/* ============================================================
 *
 * This file is a part of digiKam project
 * https://www.digikam.org
 *
 * Date        : 2023-05-15
 * Description : geolocation engine based on Marble.
 *               (c) 2007-2022 Marble Team
 *               https://invent.kde.org/education/marble/-/raw/master/data/credits_authors.html
 *
 * SPDX-FileCopyrightText: 2023-2026 by Gilles Caulier <caulier dot gilles at gmail dot com>
 *
 * SPDX-License-Identifier: LGPL-2.1-or-later
 *
 * ============================================================ */

#include "GeoPainter.h"
#include "GeoPainter_p.h"

// Qt includes

#include <QList>
#include <QPainterPath>
#include <QPixmapCache>
#include <QRegion>
#include <qmath.h>

// Local includes

#include "GeoDataCoordinates.h"
#include "GeoDataLatLonAltBox.h"
#include "GeoDataLineString.h"
#include "GeoDataLinearRing.h"
#include "GeoDataPoint.h"
#include "GeoDataPolygon.h"
#include "ViewportParams.h"
#include "AbstractProjection.h"
#include "digikam_debug.h"

namespace Marble
{

GeoPainterPrivate::GeoPainterPrivate(GeoPainter* q, const ViewportParams* viewport, MapQuality mapQuality)
    : m_viewport  (viewport),
      m_mapQuality(mapQuality),
      m_x         (new qreal[100]),
      m_parent    (q)
{
}

GeoPainterPrivate::~GeoPainterPrivate()
{
    delete [] m_x;
}

void GeoPainterPrivate::createAnnotationLayout(qreal x, qreal y,
                                               const QSizeF& bubbleSize,
                                               qreal bubbleOffsetX, qreal bubbleOffsetY,
                                               qreal xRnd, qreal yRnd,
                                               QPainterPath& path, QRectF& rect)
{
    // TODO: MOVE this into an own Annotation class
    qreal arrowPosition = 0.3;
    qreal arrowWidth    = 12.0;

    qreal width         =  bubbleSize.width();
    qreal height        = bubbleSize.height();

    qreal dx            = (bubbleOffsetX > 0) ? 1.0 : -1.0;    // x-Mirror
    qreal dy            = (bubbleOffsetY < 0) ? 1.0 : -1.0;    // y-Mirror

    qreal x0 = (x + bubbleOffsetX) - dx * (1.0 - arrowPosition) * (width - 2.0 * xRnd) - xRnd * dx;
    qreal x1 = (x + bubbleOffsetX) - dx * (1.0 - arrowPosition) * (width - 2.0 * xRnd);
    qreal x2 = (x + bubbleOffsetX) - dx * (1.0 - arrowPosition) * (width - 2.0 * xRnd) + xRnd * dx;
    qreal x3 = (x + bubbleOffsetX) - dx * arrowWidth / 2.0;
    qreal x4 = (x + bubbleOffsetX) + dx * arrowWidth / 2.0;
    qreal x5 = (x + bubbleOffsetX) + dx * arrowPosition * (width - 2.0 * xRnd) - xRnd * dx;
    qreal x6 = (x + bubbleOffsetX) + dx * arrowPosition * (width - 2.0 * xRnd);
    qreal x7 = (x + bubbleOffsetX) + dx * arrowPosition * (width - 2.0 * xRnd) + xRnd * dx;

    qreal y0 = (y + bubbleOffsetY);
    qreal y1 = (y + bubbleOffsetY) - dy * yRnd;
    qreal y2 = (y + bubbleOffsetY) - dy * 2 * yRnd;
    qreal y5 = (y + bubbleOffsetY) - dy * (height - 2 * yRnd);
    qreal y6 = (y + bubbleOffsetY) - dy * (height - yRnd);
    qreal y7 = (y + bubbleOffsetY) - dy * height;

    QPointF p1(x, y);    // pointing point
    QPointF p2(x4, y0);
    QPointF p3(x6, y0);
    QPointF p4(x7, y1);
    QPointF p5(x7, y6);
    QPointF p6(x6, y7);
    QPointF p7(x1, y7);
    QPointF p8(x0, y6);
    QPointF p9(x0, y1);
    QPointF p10(x1, y0);
    QPointF p11(x3, y0);

    QRectF bubbleBoundingBox(QPointF(x0, y7), QPointF(x7, y0));

    path.moveTo(p1);
    path.lineTo(p2);

    path.lineTo(p3);
    QRectF bottomRight(QPointF(x5, y2), QPointF(x7, y0));
    path.arcTo(bottomRight, 270.0, 90.0);

    path.lineTo(p5);
    QRectF topRight(QPointF(x5, y7), QPointF(x7, y5));
    path.arcTo(topRight, 0.0, 90.0);

    path.lineTo(p7);
    QRectF topLeft(QPointF(x0, y7), QPointF(x2, y5));
    path.arcTo(topLeft, 90.0, 90.0);

    path.lineTo(p9);
    QRectF bottomLeft(QPointF(x0, y2), QPointF(x2, y0));
    path.arcTo(bottomLeft, 180.0, 90.0);

    path.lineTo(p10);
    path.lineTo(p11);
    path.lineTo(p1);

    qreal left   = (dx > 0) ? x1 : x6;
    qreal right  = (dx > 0) ? x6 : x1;
    qreal top    = (dy > 0) ? y6 : y1;
    qreal bottom = (dy > 0) ? y1 : y6;

    rect.setTopLeft(QPointF(left, top));
    rect.setBottomRight(QPointF(right, bottom));
}

GeoDataLinearRing GeoPainterPrivate::createLinearRingFromGeoRect(const GeoDataCoordinates& centerCoordinates,
                                                                 qreal width, qreal height)
{
    qreal lon = 0.0;
    qreal lat = 0.0;
    qreal altitude = centerCoordinates.altitude();
    centerCoordinates.geoCoordinates(lon, lat, GeoDataCoordinates::Degree);

    lon = GeoDataCoordinates::normalizeLon(lon, GeoDataCoordinates::Degree);
    lat = GeoDataCoordinates::normalizeLat(lat, GeoDataCoordinates::Degree);

    qreal west = GeoDataCoordinates::normalizeLon(lon - width * 0.5, GeoDataCoordinates::Degree);
    qreal east =  GeoDataCoordinates::normalizeLon(lon + width * 0.5, GeoDataCoordinates::Degree);

    qreal north = GeoDataCoordinates::normalizeLat(lat + height * 0.5, GeoDataCoordinates::Degree);
    qreal south = GeoDataCoordinates::normalizeLat(lat - height * 0.5, GeoDataCoordinates::Degree);

    GeoDataCoordinates southWest(west, south,
                                 altitude, GeoDataCoordinates::Degree);
    GeoDataCoordinates southEast(east, south,
                                 altitude, GeoDataCoordinates::Degree);
    GeoDataCoordinates northEast(east, north,
                                 altitude, GeoDataCoordinates::Degree);
    GeoDataCoordinates northWest(west, north,
                                 altitude, GeoDataCoordinates::Degree);

    GeoDataLinearRing rectangle(Tessellate | RespectLatitudeCircle);

    // If the width of the rect is larger as 180 degree, we have to enforce the long way.

    if (width >= 180)
    {
        qreal center = lon;
        GeoDataCoordinates southCenter(center, south, altitude, GeoDataCoordinates::Degree);
        GeoDataCoordinates northCenter(center, north, altitude, GeoDataCoordinates::Degree);

        rectangle << southWest << southCenter << southEast << northEast << northCenter << northWest;
    }
    else
    {
        rectangle << southWest << southEast << northEast << northWest;
    }

    return rectangle;
}

bool GeoPainterPrivate::doClip(const ViewportParams* viewport)
{
    if (!viewport->currentProjection()->isClippedToSphere())
    {
        return true;
    }

    const qint64 radius = viewport->radius() * viewport->currentProjection()->clippingRadius();

    return (radius > viewport->width() / 2 || radius > viewport->height() / 2);
}

qreal GeoPainterPrivate::normalizeAngle(qreal angle)
{
    angle = fmodf(angle, 360);

    return (angle < 0) ? angle + 360 : angle;
}

void GeoPainterPrivate::drawTextRotated(const QPointF& startPoint, qreal angle, const QString& text)
{
    QRectF textRect(startPoint, m_parent->fontMetrics().size(0, text));
    QTransform const oldTransform = m_parent->transform();
    m_parent->translate(startPoint);
    m_parent->rotate(angle);
    m_parent->translate(-startPoint - QPointF(0.0, m_parent->fontMetrics().height() / 2.0));

    m_parent->drawText(textRect, text);
    m_parent->setTransform(oldTransform);
}

// -------------------------------------------------------------------------------------------------

GeoPainter::GeoPainter(QPaintDevice* pd, const ViewportParams* viewport, MapQuality mapQuality)
    : ClipPainter(pd, GeoPainterPrivate::doClip(viewport)),
      d          (new GeoPainterPrivate(this, viewport, mapQuality))
{
    const bool antialiased = (mapQuality == HighQuality) || (mapQuality == PrintQuality);
    setRenderHint(QPainter::Antialiasing, antialiased);
    ClipPainter::setScreenClip(false);
}

GeoPainter::~GeoPainter()
{
    delete d;
}

MapQuality GeoPainter::mapQuality() const
{
    return d->m_mapQuality;
}

void GeoPainter::drawAnnotation(const GeoDataCoordinates& position,
                                const QString& text, QSizeF bubbleSize,
                                qreal bubbleOffsetX, qreal bubbleOffsetY,
                                qreal xRnd, qreal yRnd)
{
    int pointRepeatNum   = 0;
    qreal y              = 0.0;
    bool globeHidesPoint = false;

    if (bubbleSize.height() <= 0)
    {
        QRectF rect           = QRectF(QPointF(0.0, 0.0), bubbleSize - QSizeF(2 * xRnd, 0.0));
        qreal idealTextHeight = boundingRect(rect, Qt::TextWordWrap, text).height();
        bubbleSize.setHeight(2 * yRnd + idealTextHeight);
    }

    bool visible = d->m_viewport->screenCoordinates(position, d->m_x, y, pointRepeatNum, QSizeF(), globeHidesPoint);

    if (visible)
    {
        // Draw all the x-repeat-instances of the point on the screen

        for (int it = 0 ; it < pointRepeatNum ; ++it)
        {
            QPainterPath path;
            QRectF rect;
            d->createAnnotationLayout(d->m_x[it], y, bubbleSize, bubbleOffsetX, bubbleOffsetY,  xRnd, yRnd, path, rect);
            QPainter::drawPath(path);
            QPainter::drawText(rect, Qt::TextWordWrap, text, &rect);
        }
    }
}

void GeoPainter::drawPoint(const GeoDataCoordinates& position)
{
    int pointRepeatNum      = 0;
    qreal y                 = 0.0;
    bool globeHidesPoint    = false;

    bool visible = d->m_viewport->screenCoordinates(position, d->m_x, y, pointRepeatNum, QSizeF(), globeHidesPoint);

    if (visible)
    {
        // Draw all the x-repeat-instances of the point on the screen

        for (int it = 0 ; it < pointRepeatNum ; ++it)
        {
            QPainter::drawPoint(QPointF(d->m_x[it], y));
        }
    }
}

QRegion GeoPainter::regionFromPoint(const GeoDataCoordinates& position,
                                    qreal width) const
{
    return regionFromRect(position, width, width, false, 3);
}

void GeoPainter::drawPoint(const GeoDataPoint& point)
{
    drawPoint(point.coordinates());
}

QRegion GeoPainter::regionFromPoint(const GeoDataPoint& point,
                                    qreal width) const
{
    return regionFromRect(point.coordinates(), width, width, false, 3);
}

void GeoPainter::drawText(const GeoDataCoordinates& position,
                          const QString& text,
                          qreal xOffset, qreal yOffset,
                          qreal width, qreal height,
                          const QTextOption& option)
{
    // Of course in theory we could have the "isGeoProjected" parameter used
    // for drawText as well. However this would require us to convert all
    // glyphs to PainterPaths / QPolygons. From QPolygons we could create
    // GeoDataPolygons which could get painted on screen. Any patches appreciated ;-)

    int pointRepeatNum      = 0;
    qreal y                 = 0.0;
    bool globeHidesPoint    = false;

    QSizeF textSize(fontMetrics().horizontalAdvance(text), fontMetrics().height());

    bool visible = d->m_viewport->screenCoordinates(position, d->m_x, y, pointRepeatNum, textSize, globeHidesPoint);

    if (visible)
    {
        // Draw all the x-repeat-instances of the point on the screen

        const qreal posY = y - yOffset;

        for (int it = 0 ; it < pointRepeatNum ; ++it)
        {
            const qreal posX = d->m_x[it] + xOffset;

            if (width == 0.0 && height == 0.0)
            {
                QPainter::drawText(QPointF(posX, posY), text);
            }
            else
            {
                const QRectF boundingRect(posX, posY, width, height);
                QPainter::drawText(boundingRect, text, option);
            }
        }
    }
}

void GeoPainter::drawEllipse(const GeoDataCoordinates& centerPosition,
                             qreal width, qreal height,
                             bool isGeoProjected)
{
    if (!isGeoProjected)
    {
        int pointRepeatNum      = 0;
        qreal y                 = 0.0;
        bool globeHidesPoint    = false;

        bool visible = d->m_viewport->screenCoordinates(centerPosition, d->m_x, y, pointRepeatNum, QSizeF(width, height), globeHidesPoint);

        if (visible)
        {
            // Draw all the x-repeat-instances of the point on the screen

            const qreal rx = width  / 2.0;
            const qreal ry = height / 2.0;

            for (int it = 0 ; it < pointRepeatNum ; ++it)
            {
                QPainter::drawEllipse(QPointF(d->m_x[it], y), rx, ry);
            }
        }
    }
    else
    {
        // Initialize variables
        const qreal centerLon = centerPosition.longitude(GeoDataCoordinates::Degree);
        const qreal centerLat = centerPosition.latitude(GeoDataCoordinates::Degree);
        const qreal altitude = centerPosition.altitude();

        // Ensure a valid latitude range:

        if (((centerLat + 0.5 * height) > 90.0) || ((centerLat - 0.5 * height) < -90.0))
        {
            return;
        }

        // Don't show the ellipse if it's too small:

        GeoDataLatLonBox ellipseBox(centerLat + 0.5 * height, centerLat - 0.5 * height,
                                    centerLon + 0.5 * width,  centerLon - 0.5 * width,
                                    GeoDataCoordinates::Degree);

        if (
            !d->m_viewport->viewLatLonAltBox().intersects(ellipseBox) ||
            !d->m_viewport->resolves(ellipseBox)
           )
        {
            return;
        }

        GeoDataLinearRing ellipse;

        // Optimizing the precision by determining the size which the
        // ellipse covers on the screen:

        const qreal degreeResolution = d->m_viewport->angularResolution() * RAD2DEG;

        // To create a circle shape even for very small precision we require uneven numbers:

        const int precision = qMin<qreal>(width / degreeResolution / 8 + 1, 81);

        // Calculate the shape of the upper half of the ellipse:

        for (int i = 0 ; i <= precision ; ++i)
        {
            const qreal t   = 1.0 - 2.0 * (qreal)(i) / (qreal)(precision);
            const qreal lat = centerLat + 0.5 * height * sqrt(1.0 - t * t);
            const qreal lon = centerLon + 0.5 * width * t;

            ellipse << GeoDataCoordinates(lon, lat, altitude, GeoDataCoordinates::Degree);
        }

        // Calculate the shape of the lower half of the ellipse:

        for (int i = 0 ; i <= precision ; ++i)
        {
            const qreal t   = 2.0 * (qreal)(i) / (qreal)(precision) -  1.0;
            const qreal lat = centerLat - 0.5 * height * sqrt(1.0 - t * t);
            const qreal lon = centerLon + 0.5 * width * t;

            ellipse << GeoDataCoordinates(lon, lat, altitude, GeoDataCoordinates::Degree);
        }

        drawPolygon(ellipse);
    }
}

QRegion GeoPainter::regionFromEllipse(const GeoDataCoordinates& centerPosition,
                                      qreal width, qreal height,
                                      bool isGeoProjected,
                                      qreal strokeWidth) const
{
    if (!isGeoProjected)
    {
        int pointRepeatNum      = 0;
        qreal y                 = 0.0;
        bool globeHidesPoint    = false;

        bool visible = d->m_viewport->screenCoordinates(centerPosition, d->m_x, y, pointRepeatNum, QSizeF(width, height), globeHidesPoint);

        QRegion regions;

        if (visible)
        {
            // only a hint, a backend could still ignore it, but we cannot know more

            const bool antialiased      = testRenderHint(QPainter::Antialiasing);
            const qreal halfStrokeWidth = strokeWidth / 2.0;
            const int startY            = antialiased ? (qFloor(y - halfStrokeWidth))         : (qFloor(y + 0.5 - halfStrokeWidth));
            const int endY              = antialiased ? (qCeil(y + height + halfStrokeWidth)) : (qFloor(y + 0.5 + height + halfStrokeWidth));

            // Draw all the x-repeat-instances of the point on the screen

            for (int it = 0 ; it < pointRepeatNum ; ++it)
            {
                const qreal x    = d->m_x[it];
                const int startX = antialiased ? (qFloor(x - halfStrokeWidth))        : (qFloor(x + 0.5 - halfStrokeWidth));
                const int endX   = antialiased ? (qCeil(x + width + halfStrokeWidth)) : (qFloor(x + 0.5 + width +  halfStrokeWidth));

                regions += QRegion(startX, startY, endX - startX, endY - startY, QRegion::Ellipse);
            }
        }

        return regions;
    }
    else
    {
        // Initialize variables

        const qreal centerLon = centerPosition.longitude(GeoDataCoordinates::Degree);
        const qreal centerLat = centerPosition.latitude(GeoDataCoordinates::Degree);
        const qreal altitude  = centerPosition.altitude();

        // Ensure a valid latitude range:

        if (((centerLat + 0.5 * height) > 90.0) || ((centerLat - 0.5 * height) < -90.0))
        {
            return QRegion();
        }

        // Don't show the ellipse if it's too small:

        GeoDataLatLonBox ellipseBox(centerLat + 0.5 * height, centerLat - 0.5 * height,
                                    centerLon + 0.5 * width,  centerLon - 0.5 * width,
                                    GeoDataCoordinates::Degree);

        if (
            !d->m_viewport->viewLatLonAltBox().intersects(ellipseBox) ||
            !d->m_viewport->resolves(ellipseBox)
           )
        {
            return QRegion();
        }

        GeoDataLinearRing ellipse;

        // Optimizing the precision by determining the size which the
        // ellipse covers on the screen:

        const qreal degreeResolution = d->m_viewport->angularResolution() * RAD2DEG;

        // To create a circle shape even for very small precision we require uneven numbers:

        const int precision = qMin<qreal>(width / degreeResolution / 8 + 1, 81);

        // Calculate the shape of the upper half of the ellipse:

        for (int i = 0 ; i <= precision ; ++i)
        {
            const qreal t   = 1.0 - 2.0 * (qreal)(i) / (qreal)(precision);
            const qreal lat = centerLat + 0.5 * height * sqrt(1.0 - t * t);
            const qreal lon = centerLon + 0.5 * width * t;

            ellipse << GeoDataCoordinates(lon, lat, altitude, GeoDataCoordinates::Degree);
        }

        // Calculate the shape of the lower half of the ellipse:

        for (int i = 0 ; i <= precision ; ++i)
        {
            const qreal t   = 2.0 * (qreal)(i) / (qreal)(precision) -  1.0;
            const qreal lat = centerLat - 0.5 * height * sqrt(1.0 - t * t);
            const qreal lon = centerLon + 0.5 * width * t;

            ellipse << GeoDataCoordinates(lon, lat, altitude, GeoDataCoordinates::Degree);
        }

        return regionFromPolygon(ellipse, Qt::OddEvenFill, strokeWidth);
    }
}

void GeoPainter::drawImage(const GeoDataCoordinates& centerPosition,
                           const QImage& image /*, bool isGeoProjected */)
{
    // isGeoProjected = true would project the image/pixmap onto the globe. This
    // requires to deal with the TextureMapping classes -> should get
    // implemented later on

    int pointRepeatNum      = 0;
    qreal y                 = 0.0;
    bool globeHidesPoint    = false;

    //if ( !isGeoProjected ) {

    bool visible = d->m_viewport->screenCoordinates(centerPosition, d->m_x, y, pointRepeatNum, image.size(), globeHidesPoint);

    if (visible)
    {
        // Draw all the x-repeat-instances of the point on the screen

        const qreal posY = y - (image.height() / 2.0);

        for (int it = 0 ; it < pointRepeatNum ; ++it)
        {
            const qreal posX = d->m_x[it] - (image.width() / 2.0);
            QPainter::drawImage(QPointF(posX, posY), image);
        }
    }

    //}
}


void GeoPainter::drawPixmap(const GeoDataCoordinates& centerPosition,
                            const QPixmap& pixmap /* , bool isGeoProjected */)
{
    int pointRepeatNum      = 0;
    qreal y                 = 0.0;
    bool globeHidesPoint    = false;

    //if ( !isGeoProjected ) {

    // FIXME: Better visibility detection that takes the circle geometry into account

    bool visible = d->m_viewport->screenCoordinates(centerPosition, d->m_x, y, pointRepeatNum, pixmap.size(), globeHidesPoint);

    if (visible)
    {
        // Draw all the x-repeat-instances of the point on the screen

        const qreal posY = y - (pixmap.height() / 2.0);

        for (int it = 0 ; it < pointRepeatNum ; ++it)
        {
            const qreal posX = d->m_x[it] - (pixmap.width() / 2.0);
            QPainter::drawPixmap(QPointF(posX, posY), pixmap);
        }
    }

    //}
}

QRegion GeoPainter::regionFromPixmapRect(const GeoDataCoordinates& centerCoordinates,
                                         int width, int height,
                                         int margin) const
{
    const int fullWidth  = width + 2 * margin;
    const int fullHeight = height + 2 * margin;
    int pointRepeatNum   = 0;
    qreal y              = 0.0;
    bool globeHidesPoint = false;

    const bool visible = d->m_viewport->screenCoordinates(centerCoordinates,
                                                          d->m_x, y, pointRepeatNum,
                                                          QSizeF(fullWidth, fullHeight), globeHidesPoint);

    QRegion regions;

    if (visible)
    {
        // cmp. GeoPainter::drawPixmap() position calculation
        // QPainter::drawPixmap seems to qRound the passed position
        const int posY = qRound(y - (height / 2.0)) - margin;

        for (int it = 0; it < pointRepeatNum; ++it)
        {
            const int posX = qRound(d->m_x[it] - (width / 2.0)) - margin;
            regions += QRegion(posX, posY, width, height);
        }
    }

    return regions;
}

void GeoPainter::polygonsFromLineString(const GeoDataLineString& lineString,
                                        QVector<QPolygonF*>& polygons) const
{
    // Immediately leave this method now if:
    // - the object is not visible in the viewport or if
    // - the size of the object is below the resolution of the viewport
    if (! d->m_viewport->viewLatLonAltBox().intersects(lineString.latLonAltBox()) ||
        ! d->m_viewport->resolves(lineString.latLonAltBox())
       )
    {
        // qCDebug(DIGIKAM_GEOENGINE_LOG) << "LineString doesn't get displayed on the viewport";
        return;
    }

    d->m_viewport->screenCoordinates(lineString, polygons);
}


void GeoPainter::drawPolyline(const GeoDataLineString& lineString,
                              const QString& labelText,
                              LabelPositionFlags labelPositionFlags,
                              const QColor& labelColor)
{
    // no labels to draw?
    // TODO: !labelColor.isValid() || labelColor.alpha() == 0 does not work,
    // something injects invalid labelColor for city streets
    if (labelText.isEmpty() || labelPositionFlags.testFlag(NoLabel) ||
        labelColor == Qt::transparent)
    {
        drawPolyline(lineString);
        return;
    }

    QVector<QPolygonF*> polygons;
    polygonsFromLineString(lineString, polygons);

    if (polygons.empty())
    {
        return;
    }

    for (const QPolygonF* itPolygon : polygons)
    {
        ClipPainter::drawPolyline(*itPolygon);
    }

    drawLabelsForPolygons(polygons,
                          labelText,
                          labelPositionFlags,
                          labelColor);

    qDeleteAll(polygons);
}

void GeoPainter::drawLabelsForPolygons(const QVector<QPolygonF*>& polygons,
                                       const QString& labelText,
                                       LabelPositionFlags labelPositionFlags,
                                       const QColor& labelColor)
{
    if (labelText.isEmpty())
    {
        return;
    }

    QPen const oldPen = pen();

    if (labelPositionFlags.testFlag(FollowLine))
    {
        const qreal maximumLabelFontSize = 20;
        qreal fontSize = pen().widthF() * 0.45;
        fontSize = qMin(fontSize, maximumLabelFontSize);

        if (fontSize < 6.0 || labelColor == "transparent")
        {
            return;
        }

        QFont font = this->font();
        font.setPointSizeF(fontSize);
        setFont(font);
        int labelWidth = fontMetrics().horizontalAdvance(labelText);

        if (labelText.size() < 20)
        {
            labelWidth *= (20.0 / labelText.size());
        }

        setPen(labelColor);

        QVector<QPointF> labelNodes;
        QRectF viewportRect = QRectF(QPointF(0, 0), d->m_viewport->size());

        for (QPolygonF* itPolygon : polygons)
        {
            if (!itPolygon->boundingRect().intersects(viewportRect))
            {
                continue;
            }

            labelNodes.clear();

            QPainterPath path;
            path.addPolygon(*itPolygon);
            qreal pathLength = path.length();

            if (pathLength == 0)
            {
                continue;
            }

            int maxNumLabels = static_cast<int>(pathLength / labelWidth);

            if (maxNumLabels > 0)
            {
                qreal textRelativeLength = labelWidth / pathLength;
                int numLabels = 1;

                if (maxNumLabels > 1)
                {
                    numLabels = maxNumLabels / 2;
                }

                qreal offset = (1.0 - numLabels * textRelativeLength) / numLabels;
                qreal startPercent = offset / 2.0;

                for (int k = 0; k < numLabels; ++k, startPercent += textRelativeLength + offset)
                {
                    QPointF point = path.pointAtPercent(startPercent);
                    QPointF endPoint = path.pointAtPercent(startPercent + textRelativeLength);

                    if (viewport().contains(point.toPoint()) || viewport().contains(endPoint.toPoint()))
                    {
                        qreal angle = -path.angleAtPercent(startPercent);
                        qreal angle2 = -path.angleAtPercent(startPercent + textRelativeLength);
                        angle = GeoPainterPrivate::normalizeAngle(angle);
                        angle2 = GeoPainterPrivate::normalizeAngle(angle2);
                        bool upsideDown = angle > 90.0 && angle < 270.0;

                        if (qAbs(angle - angle2) < 3.0)
                        {
                            if (upsideDown)
                            {
                                angle += 180.0;
                                point = path.pointAtPercent(startPercent + textRelativeLength);
                            }

                            d->drawTextRotated(point, angle, labelText);
                        }

                        else
                        {
                            for (int i = 0; i < labelText.length(); ++i)
                            {
                                qreal currentGlyphTextLength = fontMetrics().horizontalAdvance(labelText.left(i)) / pathLength;

                                if (!upsideDown)
                                {
                                    angle = -path.angleAtPercent(startPercent + currentGlyphTextLength);
                                    point = path.pointAtPercent(startPercent + currentGlyphTextLength);
                                }

                                else
                                {
                                    angle = -path.angleAtPercent(startPercent + textRelativeLength - currentGlyphTextLength) + 180;
                                    point = path.pointAtPercent(startPercent + textRelativeLength - currentGlyphTextLength);
                                }

                                d->drawTextRotated(point, angle, labelText.at(i));
                            }
                        }
                    }
                }
            }
        }
    }

    else
    {
        setPen(labelColor);

        int labelWidth = fontMetrics().horizontalAdvance(labelText);
        int labelAscent = fontMetrics().ascent();

        QVector<QPointF> labelNodes;

        for (QPolygonF* itPolygon : polygons)
        {
            labelNodes.clear();
            ClipPainter::labelPosition(*itPolygon, labelNodes, labelPositionFlags);

            if (!labelNodes.isEmpty())
            {
                for (const QPointF& labelNode : labelNodes)
                {
                    QPointF labelPosition = labelNode + QPointF(3.0, -2.0);

                    // FIXME: This is a Q&D fix.
                    qreal xmax = viewport().width() - 10.0 - labelWidth;

                    if (labelPosition.x() > xmax)
                    {
                        labelPosition.setX(xmax);
                    }

                    qreal ymin = 10.0 + labelAscent;

                    if (labelPosition.y() < ymin)
                    {
                        labelPosition.setY(ymin);
                    }

                    qreal ymax = viewport().height() - 10.0 - labelAscent;

                    if (labelPosition.y() > ymax)
                    {
                        labelPosition.setY(ymax);
                    }

                    drawText(QRectF(labelPosition, fontMetrics().size(0, labelText)), labelText);
                }
            }
        }
    }

    setPen(oldPen);
}

void GeoPainter::drawPolyline(const GeoDataLineString& lineString)
{
    QVector<QPolygonF*> polygons;
    polygonsFromLineString(lineString, polygons);

    if (polygons.empty())
    {
        return;
    }

    for (const QPolygonF* itPolygon : polygons)
    {
        ClipPainter::drawPolyline(*itPolygon);
    }

    qDeleteAll(polygons);
}


QRegion GeoPainter::regionFromPolyline(const GeoDataLineString& lineString,
                                       qreal strokeWidth) const
{
    // Immediately leave this method now if:
    // - the object is not visible in the viewport or if
    // - the size of the object is below the resolution of the viewport
    if (! d->m_viewport->viewLatLonAltBox().intersects(lineString.latLonAltBox()) ||
        ! d->m_viewport->resolves(lineString.latLonAltBox())
       )
    {
        // qCDebug(DIGIKAM_GEOENGINE_LOG) << "LineString doesn't get displayed on the viewport";
        return QRegion();
    }

    QPainterPath painterPath;

    QVector<QPolygonF*> polygons;
    d->m_viewport->screenCoordinates(lineString, polygons);

    for (QPolygonF* itPolygon : polygons)
    {
        painterPath.addPolygon(*itPolygon);
    }

    qDeleteAll(polygons);

    QPainterPathStroker stroker;
    stroker.setWidth(strokeWidth);
    QPainterPath strokePath = stroker.createStroke(painterPath);

    return QRegion(strokePath.toFillPolygon().toPolygon(), Qt::WindingFill);
}


void GeoPainter::drawPolygon(const GeoDataLinearRing& linearRing,
                             Qt::FillRule fillRule)
{
    // Immediately leave this method now if:
    // - the object is not visible in the viewport or if
    // - the size of the object is below the resolution of the viewport
    if (! d->m_viewport->viewLatLonAltBox().intersects(linearRing.latLonAltBox()) ||
        ! d->m_viewport->resolves(linearRing.latLonAltBox())
       )
    {
        // qCDebug(DIGIKAM_GEOENGINE_LOG) << "Polygon doesn't get displayed on the viewport";
        return;
    }

    QVector<QPolygonF*> polygons;
    d->m_viewport->screenCoordinates(linearRing, polygons);

    for (QPolygonF* itPolygon : polygons)
    {
        ClipPainter::drawPolygon(*itPolygon, fillRule);
    }

    qDeleteAll(polygons);
}


QRegion GeoPainter::regionFromPolygon(const GeoDataLinearRing& linearRing,
                                      Qt::FillRule fillRule, qreal strokeWidth) const
{
    // Immediately leave this method now if:
    // - the object is not visible in the viewport or if
    // - the size of the object is below the resolution of the viewport
    if (! d->m_viewport->viewLatLonAltBox().intersects(linearRing.latLonAltBox()) ||
        ! d->m_viewport->resolves(linearRing.latLonAltBox())
       )
    {
        return QRegion();
    }

    QRegion regions;

    QVector<QPolygonF*> polygons;
    d->m_viewport->screenCoordinates(linearRing, polygons);

    if (strokeWidth == 0)
    {
        // This is the faster way
        for (QPolygonF* itPolygon : polygons)
        {
            regions += QRegion((*itPolygon).toPolygon(), fillRule);
        }
    }

    else
    {
        QPainterPath painterPath;

        for (QPolygonF* itPolygon : polygons)
        {
            painterPath.addPolygon(*itPolygon);
        }

        QPainterPathStroker stroker;
        stroker.setWidth(strokeWidth);
        QPainterPath strokePath = stroker.createStroke(painterPath);
        painterPath = painterPath.united(strokePath);
        regions = QRegion(painterPath.toFillPolygon().toPolygon());
    }

    qDeleteAll(polygons);

    return regions;
}


void GeoPainter::drawPolygon(const GeoDataPolygon& polygon,
                             Qt::FillRule fillRule)
{
    // If the object is not visible in the viewport return
    if (! d->m_viewport->viewLatLonAltBox().intersects(polygon.outerBoundary().latLonAltBox()) ||
        // If the size of the object is below the resolution of the viewport then return
        ! d->m_viewport->resolves(polygon.outerBoundary().latLonAltBox())
       )
    {
        // qCDebug(DIGIKAM_GEOENGINE_LOG) << "Polygon doesn't get displayed on the viewport";
        return;
    }

    // qCDebug(DIGIKAM_GEOENGINE_LOG) << "Drawing Polygon";

    QVector<QPolygonF*> outerPolygons;
    QVector<QPolygonF*> innerPolygons;
    d->m_viewport->screenCoordinates(polygon.outerBoundary(), outerPolygons);

    QPen const currentPen = pen();

    bool const hasInnerBoundaries = !polygon.innerBoundaries().isEmpty();
    bool innerBoundariesOnScreen = false;

    if (hasInnerBoundaries)
    {
        QVector<GeoDataLinearRing> const& innerBoundaries = polygon.innerBoundaries();

        const GeoDataLatLonAltBox& viewLatLonAltBox = d->m_viewport->viewLatLonAltBox();

        for (const GeoDataLinearRing& itInnerBoundary : innerBoundaries)
        {
            if (viewLatLonAltBox.intersects(itInnerBoundary.latLonAltBox())
                && d->m_viewport->resolves(itInnerBoundary.latLonAltBox()), 4)
            {
                innerBoundariesOnScreen = true;
                break;
            }
        }

        if (innerBoundariesOnScreen)
        {
            // Create the inner screen polygons
            for (const GeoDataLinearRing& itInnerBoundary : innerBoundaries)
            {
                QVector<QPolygonF*> innerPolygonsPerBoundary;

                d->m_viewport->screenCoordinates(itInnerBoundary, innerPolygonsPerBoundary);

                for (QPolygonF* innerPolygonPerBoundary : innerPolygonsPerBoundary)
                {
                    innerPolygons << innerPolygonPerBoundary;
                }
            }

            setPen(Qt::NoPen);
            QVector<QPolygonF*> fillPolygons = createFillPolygons(outerPolygons,
                                                                  innerPolygons);

            for (const QPolygonF* fillPolygon : fillPolygons)
            {
                ClipPainter::drawPolygon(*fillPolygon, fillRule);
            }

            setPen(currentPen);

            for (const QPolygonF* outerPolygon : outerPolygons)
            {
                ClipPainter::drawPolyline(*outerPolygon);
            }

            for (const QPolygonF* innerPolygon : innerPolygons)
            {
                ClipPainter::drawPolyline(*innerPolygon);
            }

            qDeleteAll(fillPolygons);
        }
    }

    if (!hasInnerBoundaries || !innerBoundariesOnScreen)
    {
        drawPolygon(polygon.outerBoundary(), fillRule);
    }

    qDeleteAll(outerPolygons);
    qDeleteAll(innerPolygons);
}

QVector<QPolygonF*> GeoPainter::createFillPolygons(const QVector<QPolygonF*>& outerPolygons,
                                                   const QVector<QPolygonF*>& innerPolygons) const
{
    QVector<QPolygonF*> fillPolygons;
    fillPolygons.reserve(outerPolygons.size());

    for (const QPolygonF* outerPolygon : outerPolygons)
    {
        QPolygonF* fillPolygon = new QPolygonF;
        *fillPolygon << *outerPolygon;
        *fillPolygon << outerPolygon->first();

        for (const QPolygonF* innerPolygon : innerPolygons)
        {
            *fillPolygon << *innerPolygon;
            *fillPolygon << innerPolygon->first();
            *fillPolygon << outerPolygon->first();
        }

        fillPolygons << fillPolygon;
    }

    return fillPolygons;
}


void GeoPainter::drawRect(const GeoDataCoordinates& centerCoordinates,
                          qreal width, qreal height,
                          bool isGeoProjected)
{
    if (!isGeoProjected)
    {
        int pointRepeatNum;
        qreal y;
        bool globeHidesPoint;

        bool visible = d->m_viewport->screenCoordinates(centerCoordinates,
                                                        d->m_x, y, pointRepeatNum, QSizeF(width, height), globeHidesPoint);

        if (visible)
        {
            // Draw all the x-repeat-instances of the point on the screen
            const qreal posY = y - height / 2.0;

            for (int it = 0; it < pointRepeatNum; ++it)
            {
                const qreal posX = d->m_x[it] - width / 2.0;
                QPainter::drawRect(QRectF(posX, posY, width, height));
            }
        }
    }

    else
    {
        drawPolygon(d->createLinearRingFromGeoRect(centerCoordinates, width, height),
                    Qt::OddEvenFill);
    }
}


QRegion GeoPainter::regionFromRect(const GeoDataCoordinates& centerCoordinates,
                                   qreal width, qreal height,
                                   bool isGeoProjected,
                                   qreal strokeWidth) const
{
    if (!isGeoProjected)
    {
        int pointRepeatNum;
        qreal centerY;
        bool globeHidesPoint;

        bool visible = d->m_viewport->screenCoordinates(centerCoordinates,
                                                        d->m_x, centerY, pointRepeatNum, QSizeF(width, height), globeHidesPoint);

        QRegion regions;

        if (visible)
        {
            // only a hint, a backend could still ignore it, but we cannot know more
            const bool antialiased = testRenderHint(QPainter::Antialiasing);

            const qreal halfStrokeWidth = strokeWidth / 2.0;
            const int topY = centerY - height / 2.0;
            const int startY = antialiased ? (qFloor(topY - halfStrokeWidth)) : (qFloor(topY + 0.5 - halfStrokeWidth));
            const int endY = antialiased ? (qCeil(topY + height + halfStrokeWidth)) : (qFloor(centerY + 0.5 + height + halfStrokeWidth));

            // Draw all the x-repeat-instances of the point on the screen
            for (int it = 0; it < pointRepeatNum; ++it)
            {
                const qreal leftX = d->m_x[it] - width / 2.0;
                const int startX = antialiased ? (qFloor(leftX - halfStrokeWidth)) : (qFloor(leftX + 0.5 - halfStrokeWidth));
                const int endX = antialiased ? (qCeil(leftX + width + halfStrokeWidth)) : (qFloor(leftX + 0.5 + width +  halfStrokeWidth));
                regions += QRegion(startX, startY, endX - startX, endY - startY);
            }
        }

        return regions;
    }

    else
    {
        return regionFromPolygon(d->createLinearRingFromGeoRect(centerCoordinates, width, height),
                                 Qt::OddEvenFill, strokeWidth);
    }
}


void GeoPainter::drawRoundedRect(const GeoDataCoordinates& centerPosition,
                                 qreal width, qreal height,
                                 qreal xRnd, qreal yRnd)
{
    int pointRepeatNum;
    qreal y;
    bool globeHidesPoint;

    // FIXME: Better visibility detection that takes the circle geometry into account
    bool visible = d->m_viewport->screenCoordinates(centerPosition, d->m_x, y, pointRepeatNum, QSizeF(width, height), globeHidesPoint);

    if (visible)
    {
        // Draw all the x-repeat-instances of the point on the screen
        const qreal posY = y - height / 2.0;

        for (int it = 0; it < pointRepeatNum; ++it)
        {
            const qreal posX = d->m_x[it] - width / 2.0;
            QPainter::drawRoundedRect(QRectF(posX, posY, width, height), xRnd, yRnd);
        }
    }
}


void GeoPainter::drawTextFragment(const QPoint& position, const QString& text,
                                  const qreal fontSize, const QColor& color,
                                  const Frames& flags)
{
    const QString key = text + QString::fromUtf8(":") + QString::number(static_cast<int>(flags));

    QPixmap pixmap;

    if (!QPixmapCache::find(key, &pixmap))
    {
        const bool hasRoundFrame = flags.testFlag(RoundFrame);

        QPixmap pixmap(10, 10);
        QPainter textPainter;

        textPainter.begin(&pixmap);
        const QFontMetrics metrics = textPainter.fontMetrics();
        textPainter.end();

        const int width = metrics.horizontalAdvance(text);
        const int height = metrics.height();
        const QSize size = hasRoundFrame
                           ? QSize(qMax(1.2 * width, 1.1 * height), 1.2 * height)
                           : QSize(width, height);
        pixmap = QPixmap(size);
        pixmap.fill(Qt::transparent);
        const QRect labelRect(QPoint(), size);
        textPainter.begin(&pixmap);
        QFont textFont = textPainter.font();
        textFont.setPointSize(fontSize);
        textPainter.setFont(textFont);
        textPainter.setRenderHint(QPainter::Antialiasing, true);

        const QColor brushColor = color;

        if (hasRoundFrame)
        {
            QColor lighterColor = brushColor.lighter(110);
            lighterColor.setAlphaF(0.9);
            textPainter.setBrush(lighterColor);
            textPainter.drawRoundedRect(labelRect, 3, 3);
        }

        textPainter.setBrush(brushColor);
        textPainter.drawText(labelRect, Qt::AlignHCenter, text);

        if (hasRoundFrame)
        {
            textPainter.setBrush(brushColor);
        }

        textPainter.end();
        QPixmapCache::insert(key, pixmap);
    }

    QPainter::drawPixmap(position.x() - pixmap.width() / 2,
                         position.y() - pixmap.height() / 2,
                         pixmap);
}

} // namespace Marble
