added mplot3d/errorbar3d

Author: MamoruSobue

gallery/mplot3d/CMakeLists.txt

@@ -2,13 +2,15 @@ add_demo(lines3d lines3d.cpp)
 add_demo(lorenz_attractor lorenz_attractor.cpp)
 add_demo(contour3d contour3d.cpp)
 add_demo(subplot3d subplot3d.cpp)
+add_demo(errorbar3d errorbar3d.cpp)
 
 add_custom_target(mplot3d
-  DEPENDS lines3d lorenz_attractor contour3d subplot3d
+  DEPENDS lines3d lorenz_attractor contour3d subplot3d errorbar3d
   COMMAND lines3d
   COMMAND lorenz_attractor
   COMMAND contour3d
   COMMAND subplot3d
+  COMMAND errorbar3d
   COMMENT "running mplot3d"
   WORKING_DIRECTORY "${CMAKE_CURRENT_SOURCE_DIR}/../images"
 )

gallery/mplot3d/errorbar3d.cpp

@@ -0,0 +1,49 @@
+// example from https://matplotlib.org/stable/gallery/mplot3d/errorbar3d.html
+
+#include <pybind11/embed.h>
+#include <pybind11/stl.h>
+
+#include <matplotlibcpp17/pyplot.h>
+
+#include <xtensor/xbuilder.hpp>
+#include <xtensor/xmath.hpp>
+
+#include <vector>
+#include <algorithm>
+
+namespace py = pybind11;
+using namespace py::literals;
+using namespace std;
+using namespace matplotlibcpp17;
+
+int main() {
+  py::scoped_interpreter guard{};
+  auto plt = pyplot::import();
+  auto ax = plt.figure().add_subplot(Args(), Kwargs("projection"_a = "3d"));
+  auto t_ = xt::arange(0.0, 2 * M_PI + 0.1, 0.01);
+  auto x_ = xt::sin(1.0 * t_);
+  auto y_ = xt::cos(3.0 * t_);
+  auto z_ = xt::sin(5.0 * t_);
+  vector<double> t(t_.begin(), t_.end()), x(x_.begin(), x_.end()),
+      y(y_.begin(), y_.end()), z(z_.begin(), z_.end());
+
+  const int estep = 15;
+  vector<int> i, zuplims, zlolims;
+  std::iota(i.begin(), i.end(), 0);
+  std::transform(i.begin(), i.end(), std::back_inserter(zuplims), [](int i) {
+    return (i % 15 == 0) and ((i / estep) % 3 == 0);
+  });
+  std::transform(i.begin(), i.end(), std::back_inserter(zlolims), [](int i) {
+    return (i % 15 == 0) and ((i / estep) % 3 == 2);
+  });
+
+  ax.errorbar(Args(x, y, z, 0.2),
+              Kwargs("zuplims"_a = zuplims, "zlolims"_a = zlolims,
+                     "errorevery"_a = estep));
+
+  ax.set_xlabel(Args("X label"));
+  ax.set_ylabel(Args("Y label"));
+  ax.set_zlabel(Args("Z label"));
+
+  plt.show();
+}

include/matplotlibcpp17/axes.h

@@ -237,8 +237,10 @@ struct DECL_STRUCT_ATTR Axes : public BaseWrapper {
       plot_wireframe_attr = self.attr("plot_wireframe");
       set_zlabel_attr = self.attr("set_zlabel");
       INFO_MSG("Loaded Axes3D");
+      projection_3d = true;
+    } catch (...) {
+      projection_3d = false;
     }
-    catch(...) {}
     LOAD_FUNC_ATTR(quiver, self);
     LOAD_FUNC_ATTR(quiverkey, self);
     LOAD_FUNC_ATTR(scatter, self);
@@ -295,6 +297,7 @@ struct DECL_STRUCT_ATTR Axes : public BaseWrapper {
   pybind11::object set_zlabel_attr;
   pybind11::object text_attr;
   pybind11::object tick_params_attr;
+  bool projection_3d;
 };
 
 // add_artist
@@ -362,8 +365,14 @@ pybind11::object Axes::contour(const pybind11::tuple &args,
 // errorbar
 pybind11::object Axes::errorbar(const pybind11::tuple &args,
                                 const pybind11::dict &kwargs) {
-  pybind11::object obj = errorbar_attr(*args, **kwargs);
-  return obj;
+  if (not projection_3d) {
+    pybind11::object obj = errorbar_attr(*args, **kwargs);
+    return obj;
+  } else {
+    ERROR_MSG("Call to errorbar with projection='3d' is invalid because "
+              "matplotlib version is < 3.4.0");
+    std::exit(0);
+  }
 }
 
 // fill