撤消重做问题与CGLayer [英] undo redo issues with CGLayer
问题描述
我使用CgLayer unod重做操作，我已经尝试了一些代码，但不能得到它的工作，不知道，我错了，下面是我的代码，我写了
I am working with unod redo operations on CgLayer, I have tried some code, but not able to get it working, dont know , where I am getting wrong, below is my code, which i have written
这是我的drawRect函数
this is my drawRect function
- (void)drawRect:(CGRect)rect
{
m_backgroundImage = [UIImage imageNamed:@"bridge.jpg"];
CGPoint drawingTargetPoint = CGPointMake(0,0);
[m_backgroundImage drawAtPoint:drawingTargetPoint];
switch(drawStep)
{
case DRAW:
{
CGContextRef context = UIGraphicsGetCurrentContext();
if(myLayerRef == nil)
{
myLayerRef = CGLayerCreateWithContext(context, self.bounds.size, NULL);
}
CGContextDrawLayerAtPoint(context, CGPointZero, myLayerRef);
break;
}
case UNDO:
{
[curImage drawInRect:self.bounds];
break;
}
default:
break;
}
}
触摸结束后，我将图层转换为NSValue并将其作为keyValue对存储到NSDictionary中，然后将字典对象添加到数组中。
On touches ended , I am converting the layer into NSValue and storing as keyValue pair into NSDictionary and then adding the dictionary object to array.
- (void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event
{
NSValue *layerCopy = [NSValue valueWithPointer:myLayerRef];
NSDictionary *lineInfo = [NSDictionary dictionaryWithObjectsAndKeys:layerCopy, @"IMAGE",
nil];
[m_pathArray addObject:lineInfo];
NSLog(@"%i",[m_pathArray count]);
}
是我的撤消功能
- (void)undoButtonClicked
{
if([m_pathArray count]>0)
{
NSMutableArray *_line=[m_pathArray lastObject];
[m_bufferArray addObject:[_line copy]];
[m_pathArray removeLastObject];
drawStep = UNDO;
[self redrawLine];
}
}
//Redraw functions
- (void)redrawLine
{
NSDictionary *lineInfo = [m_pathArray lastObject];
NSValue *val = [lineInfo valueForKey:@"IMAGE"];
CGLayerRef layerToShow = (CGLayerRef) [val pointerValue];
CGContextRef context1 = CGLayerGetContext(layerToShow);
CGContextDrawLayerAtPoint(context1, CGPointMake(00, 00),layerToShow);
[self setNeedsDisplayInRect:self.bounds];
}
我认为它在这里我做错了。所以朋友请帮助我。
I think its here where I am goin wrong. So friends please help me out.
从下面的评论，我已经添加了函数，它的绘制到Cglayer（这个函数我调用到touchesMovedEvent。
From the comments below, I have added the function, where its draws into Cglayer(this function I am calling into touchesMovedEvent.
- (void) drawingOperations
{
CGContextRef context1 = CGLayerGetContext(myLayerRef);
CGPoint mid1 = midPoint(m_previousPoint1, m_previousPoint2);
CGPoint mid2 = midPoint(m_currentPoint, m_previousPoint1);
CGContextMoveToPoint(context1, mid1.x, mid1.y);
CGContextAddQuadCurveToPoint(context1, m_previousPoint1.x, m_previousPoint1.y, mid2.x, mid2.y);
CGContextSetLineCap(context1, kCGLineCapRound);
CGContextSetLineWidth(context1, self.lineWidth);
CGContextSetStrokeColorWithColor(context1, self.lineColor.CGColor);
CGContextSetAllowsAntialiasing(context1, YES);
CGContextSetInterpolationQuality(context1, kCGInterpolationHigh);
CGContextSetAlpha(context1, self.lineAlpha);
CGContextStrokePath(context1);
}
尊敬
Ranjit
Regards Ranjit
推荐答案
实现撤消和重做的最好方法是实现 NSUndoManager 必须保存要撤消的每个对象的状态或重做NSUndoManager本身为您...
The best way to implement Undo and Redo is to implement NSUndoManager as a brief description of it you don't have to save each state of Object that you want to undo or redo the NSUndoManager itself make this for you ...
达到此步骤的步骤是：
1-初始化NSUndoManager。
1- Initialize NSUndoManager.
2-注册NSUndoManager对象中的对象状态，带有指定的函数调用， 。
2- Register Object state in the NSUndoManager object with specified function call will discuss this for you case later.
3在NSUndoManager对象中使用撤销或重做或清除操作功能。
3-use undo or redo or clear actions function in NSUndoManager Object.
从我的工作解决方案
-in .h文件
@property (nonatomic,retain) NSUndoManager *undoManager;
-
in .m file
in .m file
@synthesize undoManager;
@synthesize undoManager;
- 初始化您的NSUndoManager
in "viewDidLoad" method -- initialize your NSUndoManager
undoManager = [[NSUndoManager alloc] init];
undoManager = [[NSUndoManager alloc] init];
假设您在在你的viewDidLoad中放大/缩小的类，你将有
Suppose that you have a function in your class that zoom in/out using pinch so in your "viewDidLoad" you will have
UIPinchGestureRecognizer *pinchGesture = [[UIPinchGestureRecognizer alloc] initWithTarget:self action:@selector(pinch:)]; pinchGesture.delegate = (id)self; [self.view addGestureRecognizer:pinchGesture];因此，pinch会放大/缩小这样的
注意MyImageView我们要放大/缩小So pinch will zoom in/out such Note that "MyImageView" is the image that we want to zoom in/out
- (void)pinch:(UIPinchGestureRecognizer*)recognizer{ if (recognizer.state == UIGestureRecognizerStateEnded || recognizer.state == UIGestureRecognizerStateChanged) { NSLog(@"gesture.scale = %f", recognizer.scale); CGFloat currentScale = self.MyImageView.frame.size.width / self.MyImageView.bounds.size.width; CGFloat newScale = currentScale * recognizer.scale; //Here is the line that register image to NSUndoManager before making and adjustments to the image "save current image before changing the transformation" //Add image function is function that fired when you Make undo action using NSUndoManager "and so we maintain only image transformation that changed when you zoom in/out" [[undoManager prepareWithInvocationTarget:self] AddImage:self.MyImageView.transform]; if (newScale < 0.5) { newScale = 0.5; } if (newScale > 5) { newScale = 5; } CGAffineTransform transform = CGAffineTransformMakeScale(newScale, newScale); self.MyImageView.transform = transform; recognizer.scale = 1; } }-AddImage函数将在NSUndoManager中保存当前图像变换状态。
-AddImage Function will save current image transformation state in NSUndoManager.
-(void)AddImage:(CGAffineTransform)sender{ CGAffineTransform transform = sender; self.MyImageView.transform = transform; }所以，如果你有按钮使撤消操作
So if you have button that make Undo action
-(IBAction)OptionsBtn:(id)sender{ if ([undoManager canUndo]) { [undoManager undo]; } }因此，如果您想取消所有操作方法
So if you want to cancel all action you have both ways
while ([undoManager canUndo]) { [undoManager undo]; }或
[undoManager removeAllActions];这篇关于撤消重做问题与CGLayer的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
