From 602cd4845dff2bbe5a8118899f1dfbcca9d614f1 Mon Sep 17 00:00:00 2001 From: Paolo Angelelli Date: Fri, 4 Aug 2017 13:22:43 +0200 Subject: Fix visible region computation in QGeoProjectionWebMercator Currently the visible region is calculated as the intersection between the viewing frustum and the map plane clipped against the map extended rectangle in mercator space (from -1 to 2 in x coords, 0 to 1 in y coords). The result is correct in the extended mercator space. However, this may lead to overlapping coordinates when converted back to latitude and longitude. For this reason, this patch changes the clipping geometry to be the map un-extended rectangle centered around the current map center. The result is a geometry that never wraps around or overlaps, thus removing the need for handling separately the case when the map is fully visible when returning the visible region. Task-number: QTBUG-57690 Change-Id: I8396c40a123ce94bff4388dfefbd8a694657b8bd Reviewed-by: BogDan Vatra --- .../declarativemaps/qdeclarativegeomap.cpp | 23 +++++++++++----------- src/location/maps/qgeoprojection.cpp | 20 +++++++++++++++---- src/positioning/qlocationutils_p.h | 2 +- 3 files changed, 29 insertions(+), 16 deletions(-) (limited to 'src') diff --git a/src/location/declarativemaps/qdeclarativegeomap.cpp b/src/location/declarativemaps/qdeclarativegeomap.cpp index 90ae2b34..dedb590e 100644 --- a/src/location/declarativemaps/qdeclarativegeomap.cpp +++ b/src/location/declarativemaps/qdeclarativegeomap.cpp @@ -1323,20 +1323,21 @@ QGeoShape QDeclarativeGeoMap::visibleRegion() const const QList &visibleRegion = m_map->geoProjection().visibleRegion(); QGeoPath path; - for (const QDoubleVector2D &c: visibleRegion) + for (int i = 0; i < visibleRegion.size(); ++i) { + const QDoubleVector2D &c = visibleRegion.at(i); + // If a segment spans more than half of the map longitudinally, split in 2. + if (i && qAbs(visibleRegion.at(i-1).x() - c.x()) >= 0.5) { // This assumes a segment is never >= 1.0 (whole map span) + QDoubleVector2D extraPoint = (visibleRegion.at(i-1) + c) * 0.5; + path.addCoordinate(m_map->geoProjection().wrappedMapProjectionToGeo(extraPoint)); + } path.addCoordinate(m_map->geoProjection().wrappedMapProjectionToGeo(c)); - - QGeoRectangle vr = path.boundingGeoRectangle(); - - bool empty = vr.topLeft().latitude() == vr.bottomRight().latitude() || - qFuzzyCompare(vr.topLeft().longitude(), vr.bottomRight().longitude()); // QTBUG-57690 - - if (empty) { - vr.setTopLeft(QGeoCoordinate(vr.topLeft().latitude(), -180)); - vr.setBottomRight(QGeoCoordinate(vr.bottomRight().latitude(), 180)); + } + if (visibleRegion.size() >= 2 && qAbs(visibleRegion.last().x() - visibleRegion.first().x()) >= 0.5) { + QDoubleVector2D extraPoint = (visibleRegion.last() + visibleRegion.first()) * 0.5; + path.addCoordinate(m_map->geoProjection().wrappedMapProjectionToGeo(extraPoint)); } - return vr; + return path.boundingGeoRectangle(); } /*! diff --git a/src/location/maps/qgeoprojection.cpp b/src/location/maps/qgeoprojection.cpp index 609fb934..013a8c33 100644 --- a/src/location/maps/qgeoprojection.cpp +++ b/src/location/maps/qgeoprojection.cpp @@ -491,11 +491,17 @@ void QGeoProjectionWebMercator::updateVisibleRegion() QDoubleVector2D bl = viewportToWrappedMapProjection(QDoubleVector2D(-1, 1 )); QDoubleVector2D br = viewportToWrappedMapProjection(QDoubleVector2D( 1, 1 )); + // To make sure that what is returned can be safely converted back to lat/lon without risking overlaps + double mapLeftLongitude = QLocationUtils::mapLeftLongitude(m_cameraData.center().longitude()); + double mapRightLongitude = QLocationUtils::mapRightLongitude(m_cameraData.center().longitude()); + double leftX = geoToWrappedMapProjection(QGeoCoordinate(0, mapLeftLongitude)).x(); + double rightX = geoToWrappedMapProjection(QGeoCoordinate(0, mapRightLongitude)).x(); + QList mapRect; - mapRect.push_back(QDoubleVector2D(-1.0, 1.0)); - mapRect.push_back(QDoubleVector2D( 2.0, 1.0)); - mapRect.push_back(QDoubleVector2D( 2.0, 0.0)); - mapRect.push_back(QDoubleVector2D(-1.0, 0.0)); + mapRect.push_back(QDoubleVector2D(leftX, 1.0)); + mapRect.push_back(QDoubleVector2D(rightX, 1.0)); + mapRect.push_back(QDoubleVector2D(rightX, 0.0)); + mapRect.push_back(QDoubleVector2D(leftX, 0.0)); QList viewportRect; viewportRect.push_back(bl); @@ -514,6 +520,12 @@ void QGeoProjectionWebMercator::updateVisibleRegion() m_visibleRegion = QClipperUtils::pathToQList(res[0]); // Intersection between two convex quadrilaterals should always be a single polygon m_projectableRegion.clear(); + mapRect.clear(); + // The full map rectangle in extended mercator space + mapRect.push_back(QDoubleVector2D(-1.0, 1.0)); + mapRect.push_back(QDoubleVector2D( 2.0, 1.0)); + mapRect.push_back(QDoubleVector2D( 2.0, 0.0)); + mapRect.push_back(QDoubleVector2D(-1.0, 0.0)); if (m_cameraData.tilt() == 0) { m_projectableRegion = mapRect; } else { diff --git a/src/positioning/qlocationutils_p.h b/src/positioning/qlocationutils_p.h index 75c4b7f4..69cf0fee 100644 --- a/src/positioning/qlocationutils_p.h +++ b/src/positioning/qlocationutils_p.h @@ -55,7 +55,7 @@ #include #include -static const double offsetEpsilon = 0.0000000000001; +static const double offsetEpsilon = 1e-12; // = 0.000000000001 static const double leftOffset = -180.0 + offsetEpsilon; static const double rightOffset = 180.0 - offsetEpsilon; -- cgit v1.2.1