/*建立并初始化*/
+ (instancetype)layer;
/*这个初始化方法被coreAnimation 用来建立layer 的阴影 */
- (instancetype)initWithLayer:(id)layer;
/*返回当前正在显示的呈现图层, 动画被激活以后调用此方法才有效*/
- (nullable id)presentationLayer;
/*key 为须要动画的属性, 若是该属性须要自定义动画,则调用测方法返回 YES 便可.
此方法被子类重写. 对于给定的属性返回 YES, 若是该属性的值发生改变(包括附加在 layer 上的动画使该属性的值发生改变),则该属性所在的图层将会进行重绘.
若是此方法指定的属性没有发生改变, 则应调用父类的此方法[super needsDisplayForKey:key].
*/
+ (BOOL)needsDisplayForKey:(NSString *)key;
/*可动画属性: 默认为CGRectZero, layer 的大小*/
@property CGRect bounds;
/*可动画属性, layer 的锚点在 superLayer 中的位置, 锚点默认在试图的中点位置*/
@property CGPoint position;
/*layer 在 superLayer 中z 方向图层树的位置, 默认为0, 可动画*/
@property CGFloat zPosition;
/*锚点: 图层的定点, 相对于图层自己的单位点, 可动画属性*/
@property CGPoint anchorPoint;
/*应用于 layer 的形变(transform), 依赖于锚点, 默认为 identityTransform, 可动画属性*/
@property CATransform3D transform;
/*便利方法 对于访问 layer 的 transform 属性 CGAffineTransform类型*/
- (CGAffineTransform)affineTransform;
- (void)setAffineTransform:(CGAffineTransform)m;
/*隐藏 layer , 不可动画*/
@property(getter=isHidden) BOOL hidden;
/*图层能够双面渲染 , 可动画属性*/
@property(getter=isDoubleSided) BOOL doubleSided;
/*父图层*/
@property(nullable, readonly) CALayer *superlayer;
/*将 layer 从它的父视图中移除, 接受对象:1. layer 在父视图的子视图数组中,; 2. layer 设置为父视图的 mask 属性*/
- (void)removeFromSuperlayer;
/*将 layer 做为子视图插入到 接收者的subLayers 中制定的位置 idx, 若是 layer 有父视图, 则会先将 layer 从父视图中移除, 再插入到新的父视图中的位置 idx*/
- (void)insertSublayer:(CALayer *)layer atIndex:(unsigned)idx;
/* layer: 被插入的对象, receiver: 将要插入到的父视图 sibling: 在父视图中已经存在的子视图, 若为 nil (below:将 layer 插入到第一个位置, above: 插入到最后一个位置.
将 layer 插入到父视图中 sibling 的前面(below)或者后面(above:被当前显示出来的), 插入前会将 layer 从它的父视图中移除
*/
- (void)insertSublayer:(CALayer *)layer below:(nullable CALayer *)sibling;
- (void)insertSublayer:(CALayer *)layer above:(nullable CALayer *)sibling;
/*遮罩属性, layer 定义形状, 父视图定义显示的内容*/
@property(nullable, strong) CALayer *mask;
/*返回 YES 时, 会剪切边界,*/
@property BOOL masksToBounds; /** Mapping between layer coordinate and time spaces. **/
/*点/时间 或者 Rect 在不一样坐标系之间的转换*/
- (CGPoint)convertPoint:(CGPoint)p fromLayer:(nullable CALayer *)l; - (CGPoint)convertPoint:(CGPoint)p toLayer:(nullable CALayer *)l; - (CGRect)convertRect:(CGRect)r fromLayer:(nullable CALayer *)l; - (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. **/
/*判断点 p 是否在当前 layer 的坐标系中, 在则返回 layer , 不在则返回 nil*/
- (nullable CALayer *)hitTest:(CGPoint)p; /* Returns true if the bounds of the layer contains point 'p'. */
- (BOOL)containsPoint:(CGPoint)p; /** Layer content properties and methods. **/
/* An object providing the contents of the layer, typically a CGImageRef, * but may be something else. (For example, NSImage objects are * supported on Mac OS X 10.6 and later.) Default value is nil. * Animatable. */
/*通常用来设置 layer 的图片*/
@property(nullable, strong) id contents;
/* Reload the content of this layer. Calls the -drawInContext: method * then updates the `contents' property of the layer. Typically this is * not called directly. */
/*调用此方法会执行 -drawInContext: 方法, 来更新layer 的 contents 属性, 通常不直接调用此方法*/
- (void)display; /* Marks that -display needs to be called before the layer is next * committed. If a region is specified, only that region of the layer * is invalidated. */
/*UIview 的 setNeedsDisplay 和 setNeedsLayout 方法区别
1. 两个方法都是异步执行的, 而 setNeedsDisplay 方法会自动调用 drawRect 方法, 这样能够拿到当前的 Context, 就能对 layer 进行从新绘制
2. setNeedsLayout 会调用 layoutSubViews 方法, 进行对子控件的从新布局.
*/
- (void)setNeedsDisplay; - (void)setNeedsDisplayInRect:(CGRect)r;
/* Returns true when the layer is marked as needing redrawing. */
/*标记 layer 须要进行从新绘制*/
- (BOOL)needsDisplay; /* Call -display if receiver is marked as needing redrawing. */
/*回调 -displayer 方法, 若是接收者须要进行重绘*/ - (void)displayIfNeeded;
/* When true -setNeedsDisplay will automatically be called when the * bounds of the layer changes. Default value is NO. */ @property BOOL needsDisplayOnBoundsChange;/** Rendering properties and methods. **/ /* Renders the receiver and its sublayers into 'ctx'. This method * renders directly from the layer tree. Renders in the coordinate space * of the layer. * * WARNING: currently this method does not implement the full * CoreAnimation composition model, use with caution. */ - (void)renderInContext:(CGContextRef)ctx;/* The background color of the layer. Default value is nil. Colors * created from tiled patterns are supported. Animatable. */
/*设置背景颜色*/
@property(nullable) CGColorRef backgroundColor; /* When positive, the background of the layer will be drawn with * rounded corners. Also effects the mask generated by the * `masksToBounds' property. Defaults to zero. Animatable. */
/*角半径: 设置圆角*/ @property CGFloat cornerRadius; /* The width of the layer's border, inset from the layer bounds. The * border is composited above the layer's content and sublayers and * includes the effects of the `cornerRadius' property. Defaults to * zero. Animatable. */
/*设置 layer 的边界宽度*/ @property CGFloat borderWidth; /* The color of the layer's border. Defaults to opaque black. Colors * created from tiled patterns are supported. Animatable. */
/*设置边界的颜色, 可动画*/ @property(nullable) CGColorRef borderColor; /* The opacity of the layer, as a value between zero and one. Defaults * to one. Specifying a value outside the [0,1] range will give undefined * results. Animatable. */
/*layer 的透明度, 可动画*/ @property float opacity;/** Shadow properties. **/ /* The color of the shadow. Defaults to opaque black. Colors created * from patterns are currently NOT supported. Animatable. */
/*阴影颜色*/ @property(nullable) CGColorRef shadowColor; /* The opacity of the shadow. Defaults to 0. Specifying a value outside the * [0,1] range will give undefined results. Animatable. */
/*阴影透明度*/ @property float shadowOpacity; /* The shadow offset. Defaults to (0, -3). Animatable. */
/*阴影偏移量*/ @property CGSize shadowOffset; /* The blur radius used to create the shadow. Defaults to 3. Animatable. */
/*阴影圆角属性*/ @property CGFloat shadowRadius; /* When non-null this path defines the outline used to construct the * layer's shadow instead of using the layer's composited alpha * channel. The path is rendered using the non-zero winding rule. * Specifying the path explicitly using this property will usually * improve rendering performance, as will sharing the same path * reference across multiple layers. Upon assignment the path is copied. * Defaults to null. Animatable. */
/*自定义阴影的形状*/ @property(nullable) CGPathRef shadowPath; /** Layout methods. **//* Marks that -layoutSublayers needs to be invoked on the receiver * before the next update. If the receiver's layout manager implements * the -invalidateLayoutOfLayer: method it will be called. * * This method is automatically invoked on a layer whenever its * `sublayers' or `layoutManager' property is modified, and is invoked * on the layer and its superlayer whenever its `bounds' or `transform' * properties are modified. Implicit calls to -setNeedsLayout are * skipped if the layer is currently executing its -layoutSublayers * method. *//**/ - (void)setNeedsLayout; /* Returns true when the receiver is marked as needing layout. */ - (BOOL)needsLayout; /* Traverse upwards from the layer while the superlayer requires layout. * Then layout the entire tree beneath that ancestor. */ - (void)layoutIfNeeded; /* Called when the layer requires layout. The default implementation * calls the layout manager if one exists and it implements the * -layoutSublayersOfLayer: method. Subclasses can override this to * provide their own layout algorithm, which should set the frame of * each sublayer. */
/*当 layer 须要布局的时候调用此方法.*/ - (void)layoutSublayers; /** Action methods. **/ /* An "action" is an object that responds to an "event" via the * CAAction protocol (see below). Events are named using standard * dot-separated key paths. Each layer defines a mapping from event key * paths to action objects. Events are posted by looking up the action * object associated with the key path and sending it the method * defined by the CAAction protocol. * * When an action object is invoked it receives three parameters: the * key path naming the event, the object on which the event happened * (i.e. the layer), and optionally a dictionary of named arguments * specific to each event. * * To provide implicit animations for layer properties, an event with * the same name as each property is posted whenever the value of the * property is modified. A suitable CAAnimation object is associated by * default with each implicit event (CAAnimation implements the action * protocol). * * The layer class also defines the following events that are not * linked directly to properties: * onOrderIn * Invoked when the layer is made visible, i.e. either its * superlayer becomes visible, or it's added as a sublayer of a * visible layer * onOrderOut * Invoked when the layer becomes non-visible. */ /* Returns the default action object associated with the event named by * the string 'event'. The default implementation returns a suitable * animation object for events posted by animatable properties, nil * otherwise. */ + (nullable id<CAAction>)defaultActionForKey:(NSString *)event; /* Returns the action object associated with the event named by the * string 'event'. The default implementation searches for an action * object in the following places: * * 1. if defined, call the delegate method -actionForLayer:forKey: * 2. look in the layer's `actions' dictionary * 3. look in any `actions' dictionaries in the `style' hierarchy * 4. call +defaultActionForKey: on the layer's class * * If any of these steps results in a non-nil action object, the * following steps are ignored. If the final result is an instance of * NSNull, it is converted to `nil'. */ - (nullable id<CAAction>)actionForKey:(NSString *)event; /* A dictionary mapping keys to objects implementing the CAAction * protocol. Default value is nil. */ @property(nullable, copy) NSDictionary<NSString *, id<CAAction>> *actions; /** Animation methods. **/ /* Attach an animation object to the layer. Typically this is implicitly * invoked through an action that is an CAAnimation object. * * 'key' may be any string such that only one animation per unique key * is added per layer. The special key 'transition' is automatically * used for transition animations. The nil pointer is also a valid key. * * If the `duration' property of the animation is zero or negative it * is given the default duration, either the value of the * `animationDuration' transaction property or .25 seconds otherwise. * * The animation is copied before being added to the layer, so any * subsequent modifications to `anim' will have no affect unless it is * added to another layer. */ - (void)addAnimation:(CAAnimation *)anim forKey:(nullable NSString *)key; /* Remove all animations attached to the layer. */ - (void)removeAllAnimations; /* Remove any animation attached to the layer for 'key'. */ - (void)removeAnimationForKey:(NSString *)key; /* Returns an array containing the keys of all animations currently * attached to the receiver. The order of the array matches the order * in which animations will be applied. */ - (nullable NSArray<NSString *> *)animationKeys; /* Returns the animation added to the layer with identifier 'key', or nil * if no such animation exists. Attempting to modify any properties of * the returned object will result in undefined behavior. */ - (nullable CAAnimation *)animationForKey:(NSString *)key; /** Miscellaneous properties. **/ /* The name of the layer. Used by some layout managers. Defaults to nil. */ @property(nullable, copy) NSString *name; /* An object that will receive the CALayer delegate methods defined * below (for those that it implements). The value of this property is * not retained. Default value is nil. */ @property(nullable, weak) id delegate; /* When non-nil, a dictionary dereferenced to find property values that * aren't explicitly defined by the layer. (This dictionary may in turn * have a `style' property, forming a hierarchy of default values.) * If the style dictionary doesn't define a value for an attribute, the * +defaultValueForKey: method is called. Defaults to nil. * * Note that if the dictionary or any of its ancestors are modified, * the values of the layer's properties are undefined until the `style' * property is reset. */ @property(nullable, copy) NSDictionary *style; @end /** Action (event handler) protocol. **/ @protocol CAAction /* Called to trigger the event named 'path' on the receiver. The object * (e.g. the layer) on which the event happened is 'anObject'. The * arguments dictionary may be nil, if non-nil it carries parameters * associated with the event. */ - (void)runActionForKey:(NSString *)event object:(id)anObject arguments:(nullable NSDictionary *)dict; @end /** NSNull protocol conformance. **/ @interface NSNull (CAActionAdditions) <CAAction> @end /** Delegate methods. **/ @interface NSObject (CALayerDelegate) /* If defined, called by the default implementation of the -display * method, in which case it should implement the entire display * process (typically by setting the `contents' property). */ - (void)displayLayer:(CALayer *)layer; /* If defined, called by the default implementation of -drawInContext: */ - (void)drawLayer:(CALayer *)layer inContext:(CGContextRef)ctx; /* Called by the default -layoutSublayers implementation before the layout * manager is checked. Note that if the delegate method is invoked, the * layout manager will be ignored. */ - (void)layoutSublayersOfLayer:(CALayer *)layer; /* If defined, called by the default implementation of the * -actionForKey: method. Should return an object implementating the * CAAction protocol. May return 'nil' if the delegate doesn't specify * a behavior for the current event. Returning the null object (i.e. * '[NSNull null]') explicitly forces no further search. (I.e. the * +defaultActionForKey: method will not be called.) */ - (nullable id<CAAction>)actionForLayer:(CALayer *)layer forKey:(NSString *)event;