ElisUndoManager.m

   1 //
   2 //  ElisUndoManager.m
   3 //  Elis Colors
   4 //
   5 //  Created by 柳 on 09/09/24.
   6 //  Copyright 2009 __MyCompanyName__. All rights reserved.
   7 //
   8
   9 #import "ElisUndoManager.h"
  10
  11
  12 @implementation ElisUndoManager
  13
  14 - (void)awakeFromNib
  15 {
  16     undoStack = [[NSMutableArray alloc] init];
  17     index = 0;
  18 }
  19
  20 - (void)pushOperation:(ElisLayer*)layer
  21 {
  22     NSMutableData* data = [[NSMutableData alloc] init];
  23     NSKeyedArchiver* encoder = [[NSKeyedArchiver alloc] initForWritingWithMutableData:data];
  24
  25     [layer saveToEncoder:encoder];
  26     [encoder finishEncoding];
  27
  28 //    [undoStack addObject:layer];
  29 //    [undoStack addObject:data];
  30     [undoStack removeObjectsInRange:NSMakeRange(index, [undoStack count] - index)];
  31
  32     if(index != 0)
  33         if([data isEqualToData:[undoStack objectAtIndex:index-1]])
  34             return;
  35
  36     [undoStack insertObject:layer atIndex:index];
  37     [undoStack insertObject:data atIndex:index+1];
  38     index += 2;
  39 }
  40
  41 - (ElisLayer*)popOperation
  42 {
  43     NSData* data = [undoStack objectAtIndex:index-1];
  44     ElisLayer* layer = [undoStack objectAtIndex:index-2];
  45
  46     NSKeyedUnarchiver* decoder = [[NSKeyedUnarchiver alloc] initForReadingWithData:data];
  47     [layer loadFromDecoder:decoder];
  48     [decoder finishDecoding];
  49
  50     index -= 2;
  51
  52     return layer;
  53 }
  54
  55 - (void)redoOperation
  56 {
  57     index += 4;
  58     [self popOperation];
  59 }
  60
  61 - (BOOL)canUndo
  62 {
  63     return index != 0;
  64     return [undoStack count] != 0;
  65 }
  66
  67 - (BOOL)canRedo
  68 {
  69     return index+2 < [undoStack count];
  70 }
  71
  72 @end