From 1a9637a384fde657d86d28ea040ed09134f5d812 Mon Sep 17 00:00:00 2001
From: wandererfan <wandererfan@gmail.com>
Date: Thu, 10 Nov 2022 16:22:23 -0500
Subject: [PATCH] [TD]fix XDirection rotation of simple sections

---
 src/Mod/TechDraw/App/DrawViewPart.cpp    | 27 ++++++++++++------------
 src/Mod/TechDraw/App/DrawViewSection.cpp | 10 ++++-----
 2 files changed, 19 insertions(+), 18 deletions(-)

diff --git a/src/Mod/TechDraw/App/DrawViewPart.cpp b/src/Mod/TechDraw/App/DrawViewPart.cpp
index 73996ded23..c60dd6b08f 100644
--- a/src/Mod/TechDraw/App/DrawViewPart.cpp
+++ b/src/Mod/TechDraw/App/DrawViewPart.cpp
@@ -79,6 +79,7 @@
 
 
 using namespace TechDraw;
+using DU = DrawUtil;
 
 //===========================================================================
 // DrawViewPart
@@ -342,7 +343,7 @@ GeometryObject* DrawViewPart::makeGeometryForShape(TopoDS_Shape& shape)
                                             viewAxis,
                                             Rotation.getValue());  //conventional rotation
      }
-//    BRepTools::Write(scaledShape, "DVPScaled.brep");            //debug
+    BRepTools::Write(scaledShape, "DVPScaled.brep");            //debug
     GeometryObject* go =  buildGeometryObject(scaledShape, viewAxis);
     return go;
 }
@@ -1011,23 +1012,23 @@ bool DrawViewPart::hasGeometry(void) const
 //in the derived view.
 gp_Ax2 DrawViewPart::localVectorToCS(const Base::Vector3d localUnit) const
 {
-    gp_Pnt stdOrigin(0.0, 0.0, 0.0);
-    gp_Ax2 dvpCS = getProjectionCS(DrawUtil::toVector3d(stdOrigin));
-    gp_Vec gLocalUnit = DrawUtil::togp_Dir(localUnit);
-    gp_Vec gLocalX(-gLocalUnit.Y(), gLocalUnit.X(), 0.0);    //clockwise perp for 2d
+    double angle = atan2(localUnit.y, localUnit.x);     //radians
+    gp_Ax1 rotateAxisDir(gp_Pnt(0.0, 0.0, 0.0), getProjectionCS().Direction());
+    gp_Vec gNewDirection = getProjectionCS().XDirection().Rotated(rotateAxisDir, angle);
 
-    gp_Ax3 OXYZ;
-    gp_Trsf xLocalOXYZ;
-    xLocalOXYZ.SetTransformation(OXYZ, gp_Ax3(dvpCS));
-    gp_Vec gLocalUnitOXYZ = gLocalUnit.Transformed(xLocalOXYZ);
-    gp_Vec gLocalXOXYZ = gLocalX.Transformed(xLocalOXYZ);
-
-    return { stdOrigin, gp_Dir(gLocalUnitOXYZ), gp_Dir(gLocalXOXYZ) };
+    gp_Vec crossDirs = getProjectionCS().Direction().Crossed(gNewDirection);
+    gp_Vec gNewX = getProjectionCS().XDirection();
+    gp_Vec triple = crossDirs.Crossed(getProjectionCS().XDirection());
+    if (!DU::fpCompare(triple.Magnitude(), 0.0, EWTOLERANCE)) {
+        gNewX = triple;
+    }
+    return { gp_Pnt(0.0, 0.0, 0.0), gp_Dir(gNewDirection), gp_Dir(gNewX) };
 }
 
+
 Base::Vector3d DrawViewPart::localVectorToDirection(const Base::Vector3d localUnit) const
 {
-    Base::Console().Message("DVP::localVectorToDirection() - localUnit: %s\n", DrawUtil::formatVector(localUnit).c_str());
+//    Base::Console().Message("DVP::localVectorToDirection() - localUnit: %s\n", DrawUtil::formatVector(localUnit).c_str());
     gp_Ax2 cs = localVectorToCS(localUnit);
     return DrawUtil::toVector3d(cs.Direction());
 }
diff --git a/src/Mod/TechDraw/App/DrawViewSection.cpp b/src/Mod/TechDraw/App/DrawViewSection.cpp
index dc587b1e03..afa86bd7c6 100644
--- a/src/Mod/TechDraw/App/DrawViewSection.cpp
+++ b/src/Mod/TechDraw/App/DrawViewSection.cpp
@@ -492,7 +492,7 @@ void DrawViewSection::onSectionCutFinished()
     postSectionCutTasks();
 
     //display geometry for cut shape is in geometryObject as in DVP
-    m_tempGeometryObject = buildGeometryObject(m_preparedShape, getSectionCS());
+    m_tempGeometryObject = buildGeometryObject(m_preparedShape, getProjectionCS());
 }
 
 //activities that depend on updated geometry object
@@ -651,7 +651,7 @@ TopoDS_Compound DrawViewSection::mapToPage(TopoDS_Shape& shapeToAlign)
         TopExp_Explorer expWires(face, TopAbs_WIRE);
         for ( ; expWires.More(); expWires.Next()) {
             const TopoDS_Wire& wire = TopoDS::Wire(expWires.Current());
-            TopoDS_Shape projectedShape = GeometryObject::projectSimpleShape(wire, getSectionCS());
+            TopoDS_Shape projectedShape = GeometryObject::projectSimpleShape(wire, getProjectionCS());
             std::vector<TopoDS_Edge> wireEdges;
             //projectedShape is just a bunch of edges. we have to rebuild the wire.
             TopExp_Explorer expEdges(projectedShape, TopAbs_EDGE);
@@ -814,7 +814,7 @@ void DrawViewSection::setCSFromBase(const Base::Vector3d localUnit)
     Base::Vector3d vXDir(newSectionCS.XDirection().X(),
                          newSectionCS.XDirection().Y(),
                          newSectionCS.XDirection().Z());
-    XDirection.setValue(vXDir);
+    XDirection.setValue(vXDir);         //XDir is for projection
 }
 
 //reset the section CS based on an XY vector in current section CS
@@ -858,8 +858,8 @@ gp_Ax2 DrawViewSection::getCSFromBase(const std::string sectionName) const
         dvsDir  = dvpUp;
         dvsXDir = dvpRight;
     } else if (sectionName == "Left") {
-        dvsDir = dvpRight;
-        dvsXDir = dvpDir.Reversed();
+        dvsDir = dvpRight;   //dvpX
+        dvsXDir = dvpDir.Reversed();  //-dvpZ
     } else if (sectionName == "Right") {
         dvsDir = dvpRight.Reversed();
         dvsXDir = dvpDir;