convert FOPlot to oo-interface so it returns fig properly

rubin_sim/maf/plots/special_plotters.py

@@ -64,11 +64,11 @@ def __call__(self, metric_value, slicer, user_plot_dict, fig=None):
             plot_dict["scale"] = hp.nside2pixarea(slicer.nside, degrees=True) / 1000.0
 
         if fig is None:
-            fig = plt.Figure(figsize=plot_dict["figsize"])
+            fig, ax = plt.subplots(figsize=plot_dict["figsize"])
 
         # Expect metric_value to be something like number of visits
         cumulative_area = np.arange(1, metric_value.compressed().size + 1)[::-1] * plot_dict["scale"]
-        plt.plot(
+        ax.plot(
             np.sort(metric_value.compressed()),
             cumulative_area,
             "k-",
@@ -83,42 +83,42 @@ def __call__(self, metric_value, slicer, user_plot_dict, fig=None):
         f_o_area = metrics.FOArea(col="fO", n_visit=n_visits, norm=False, nside=slicer.nside).run(rarr)
         f_o_nv = metrics.FONv(col="fO", asky=asky, norm=False, nside=slicer.nside).run(rarr)
 
-        plt.axvline(x=n_visits, linewidth=plot_dict["reflinewidth"], color="b", linestyle=":")
-        plt.axhline(y=asky / 1000.0, linewidth=plot_dict["reflinewidth"], color="r", linestyle=":")
+        ax.axvline(x=n_visits, linewidth=plot_dict["reflinewidth"], color="b", linestyle=":")
+        ax.axhline(y=asky / 1000.0, linewidth=plot_dict["reflinewidth"], color="r", linestyle=":")
         # Add lines for nvis_median and f_o_area:
         # note if these are -666 (badval), they will 'disappear'
         nvis_median = f_o_nv["value"][np.where(f_o_nv["name"] == "MedianNvis")][0]
 
-        plt.axvline(
+        ax.axvline(
             x=nvis_median,
             linewidth=plot_dict["reflinewidth"],
             color="b",
             alpha=0.5,
             linestyle="-",
             label=f"f$_0$ Med. Nvis. (@ {asky/1000 :.0f}K sq deg) = {nvis_median :.0f} visits",
         )
-        plt.axhline(
+        ax.axhline(
             y=f_o_area / 1000.0,
             linewidth=plot_dict["reflinewidth"],
             color="r",
             alpha=0.5,
             linestyle="-",
             label=f"f$_0$ Area (@ {n_visits :.0f} visits) = {f_o_area/1000 :.01f}K sq deg",
         )
-        plt.legend(loc="upper right", fontsize="small", numpoints=1, framealpha=1.0)
+        ax.legend(loc="upper right", fontsize="small", numpoints=1, framealpha=1.0)
 
-        plt.xlabel(plot_dict["xlabel"])
-        plt.ylabel(plot_dict["ylabel"])
-        plt.title(plot_dict["title"])
+        ax.set_xlabel(plot_dict["xlabel"])
+        ax.set_ylabel(plot_dict["ylabel"])
+        ax.set_title(plot_dict["title"])
 
         x_min = plot_dict["x_min"]
         x_max = plot_dict["x_max"]
         y_min = plot_dict["y_min"]
         y_max = plot_dict["y_max"]
         if (x_min is not None) or (x_max is not None):
-            plt.xlim([x_min, x_max])
+            ax.set_xlim([x_min, x_max])
         if (y_min is not None) or (y_max is not None):
-            plt.ylim([y_min, y_max])
+            ax.set_ylim([y_min, y_max])
         return fig