Merge pull request #22 from soblin/feature/twinx

added subplots_axes_and_figures/two_scales

gallery/subplots_axes_and_figures/CMakeLists.txt

@@ -3,13 +3,15 @@ add_demo(gridspec_multicolumn gridspec_multicolumn.cpp)
 add_demo(multiple_figs_demo multiple_figs_demo.cpp)
 add_demo(colorbar_placement colorbar_placement.cpp)
 add_demo(subplots subplots.cpp)
+add_demo(two_scales two_scales.cpp)
 
 add_custom_target(subplots_axes_and_figures
-  DEPENDS align_labels_demo gridspec_multicolumn multiple_figs_demo colorbar_placement
+  DEPENDS align_labels_demo gridspec_multicolumn multiple_figs_demo colorbar_placement two_scales
   COMMAND align_labels_demo
   COMMAND gridspec_multicolumn
   COMMAND multiple_figs_demo
   COMMAND colorbar_placement
+  COMMAND two_scales
   COMMENT "subplots_axes_and_figures"
   WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
 )

gallery/subplots_axes_and_figures/two_scales.cpp

+// example from
+// https://matplotlib.org/stable/gallery/subplots_axes_and_figures/two_scales.html
+
+#include <matplotlibcpp17/pyplot.h>
+
+#include <xtensor/xbuilder.hpp>
+#include <xtensor/xmath.hpp>
+
+#include <vector>
+
+using namespace std;
+using namespace matplotlibcpp17;
+
+int main() {
+  auto t_ = xt::arange(0.01, 10.0, 0.01);
+  auto data1_ = xt::exp(t_);
+  auto data2_ = xt::sin(2 * M_PI * t_);
+  vector<double> t(t_.begin(), t_.end()), data1(data1_.begin(), data1_.end()),
+      data2(data2_.begin(), data2_.end());
+
+  py::scoped_interpreter guard{};
+  auto plt = pyplot::import();
+  auto [fig, ax1] = plt.subplots();
+
+  auto color = "tab:red";
+  ax1.set_xlabel(Args("time (s)"));
+  ax1.set_ylabel(Args("exp"), Kwargs("color"_a = color));
+  ax1.plot(Args(t, data1), Kwargs("color"_a = color));
+  ax1.tick_params(Args(), Kwargs("axis"_a = "y", "labelcolor"_a = color));
+
+  auto ax2 =
+      ax1.twinx(); // instantiate a second axes that shares the same x-axis
+
+  color = "tab:blue";
+  ax2.set_ylabel(Args("sin"), Kwargs("color"_a = color));
+  ax2.plot(Args(t, data2), Kwargs("color"_a = color));
+  ax2.tick_params(Args(), Kwargs("axis"_a = "y", "labelcolor"_a = color));
+
+  fig.tight_layout();
+  plt.show();
+}

include/matplotlibcpp17/axes.h

@@ -229,6 +229,10 @@ public:
   pybind11::object tick_params(const pybind11::tuple &args = pybind11::tuple(),
                                const pybind11::dict &kwargs = pybind11::dict());
 
+  // twinx
+  Axes twinx(const pybind11::tuple &args = pybind11::tuple(),
+             const pybind11::dict &kwargs = pybind11::dict());
+
 private:
   void load_attrs() {
     LOAD_FUNC_ATTR(add_artist, self);
@@ -288,6 +292,7 @@ private:
     LOAD_FUNC_ATTR(set_yticks, self);
     LOAD_FUNC_ATTR(text, self);
     LOAD_FUNC_ATTR(tick_params, self);
+    LOAD_FUNC_ATTR(twinx, self);
   }
   pybind11::object add_artist_attr;
   pybind11::object add_collection_attr;
@@ -335,6 +340,7 @@ private:
   pybind11::object set_zlim_attr;
   pybind11::object text_attr;
   pybind11::object tick_params_attr;
+  pybind11::object twinx_attr;
   bool projection_3d;
 };
 
@@ -691,6 +697,12 @@ pybind11::object Axes::tick_params(const pybind11::tuple &args,
   return ret;
 }
 
+// twinx
+Axes Axes::twinx(const pybind11::tuple &args, const pybind11::dict &kwargs) {
+  pybind11::object ret = twinx_attr(*args, **kwargs);
+  return Axes(ret);
+}
+
 } // namespace matplotlibcpp17::axes
 
 #endif /* MATPLOTLIBCPP17_AXES_H */