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nyalldawsonnyalldawson
committedAug 29, 2016
Add QgsGeometry method to get bisector of angle at vertex
Sponsored by Andreas Neumann (cherry-picked from 986b531)
·
ltr-2_18archive/master_2
1 parent 41a9631 commit 524d22f

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6 files changed

+109
-3
lines changed

6 files changed

+109
-3
lines changed
 

‎python/core/geometry/qgsgeometry.sip

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Original file line numberDiff line numberDiff line change
@@ -192,6 +192,15 @@ class QgsGeometry
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*/
193193
double distanceToVertex( int vertex ) const;
194194

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/**
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* Returns the bisector angle for this geometry at the specified vertex.
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* @param vertex vertex index to calculate bisector angle at
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* @returns bisector angle, in radians clockwise from north
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* @note added in QGIS 3.0
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* @see interpolateAngle()
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*/
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double angleAtVertex( int vertex ) const;
203+
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/**
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* Returns the indexes of the vertices before and after the given vertex index.
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*
@@ -494,6 +503,7 @@ class QgsGeometry
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* of the node is returned.
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* @param distance distance along geometry
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* @note added in QGIS 3.0
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* @see angleAtVertex()
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*/
498508
double interpolateAngle( double distance ) const;
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‎src/core/geometry/qgsgeometry.cpp

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Original file line numberDiff line numberDiff line change
@@ -382,6 +382,46 @@ double QgsGeometry::distanceToVertex( int vertex ) const
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return QgsGeometryUtils::distanceToVertex( *( d->geometry ), id );
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}
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double QgsGeometry::angleAtVertex( int vertex ) const
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{
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if ( !d->geometry )
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{
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return 0;
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}
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QgsVertexId v2;
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if ( !vertexIdFromVertexNr( vertex, v2 ) )
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{
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return 0;
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}
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QgsVertexId v1;
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QgsVertexId v3;
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QgsGeometryUtils::adjacentVertices( *d->geometry, v2, v1, v3 );
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if ( v1.isValid() && v3.isValid() )
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{
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QgsPointV2 p1 = d->geometry->vertexAt( v1 );
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QgsPointV2 p2 = d->geometry->vertexAt( v2 );
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QgsPointV2 p3 = d->geometry->vertexAt( v3 );
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double angle1 = QgsGeometryUtils::lineAngle( p1.x(), p1.y(), p2.x(), p2.y() );
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double angle2 = QgsGeometryUtils::lineAngle( p2.x(), p2.y(), p3.x(), p3.y() );
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return QgsGeometryUtils::averageAngle( angle1, angle2 );
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}
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else if ( v3.isValid() )
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{
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QgsPointV2 p1 = d->geometry->vertexAt( v2 );
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QgsPointV2 p2 = d->geometry->vertexAt( v3 );
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return QgsGeometryUtils::lineAngle( p1.x(), p1.y(), p2.x(), p2.y() );
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}
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else if ( v1.isValid() )
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{
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QgsPointV2 p1 = d->geometry->vertexAt( v1 );
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QgsPointV2 p2 = d->geometry->vertexAt( v2 );
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return QgsGeometryUtils::lineAngle( p1.x(), p1.y(), p2.x(), p2.y() );
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}
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return 0.0;
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}
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385425
void QgsGeometry::adjacentVertices( int atVertex, int& beforeVertex, int& afterVertex ) const
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{
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if ( !d->geometry )

‎src/core/geometry/qgsgeometry.h

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Original file line numberDiff line numberDiff line change
@@ -234,6 +234,15 @@ class CORE_EXPORT QgsGeometry
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*/
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double distanceToVertex( int vertex ) const;
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/**
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* Returns the bisector angle for this geometry at the specified vertex.
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* @param vertex vertex index to calculate bisector angle at
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* @returns bisector angle, in radians clockwise from north
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* @note added in QGIS 3.0
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* @see interpolateAngle()
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*/
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double angleAtVertex( int vertex ) const;
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/**
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* Returns the indexes of the vertices before and after the given vertex index.
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*
@@ -537,6 +546,7 @@ class CORE_EXPORT QgsGeometry
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* of the node is returned.
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* @param distance distance along geometry
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* @note added in QGIS 3.0
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* @see angleAtVertex()
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*/
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double interpolateAngle( double distance ) const;
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‎src/core/geometry/qgsgeometryutils.cpp

Lines changed: 10 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -201,9 +201,16 @@ void QgsGeometryUtils::adjacentVertices( const QgsAbstractGeometryV2& geom, QgsV
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}
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else if ( atVertex.vertex == 0 )
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{
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afterVertex.part = atVertex.part;
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afterVertex.ring = atVertex.ring;
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afterVertex.vertex = atVertex.vertex + 1;
204+
if ( ring.size() > 1 )
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{
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afterVertex.part = atVertex.part;
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afterVertex.ring = atVertex.ring;
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afterVertex.vertex = atVertex.vertex + 1;
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}
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else
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{
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afterVertex = QgsVertexId(); //after vertex invalid
213+
}
207214
if ( polygonType && ring.size() > 3 )
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{
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beforeVertex.part = atVertex.part;

‎tests/src/core/testqgsgeometryutils.cpp

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Original file line numberDiff line numberDiff line change
@@ -350,6 +350,12 @@ void TestQgsGeometryUtils::testAdjacentVertices()
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QgsGeometryUtils::adjacentVertices( polygon1, QgsVertexId( 0, 0, 0 ), previous, next );
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QCOMPARE( previous, QgsVertexId( 0, 0, 3 ) );
352352
QCOMPARE( next, QgsVertexId( 0, 0, 1 ) );
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// test point - both vertices should be invalid
355+
QgsPointV2 point( 1, 2 );
356+
QgsGeometryUtils::adjacentVertices( point, QgsVertexId( 0, 0, 0 ), previous, next );
357+
QVERIFY( !previous.isValid() );
358+
QVERIFY( !next.isValid() );
353359
}
354360

355361
void TestQgsGeometryUtils::testDistanceToVertex()

‎tests/src/python/test_qgsgeometry.py

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Original file line numberDiff line numberDiff line change
@@ -3481,6 +3481,39 @@ def testInterpolate(self):
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self.assertTrue(compareWkt(result, exp, 0.00001),
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"Interpolate: mismatch Expected:\n{}\nGot:\n{}\n".format(exp, result))
34833483

3484+
def testAngleAtVertex(self):
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""" test QgsGeometry.angleAtVertex """
3486+
3487+
empty = QgsGeometry()
3488+
# just test no crash
3489+
self.assertEqual(empty.angleAtVertex(0), 0)
3490+
3491+
# not a linestring
3492+
point = QgsGeometry.fromWkt('Point(1 2)')
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# no meaning, just test no crash!
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self.assertEqual(point.angleAtVertex(0), 0)
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3496+
# linestring
3497+
linestring = QgsGeometry.fromWkt('LineString(0 0, 10 0, 20 10, 20 20, 10 20)')
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self.assertAlmostEqual(linestring.angleAtVertex(1), math.radians(67.5), places=3)
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self.assertAlmostEqual(linestring.angleAtVertex(2), math.radians(22.5), places=3)
3500+
self.assertAlmostEqual(linestring.angleAtVertex(3), math.radians(315.0), places=3)
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self.assertAlmostEqual(linestring.angleAtVertex(5), 0, places=3)
3502+
self.assertAlmostEqual(linestring.angleAtVertex(-1), 0, places=3)
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3504+
# test first and last points in a linestring - angle should be angle of
3505+
# first/last segment
3506+
linestring = QgsGeometry.fromWkt('LineString(20 0, 10 0, 10 -10)')
3507+
self.assertAlmostEqual(linestring.angleAtVertex(0), math.radians(270), places=3)
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self.assertAlmostEqual(linestring.angleAtVertex(2), math.radians(180), places=3)
3509+
3510+
# polygon
3511+
polygon = QgsGeometry.fromWkt('Polygon((0 0, 10 0, 10 10, 0 10, 0 0))')
3512+
self.assertAlmostEqual(polygon.angleAtVertex(0), math.radians(135.0), places=3)
3513+
self.assertAlmostEqual(polygon.angleAtVertex(1), math.radians(45.0), places=3)
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self.assertAlmostEqual(polygon.angleAtVertex(2), math.radians(315.0), places=3)
3515+
self.assertAlmostEqual(polygon.angleAtVertex(3), math.radians(225.0), places=3)
3516+
self.assertAlmostEqual(polygon.angleAtVertex(4), math.radians(135.0), places=3)
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34853518
if __name__ == '__main__':
34863519
unittest.main()

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