[python] Add an "axis" function to the matplotlib module

python/port/mod/matplotlib/modpyplot.cpp

@@ -1,17 +1,72 @@
 extern "C" {
 #include "modpyplot.h"
 }
+#include <assert.h>
 #include "port.h"
 #include "plot_controller.h"
 
-Matplotlib::PlotController sPlotController;
+Matplotlib::PlotStore * sPlotStore = nullptr;
+Matplotlib::PlotController * sPlotController = nullptr;
+
+// Internal functions
+
+mp_obj_t modpyplot___init__() {
+  static Matplotlib::PlotStore plotStore;
+  static Matplotlib::PlotController plotController(&plotStore);
+  sPlotStore = &plotStore;
+  sPlotController = &plotController;
+  sPlotStore->flush();
+  return mp_const_none;
+}
+
+void modpyplot_gc_collect() {
+  if (sPlotStore != nullptr) {
+    return;
+  }
+  MicroPython::collectRootsAtAddress(
+    reinterpret_cast<char *>(&sPlotStore),
+    sizeof(Matplotlib::PlotStore)
+  );
+}
+
+/* axis(arg)
+ *  - arg = [xmin, xmax, ymin, ymax]
+ *  - arg = True, False
+ * Returns : xmin, xmax, ymin, ymax : float */
+
+mp_obj_t modpyplot_axis(mp_obj_t arg) {
+  mp_obj_is_type(arg, &mp_type_enumerate);
+#warning Use mp_obj_is_bool when upgrading uPy
+  if (mp_obj_is_type(arg, &mp_type_bool)) {
+    sPlotStore->setGrid(mp_obj_is_true(arg));
+  } else {
+    mp_obj_t * items;
+    mp_obj_get_array_fixed_n(arg, 4, &items);
+    sPlotStore->setXMin(mp_obj_get_float(items[0]));
+    sPlotStore->setXMax(mp_obj_get_float(items[1]));
+    sPlotStore->setYMin(mp_obj_get_float(items[2]));
+    sPlotStore->setYMax(mp_obj_get_float(items[3]));
+  }
+
+  // Build the return value
+  mp_obj_t coords[4];
+  coords[0] = mp_obj_new_float(sPlotStore->xMin());
+  coords[1] = mp_obj_new_float(sPlotStore->xMax());
+  coords[2] = mp_obj_new_float(sPlotStore->yMin());
+  coords[3] = mp_obj_new_float(sPlotStore->yMax());
+  return mp_obj_new_tuple(4, coords);
+}
 
 mp_obj_t modpyplot_plot(mp_obj_t x, mp_obj_t y) {
+  assert(sPlotStore != nullptr);
+  sPlotStore->addDots(x, y);
   // Ensure x and y are arrays
   // "Push" x and y on bigger arrays
+  return mp_const_none;
 }
 
 mp_obj_t modpyplot_show() {
   MicroPython::ExecutionEnvironment * env = MicroPython::ExecutionEnvironment::currentExecutionEnvironment();
-  env->displayViewController(&sPlotController);
+  env->displayViewController(sPlotController);
+  return mp_const_none;
 }