From 423f923b4ede6fa5092375de52cb821582d26f49 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Lucio=20Andr=C3=A9s=20Illanes=20Albornoz?=
 <lucio@lucioillanes.de>
Date: Fri, 5 Jan 2018 01:34:57 +0100
Subject: [PATCH] MiRCART.py:MiRCARTCanvas._processMapPatches(): don't process
 patches that don't introduce changes..
 MiRCART.py:MiRCARTCanvas._processMapPatches(): append redo and undo patches
 to self.patchesUndo. MiRCART.py:MiRCARTCanvas.undo(): initial implementation.
 MiRCART.py:MiRCARTFrame.{menuFileUndo,onFileUndo,__init__}(): add GUI for
 MiRCARTCanvas.undo().

---
 MiRCART.py | 33 +++++++++++++++++++++++++++++----
 1 file changed, 29 insertions(+), 4 deletions(-)

diff --git a/MiRCART.py b/MiRCART.py
index f940fb3..c3a1a70 100755
--- a/MiRCART.py
+++ b/MiRCART.py
@@ -105,9 +105,15 @@ class MiRCARTCanvas(wx.Panel):
                         atY + patch[1], mapItem[0], mapItem[1], mapItem[2]))
                     self._drawPatch(patch, eventDc, tmpDc, atX, atY)
                 else:
-                    self._drawPatch(patch, eventDc, tmpDc, atX, atY)
-                    self.canvasMap[atY + patch[1]][atX + patch[0]] =\
-                        [patch[2], patch[3], " "];
+                    mapItem = self.canvasMap[atY + patch[1]][atX + patch[0]]
+                    if mapItem != [patch[2], patch[3], patch[4]]:
+                        self.patchesUndo.append((atX + patch[0],    \
+                            atY + patch[1], patch[2], patch[3], " "))
+                        self.patchesUndo.append((atX + patch[0],    \
+                            atY + patch[1], mapItem[0], mapItem[1], mapItem[2]))
+                        self.canvasMap[atY + patch[1]][atX + patch[0]] =\
+                            [patch[2], patch[3], " "];
+                        self._drawPatch(patch, eventDc, tmpDc, atX, atY)
     # }}}
     # {{{ getBackgroundColour(): XXX
     def getBackgroundColour(self):
@@ -160,6 +166,19 @@ class MiRCARTCanvas(wx.Panel):
     def onRightDown(self, event):
         self._onMouseEvent(event)
     # }}}
+    # {{{ undo(): XXX
+    def undo(self):
+        if len(self.patchesUndo) >= 2:
+            deltaPatch = self.patchesUndo[-1];
+            del self.patchesUndo[-1]; del self.patchesUndo[-1];
+            self.canvasMap[deltaPatch[1]][deltaPatch[0]] =          \
+                [deltaPatch[2], deltaPatch[3], deltaPatch[4]]
+            eventDc = wx.ClientDC(self); tmpDc = wx.MemoryDC();
+            tmpDc.SelectObject(self.canvasBitmap)
+            self._drawPatch(deltaPatch, eventDc, tmpDc, 0, 0)
+        else:
+            return False
+    # }}}
     # {{{ Initialisation method
     def __init__(self, parent, canvasPos, cellSize, canvasSize, canvasTools):
         canvasWinSize = (cellSize[0] * canvasSize[0], cellSize[1] * canvasSize[1])
@@ -278,7 +297,7 @@ class MiRCARTPalette(wx.Panel):
 
 class MiRCARTFrame(wx.Frame):
     """XXX"""
-    menuFile = menuFileSaveAs = menuFileExit = menuBar = None
+    menuFile = menuFileUndo = menuFileSaveAs = menuFileExit = menuBar = None
     panelSkin = panelCanvas = panelPalette = None
     statusBar = None
 
@@ -291,6 +310,10 @@ class MiRCARTFrame(wx.Frame):
         text += " " + str(self.panelCanvas.getBackgroundColour())
         self.statusBar.SetStatusText(text)
     # }}}
+    # {{{ onFileUndo(): XXX
+    def onFileUndo(self, event):
+        self.panelCanvas.undo()
+    # }}}
     # {{{ onFileSaveAs(): XXX
     def onFileSaveAs(self, event):
         with wx.FileDialog(self, "Save As...", os.getcwd(), "",     \
@@ -332,6 +355,7 @@ class MiRCARTFrame(wx.Frame):
         super().__init__(parent, wx.ID_ANY, "MiRCART", size=appSize)
 
         self.menuFile = wx.Menu()
+        self.menuFileUndo = self.menuFile.Append(wx.ID_SAVE, "&Undo", "Undo")
         self.menuFileSaveAs = self.menuFile.Append(wx.ID_SAVE, "Save &As...", "Save As...")
         self.menuFileExit = self.menuFile.Append(wx.ID_EXIT, "E&xit", "Exit")
         self.menuBar = wx.MenuBar()
@@ -349,6 +373,7 @@ class MiRCARTFrame(wx.Frame):
 
         self.Bind(wx.EVT_MENU, self.onFileExit, self.menuFileExit)
         self.Bind(wx.EVT_MENU, self.onFileSaveAs, self.menuFileSaveAs)
+        self.Bind(wx.EVT_MENU, self.onFileUndo, self.menuFileUndo)
         self.SetMenuBar(self.menuBar)
         self.Show(True)
     # }}}