
    return m_d->updateMapItemPaintNode(oldNode, data);
}
 
bool QDeclarativePolylineMapItem::contains(const QPointF &point) const
{
    return m_d->contains(point);
}
 
const QGeoShape &QDeclarativePolylineMapItem::geoShape() const
{
    return m_geopath;
}
 
void QDeclarativePolylineMapItem::setGeoShape(const QGeoShape &shape)
{
    const QGeoPath geopath(shape); // if shape isn't a path, path will be created as a default-constructed path
    setPath(geopath);
}
 
 
QT_END_NAMESPACE