From d330ad1b40242e4d78289a5595fa70c158c07e6c Mon Sep 17 00:00:00 2001
From: Robin Dunn <robin@alldunn.com>
Date: Mon, 29 Jan 2018 12:23:57 -0800
Subject: [PATCH] Add context manager methods to wx.DC

---
 CHANGES.rst          |  6 ++++++
 etg/dc.py            |  4 ++++
 unittests/test_dc.py | 12 ++++++++++++
 3 files changed, 22 insertions(+)

diff --git a/CHANGES.rst b/CHANGES.rst
index 12197b12..1c6291bb 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -210,6 +210,12 @@ Changes in this release include the following:
   point values to integers, and a couple other possible incorrect
   conversions.  (#536)
 
+* Added context manager methods to wx.DC that explicitly destroys the C++
+  part of the DC upon exit. Using DCs as context managers is not required, but
+  can be handy in the rare cases where something holds on to a DC for too
+  long, perhaps unintentionally. (#680)
+
+
 
 
 
diff --git a/etg/dc.py b/etg/dc.py
index a62c481b..d320d9ee 100644
--- a/etg/dc.py
+++ b/etg/dc.py
@@ -264,6 +264,10 @@ def run():
     c.addPyCode('DC.GetCGContext = wx.deprecated(DC.GetCGContext, "Use GetHandle instead.")')
     c.addPyCode('DC.GetGdkDrawable = wx.deprecated(DC.GetGdkDrawable, "Use GetHandle instead.")')
 
+    # context manager methods
+    c.addPyMethod('__enter__', '(self)', 'return self')
+    c.addPyMethod('__exit__', '(self, exc_type, exc_val, exc_tb)', 'self.Destroy()')
+
 
     # This file contains implementations of functions for quickly drawing
     # lists of items on the DC. They are called from the CppMethods defined
diff --git a/unittests/test_dc.py b/unittests/test_dc.py
index c38c1fec..466e6841 100644
--- a/unittests/test_dc.py
+++ b/unittests/test_dc.py
@@ -175,6 +175,18 @@ class dc_Tests(wtc.WidgetTestCase):
         dc.DrawLines( [(15,15), (35,15), (35,35), (35,15), (15,15)] )
 
 
+    def test_dcContextManager(self):
+        import wx.siplib
+        with wx.ClientDC(self.frame) as dc:
+            dc.DrawLine(0,0,100,100)
+
+            # check ownership
+            assert wx.siplib.ispyowned(dc)
+
+        # check the DC's ownership has changed
+        assert not wx.siplib.ispyowned(dc)
+
+
 #---------------------------------------------------------------------------