Merge branch 'region_plot' of github.com:egourgoulhon/sage into options_fix_in_contour_plot

This also fixes a bug in region_plot, so that plot_points are not
passed in calls to other functions via options.

This is because a @options decorator's argument are automatically popped
from "options" dict as soon as the function it decorates has an arg
with the same name.

In the change we reduce the number of positional arguments of
region_plot; thus the corresponding args of @options have to be popped
manually in the function body; we don't pop plot_points, to
pass it correctly in function calls.

Author: dimpase

src/sage/plot/contour_plot.py

@@ -1391,9 +1391,10 @@ def f(x,y):
         raise ValueError("fill=%s is not supported" % options['fill'])
 
 
-@options(frame=False, axes=True, legend_label=None, aspect_ratio=1)
-def region_plot(f, xrange, yrange, plot_points=100, incol='blue', outcol=None, bordercol=None,
-                borderstyle=None, borderwidth=None, alpha=1, **options):
+@options(plot_points=100, incol='blue', outcol=None, bordercol=None,
+         borderstyle=None, borderwidth=None, frame=False, axes=True,
+         legend_label=None, aspect_ratio=1, alpha=1)
+def region_plot(f, xrange, yrange, **options):
     r"""
     ``region_plot`` takes a boolean function of two variables, `f(x, y)`
     and plots the region where f is True over the specified
@@ -1657,6 +1658,14 @@ def region_plot(f, xrange, yrange, plot_points=100, incol='blue', outcol=None, b
     from warnings import warn
     import numpy
 
+    plot_points = options['plot_points']
+    incol = options.pop('incol')
+    outcol = options.pop('outcol')
+    bordercol = options.pop('bordercol')
+    borderstyle = options.pop('borderstyle')
+    borderwidth = options.pop('borderwidth')
+    alpha = options.pop('alpha')
+
     if not isinstance(f, (list, tuple)):
         f = [f]
 
@@ -1675,9 +1684,9 @@ def region_plot(f, xrange, yrange, plot_points=100, incol='blue', outcol=None, b
     if neqs and not bordercol:
         bordercol = incol
     if not f:
-        return implicit_plot(feqs[0], xrange, yrange, plot_points=plot_points,
-                             fill=False, linewidth=borderwidth,
-                             linestyle=borderstyle, color=bordercol, **options)
+        return implicit_plot(feqs[0], xrange, yrange, fill=False,
+                             linewidth=borderwidth, linestyle=borderstyle,
+                             color=bordercol, **options)
     f_all, ranges = setup_for_eval_on_grid(feqs + f,
                                            [xrange, yrange],
                                            plot_points)