Move private arc segmentization routines to QgsGeometryUtils

qgis · Apr 2, 2017 · ab58413 · ab58413
1 parent d0a36d3
commit ab58413
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Showing 5 changed files with 164 additions and 150 deletions.
diff --git a/python/core/geometry/qgsgeometryutils.sip b/python/core/geometry/qgsgeometryutils.sip
@@ -52,6 +52,12 @@ class QgsGeometryUtils
 
     static double circleTangentDirection( const QgsPointV2& tangentPoint, const QgsPointV2& cp1, const QgsPointV2& cp2, const QgsPointV2& cp3 );
 
+    static void segmentizeArc( const QgsPointV2 &p1, const QgsPointV2 &p2, const QgsPointV2 &p3, QList<QgsPointV2> &points /Out/, double tolerance = M_PI_2 / 90, QgsAbstractGeometry::SegmentationToleranceType toleranceType = QgsAbstractGeometry::MaximumAngle, bool hasZ = false, bool hasM = false );
+
+    static int segmentSide( const QgsPointV2 &pt1, const QgsPointV2 &pt3, const QgsPointV2 &pt2 );
+
+    static double interpolateArcValue( double angle, double a1, double a2, double a3, double zm1, double zm2, double zm3 );
+
     static double normalizedAngle( double angle );
 
     static double lineAngle( double x1, double y1, double x2, double y2 );

diff --git a/src/core/geometry/qgscircularstring.cpp b/src/core/geometry/qgscircularstring.cpp
@@ -355,7 +355,7 @@ QgsLineString *QgsCircularString::curveToLine( double tolerance, SegmentationTol
 
   for ( int i = 0; i < ( nPoints - 2 ) ; i += 2 )
   {
-    segmentize( pointN( i ), pointN( i + 1 ), pointN( i + 2 ), points, tolerance, toleranceType );
+    QgsGeometryUtils::segmentizeArc( pointN( i ), pointN( i + 1 ), pointN( i + 2 ), points, tolerance, toleranceType, is3D(), isMeasure() );
   }
 
   line->setPoints( points );
@@ -485,150 +485,6 @@ void QgsCircularString::setPoints( const QgsPointSequence &points )
   }
 }
 
-void QgsCircularString::segmentize( const QgsPointV2 &p1, const QgsPointV2 &p2, const QgsPointV2 &p3, QgsPointSequence &points, double tolerance, SegmentationToleranceType toleranceType ) const
-{
-  bool clockwise = false;
-  int segSide = segmentSide( p1, p3, p2 );
-  if ( segSide == -1 )
-  {
-    clockwise = true;
-  }
-
-  QgsPointV2 circlePoint1 = clockwise ? p3 : p1;
-  QgsPointV2 circlePoint2 = p2;
-  QgsPointV2 circlePoint3 = clockwise ? p1 : p3 ;
-
-  //adapted code from postgis
-  double radius = 0;
-  double centerX = 0;
-  double centerY = 0;
-  QgsGeometryUtils::circleCenterRadius( circlePoint1, circlePoint2, circlePoint3, radius, centerX, centerY );
-
-
-  if ( circlePoint1 != circlePoint3 && ( radius < 0 || qgsDoubleNear( segSide, 0.0 ) ) ) //points are colinear
-  {
-    points.append( p1 );
-    points.append( p2 );
-    points.append( p3 );
-    return;
-  }
-
-  double increment = tolerance; //one segment per degree
-  if ( toleranceType == QgsAbstractGeometry::MaximumDifference )
-  {
-    double halfAngle = acos( -tolerance / radius + 1 );
-    increment = 2 * halfAngle;
-  }
-
-  //angles of pt1, pt2, pt3
-  double a1 = atan2( circlePoint1.y() - centerY, circlePoint1.x() - centerX );
-  double a2 = atan2( circlePoint2.y() - centerY, circlePoint2.x() - centerX );
-  double a3 = atan2( circlePoint3.y() - centerY, circlePoint3.x() - centerX );
-
-  /* Adjust a3 up so we can increment from a1 to a3 cleanly */
-  if ( a3 <= a1 )
-    a3 += 2.0 * M_PI;
-  if ( a2 < a1 )
-    a2 += 2.0 * M_PI;
-
-  bool hasZ = is3D();
-  bool hasM = isMeasure();
-
-  double x, y;
-  double z = 0;
-  double m = 0;
-
-  QList<QgsPointV2> stringPoints;
-  stringPoints.insert( clockwise ? 0 : stringPoints.size(), circlePoint1 );
-  if ( circlePoint2 != circlePoint3 && circlePoint1 != circlePoint2 ) //draw straight line segment if two points have the same position
-  {
-    QgsWkbTypes::Type pointWkbType = QgsWkbTypes::Point;
-    if ( hasZ )
-      pointWkbType = QgsWkbTypes::addZ( pointWkbType );
-    if ( hasM )
-      pointWkbType = QgsWkbTypes::addM( pointWkbType );
-
-    //make sure the curve point p2 is part of the segmentized vertices. But only if p1 != p3
-    bool addP2 = true;
-    if ( qgsDoubleNear( circlePoint1.x(), circlePoint3.x() ) && qgsDoubleNear( circlePoint1.y(), circlePoint3.y() ) )
-    {
-      addP2 = false;
-    }
-
-    for ( double angle = a1 + increment; angle < a3; angle += increment )
-    {
-      if ( ( addP2 && angle > a2 ) )
-      {
-        stringPoints.insert( clockwise ? 0 : stringPoints.size(), circlePoint2 );
-        addP2 = false;
-      }
-
-      x = centerX + radius * cos( angle );
-      y = centerY + radius * sin( angle );
-
-      if ( !hasZ && !hasM )
-      {
-        stringPoints.insert( clockwise ? 0 : stringPoints.size(), QgsPointV2( x, y ) );
-        continue;
-      }
-
-      if ( hasZ )
-      {
-        z = interpolateArc( angle, a1, a2, a3, circlePoint1.z(), circlePoint2.z(), circlePoint3.z() );
-      }
-      if ( hasM )
-      {
-        m = interpolateArc( angle, a1, a2, a3, circlePoint1.m(), circlePoint2.m(), circlePoint3.m() );
-      }
-
-      stringPoints.insert( clockwise ? 0 : stringPoints.size(), QgsPointV2( pointWkbType, x, y, z, m ) );
-    }
-  }
-  stringPoints.insert( clockwise ? 0 : stringPoints.size(), circlePoint3 );
-  points.append( stringPoints );
-}
-
-int QgsCircularString::segmentSide( const QgsPointV2 &pt1, const QgsPointV2 &pt3, const QgsPointV2 &pt2 ) const
-{
-  double side = ( ( pt2.x() - pt1.x() ) * ( pt3.y() - pt1.y() ) - ( pt3.x() - pt1.x() ) * ( pt2.y() - pt1.y() ) );
-  if ( side == 0.0 )
-  {
-    return 0;
-  }
-  else
-  {
-    if ( side < 0 )
-    {
-      return -1;
-    }
-    if ( side > 0 )
-    {
-      return 1;
-    }
-    return 0;
-  }
-}
-
-double QgsCircularString::interpolateArc( double angle, double a1, double a2, double a3, double zm1, double zm2, double zm3 ) const
-{
-  /* Counter-clockwise sweep */
-  if ( a1 < a2 )
-  {
-    if ( angle <= a2 )
-      return zm1 + ( zm2 - zm1 ) * ( angle - a1 ) / ( a2 - a1 );
-    else
-      return zm2 + ( zm3 - zm2 ) * ( angle - a2 ) / ( a3 - a2 );
-  }
-  /* Clockwise sweep */
-  else
-  {
-    if ( angle >= a2 )
-      return zm1 + ( zm2 - zm1 ) * ( a1 - angle ) / ( a1 - a2 );
-    else
-      return zm2 + ( zm3 - zm2 ) * ( a2 - angle ) / ( a2 - a3 );
-  }
-}
-
 void QgsCircularString::draw( QPainter &p ) const
 {
   QPainterPath path;
@@ -697,7 +553,7 @@ void QgsCircularString::addToPainterPath( QPainterPath &path ) const
   for ( int i = 0; i < ( nPoints - 2 ) ; i += 2 )
   {
     QgsPointSequence pt;
-    segmentize( QgsPointV2( mX[i], mY[i] ), QgsPointV2( mX[i + 1], mY[i + 1] ), QgsPointV2( mX[i + 2], mY[i + 2] ), pt );
+    QgsGeometryUtils::segmentizeArc( QgsPointV2( mX[i], mY[i] ), QgsPointV2( mX[i + 1], mY[i + 1] ), QgsPointV2( mX[i + 2], mY[i + 2] ), pt );
     for ( int j = 1; j < pt.size(); ++j )
     {
       path.lineTo( pt.at( j ).x(), pt.at( j ).y() );

diff --git a/src/core/geometry/qgscircularstring.h b/src/core/geometry/qgscircularstring.h
@@ -145,10 +145,6 @@ class CORE_EXPORT QgsCircularString: public QgsCurve
     QVector<double> mZ;
     QVector<double> mM;
 
-    //helper methods for curveToLine
-    void segmentize( const QgsPointV2 &p1, const QgsPointV2 &p2, const QgsPointV2 &p3, QgsPointSequence &points, double tolerance = M_PI_2 / 90, SegmentationToleranceType toleranceType = MaximumAngle ) const;
-    int segmentSide( const QgsPointV2 &pt1, const QgsPointV2 &pt3, const QgsPointV2 &pt2 ) const;
-    double interpolateArc( double angle, double a1, double a2, double a3, double zm1, double zm2, double zm3 ) const;
     static void arcTo( QPainterPath &path, QPointF pt1, QPointF pt2, QPointF pt3 );
     //bounding box of a single segment
     static QgsRectangle segmentBoundingBox( const QgsPointV2 &pt1, const QgsPointV2 &pt2, const QgsPointV2 &pt3 );

diff --git a/src/core/geometry/qgsgeometryutils.cpp b/src/core/geometry/qgsgeometryutils.cpp
@@ -595,6 +595,146 @@ double QgsGeometryUtils::circleTangentDirection( const QgsPointV2 &tangentPoint,
   }
 }
 
+void QgsGeometryUtils::segmentizeArc( const QgsPointV2 &p1, const QgsPointV2 &p2, const QgsPointV2 &p3, QgsPointSequence &points, double tolerance, QgsAbstractGeometry::SegmentationToleranceType toleranceType, bool hasZ, bool hasM )
+{
+  bool clockwise = false;
+  int segSide = segmentSide( p1, p3, p2 );
+  if ( segSide == -1 )
+  {
+    clockwise = true;
+  }
+
+  QgsPointV2 circlePoint1 = clockwise ? p3 : p1;
+  QgsPointV2 circlePoint2 = p2;
+  QgsPointV2 circlePoint3 = clockwise ? p1 : p3 ;
+
+  //adapted code from postgis
+  double radius = 0;
+  double centerX = 0;
+  double centerY = 0;
+  circleCenterRadius( circlePoint1, circlePoint2, circlePoint3, radius, centerX, centerY );
+
+  if ( circlePoint1 != circlePoint3 && ( radius < 0 || qgsDoubleNear( segSide, 0.0 ) ) ) //points are colinear
+  {
+    points.append( p1 );
+    points.append( p2 );
+    points.append( p3 );
+    return;
+  }
+
+  double increment = tolerance; //one segment per degree
+  if ( toleranceType == QgsAbstractGeometry::MaximumDifference )
+  {
+    double halfAngle = acos( -tolerance / radius + 1 );
+    increment = 2 * halfAngle;
+  }
+
+  //angles of pt1, pt2, pt3
+  double a1 = atan2( circlePoint1.y() - centerY, circlePoint1.x() - centerX );
+  double a2 = atan2( circlePoint2.y() - centerY, circlePoint2.x() - centerX );
+  double a3 = atan2( circlePoint3.y() - centerY, circlePoint3.x() - centerX );
+
+  /* Adjust a3 up so we can increment from a1 to a3 cleanly */
+  if ( a3 <= a1 )
+    a3 += 2.0 * M_PI;
+  if ( a2 < a1 )
+    a2 += 2.0 * M_PI;
+
+  double x, y;
+  double z = 0;
+  double m = 0;
+
+  QList<QgsPointV2> stringPoints;
+  stringPoints.insert( clockwise ? 0 : stringPoints.size(), circlePoint1 );
+  if ( circlePoint2 != circlePoint3 && circlePoint1 != circlePoint2 ) //draw straight line segment if two points have the same position
+  {
+    QgsWkbTypes::Type pointWkbType = QgsWkbTypes::Point;
+    if ( hasZ )
+      pointWkbType = QgsWkbTypes::addZ( pointWkbType );
+    if ( hasM )
+      pointWkbType = QgsWkbTypes::addM( pointWkbType );
+
+    //make sure the curve point p2 is part of the segmentized vertices. But only if p1 != p3
+    bool addP2 = true;
+    if ( qgsDoubleNear( circlePoint1.x(), circlePoint3.x() ) && qgsDoubleNear( circlePoint1.y(), circlePoint3.y() ) )
+    {
+      addP2 = false;
+    }
+
+    for ( double angle = a1 + increment; angle < a3; angle += increment )
+    {
+      if ( ( addP2 && angle > a2 ) )
+      {
+        stringPoints.insert( clockwise ? 0 : stringPoints.size(), circlePoint2 );
+        addP2 = false;
+      }
+
+      x = centerX + radius * cos( angle );
+      y = centerY + radius * sin( angle );
+
+      if ( !hasZ && !hasM )
+      {
+        stringPoints.insert( clockwise ? 0 : stringPoints.size(), QgsPointV2( x, y ) );
+        continue;
+      }
+
+      if ( hasZ )
+      {
+        z = interpolateArcValue( angle, a1, a2, a3, circlePoint1.z(), circlePoint2.z(), circlePoint3.z() );
+      }
+      if ( hasM )
+      {
+        m = interpolateArcValue( angle, a1, a2, a3, circlePoint1.m(), circlePoint2.m(), circlePoint3.m() );
+      }
+
+      stringPoints.insert( clockwise ? 0 : stringPoints.size(), QgsPointV2( pointWkbType, x, y, z, m ) );
+    }
+  }
+  stringPoints.insert( clockwise ? 0 : stringPoints.size(), circlePoint3 );
+  points.append( stringPoints );
+}
+
+int QgsGeometryUtils::segmentSide( const QgsPointV2 &pt1, const QgsPointV2 &pt3, const QgsPointV2 &pt2 )
+{
+  double side = ( ( pt2.x() - pt1.x() ) * ( pt3.y() - pt1.y() ) - ( pt3.x() - pt1.x() ) * ( pt2.y() - pt1.y() ) );
+  if ( side == 0.0 )
+  {
+    return 0;
+  }
+  else
+  {
+    if ( side < 0 )
+    {
+      return -1;
+    }
+    if ( side > 0 )
+    {
+      return 1;
+    }
+    return 0;
+  }
+}
+
+double QgsGeometryUtils::interpolateArcValue( double angle, double a1, double a2, double a3, double zm1, double zm2, double zm3 )
+{
+  /* Counter-clockwise sweep */
+  if ( a1 < a2 )
+  {
+    if ( angle <= a2 )
+      return zm1 + ( zm2 - zm1 ) * ( angle - a1 ) / ( a2 - a1 );
+    else
+      return zm2 + ( zm3 - zm2 ) * ( angle - a2 ) / ( a3 - a2 );
+  }
+  /* Clockwise sweep */
+  else
+  {
+    if ( angle >= a2 )
+      return zm1 + ( zm2 - zm1 ) * ( a1 - angle ) / ( a1 - a2 );
+    else
+      return zm2 + ( zm3 - zm2 ) * ( a2 - angle ) / ( a2 - a3 );
+  }
+}
+
 QgsPointSequence QgsGeometryUtils::pointsFromWKT( const QString &wktCoordinateList, bool is3D, bool isMeasure )
 {
   int dim = 2 + is3D + isMeasure;

diff --git a/src/core/geometry/qgsgeometryutils.h b/src/core/geometry/qgsgeometryutils.h
@@ -171,6 +171,22 @@ class CORE_EXPORT QgsGeometryUtils
     //! Calculates the direction angle of a circle tangent (clockwise from north in radians)
     static double circleTangentDirection( const QgsPointV2 &tangentPoint, const QgsPointV2 &cp1, const QgsPointV2 &cp2, const QgsPointV2 &cp3 );
 
+    /** Convert circular arc defined by p1, p2, p3 (p1/p3 being start resp. end point, p2 lies on the arc) into a sequence of points.
+     * @note added in 3.0
+     */
+    static void segmentizeArc( const QgsPointV2 &p1, const QgsPointV2 &p2, const QgsPointV2 &p3, QgsPointSequence &points, double tolerance = M_PI_2 / 90, QgsAbstractGeometry::SegmentationToleranceType toleranceType = QgsAbstractGeometry::MaximumAngle, bool hasZ = false, bool hasM = false );
+
+    /** For line defined by points pt1 and pt3, find out on which side of the line is point pt3.
+     * Returns -1 if pt3 on the left side, 1 if pt3 is on the right side or 0 if pt3 lies on the line.
+     * @note added in 3.0
+     */
+    static int segmentSide( const QgsPointV2 &pt1, const QgsPointV2 &pt3, const QgsPointV2 &pt2 );
+
+    /** Interpolate a value at given angle on circular arc given values (zm1, zm2, zm3) at three different angles (a1, a2, a3).
+     * @note added in 3.0
+     */
+    static double interpolateArcValue( double angle, double a1, double a2, double a3, double zm1, double zm2, double zm3 );
+
     /** Returns a list of points contained in a WKT string.
      * @note not available in Python bindings
      */