QuartzCore 之 CALayer.h了解

在CoreAnimation中，动画效果都是通过Layer层来实现的，通过CALayer，我们可以嵌套复杂的层级结构。大多数的动画效果是添加在图层属性的变化上，在这变化的过程中，我们需要清楚一个概念“锚点” (anchorPoint)。

frame

frame属性和view中的frame属性完全相同.

@property(nonatomic) CGRect            frame;

• x , y表示subLayer左上角相对于superlayer左上角的位置关系。(与layer的锚点没有关系,始终是左上角的位置关系)
• width, height表示subLayer的宽度和高度

bounds

此属性和view中的bounds属性相同

@property(nonatomic) CGRect            bounds;

• x , y为0

• width, height表示subLayer的宽度和高度

anchorPoint（锚点）

anchorPoint的值是用相对bounds的比例值来确定的。取值范围0 ~ 1。例如（0 , 0）, （1 , 1）分别表示左上角、右下角，默认值（0.5 , 0.5）。

1、锚点都是对于自身来讲的。锚点通常用于做相对的tranform变换。当然也可以用来确定位置。

如下图，为不同锚点做旋转的变化。

anchorPoint

2、锚点决定进行动作的参照点

例如：一个旋转动作，锚点决定了层旋转的中心点，对于放大缩小的动作，锚点决定了放大或者缩小参照的中心点。

anchorPoint运动参照点

第一行两个矩形，frame和bounds都是一样的。
假如，第一个矩形的锚点位置为(0.5,0.5)，第二个为(0,0)。
所以，两个矩形的position点是不同的，第一个是(100,100),第二个是(40,60)。再看当产生动作时锚点的影响（参照第二行两个矩形）
结论：锚点即为参照点，锚点的不同直接影响了运动轨迹。

• 确定锚点，改变frame时，position的值为:

position.x = frame.origin.x + anchorPoint.x * bounds.size.width；  
position.y = frame.origin.y + anchorPoint.y * bounds.size.height；

• 确定锚点，改变position时，frame的值为:

frame.origin.x = position.x - anchorPoint.x * bounds.size.width； 
frame.origin.y = position.y - anchorPoint.y * bounds.size.height；

• 改变锚点，position不影响，frame的值变化为:

frame.origin.x = - anchorPoint.x * bounds.size.width + position.x；  
frame.origin.y = - anchorPoint.y * bounds.size.height + position.y；

3、系统提供的 Layer

CALayer和UIView相似，CALayer也根据功能衍生出许多子类，有如下几种：
0、CALayer

#import <QuartzCore/CAMediaTiming.h>
#import <QuartzCore/CATransform3D.h>
#import <Foundation/NSObject.h>
#import <Foundation/NSNull.h>
#import <Foundation/NSArray.h>
#import <Foundation/NSDictionary.h>

@class NSEnumerator, CAAnimation, CALayerArray;
@protocol CAAction, CALayerDelegate;

NS_ASSUME_NONNULL_BEGIN

/** Layer基础层类。**/
CA_CLASS_AVAILABLE (10.5, 2.0, 9.0, 2.0)
@interface CALayer : NSObject <NSCoding, CAMediaTiming>
{
@private
  struct _CALayerIvars {
    int32_t refcount;
    uint32_t magic;
    void *layer;
#if TARGET_OS_MAC && !TARGET_RT_64_BIT
    void *unused1[8];
#endif
  } _attr;
}

// 通过类方法创建并初始化一个layer *
+ (instancetype)layer;

// 初始化方法
- (instancetype)init;

/* 通过一个layer创建一个副本 */
- (instancetype)initWithLayer:(id)layer;

/* 渲染层layer */
- (nullable instancetype)presentationLayer;

/* 模型层layer */
- (instancetype)modelLayer;

/*
+(id)defaultValueForKey:(NSString *)key{
    if ([key isEqualToString:@"backgroundColor"]) {
        return (id)[UIColor redColor].CGColor;
    }
    return [super defaultValueForKey:key];
}
*/
// Property methods。在子类中重写这个方法来改变默认创建的layer的一些属性
+ (nullable id)defaultValueForKey:(NSString *)key;

// 这个方法也只使用在子类中重写，用于设置在某些属性改变时是否进行layer重绘
+ (BOOL)needsDisplayForKey:(NSString *)key;

// 子类重写这个方法设置属性是否可以被归档
- (BOOL)shouldArchiveValueForKey:(NSString *)key;

// 设置layer尺寸。 默认是CGRectZero 。 
@property CGRect bounds;

// 设置layer位置。默认是（0 , 0）
@property CGPoint position;

// 设置其在父layer中的层次，默认为0，这个值越大，层次越靠上
@property CGFloat zPosition;

// 锚点 默认是(0.5, 0.5)。
@property CGPoint anchorPoint;

// 在Z轴上的锚点位置 3D变换时会有很大影响。 Defaults to zero。
@property CGFloat anchorPointZ;

// 进行3D变换。
@property CATransform3D transform;

// 获取和设置CGAffineTransform变换
- (CGAffineTransform)affineTransform;
- (void)setAffineTransform:(CGAffineTransform)m;

// 设置layer的frame
@property CGRect frame;

// 设置是否隐藏 Defaults to NO。
@property(getter=isHidden) BOOL hidden;

// 每个layer层有两面，这个属性确定是否两面都显示 Defaults to YES。
@property(getter=isDoubleSided) BOOL doubleSided;

// 是否进行y轴的方向翻转。 Defaults to NO。
@property(getter=isGeometryFlipped) BOOL geometryFlipped;

// 获取当前layer内容y轴方向是否被翻转了
- (BOOL)contentsAreFlipped;

// 父layer视图
@property(nullable, readonly) CALayer *superlayer;

// 从其父layer层上移除
- (void)removeFromSuperlayer;

// 所有子layer数组
@property(nullable, copy) NSArray<CALayer *> *sublayers;

// 添加一个字layer
- (void)addSublayer:(CALayer *)layer;

// 插入一个子layer
- (void)insertSublayer:(CALayer *)layer atIndex:(unsigned)idx;

// 将一个子layer插入到最下面
- (void)insertSublayer:(CALayer *)layer below:(nullable CALayer *)sibling;
// 将一个子layer插入到最上面
- (void)insertSublayer:(CALayer *)layer above:(nullable CALayer *)sibling;

// 替换一个子layer
- (void)replaceSublayer:(CALayer *)layer with:(CALayer *)layer2;

// 对其子layer进行3D变换
@property CATransform3D sublayerTransform;

// 遮罩层layer
@property(nullable, strong) CALayer *mask;

// 舍否进行bounds的切割，在设置圆角属性时会设置为YES。Defaults to NO。
@property BOOL masksToBounds;

/* 下面这些方法用于坐标转换 */
//把点从指定的layer坐标系统转换到接收者的坐标系统中
- (CGPoint)convertPoint:(CGPoint)p fromLayer:(nullable CALayer *)l;
//把点从指定的layer坐标系统转换到接收者的坐标系统中
- (CGPoint)convertPoint:(CGPoint)p toLayer:(nullable CALayer *)l;
//把矩形从指定的layer坐标系统中转换到接收者坐标系统中
- (CGRect)convertRect:(CGRect)r fromLayer:(nullable CALayer *)l;
//把矩形从指定的layer坐标系统中转换到接收者坐标系统中
- (CGRect)convertRect:(CGRect)r toLayer:(nullable CALayer *)l;

- (CFTimeInterval)convertTime:(CFTimeInterval)t fromLayer:(nullable CALayer *)l;
- (CFTimeInterval)convertTime:(CFTimeInterval)t toLayer:(nullable CALayer *)l;

/** Hit testing methods. **/
// 返回包含某一点的最上层的子layer
- (nullable CALayer *)hitTest:(CGPoint)p;

// 返回layer的bounds内是否包含某一点
- (BOOL)containsPoint:(CGPoint)p;

/** Contents filter names. **/
CA_EXTERN NSString * const kCAFilterNearest
    CA_AVAILABLE_STARTING (10.5, 2.0, 9.0, 2.0);
CA_EXTERN NSString * const kCAFilterLinear
    CA_AVAILABLE_STARTING (10.5, 2.0, 9.0, 2.0);
// 一个提供layer目录的对象
@property(nullable, strong) id contents;

// 获取目录内容的rect尺寸。
@property CGRect contentsRect;

/** Layer `contentsGravity' values. **/
CA_EXTERN NSString * const kCAGravityCenter
    CA_AVAILABLE_STARTING (10.5, 2.0, 9.0, 2.0); //重力中心在中心
CA_EXTERN NSString * const kCAGravityTop
    CA_AVAILABLE_STARTING (10.5, 2.0, 9.0, 2.0); //重力中心在顶部
CA_EXTERN NSString * const kCAGravityBottom
    CA_AVAILABLE_STARTING (10.5, 2.0, 9.0, 2.0); //重力中心在底部
CA_EXTERN NSString * const kCAGravityLeft
    CA_AVAILABLE_STARTING (10.5, 2.0, 9.0, 2.0); //重力中心在左边
CA_EXTERN NSString * const kCAGravityRight
    CA_AVAILABLE_STARTING (10.5, 2.0, 9.0, 2.0); //重力中心在右边
CA_EXTERN NSString * const kCAGravityTopLeft
    CA_AVAILABLE_STARTING (10.5, 2.0, 9.0, 2.0); //重力中心在左上方
CA_EXTERN NSString * const kCAGravityTopRight
    CA_AVAILABLE_STARTING (10.5, 2.0, 9.0, 2.0); //重力中心在右上方
CA_EXTERN NSString * const kCAGravityBottomLeft
    CA_AVAILABLE_STARTING (10.5, 2.0, 9.0, 2.0); //重力中心在左下角
CA_EXTERN NSString * const kCAGravityBottomRight
    CA_AVAILABLE_STARTING (10.5, 2.0, 9.0, 2.0); //重力中心在右下角
CA_EXTERN NSString * const kCAGravityResize
    CA_AVAILABLE_STARTING (10.5, 2.0, 9.0, 2.0); //
CA_EXTERN NSString * const kCAGravityResizeAspect
    CA_AVAILABLE_STARTING (10.5, 2.0, 9.0, 2.0); //
CA_EXTERN NSString * const kCAGravityResizeAspectFill
    CA_AVAILABLE_STARTING (10.5, 2.0, 9.0, 2.0); //
// 设置内容的填充和对其方式，具体下面见下面
@property(copy) NSString *contentsGravity; 

// 设置内容的缩放
@property CGFloat contentsScale
  CA_AVAILABLE_STARTING (10.7, 4.0, 9.0, 2.0);

/* 确定一个矩形区域，当内容进行拉伸或者缩放的时候，这一部分的区域是会被形变的。
例如，默认设置为(0,0,1,1)，则整个内容区域都会参与形变。
如果我们设置为(0.25,0.25,0.5,0.5),那么只有中间0.5*0.5比例宽高的区域会被拉伸，四周都不会。*/
@property CGRect contentsCenter;

/** Layer `contentsFormat` values. **/
CA_EXTERN NSString * const kCAContentsFormatRGBA8Uint /* RGBA UInt8 per component */
  CA_AVAILABLE_STARTING (10.12, 10.0, 10.0, 3.0);
CA_EXTERN NSString * const kCAContentsFormatRGBA16Float /* RGBA half-float 16-bit per component */
  CA_AVAILABLE_STARTING (10.12, 10.0, 10.0, 3.0);
CA_EXTERN NSString * const kCAContentsFormatGray8Uint /* Grayscale with alpha (if not opaque) UInt8 per component */
  CA_AVAILABLE_STARTING (10.12, 10.0, 10.0, 3.0);
// 
@property(copy) NSString *contentsFormat
  CA_AVAILABLE_STARTING (10.12, 10.0, 10.0, 3.0);

// 设置缩小的模式
@property(copy) NSString *minificationFilter;
// 设置放大的模式
@property(copy) NSString *magnificationFilter;

// 缩放因子
@property float minificationFilterBias;

// 设置内容是否完全不透明。 Defaults to NO
@property(getter=isOpaque) BOOL opaque;

// 重新加载绘制内容 
- (void)display;

// 设置内容为需要重新绘制
- (void)setNeedsDisplay;
// 设置某一区域内容需要重新绘制
- (void)setNeedsDisplayInRect:(CGRect)r;

// 获取是否需要重新绘制
- (BOOL)needsDisplay;

// 如果需要，进行内容重绘
- (void)displayIfNeeded;

/* 这个属性设置为YES，当内容改变时会自动调用 - (void)setNeedsDisplay函数. Default value is NO. */
@property BOOL needsDisplayOnBoundsChange;

//是否异步绘制，默认是no
@property BOOL drawsAsynchronously
  CA_AVAILABLE_STARTING (10.8, 6.0, 9.0, 2.0);

/* 绘制与读取内容 */
//使用指定的图像上下文来绘制layer的内容
- (void)drawInContext:(CGContextRef)ctx;
//显在指定的上下文中渲染接收者
- (void)renderInContext:(CGContextRef)ctx;

/* “edgeAntialiasingMask”属性的定义。 */
typedef NS_OPTIONS (unsigned int, CAEdgeAntialiasingMask)
{
  kCALayerLeftEdge      = 1U << 0,      /* 左边的边缘设置为抗齿轮属性*/
  kCALayerRightEdge     = 1U << 1,      /* 右边的边缘设置为抗齿轮属性 */
  kCALayerBottomEdge    = 1U << 2,      /* 底部的边缘设置为抗齿轮属性 */
  kCALayerTopEdge       = 1U << 3,      /* 底部的边缘设置为抗齿轮属性 */
};
//用于限定层的边缘是如何栅格化，默认值都是抗齿轮的
@property CAEdgeAntialiasingMask edgeAntialiasingMask;

@property BOOL allowsEdgeAntialiasing;

/* 设置背景颜色*/
@property(nullable) CGColorRef backgroundColor;

/* 设置圆角半径 */
@property CGFloat cornerRadius;

/* 设置边框宽度 */
@property CGFloat borderWidth;

/* 设置边框颜色 */
@property(nullable) CGColorRef borderColor;

/* 设置透明度 */
@property float opacity;

@property BOOL allowsGroupOpacity;

@property(nullable, strong) id compositingFilter;

@property(nullable, copy) NSArray *filters;

@property(nullable, copy) NSArray *backgroundFilters;

@property BOOL shouldRasterize;
//栅格化的比例
@property CGFloat rasterizationScale;

/** Shadow properties. **/

/* 设置阴影颜色 */
@property(nullable) CGColorRef shadowColor;

/* 设置阴影透明度 */
@property float shadowOpacity;

/* 设置阴影偏移量。 Defaults to (0, -3).  */
@property CGSize shadowOffset;

/* /设置阴影圆角半径。 Defaults to 3. */
@property CGFloat shadowRadius;

/* 设置阴影路径 Defaults to null. */
@property(nullable) CGPathRef shadowPath;

/** 布局方法 **/

- (CGSize)preferredFrameSize;
//取消旧的布局，根据需要新型更新布局（重绘）
- (void)setNeedsLayout;
//是否需要布局
- (BOOL)needsLayout;
//重新计算接收者的布局，如果有需要的话
- (void)layoutIfNeeded;
//通知layer来更新布局
- (void)layoutSublayers;

/** Action methods. **/
//返回当前类的默认动作
+ (nullable id<CAAction>)defaultActionForKey:(NSString *)event;
//通过指定的key来获取action对象
- (nullable id<CAAction>)actionForKey:(NSString *)event;

//返回由layer动作组成的字典
@property(nullable, copy) NSDictionary<NSString *, id<CAAction>> *actions;

/** 动画方法 **/

/* 添加一个动画对象 key值起到id的作用，通过key值，可以取到这个动画对象 */
- (void)addAnimation:(CAAnimation *)anim forKey:(nullable NSString *)key;

/* 移除所有动画对象 */
- (void)removeAllAnimations;

/* 移除某个动画对象 */
- (void)removeAnimationForKey:(NSString *)key;

/* 获取所有动画对象的key值 */
- (nullable NSArray<NSString *> *)animationKeys;

/* 通过key值获取动画对象 */
- (nullable CAAnimation *)animationForKey:(NSString *)key;


/** 其他属性 **/
//接收者的名字
@property(nullable, copy) NSString *name;
//设置委托，遵守的协议为 CALayerDelegate
@property(nullable, weak) id <CALayerDelegate> delegate;

@property(nullable, copy) NSDictionary *style;

@end

/** Action (event handler) protocol. **/

@protocol CAAction


- (void)runActionForKey:(NSString *)event object:(id)anObject
    arguments:(nullable NSDictionary *)dict;

@end


@interface NSNull (CAActionAdditions) <CAAction>

@end

/** Delegate methods. **/

@protocol CALayerDelegate <NSObject>
@optional

- (void)displayLayer:(CALayer *)layer;

- (void)drawLayer:(CALayer *)layer inContext:(CGContextRef)ctx;

- (void)layerWillDraw:(CALayer *)layer
  CA_AVAILABLE_STARTING (10.12, 10.0, 10.0, 3.0);

- (void)layoutSublayersOfLayer:(CALayer *)layer;

- (nullable id<CAAction>)actionForLayer:(CALayer *)layer forKey:(NSString *)event;

@end

/* Trilinear minification filter. Enables mipmap generation. Some
 * renderers may ignore this, or impose additional restrictions, such
 * as source images requiring power-of-two dimensions. */

CA_EXTERN NSString * const kCAFilterTrilinear
    CA_AVAILABLE_STARTING (10.6, 3.0, 9.0, 2.0);

/** Layer event names. **/
CA_EXTERN NSString * const kCAOnOrderIn
    CA_AVAILABLE_STARTING (10.5, 2.0, 9.0, 2.0);
CA_EXTERN NSString * const kCAOnOrderOut
    CA_AVAILABLE_STARTING (10.5, 2.0, 9.0, 2.0);

/** The animation key used for transitions. **/
CA_EXTERN NSString * const kCATransition
    CA_AVAILABLE_STARTING (10.5, 2.0, 9.0, 2.0);

NS_ASSUME_NONNULL_END

1、CAEmitterLayer.h
CAEmitterLayer是一个粒子发射器系统，负责粒子的创建和发射源属性。通过它，我们可以轻松创建出炫酷的粒子效果。

/* CoreAnimation - CAEmitterLayer.h

   Copyright (c) 2007-2017, Apple Inc.
   All rights reserved. */

/* Particle emitter layer.
 *
 * Each emitter has an array of cells, the cells define how particles
 * are emitted and rendered by the layer.
 *
 * Particle system is affected by layer's timing. The simulation starts
 * at layer's beginTime.
 *
 * The particles are drawn above the backgroundColor and border of the
 * layer. */

#import <QuartzCore/CALayer.h>

@class CAEmitterCell;

NS_ASSUME_NONNULL_BEGIN

CA_CLASS_AVAILABLE (10.6, 5.0, 9.0, 2.0)
@interface CAEmitterLayer : CALayer

/* The array of emitter cells attached to the layer. Each object must
 * have the CAEmitterCell class. */

@property(nullable, copy) NSArray<CAEmitterCell *> *emitterCells;

/* The birth rate of each cell is multiplied by this number to give the
 * actual number of particles created every second. Default value is one.
 * Animatable. */

@property float birthRate;

/* The cell lifetime range is multiplied by this value when particles are
 * created. Defaults to one. Animatable. */

@property float lifetime;

/* The center of the emission shape. Defaults to (0, 0, 0). Animatable. */

@property CGPoint emitterPosition;
@property CGFloat emitterZPosition;

/* The size of the emission shape. Defaults to (0, 0, 0). Animatable.
 * Depending on the `emitterShape' property some of the values may be
 * ignored. */

@property CGSize emitterSize;
@property CGFloat emitterDepth;

/* A string defining the type of emission shape used. Current options are:
 * `point' (the default), `line', `rectangle', `circle', `cuboid' and
 * `sphere'. */

@property(copy) NSString *emitterShape;

/* A string defining how particles are created relative to the emission
 * shape. Current options are `points', `outline', `surface' and
 * `volume' (the default). */

@property(copy) NSString *emitterMode;

/* A string defining how particles are composited into the layer's
 * image. Current options are `unordered' (the default), `oldestFirst',
 * `oldestLast', `backToFront' (i.e. sorted into Z order) and
 * `additive'. The first four use source-over compositing, the last
 * uses additive compositing. */

@property(copy) NSString *renderMode;

/* When true the particles are rendered as if they directly inhabit the
 * three dimensional coordinate space of the layer's superlayer, rather
 * than being flattened into the layer's plane first. Defaults to NO.
 * If true, the effect of the `filters', `backgroundFilters' and shadow-
 * related properties of the layer is undefined. */

@property BOOL preservesDepth;

/* Multiplies the cell-defined particle velocity. Defaults to one.
 * Animatable. */

@property float velocity;

/* Multiplies the cell-defined particle scale. Defaults to one. Animatable. */

@property float scale;

/* Multiplies the cell-defined particle spin. Defaults to one. Animatable. */

@property float spin;

/* The seed used to initialize the random number generator. Defaults to
 * zero. Each layer has its own RNG state. For properties with a mean M
 * and a range R, random values of the properties are uniformly
 * distributed in the interval [M - R/2, M + R/2]. */

@property unsigned int seed;

@end

/** `emitterShape' values. **/
CA_EXTERN NSString * const kCAEmitterLayerPoint
    CA_AVAILABLE_STARTING (10.6, 5.0, 9.0, 2.0);
CA_EXTERN NSString * const kCAEmitterLayerLine
    CA_AVAILABLE_STARTING (10.6, 5.0, 9.0, 2.0);
CA_EXTERN NSString * const kCAEmitterLayerRectangle
    CA_AVAILABLE_STARTING (10.6, 5.0, 9.0, 2.0);
CA_EXTERN NSString * const kCAEmitterLayerCuboid
    CA_AVAILABLE_STARTING (10.6, 5.0, 9.0, 2.0);
CA_EXTERN NSString * const kCAEmitterLayerCircle
    CA_AVAILABLE_STARTING (10.6, 5.0, 9.0, 2.0);
CA_EXTERN NSString * const kCAEmitterLayerSphere
    CA_AVAILABLE_STARTING (10.6, 5.0, 9.0, 2.0);

/** `emitterMode' values. **/
CA_EXTERN NSString * const kCAEmitterLayerPoints
    CA_AVAILABLE_STARTING (10.6, 5.0, 9.0, 2.0);
CA_EXTERN NSString * const kCAEmitterLayerOutline
    CA_AVAILABLE_STARTING (10.6, 5.0, 9.0, 2.0);
CA_EXTERN NSString * const kCAEmitterLayerSurface
    CA_AVAILABLE_STARTING (10.6, 5.0, 9.0, 2.0);
CA_EXTERN NSString * const kCAEmitterLayerVolume
    CA_AVAILABLE_STARTING (10.6, 5.0, 9.0, 2.0);

/** `renderMode' values. **/
CA_EXTERN NSString * const kCAEmitterLayerUnordered
    CA_AVAILABLE_STARTING (10.6, 5.0, 9.0, 2.0);
CA_EXTERN NSString * const kCAEmitterLayerOldestFirst
    CA_AVAILABLE_STARTING (10.6, 5.0, 9.0, 2.0);
CA_EXTERN NSString * const kCAEmitterLayerOldestLast
    CA_AVAILABLE_STARTING (10.6, 5.0, 9.0, 2.0);
CA_EXTERN NSString * const kCAEmitterLayerBackToFront
    CA_AVAILABLE_STARTING (10.6, 5.0, 9.0, 2.0);
CA_EXTERN NSString * const kCAEmitterLayerAdditive
    CA_AVAILABLE_STARTING (10.6, 5.0, 9.0, 2.0);

NS_ASSUME_NONNULL_END

2、CAEAGLLayer.h
CAEAGLLayer可以通过OpenGL ES来进行界面的绘制。

#import <QuartzCore/CALayer.h>
#import <OpenGLES/EAGLDrawable.h>

NS_ASSUME_NONNULL_BEGIN

CA_CLASS_AVAILABLE_IOS(2.0, 9.0, 2.0)
@interface CAEAGLLayer : CALayer <EAGLDrawable>
{
@private
  struct _CAEAGLNativeWindow *_win;
}

@property BOOL presentsWithTransaction CA_AVAILABLE_IOS_STARTING (9.0, 9.0, 2.0);

@end

NS_ASSUME_NONNULL_END

3、CAGradientLayer.h
CAGradientLayer可以创建出色彩渐变的图层效果。

#import <QuartzCore/CALayer.h>
#import <Foundation/NSArray.h>

NS_ASSUME_NONNULL_BEGIN

CA_CLASS_AVAILABLE (10.6, 3.0, 9.0, 2.0)
@interface CAGradientLayer : CALayer

//颜色分配
@property(nullable, copy) NSArray *colors;

//颜色分割线
@property(nullable, copy) NSArray<NSNumber *> *locations;

//起始点 
@property CGPoint startPoint;
//结束点
@property CGPoint endPoint;

/** `type' values. **/
CA_EXTERN NSString * const kCAGradientLayerAxial
    CA_AVAILABLE_STARTING (10.6, 3.0, 9.0, 2.0);
//
@property(copy) NSString *type;

@end

NS_ASSUME_NONNULL_END

5、CAScrollLayer.h
CAScrollLayer可以支持其上管理的多个子层进行滑动，但是只能通过代码进行管理，不能进行用户点按触发。

#import <QuartzCore/CALayer.h>

NS_ASSUME_NONNULL_BEGIN

CA_CLASS_AVAILABLE (10.5, 2.0, 9.0, 2.0)
@interface CAScrollLayer : CALayer

//把指定点p滚动到左上角。点坐标可以是负值。
- (void)scrollToPoint:(CGPoint)p;
//滚动使指定区域 r 可见。 
- (void)scrollToRect:(CGRect)r;

/* `scrollMode' values. */
CA_EXTERN NSString * const kCAScrollNone
    CA_AVAILABLE_STARTING (10.5, 2.0, 9.0, 2.0); //禁止滚动
CA_EXTERN NSString * const kCAScrollVertically
    CA_AVAILABLE_STARTING (10.5, 2.0, 9.0, 2.0); //只允许垂直滚动
CA_EXTERN NSString * const kCAScrollHorizontally
    CA_AVAILABLE_STARTING (10.5, 2.0, 9.0, 2.0); //只允许水平滚动
CA_EXTERN NSString * const kCAScrollBoth
    CA_AVAILABLE_STARTING (10.5, 2.0, 9.0, 2.0); //可以随便滚动，默认
//允许滚动方向
@property(copy) NSString *scrollMode;

@end

//此方法是在CALayer的分类中实现。
@interface CALayer (CALayerScrolling)

//改方法是从自身开始往父图层找到最近的CAScrollLayer层，然后调用-scrollToPoint: 方法，如果没有找到CAScrollLayer层则不做任何处理。
- (void)scrollPoint:(CGPoint)p;

//改方法是从自身开始往父图层找到最近的CAScrollLayer层，然后调用-scrollToRect: 方法，如果没有找到CAScrollLayer层则不做任何处理。
- (void)scrollRectToVisible:(CGRect)r;
//返回可见区域范围
@property(readonly) CGRect visibleRect;

@end


NS_ASSUME_NONNULL_END

6、CAShapeLayer.h
CAShapeLayer可以让我们在layer层是直接绘制出自定义的形状。

#import <QuartzCore/CALayer.h>

NS_ASSUME_NONNULL_BEGIN

CA_CLASS_AVAILABLE (10.6, 3.0, 9.0, 2.0)
@interface CAShapeLayer : CALayer

@property(nullable) CGPathRef path;

@property(nullable) CGColorRef fillColor;

/* `fillRule' values. */
CA_EXTERN NSString *const kCAFillRuleNonZero
    CA_AVAILABLE_STARTING (10.6, 3.0, 9.0, 2.0);
CA_EXTERN NSString *const kCAFillRuleEvenOdd
    CA_AVAILABLE_STARTING (10.6, 3.0, 9.0, 2.0);
//
@property(copy) NSString *fillRule;

@property(nullable) CGColorRef strokeColor;

@property CGFloat strokeStart;
@property CGFloat strokeEnd;

@property CGFloat lineWidth;

@property CGFloat miterLimit;

/* `lineCap' values. */
CA_EXTERN NSString *const kCALineCapButt
    CA_AVAILABLE_STARTING (10.6, 3.0, 9.0, 2.0);
CA_EXTERN NSString *const kCALineCapRound
    CA_AVAILABLE_STARTING (10.6, 3.0, 9.0, 2.0);
CA_EXTERN NSString *const kCALineCapSquare
    CA_AVAILABLE_STARTING (10.6, 3.0, 9.0, 2.0);
//
@property(copy) NSString *lineCap;

/* `lineJoin' values. */
CA_EXTERN NSString *const kCALineJoinMiter
    CA_AVAILABLE_STARTING (10.6, 3.0, 9.0, 2.0);
CA_EXTERN NSString *const kCALineJoinRound
    CA_AVAILABLE_STARTING (10.6, 3.0, 9.0, 2.0);
CA_EXTERN NSString *const kCALineJoinBevel
    CA_AVAILABLE_STARTING (10.6, 3.0, 9.0, 2.0);
//
@property(copy) NSString *lineJoin;

@property CGFloat lineDashPhase;

@property(nullable, copy) NSArray<NSNumber *> *lineDashPattern;

@end

NS_ASSUME_NONNULL_END

7、CATextLayer.h
CATextLayer可以通过字符串进行文字的绘制。

#import <QuartzCore/CALayer.h>

NS_ASSUME_NONNULL_BEGIN

CA_CLASS_AVAILABLE (10.5, 2.0, 9.0, 2.0)
@interface CATextLayer : CALayer
{
@private
  struct CATextLayerPrivate *_state;
}

@property(nullable, copy) id string;

@property(nullable) CFTypeRef font;

@property CGFloat fontSize;

@property(nullable) CGColorRef foregroundColor;

@property(getter=isWrapped) BOOL wrapped;

/* Truncation modes. */
CA_EXTERN NSString * const kCATruncationNone
    CA_AVAILABLE_STARTING (10.5, 3.2, 9.0, 2.0);
CA_EXTERN NSString * const kCATruncationStart
    CA_AVAILABLE_STARTING (10.5, 3.2, 9.0, 2.0);
CA_EXTERN NSString * const kCATruncationEnd
    CA_AVAILABLE_STARTING (10.5, 3.2, 9.0, 2.0);
CA_EXTERN NSString * const kCATruncationMiddle
    CA_AVAILABLE_STARTING (10.5, 3.2, 9.0, 2.0);
//
@property(copy) NSString *truncationMode;

/* Alignment modes. */
CA_EXTERN NSString * const kCAAlignmentNatural
    CA_AVAILABLE_STARTING (10.5, 3.2, 9.0, 2.0);
CA_EXTERN NSString * const kCAAlignmentLeft
    CA_AVAILABLE_STARTING (10.5, 3.2, 9.0, 2.0);
CA_EXTERN NSString * const kCAAlignmentRight
    CA_AVAILABLE_STARTING (10.5, 3.2, 9.0, 2.0);
CA_EXTERN NSString * const kCAAlignmentCenter
    CA_AVAILABLE_STARTING (10.5, 3.2, 9.0, 2.0);
CA_EXTERN NSString * const kCAAlignmentJustified
    CA_AVAILABLE_STARTING (10.5, 3.2, 9.0, 2.0);
//
@property(copy) NSString *alignmentMode;

@property BOOL allowsFontSubpixelQuantization;

@end

NS_ASSUME_NONNULL_END

8、CATiledLayer.h
CATiledLayer类似瓦片视图，可以将绘制分区域进行，常用于一张大的图片的分不分绘制。

#import <QuartzCore/CALayer.h>

NS_ASSUME_NONNULL_BEGIN

CA_CLASS_AVAILABLE (10.5, 2.0, 9.0, 2.0)
@interface CATiledLayer : CALayer

+ (CFTimeInterval)fadeDuration;

@property size_t levelsOfDetail;

@property size_t levelsOfDetailBias;

@property CGSize tileSize;

@end

NS_ASSUME_NONNULL_END

9、CATransformLayer.h
CATransformLayer用于构建一些3D效果的图层。

#import <QuartzCore/CALayer.h>

NS_ASSUME_NONNULL_BEGIN

CA_CLASS_AVAILABLE (10.6, 3.0, 9.0, 2.0)
@interface CATransformLayer : CALayer
@end

NS_ASSUME_NONNULL_END