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nearest point measure in identify tool

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This commit is contained in:
Radim Blazek 2017-06-22 15:31:21 +02:00
parent 7cd517c6ba
commit 5c6e794b2d
5 changed files with 56 additions and 0 deletions
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6
python/core/geometry/qgsgeometryutils.sip
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@ -37,6 +37,12 @@ class QgsGeometryUtils
:rtype: QgsPoint
%End
static double closestPointMeasure( const QgsAbstractGeometry &geom, const QgsPoint &pt );
%Docstring
Returns measure of nearest point on a geometry for a specified point or NaN if geometry does not have measures
:rtype: float
%End
static double distanceToVertex( const QgsAbstractGeometry &geom, QgsVertexId id );
%Docstring
Returns the distance along a geometry from its first vertex to the specified vertex.

29
src/core/geometry/qgsgeometryutils.cpp
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@ -93,6 +93,35 @@ QgsPoint QgsGeometryUtils::closestVertex( const QgsAbstractGeometry &geom, const
return minDistPoint;
}
double QgsGeometryUtils::closestPointMeasure( const QgsAbstractGeometry &geom, const QgsPoint &pt )
{
if ( QgsWkbTypes::hasM( geom.wkbType() ) )
{
QgsPoint closestPoint;
QgsVertexId vertexAfter;
bool leftOf;
geom.closestSegment( pt, closestPoint, vertexAfter, &leftOf, DEFAULT_SEGMENT_EPSILON );
if ( vertexAfter.isValid() )
{
QgsPoint pointAfter = geom.vertexAt( vertexAfter );
if ( vertexAfter.vertex > 0 )
{
QgsVertexId vertexBefore = vertexAfter;
vertexBefore.vertex--;
QgsPoint pointBefore = geom.vertexAt( vertexBefore );
double length = pointBefore.distance( pointAfter );
double distance = pointBefore.distance( closestPoint );
return pointBefore.m() + ( pointAfter.m() - pointBefore.m() ) * distance / length;
}
else
{
return pointAfter.m();
}
}
}
return std::numeric_limits<double>::quiet_NaN();
}
double QgsGeometryUtils::distanceToVertex( const QgsAbstractGeometry &geom, QgsVertexId id )
{
double currentDist = 0;

4
src/core/geometry/qgsgeometryutils.h
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@ -44,6 +44,10 @@ class CORE_EXPORT QgsGeometryUtils
*/
static QgsPoint closestVertex( const QgsAbstractGeometry &geom, const QgsPoint &pt, QgsVertexId &id SIP_OUT );
/** Returns measure of nearest point on a geometry for a specified point or NaN if geometry does not have measures
*/
static double closestPointMeasure( const QgsAbstractGeometry &geom, const QgsPoint &pt );
/** Returns the distance along a geometry from its first vertex to the specified vertex.
* \param geom geometry
* \param id vertex id to find distance to

13
src/gui/qgsmaptoolidentify.cpp
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@ -326,6 +326,18 @@ void QgsMapToolIdentify::closestVertexAttributes( const QgsAbstractGeometry &geo
}
}
void QgsMapToolIdentify::closestPointAttributes( const QgsAbstractGeometry &geometry, QgsMapLayer *layer, const QgsPointXY &layerPoint, QMap< QString, QString > &derivedAttributes )
{
Q_UNUSED( layer );
// measure
if ( QgsWkbTypes::hasM( geometry.wkbType() ) )
{
double measure = QgsGeometryUtils::closestPointMeasure( geometry, QgsPoint( layerPoint.x(), layerPoint.y() ) );
QString str = QLocale::system().toString( measure, 'g', 10 );
derivedAttributes.insert( QStringLiteral( "Closest point M" ), str );
}
}
QString QgsMapToolIdentify::formatCoordinate( const QgsPointXY &canvasPoint ) const
{
return QgsCoordinateUtils::formatCoordinateForProject( canvasPoint, mCanvas->mapSettings().destinationCrs(),
@ -392,6 +404,7 @@ QMap< QString, QString > QgsMapToolIdentify::featureDerivedAttributes( QgsFeatur
//add details of closest vertex to identify point
closestVertexAttributes( *curve, vId, layer, derivedAttributes );
closestPointAttributes( *curve, layer, layerPoint, derivedAttributes );
// Add the start and end points in as derived attributes
QgsPointXY pnt = mCanvas->mapSettings().layerToMapCoordinates( layer, QgsPointXY( curve->startPoint().x(), curve->startPoint().y() ) );

4
src/gui/qgsmaptoolidentify.h
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@ -183,6 +183,10 @@ class GUI_EXPORT QgsMapToolIdentify : public QgsMapTool
*/
void closestVertexAttributes( const QgsAbstractGeometry &geometry, QgsVertexId vId, QgsMapLayer *layer, QMap< QString, QString > &derivedAttributes );
/** Adds details of the closest point to derived attributes
*/
void closestPointAttributes( const QgsAbstractGeometry &geometry, QgsMapLayer *layer, const QgsPointXY &layerPoint, QMap< QString, QString > &derivedAttributes );
QString formatCoordinate( const QgsPointXY &canvasPoint ) const;
QString formatXCoordinate( const QgsPointXY &canvasPoint ) const;
QString formatYCoordinate( const QgsPointXY &canvasPoint ) const;