Deprecate NavigationToolbar2GTK3.ctx.

anntzer · anntzer · commit c5946e1c9839 · 2020-04-22T10:02:27.000+02:00
No alternative documented: messing with the window cairo context is
quite low level; if you're doing that, creating the context should not
be that hard.
diff --git a/doc/api/api_changes_3.3/deprecations.rst b/doc/api/api_changes_3.3/deprecations.rst
@@ -373,6 +373,10 @@ These attributes are deprecated.  In order to access the parent window, use
 also be accessible as ``toolbar.parent()``.  The base directory to the icons
 is ``os.path.join(mpl.get_data_path(), "images")``.
 
+NavigationToolbar2QT.ctx
+~~~~~~~~~~~~~~~~~~~~~~~~
+This attribute is deprecated.
+
 Path helpers in :mod:`.bezier`
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
diff --git a/lib/matplotlib/backends/backend_gtk3.py b/lib/matplotlib/backends/backend_gtk3.py
@@ -452,7 +452,11 @@ def __init__(self, canvas, window):
         self.win = window
         GObject.GObject.__init__(self)
         NavigationToolbar2.__init__(self, canvas)
-        self.ctx = None
+
+    @cbook.deprecated("3.3")
+    @property
+    def ctx(self):
+        return self.canvas.get_property("window").cairo_create()
 
     def set_message(self, s):
         self.message.set_label(s)
@@ -464,7 +468,7 @@ def set_cursor(self, cursor):
     def draw_rubberband(self, event, x0, y0, x1, y1):
         # adapted from
         # http://aspn.activestate.com/ASPN/Cookbook/Python/Recipe/189744
-        self.ctx = self.canvas.get_property("window").cairo_create()
+        ctx = self.canvas.get_property("window").cairo_create()
 
         # todo: instead of redrawing the entire figure, copy the part of
         # the figure that was covered by the previous rubberband rectangle
@@ -477,11 +481,11 @@ def draw_rubberband(self, event, x0, y0, x1, y1):
         h = abs(y1 - y0)
         rect = [int(val) for val in (min(x0, x1), min(y0, y1), w, h)]
 
-        self.ctx.new_path()
-        self.ctx.set_line_width(0.5)
-        self.ctx.rectangle(rect[0], rect[1], rect[2], rect[3])
-        self.ctx.set_source_rgb(0, 0, 0)
-        self.ctx.stroke()
+        ctx.new_path()
+        ctx.set_line_width(0.5)
+        ctx.rectangle(*rect)
+        ctx.set_source_rgb(0, 0, 0)
+        ctx.stroke()
 
     def _init_toolbar(self):
         self.set_style(Gtk.ToolbarStyle.ICONS)
