From e0bd4e45ab947aef0600025d16d7df6502238e92 Mon Sep 17 00:00:00 2001
From: Dan Gudmundsson <dgud@erlang.org>
Date: Wed, 21 Nov 2012 14:46:57 +0100
Subject: observer: Fix check for graphics contexts

wxWidgets-2.9 seg faults if you try to create a graphics context
before the window is shown.

With bad timing this can happen.

So change the haveGC test to check if the functionality is available
without creating the GraphicsContext.
---
 lib/observer/src/observer_app_wx.erl  | 4 ++--
 lib/observer/src/observer_perf_wx.erl | 9 ++++-----
 2 files changed, 6 insertions(+), 7 deletions(-)

diff --git a/lib/observer/src/observer_app_wx.erl b/lib/observer/src/observer_app_wx.erl
index b574307007..72bafcc5e0 100644
--- a/lib/observer/src/observer_app_wx.erl
+++ b/lib/observer/src/observer_app_wx.erl
@@ -28,7 +28,7 @@
 -include("observer_defs.hrl").
 
 %% Import drawing wrappers
--import(observer_perf_wx, [haveGC/1,
+-import(observer_perf_wx, [haveGC/0,
 			   setPen/2, setFont/3, setBrush/2,
 			   strokeLine/5, strokeLines/2, drawRoundedRectangle/6,
 			   drawText/4, getTextExtent/2]).
@@ -114,7 +114,7 @@ init([Notebook, Parent]) ->
 	_ -> ok
     end,
 
-    UseGC = haveGC(DrawingArea),
+    UseGC = haveGC(),
     Version28 = ?wxMAJOR_VERSION =:= 2 andalso ?wxMINOR_VERSION =:= 8,
     Font = case os:type() of
 	       {unix,_} when UseGC, Version28 ->
diff --git a/lib/observer/src/observer_perf_wx.erl b/lib/observer/src/observer_perf_wx.erl
index d0dd46b402..54c98f3ba3 100644
--- a/lib/observer/src/observer_perf_wx.erl
+++ b/lib/observer/src/observer_perf_wx.erl
@@ -24,7 +24,7 @@
 	 handle_event/2, handle_sync_event/3, handle_cast/2]).
 
 %% Drawing wrappers for DC and GC areas
--export([haveGC/1,
+-export([haveGC/0,
 	 setPen/2, setFont/3, setBrush/2,
 	 strokeLine/5, strokeLines/2, drawRoundedRectangle/6,
 	 drawText/4, getTextExtent/2]).
@@ -90,7 +90,7 @@ init([Notebook, Parent]) ->
 	_ -> ok
     end,
 
-    UseGC = haveGC(Panel),
+    UseGC = haveGC(),
     Version28 = ?wxMAJOR_VERSION =:= 2 andalso ?wxMINOR_VERSION =:= 8,
     {Font, SmallFont}
 	= case os:type() of
@@ -525,10 +525,9 @@ colors() ->
 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
 %% wxDC and ?wxGC wrappers
 
-haveGC(Win) ->
+haveGC() ->
     try
-	GC = ?wxGC:create(Win),
-	?wxGC:destroy(GC),
+	wxGraphicsRenderer:getDefaultRenderer(),
 	true
     catch _:_  -> false
     end.
-- 
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