媒体层图形技术之Core Animation 学习笔记

1.CADisplayLink

//自行定義的函式,用來設定使用CADisplayLink的相關參數
-(void)initializeTimer {

    //theTimer是CADisplayLink型態的指標,用來存放當前的設定狀態
    theTimer = [CADisplayLink displayLinkWithTarget:self selector:@selector(countTotalFrames)];

    //CADisplayLink內定值就是每秒60張(參數=1),參數=2就是每秒30張,以此類推
    double fps = 60 / theTimer.frameInterval;
    fpsLabel.text = [NSString stringWithFormat:@"%0.1f" , fps];

    //設定執行狀態並啟動theTimer
    [theTimer addToRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
}

如同 Timer / 計時器一樣,selector 是設定每次觸發時所需要呼叫的函式,其寫法如下。

-(void)countTotalFrames {
    frameCount ++;
    framesLabel.text = [NSString stringWithFormat:@"%d", frameCount];
}

2.CAScrollLayer
使用cascrolllayer可以实现:通过改变一个layer的origin坐标,显示它的一部分内容.它的maskstobounds属性一般设为yes,这样就只能看见它的bounds内的内容.可以通过调用cascrolllayer本身的函数或者调用它的sublayer函数实现layer的滚动功能

3.CATextLayer可以直接支持NSAttributedString!

CATextLayer代码:
CATextLayer *lary = [CATextLayer layer];
    lary.string = @"dasfasa";
    lary.bounds = CGRectMake(0, 0, 320, 20);
       lary.font = @"HiraKakuProN-W3"; //字体的名字 不是 UIFont
    lary.fontSize = 12.f; //字体的大小
       lary.alignmentMode = kCAAlignmentCenter;//字体的对齐方式
    lary.position = CGPointMake(160, 410);
       lary.foregroundColor = [UIColor redColor].CGColor;//字体的颜色
    [self.view.layer addSublayer:lary];

4.CATiledLayer

demon:http://www.cocoachina.com/bbs/read.php?tid=31132

levelsOfDetail是指,从UIScrollView的1倍zoomScale开始,能够支持细节刷新的缩小级数。每一级是上一级的1/2,所以假设levelsOfDetail
= n,levelsOfDetailBias不指定的话,CATiledLayer将会在UIScrollView的zoomScale为以下数字时重新drawLayer
2^-1 -> 2^-2 -> ... -> 2^-n
也就是
1/2, 1/4, 1/8, 1/16, ... , 1/2^n

在levelsOfDetailBias不指定的情况下,zoomScale大于0.5后就不会再drawLayer,所以若继续放大UIScrollView的话,画面将越来越模糊。

这个时候levelsOfDetailBias就有用了。
levelsOfDetailBias = m表示,将原来的1/2,移到2^m倍的位置。
假设levelsOfDetail = n,levelsOfDetailBias = m的话,会有如下队列:
2^m * 2^-1 -> 2^m * 2^-2 -> ... -> 2^m * 2^-n
简化一下即
2^(m - 1) -> 2^(m - 2) -> 2^(m - 3) ->... -> 2^(m - n)

举例,levelsOfDetail = 3,levelsOfDetailBias = 3,则你的UIScrollView将会在以下zoomScale时drawLayer
2^(3 - 1) -> 2^(3 - 2) -> 2^(3 - 3)
即4 -> 2 -> 1

特例是,levelsOfDetailBias > levelsOfDetail时,则每相差2倍就会drawLayer一下。

可以简单理解成:
levelsOfDetail表示一共有多少个drawLayer的位置
levelsOfDetailBias表示比1大的位置里有多少个drawLayer的位置(包括1)

CAShapeLayer

利用CAShapeLayer可以制作出任意的几何图形,其一是把它作为UIImageView的遮罩,达到把图片做成圆形效果。

 //创建个人主页头部的用户头像

        self.userHead = [[UIImageView alloc]initWithFrame:CGRectMake(10, 35, 80, 80)];
        self.userHead.image = [UIImage imageNamed:@"start.jpg"];

        //创建圆形遮罩,把用户头像变成圆形
        UIBezierPath* path = [UIBezierPath bezierPathWithArcCenter:CGPointMake(40, 40) radius:40 startAngle:0 endAngle:2*M_PI clockwise:YES];
        CAShapeLayer* shape = [CAShapeLayer layer];
        shape.path = path.CGPath;
        self.userHead.layer.mask = shape;
        [self addSubview:self.userHead];

6.CAReplicatorLayer

使用CAReplicatorLayer重建动态的倒影


自己能够重建包括自己在内的n个copies,这些copies是原layer中的所有sublayers,并且任何对原layer的sublayers
设置的transform是可以积累的(accumulative).
基本上这样的一个关系:我们首先会重建一个CAReplicatorLayer实例,作为我们的sourceLayer,
这个sourceLayer我们需要一份copy,那包括自己在内就是2; 所以我们设置了它的instantCount =
2;这个是包括自己在内总共为2.
然后我们将SourceLayer的宽度设置为image的宽度,但是将其高度设置为image.size.height * 1.5;
并且在sourcelayer上加上masksToBounds为true的属性,这样一来我们可以保证超出的倒影部分会cut调一半,加上
sourceLayer上正常的image,刚刚好组成了我们的完整的倒影。我们sourceLayer的sublayer就是
_imageLayer,。但是我们只是单纯设置instantCount
= 2的话,
那个_imageReplicatorLayer(这个就指代的是copy过来的第一个变量)是会继承sourceLayers中_imagelayer
的Geometry,所以它两是重合的。那么我们必须做出transform,
CARepliatorLayer有一个属性叫做instantTransform,这个属性指定了除了原来copy之外所有replication
layer的trasnform规则,重要的是它是递增的。比如我们这里需要将imageReplicatorLayer应该往下移动image的高度,
这一样来可以保证它是刚刚好在原来imagelayer的正下方,就跟倒影一样。
但是不一样的地方是:这个复制的imageReplicatorLayer它不是正常的,它是需要倒过来的,所以我们在transform上使用了 transform = CATransform3DScale(transform,
1.0, -1.0, 1.0); 这一个的意思是大小不变,但是y轴倒过来,这个应用到imageReplicatorLayer的坐标系是y轴朝上。 这样以来你就不能单纯是向原来一样移动image.height了, 因为y轴反了过来,所以你应该是 -2 * image.size.height
这样以来就搞定了。 最后我们给它加了一个渐变层,让它看起来更接近倒影的感觉。

- (void)viewDidLoad
{
    [super viewDidLoad];

    UIView *view = [self view];

    //
    // Yes, this is a very long method. I find it easier to explain what is happening by
    // keeping the code in a single location (instead of breaking it up over multiple methods).
    // 

    // Load the image to "reflect"
    UIImage *image = [UIImage imageNamed:@"american-flag"];

    // The replicator layer is where all of the magic happens
    CAReplicatorLayer *replicatorLayer = [CAReplicatorLayer layer];
    [replicatorLayer setContentsScale:[[UIScreen mainScreen] scale]];

    // The replicator layer‘s height is 1.5 times the size of the image. This means that
    // we will effectively clip/ fade out our "reflection".
    //
    // ********    <- any y-flipping is performed along this plane
    // *  %%  *
    // *      *    image height
    // *  ^^  *
    // ********
    // ========
    // =  ^^  =  + half height (mask to bounds effectively clips the reflected image)
    // =      =
    //
    //           = total height of layer
    [replicatorLayer setBounds:CGRectMake(0.0, 0.0, [image size].width, [image size].height * 1.5)];

    // This ensures that the replicated image is clipped to the replicator‘s height
    [replicatorLayer setMasksToBounds:YES];

    // Position the replicator layer at the top of the view
    // - use the x center point to make the math easy (place in center of view)
    // - use the y upper point to position the layer 10 points below the top of the view (just a little bit of padding)
    [replicatorLayer setAnchorPoint:CGPointMake(0.5, 0.0)];

    [replicatorLayer setPosition:CGPointMake(view.frame.size.width / 2.0, 80.0)];

    // We need two instances:
    //   1) the main image layer
    //   2) a replicated layer for the reflection
    [replicatorLayer setInstanceCount:2];

    // Create a transform used by the replicator layer to "flip" and position our reflected layer below the original image
    //
    // I will see if I can explain this.
    // For clarity... we start with an identity
    CATransform3D transform = CATransform3DIdentity;

    //
    // @*******    <- this is the top of the replicator layer (the X,Y origin is at the @, with Y going down)
    // *  %%  *
    // *      *
    // *  ^^  *
    // ********
    //
    //
    // Apply a negative scale to y (effectively flips)
    //
    // For example, hold your right hand in front of your face (knuckles facing you, thumb down). Now flip your
    // hand up keeping your pinky finger in place (i.e. your pinky is a hinge).
    //
    // ========    <- will draw a flipped version up here
    // =  ^^  =
    // =      =
    // =  %%  =
    // ========
    // ********    <- the "flip" is performed along here
    // *  %%  *
    // *      *    image height
    // *  ^^  *
    // ********
    transform = CATransform3DScale(transform, 1.0, -1.0, 1.0);

    // translate down by 2x height to position the "flipped" layer below the main layer
    // - 2x moves the flipped image under the main image giving us the "reflection"
    //
    // ********    <- y plane (any flipping is performed along this plane)
    // *  %%  *
    // *      *    image height
    // *  ^^  *
    // ********
    // ========
    // =  ^^  =
    // =      =    <-- Remember: only half of the "relection" layer renders because the replicator layer clips to bounds.
    // =  %%  =
    // ========
    transform = CATransform3DTranslate(transform, 0.0, -[image size].height * 2, 1.0);

    [replicatorLayer setInstanceTransform:transform];

    // Next we create a layer that displays the American flag image.
    _imageLayer = [CALayer layer];
    [_imageLayer setContentsScale:[[UIScreen mainScreen] scale]];
    [_imageLayer setContents:(__bridge id)[image CGImage]];
    [_imageLayer setBounds:CGRectMake(0.0, 0.0, [image size].width, [image size].height)];
    [_imageLayer setAnchorPoint:CGPointMake(0.0, 0.0)];

    [replicatorLayer addSublayer:_imageLayer];

    // Finally overlay a gradient layer on top of the "reflection" layer.
    CAGradientLayer *gradientLayer = [CAGradientLayer layer];
    [gradientLayer setContentsScale:[[UIScreen mainScreen] scale]];
    [gradientLayer setColors:@[
        (__bridge id)[[[UIColor whiteColor] colorWithAlphaComponent:0.25] CGColor],
        (__bridge id)[[UIColor whiteColor] CGColor]
    ]];

    // Remember that the reflected layer is half the size, which is why the height of the gradient layer is cut in half.
    [gradientLayer setBounds:CGRectMake(0.0, 0.0, replicatorLayer.frame.size.width, [image size].height * 0.5 + 1.0)];
    [gradientLayer setAnchorPoint:CGPointMake(0.5, 0.0)];
    [gradientLayer setPosition:CGPointMake(view.frame.size.width / 2, [image size].height + 80.0)];
    [gradientLayer setZPosition:1]; // make sure the gradient is placed on top of the reflection.

    [[view layer] addSublayer:replicatorLayer];
    [[view layer] addSublayer:gradientLayer];

    // One final (and fun step):
    //   Create a text layer that is a sublayer of the image layer.
    //   Core Animation will animate the text in all replicated layers. VERY COOL!!
    CATextLayer *textLayer = [CATextLayer layer];
    [textLayer setContentsScale:[[UIScreen mainScreen] scale]];
    [textLayer setString:@"U.S.A."];
    [textLayer setAlignmentMode:kCAAlignmentCenter];

    CGFloat height = [(UIFont *)[textLayer font] lineHeight];
    [textLayer setBounds:CGRectMake(0.0, 0.0, [_imageLayer frame].size.width, height)];
    [textLayer setPosition:CGPointMake([_imageLayer frame].size.width / 2.0, [_imageLayer frame].size.height - 25.0)];
    [textLayer setAnchorPoint:CGPointMake(0.5, 0.5)];
    [_imageLayer addSublayer:textLayer];

    // When the user taps, start _animating the image‘s text layer up and down.
    [view setUserInteractionEnabled:YES];
    [view setMultipleTouchEnabled:YES];
    [view addGestureRecognizer:[[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(animateTextLayer:)]];
}

- (void)animateTextLayer:(UIGestureRecognizer *)recognizer
{
    CALayer *textLayer = (CALayer *)[[_imageLayer sublayers] objectAtIndex:0];

    CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:@"position.y"];

    CGFloat halfBoxHeight = [textLayer frame].size.height / 2.0;
    [animation setFromValue:@([textLayer frame].origin.y + halfBoxHeight)];
    [animation setToValue:@(halfBoxHeight)];
    [animation setDuration:3.0];
    [animation setRepeatCount:MAXFLOAT];
    [animation setAutoreverses:YES];

    [textLayer addAnimation:animation forKey:nil];
}

7.
区分隐式动画和隐式事务:隐式动画通过隐式事务实现动画 。

区分显式动画和显式事务:显式动画有多种实现方式,显式事务是一种实现显式动画的方式。

->隐式事务
除显式事务外,任何对于CALayer属性的修改,都是隐式事务.这样的事务会在run-loop中被提交.

- (void)viewDidLoad {
    //初始化一个layer,添加到主视图
    layer=[CALayer layer];
    layer.bounds = CGRectMake(0, 0, 200, 200);
    layer.position = CGPointMake(160, 250);
    layer.backgroundColor = [UIColor redColor].CGColor;
    layer.borderColor = [UIColor blackColor].CGColor;
    layer.opacity = 1.0f;
    [self.view.layer addSublayer:layer];
    [super viewDidLoad];
}

-(IBAction)changeLayerProperty
{
    //设置变化动画过程是否显示,默认为YES不显示
    [CATransaction setDisableActions:NO];
    //设置圆角
    layer.cornerRadius = (layer.cornerRadius == 0.0f) ? 30.0f : 0.0f;
    //设置透明度
    layer.opacity = (layer.opacity == 1.0f) ? 0.5f : 1.0f;
}  

->显式事务

通过明确的调用begin,commit来提交动画

修改执行时间

 [CATransaction begin];

//显式事务默认开启动画效果,kCFBooleanTrue关闭

[CATransaction setValue:(id)kCFBooleanFalse

forKey:kCATransactionDisableActions];

//动画执行时间

[CATransaction setValue:[NSNumber numberWithFloat:5.0f] forKey:kCATransactionAnimationDuration];

    //[CATransaction setAnimationDuration:[NSNumber numberWithFloat:5.0f]];

anotherLayer.cornerRadius = (anotherLayer.cornerRadius == 0.0f) ? 30.0f : 0.0f;

layer.opacity = (layer.opacity == 1.0f) ? 0.5f : 1.0f;

[CATransaction commit];

->事物嵌套

事务嵌套
        [CATransaction begin];
     [CATransaction begin];
    [CATransaction setDisableActions:YES];
     layer.cornerRadius = (layer.cornerRadius == 0.0f) ? 30.0f : 0.0f;
    [CATransaction commit];
    //上面的动画并不会立即执行,需要等最外层的commit
    [NSThread sleepForTimeInterval:10];
    //显式事务默认开启动画效果,kCFBooleanTrue关闭
    [CATransaction setValue:(id)kCFBooleanFalse
                     forKey:kCATransactionDisableActions];
    //动画执行时间
    [CATransaction setValue:[NSNumber numberWithFloat:10.0f] forKey:kCATransactionAnimationDuration];
    //[CATransaction setAnimationDuration:[NSNumber numberWithFloat:5.0f]];
    anotherLayer.cornerRadius = (anotherLayer.cornerRadius == 0.0f) ? 30.0f : 0.0f;

    [CATransaction commit];

8.CATransform3D

{

  • ;
  • CGFloat m21(x切变), m22(y缩放), m23(), m24();
  1. ;
  2. CGFloat m41(x平移), m42(y平移), m43(z平移), m44();
  • };

首先要实现view(layer)的透视效果(就是近大远小),是通过设置m34的:

CABasicAnimation *pulseAnimation = [CABasicAnimation animationWithKeyPath:@"transform"];
    [pulseAnimation setDuration:_animationDuration];
    [pulseAnimation setRepeatCount:MAXFLOAT];

    // The built-in ease in/ ease out timing function is used to make the animation look smooth as the layer
    // animates between the two scaling transformations.
    [pulseAnimation setTimingFunction:[CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionEaseInEaseOut]];

    // Scale the layer to half the size
    //CATransform3D transform_1 = CATransform3DIdentity;//CATransform3DMakeScale(1.5, 1.5, 1.0);

    CATransform3D transform = CATransform3DMakeRotation((M_PI/180*180), 1, 0, 1);

    transform.m34 = 0.5;

    // Tell CA to interpolate to this transformation matrix
    [pulseAnimation setToValue:[NSValue valueWithCATransform3D:transform]];

    // Tells CA to reverse the animation (e.g. animate back to the layer‘s transform)
    [pulseAnimation setAutoreverses:_autoreverses];

    // Finally... add the explicit animation to the layer... the animation automatically starts.
    [_layer addAnimation:pulseAnimation forKey:kBTSPulseAnimation];

9.CAValueFunction

动画类型:平移、缩放、旋转

如把一个对象旋转180度可以使用一下方式:

CABasicAnimation * rotationAni = [CAAnimation animation];
    CAValueFunction * valuFunction = [CAValueFunction functionWithName:kCAValueFunctionRotateZ];
    [rotationAni setFromValue:0];
    [rotationAni setToValue:@(M_PI)];
    [rotationAni setValueFunction:valuFunction];

10.CAEmitterCell、CAEmitterLayer 实现粒子效果

利用Core Animation、CAEmitterCell 以及 CAEmitterLayer在iOS5中实现各种粒子动画效果,包括雪花、火焰、烟雾、飘动的花瓣、爆炸等效果。

属性详解请参考:http://guxiaojje.blog.163.com/blog/static/1409422912012813104917788/

- (void) viewDidLoad
{
    [super viewDidLoad];

	// Configure the particle emitter
	self.heartsEmitter = [CAEmitterLayer layer];
	self.heartsEmitter.emitterPosition = CGPointMake(likeButton.frame.origin.x + likeButton.frame.size.width/2.0,
													 likeButton.frame.origin.y + likeButton.frame.size.height/2.0);//放射源的位置
	self.heartsEmitter.emitterSize = likeButton.bounds.size;//放射源的大小

	// Spawn points for the hearts are within the area defined by the button frame
	self.heartsEmitter.emitterMode = kCAEmitterLayerVolume;//放射源的模式
	self.heartsEmitter.emitterShape = kCAEmitterLayerRectangle;//放射源的形状
	self.heartsEmitter.renderMode = kCAEmitterLayerAdditive;//放射源的渲染模式

	// Configure the emitter cell
	CAEmitterCell *heart = [CAEmitterCell emitterCell];//发射的粒子
	heart.name = @"heart";

	heart.emissionLongitude = M_PI/2.0; // up 粒子在xy平面内发射的方向
	heart.emissionRange = 0.55 * M_PI;  // in a wide spread 发射的水平方向的范围
	heart.birthRate		= 0.0;			// emitter is deactivated for now 粒子再生的速度,0就是不会再生
	heart.lifetime		= 10.0;			// hearts vanish after 10 seconds

	heart.velocity		= -120;			// particles get fired up fast 初始速度是-120 向上
	heart.velocityRange = 60;			// with some variation
	heart.yAcceleration = 20;			// but fall eventually

	heart.contents		= (id) [[UIImage imageNamed:@"DazHeart"] CGImage];
	heart.color			= [[UIColor colorWithRed:0.5 green:0.0 blue:0.5 alpha:0.5] CGColor];
	heart.redRange		= 0.3;			// some variation in the color
	heart.blueRange		= 0.3;
	heart.alphaSpeed	= -0.5 / heart.lifetime;  // fade over the lifetime

	heart.scale			= 0.15;			// let them start small
	heart.scaleSpeed	= 0.5;			// but then ‘explode‘ in size
	heart.spinRange		= 2.0 * M_PI;	// and send them spinning from -180 to +180 deg/s

	// Add everything to our backing layer
	self.heartsEmitter.emitterCells = [NSArray arrayWithObject:heart];
	[self.view.layer addSublayer:heartsEmitter];
}

- (void) viewWillUnload
{
	[super viewWillUnload];
	[self.heartsEmitter removeFromSuperlayer];
	self.heartsEmitter = nil;
}

- (BOOL) shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
	return (interfaceOrientation == UIDeviceOrientationPortrait);
}

// ---------------------------------------------------------------------------------------------------------------
#pragma mark -
#pragma mark Interaction
// ---------------------------------------------------------------------------------------------------------------

- (IBAction) likeButtonPressed:(id)sender
{
	// Fires up some hearts to rain on the view
	CABasicAnimation *heartsBurst = [CABasicAnimation animationWithKeyPath:@"emitterCells.heart.birthRate"];
	heartsBurst.fromValue		= [NSNumber numberWithFloat:150.0];//喷出的粒子的数量
	heartsBurst.toValue			= [NSNumber numberWithFloat:  0.0];
	heartsBurst.duration		= 5.0;
	heartsBurst.timingFunction	= [CAMediaTimingFunction functionWithName:kCAMediaTimingFunctionLinear];

	[self.heartsEmitter addAnimation:heartsBurst forKey:@"heartsBurst"];
}

时间: 2024-11-07 02:14:21

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