Fix matplotlib#1973: offset_position == 'data' is not respected by point_in_path_collection

Author: mdboom

lib/matplotlib/collections.py

@@ -302,7 +302,8 @@ def contains(self, mouseevent):
         ind = mpath.point_in_path_collection(
             mouseevent.x, mouseevent.y, pickradius,
             transform.frozen(), paths, self.get_transforms(),
-            offsets, transOffset, pickradius <= 0)
+            offsets, transOffset, pickradius <= 0,
+            self.get_offset_position())
 
         return len(ind)>0, dict(ind=ind)
 

src/_path.cpp

@@ -699,7 +699,7 @@ _path_module::get_path_collection_extents(const Py::Tuple& args)
 Py::Object
 _path_module::point_in_path_collection(const Py::Tuple& args)
 {
-    args.verify_length(9);
+    args.verify_length(10);
 
     //segments, trans, clipbox, colors, linewidths, antialiaseds
     double                  x                = Py::Float(args[0]);
@@ -711,6 +711,9 @@ _path_module::point_in_path_collection(const Py::Tuple& args)
     Py::SeqBase<Py::Object> offsets_obj      = args[6];
     agg::trans_affine       offset_trans     = py_to_agg_transformation_matrix(args[7].ptr());
     bool                    filled           = Py::Boolean(args[8]);
+    std::string             offset_position  = Py::String(args[9]);
+
+    bool data_offsets = (offset_position == "data");
 
     PyArrayObject* offsets = (PyArrayObject*)PyArray_FromObject(
         offsets_obj.ptr(), PyArray_DOUBLE, 0, 2);
@@ -761,7 +764,11 @@ _path_module::point_in_path_collection(const Py::Tuple& args)
             double xo = *(double*)PyArray_GETPTR2(offsets, i % Noffsets, 0);
             double yo = *(double*)PyArray_GETPTR2(offsets, i % Noffsets, 1);
             offset_trans.transform(&xo, &yo);
-            trans *= agg::trans_affine_translation(xo, yo);
+            if (data_offsets) {
+                trans = agg::trans_affine_translation(xo, yo) * trans;
+            } else {
+                trans *= agg::trans_affine_translation(xo, yo);
+            }
         }
 
         if (filled)