Rename Angle::sinCos -> sinCosSnap

libgeos · Nov 15, 2023 · dcde8ad · dcde8ad
1 parent 758238d
commit dcde8ad
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Showing 5 changed files with 15 additions and 14 deletions.
diff --git a/NEWS.md b/NEWS.md
@@ -2,7 +2,7 @@
 20xx-xx-xx
 
 - New things:
-  - Add Angle::sinCos to avoid small errors, e.g. with buffer operations (GH-978, Mike Taves)
+  - Add Angle::sinCosSnap to avoid small errors, e.g. with buffer operations (GH-978, Mike Taves)
 
 - Breaking Changes
 

diff --git a/include/geos/algorithm/Angle.h b/include/geos/algorithm/Angle.h
@@ -218,21 +218,22 @@ class GEOS_DLL Angle {
     static double diff(double ang1, double ang2);
 
     /// \brief
-    /// Computes both sin and cos of an angle.
+    /// Computes both sin and cos of an angle, snapping near-zero values
+    /// to zero.
     ///
     /// The angle does not need to be normalized. Unlike std::sin
-    /// and std::cos, this method will clip near-zero values to zero
+    /// and std::cos, this method will snap near-zero values to zero
     /// for (e.g.) sin(pi) and cos(pi/2).
     ///
     /// @param ang the input angle (in radians)
     /// @param rSin the result of sin(ang)
     /// @param rCos the result of cos(ang)
     ///
-    static inline void sinCos(const double ang, double& rSin, double& rCos) {
+    static inline void sinCosSnap(const double ang, double& rSin, double& rCos) {
         // calculate both; may be optimized with FSINCOS instruction
         rSin = std::sin(ang);
         rCos = std::cos(ang);
-        // clip near zero values
+        // snap near-zero values
         if (std::fabs(rSin) < 5e-16) rSin = 0.0;
         if (std::fabs(rCos) < 5e-16) rCos = 0.0;
     }

diff --git a/src/operation/buffer/OffsetSegmentGenerator.cpp b/src/operation/buffer/OffsetSegmentGenerator.cpp
@@ -222,7 +222,7 @@ OffsetSegmentGenerator::addLineEndCap(const Coordinate& p0, const Coordinate& p1
         // segment endpoints
         Coordinate squareCapSideOffset;
         double sinangle, cosangle;
-        Angle::sinCos(angle, sinangle, cosangle);
+        Angle::sinCosSnap(angle, sinangle, cosangle);
         squareCapSideOffset.x = fabs(distance) * cosangle;
         squareCapSideOffset.y = fabs(distance) * sinangle;
 
@@ -283,7 +283,7 @@ OffsetSegmentGenerator::addDirectedFillet(const Coordinate& p, double startAngle
     double sinangle, cosangle;
     Coordinate pt;
     for (int i = 0; i < nSegs; i++) {
-        Angle::sinCos(startAngle + directionFactor * i * angleInc, sinangle, cosangle);
+        Angle::sinCosSnap(startAngle + directionFactor * i * angleInc, sinangle, cosangle);
         pt.x = p.x + radius * cosangle;
         pt.y = p.y + radius * sinangle;
         segList.addPt(pt);
@@ -583,7 +583,7 @@ Coordinate
 OffsetSegmentGenerator::project(const Coordinate& pt, double d, double dir)
 {
     double sindir, cosdir;
-    Angle::sinCos(dir, sindir, cosdir);
+    Angle::sinCosSnap(dir, sindir, cosdir);
     double x = pt.x + d * cosdir;
     double y = pt.y + d * sindir;
     return Coordinate(x, y);

diff --git a/src/util/GeometricShapeFactory.cpp b/src/util/GeometricShapeFactory.cpp
@@ -138,7 +138,7 @@ GeometricShapeFactory::createCircle()
     uint32_t iPt = 0;
     double sinang, cosang;
     for(uint32_t i = 0; i < nPts; i++) {
-        Angle::sinCos(i * Angle::PI_TIMES_2 / nPts, sinang, cosang);
+        Angle::sinCosSnap(i * Angle::PI_TIMES_2 / nPts, sinang, cosang);
         double x = xRadius * cosang + centreX;
         double y = yRadius * sinang + centreY;
         (*pts)[iPt++] = coord(x, y);
@@ -170,7 +170,7 @@ GeometricShapeFactory::createArc(double startAng, double angExtent)
     uint32_t iPt = 0;
     double sinang, cosang;
     for(uint32_t i = 0; i < nPts; i++) {
-        Angle::sinCos(startAng + i * angInc, sinang, cosang);
+        Angle::sinCosSnap(startAng + i * angInc, sinang, cosang);
         double x = xRadius * cosang + centreX;
         double y = yRadius * sinang + centreY;
         (*pts)[iPt++] = coord(x, y);
@@ -201,7 +201,7 @@ GeometricShapeFactory::createArcPolygon(double startAng, double angExtent)
     (*pts)[iPt++] = coord(centreX, centreY);
     double sinang, cosang;
     for(uint32_t i = 0; i < nPts; i++) {
-        Angle::sinCos(startAng + i * angInc, sinang, cosang);
+        Angle::sinCosSnap(startAng + i * angInc, sinang, cosang);
         double x = xRadius * cosang + centreX;
         double y = yRadius * sinang + centreY;
         (*pts)[iPt++] = coord(x, y);

diff --git a/tests/unit/algorithm/AngleTest.cpp b/tests/unit/algorithm/AngleTest.cpp
@@ -162,7 +162,7 @@ void object::test<5>
         TOL);
 }
 
-// testSinCos()
+// testSinCosSnap()
 template<>
 template<>
 void object::test<6>
@@ -174,7 +174,7 @@ void object::test<6>
     for (int angdeg = -720; angdeg <= 720; angdeg++) {
         const double ang = Angle::toRadians(angdeg);
 
-        Angle::sinCos(ang, rSin, rCos);
+        Angle::sinCosSnap(ang, rSin, rCos);
 
         double cSin = std::sin(ang);
         double cCos = std::cos(ang);
@@ -192,7 +192,7 @@ void object::test<6>
     // use radian increments that don't snap to exact degrees or zero
     for (double angrad = -6.3; angrad < 6.3; angrad += 0.013) {
 
-        Angle::sinCos(angrad, rSin, rCos);
+        Angle::sinCosSnap(angrad, rSin, rCos);
 
         ensure_equals(std::to_string(angrad), rSin, std::sin(angrad));
         ensure_equals(std::to_string(angrad), rCos, std::cos(angrad));