PartDesign: Add transparent previews

src/Mod/Part/App/Tools.cpp

@@ -71,7 +71,11 @@
 
 #include "Tools.h"
 
+#include <TopExp_Explorer.hxx>
+#include <TopoShape.h>
 
+
+class TopExp_Explorer;
 void Part::closestPointsOnLines(const gp_Lin& lin1, const gp_Lin& lin2, gp_Pnt& p1, gp_Pnt& p2)
 {
     // they might be the same point
@@ -746,36 +750,71 @@ TopLoc_Location Part::Tools::fromPlacement(const Base::Placement& plm)
     return {trf};
 }
 
-bool Part::Tools::isConcave(const TopoDS_Face &face, const gp_Pnt &pointOfVue, const gp_Dir &direction){
+bool Part::Tools::isConcave(const TopoDS_Face& face,
+                            const gp_Pnt& pointOfVue,
+                            const gp_Dir& direction)
+{
     bool result = false;
 
     Handle(Geom_Surface) surf = BRep_Tool::Surface(face);
     GeomAdaptor_Surface adapt(surf);
-    if(adapt.GetType() == GeomAbs_Plane){
+    if (adapt.GetType() == GeomAbs_Plane) {
         return false;
     }
 
-            // create a line through the point of vue
+    // create a line through the point of vue
     gp_Lin line;
     line.SetLocation(pointOfVue);
     line.SetDirection(direction);
 
-            // Find intersection of line with the face
+    // Find intersection of line with the face
     BRepIntCurveSurface_Inter mkSection;
     mkSection.Init(face, line, Precision::Confusion());
 
     result = mkSection.Transition() == IntCurveSurface_In;
 
-            // compute normals at the intersection
+    // compute normals at the intersection
     gp_Pnt iPnt;
     gp_Vec dU, dV;
     surf->D1(mkSection.U(), mkSection.V(), iPnt, dU, dV);
 
-            // check normals orientation
+    // check normals orientation
     gp_Dir dirdU(dU);
-    result = (dirdU.Angle(direction) - std::numbers::pi/2) <= Precision::Confusion();
+    result = (dirdU.Angle(direction) - std::numbers::pi / 2) <= Precision::Confusion();
     gp_Dir dirdV(dV);
-    result = result || ((dirdV.Angle(direction) - std::numbers::pi/2) <= Precision::Confusion());
+    result = result || ((dirdV.Angle(direction) - std::numbers::pi / 2) <= Precision::Confusion());
 
     return result;
 }
+
+bool Part::Tools::isShapeEmpty(const TopoShape& shape)
+{
+    return shape.isEmpty();
+}
+
+bool Part::Tools::isShapeEmpty(const TopoDS_Shape& shape)
+{
+    static const auto isEveryShapeInCompoundEmpty = [](const TopoDS_Shape& shape) {
+        for (TopoDS_Iterator it(shape); it.More(); it.Next()) {
+            if (const TopoDS_Shape& sub = it.Value(); !isShapeEmpty(sub)) {
+                // Found a non-empty sub-shape
+                return false;
+            }
+        }
+
+        return true;
+    };
+
+    // If shape is null we consider it as empty
+    if (shape.IsNull()) {
+        return true;
+    }
+
+    if (shape.ShapeType() == TopAbs_COMPOUND) {
+        return isEveryShapeInCompoundEmpty(shape);
+    }
+
+    // To see if shape is non-empty we check if it has at least one vertex
+    TopExp_Explorer explorer(shape, TopAbs_VERTEX);
+    return !explorer.More();
+}