diff -r 1a30c70fa025 -r a5d1d2a2f366 dialogs/BlockPreviewDialog.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/dialogs/BlockPreviewDialog.py	Mon Jun 10 00:55:57 2013 +0200
@@ -0,0 +1,123 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+
+#This file is part of PLCOpenEditor, a library implementing an IEC 61131-3 editor
+#based on the plcopen standard. 
+#
+#Copyright (C) 2013: Edouard TISSERANT and Laurent BESSARD
+#
+#See COPYING file for copyrights details.
+#
+#This library is free software; you can redistribute it and/or
+#modify it under the terms of the GNU General Public
+#License as published by the Free Software Foundation; either
+#version 2.1 of the License, or (at your option) any later version.
+#
+#This library is distributed in the hope that it will be useful,
+#but WITHOUT ANY WARRANTY; without even the implied warranty of
+#MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+#General Public License for more details.
+#
+#You should have received a copy of the GNU General Public
+#License along with this library; if not, write to the Free Software
+#Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+
+import wx
+
+from plcopen.structures import TestIdentifier, IEC_KEYWORDS
+from graphics.GraphicCommons import FREEDRAWING_MODE
+
+#-------------------------------------------------------------------------------
+#                    Dialog with preview for graphic block
+#-------------------------------------------------------------------------------
+
+"""
+Class that implements a generic dialog containing a preview panel for displaying
+graphic created by dialog
+"""
+
+class BlockPreviewDialog(wx.Dialog):
+
+    def __init__(self, parent, controller, tagname, size, title):
+        wx.Dialog.__init__(self, parent, size=size, title=title)
+        
+        self.Controller = controller
+        self.TagName = tagname
+        
+        self.PreviewLabel = wx.StaticText(self, label=_('Preview:'))
+        
+        self.Preview = wx.Panel(self, style=wx.SIMPLE_BORDER)
+        self.Preview.SetBackgroundColour(wx.WHITE)
+        setattr(self.Preview, "GetDrawingMode", lambda:FREEDRAWING_MODE)
+        setattr(self.Preview, "GetScaling", lambda:None)
+        setattr(self.Preview, "GetBlockType", controller.GetBlockType)
+        setattr(self.Preview, "IsOfType", controller.IsOfType)
+        self.Preview.Bind(wx.EVT_PAINT, self.OnPaint)
+        
+        self.ButtonSizer = self.CreateButtonSizer(wx.OK|wx.CANCEL|wx.CENTRE)
+        self.Bind(wx.EVT_BUTTON, self.OnOK, 
+                  self.ButtonSizer.GetAffirmativeButton())
+        
+        self.Block = None
+        self.DefaultBlockName = None
+        self.MinBlockSize = None
+    
+    def __del__(self):
+        self.Controller = None
+    
+    def SetMinBlockSize(self, size):
+        self.MinBlockSize = size
+    
+    def SetPreviewFont(self, font):
+        self.Preview.SetFont(font)
+    
+    def TestBlockName(self, block_name):
+        format = None
+        uppercase_block_name = block_name.upper()
+        if not TestIdentifier(block_name):
+            format = _("\"%s\" is not a valid identifier!")
+        elif uppercase_block_name in IEC_KEYWORDS:
+            format = _("\"%s\" is a keyword. It can't be used!")
+        elif uppercase_block_name in self.Controller.GetProjectPouNames():
+            format = _("\"%s\" pou already exists!")
+        elif (self.DefaultBlockName.upper() != uppercase_block_name and 
+              uppercase_block_name in self.Controller.GetEditedElementVariables(
+                                                                self.TagName)):
+            format = _("\"%s\" element for this pou already exists!")
+        
+        if format is not None:
+            self.ShowErrorMessage(format % block_name)
+            return False
+        
+        return True
+    
+    def ShowErrorMessage(self, message):
+        dialog = wx.MessageDialog(self, message, 
+                                  _("Error"), 
+                                  wx.OK|wx.ICON_ERROR)
+        dialog.ShowModal()
+        dialog.Destroy()
+    
+    def OnOK(self, event):
+        self.EndModal(wx.ID_OK)
+    
+    def RefreshPreview(self):
+        dc = wx.ClientDC(self.Preview)
+        dc.SetFont(self.Preview.GetFont())
+        dc.Clear()
+        
+        if self.Block is not None:
+            min_width, min_height = self.Block.GetMinSize()
+            width = max(self.MinBlockSize[0], min_width)
+            height = max(self.MinBlockSize[1], min_height)
+            self.Block.SetSize(width, height)
+            clientsize = self.Preview.GetClientSize()
+            x = (clientsize.width - width) / 2
+            y = (clientsize.height - height) / 2
+            self.Block.SetPosition(x, y)
+            self.Block.Draw(dc)
+    
+    def OnPaint(self, event):
+        self.RefreshPreview()
+        event.Skip()
+        
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