Speed up QgsLineString::closestSegment

Avoid multiple detachment checks
qgis · Jul 21, 2024 · dd36e37 · dd36e37
1 parent 5a3ef35
commit dd36e37
Showing 1 changed file with 8 additions and 5 deletions.
diff --git a/src/core/geometry/qgslinestring.cpp b/src/core/geometry/qgslinestring.cpp
@@ -1992,18 +1992,21 @@ double QgsLineString::closestSegment( const QgsPoint &pt, QgsPoint &segmentPt,
   if ( leftOf )
     *leftOf = 0;
 
-  int size = mX.size();
+  const int size = mX.size();
   if ( size == 0 || size == 1 )
   {
     vertexAfter = QgsVertexId( 0, 0, 0 );
     return -1;
   }
+
+  const double *xData = mX.constData();
+  const double *yData = mY.constData();
   for ( int i = 1; i < size; ++i )
   {
-    double prevX = mX.at( i - 1 );
-    double prevY = mY.at( i - 1 );
-    double currentX = mX.at( i );
-    double currentY = mY.at( i );
+    double prevX = xData[ i - 1 ];
+    double prevY = yData[ i - 1 ];
+    double currentX = xData[ i ];
+    double currentY = yData[ i ];
     testDist = QgsGeometryUtilsBase::sqrDistToLine( pt.x(), pt.y(), prevX, prevY, currentX, currentY, segmentPtX, segmentPtY, epsilon );
     if ( testDist < sqrDist )
     {