QuartzCore.framework

头文件

#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;NS_ASSUME_NONNULL_BEGIN// 设置抗锯齿属性的范围typedef NS_OPTIONS (unsigned int, CAEdgeAntialiasingMask){  kCALayerLeftEdge      = 1U << 0,      /* Minimum X edge. */  kCALayerRightEdge     = 1U << 1,      /* Maximum X edge. */  kCALayerBottomEdge    = 1U << 2,      /* Minimum Y edge. */  kCALayerTopEdge       = 1U << 3,      /* Maximum Y edge. */};/** The base layer class. **/@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;}/** Layer creation and initialization. **/+ (instancetype)layer;/* The designated initializer. */- (instancetype)init;/* This initializer is used by CoreAnimation to create shadow copies of * layers, e.g. for use as presentation layers. Subclasses can override * this method to copy their instance variables into the presentation * layer (subclasses should call the superclass afterwards). Calling this * method in any other situation will result in undefined behavior. */- (instancetype)initWithLayer:(id)layer;/* Returns a copy of the layer containing all properties as they were * at the start of the current transaction, with any active animations * applied. This gives a close approximation to the version of the layer * that is currently displayed. Returns nil if the layer has not yet * been committed. * * The effect of attempting to modify the returned layer in any way is * undefined. * * The `sublayers', `mask' and `superlayer' properties of the returned * layer return the presentation versions of these properties. This * carries through to read-only layer methods. E.g., calling -hitTest: * on the result of the -presentationLayer will query the presentation * values of the layer tree. */- (nullable id)presentationLayer;/* When called on the result of the -presentationLayer method, returns * the underlying layer with the current model values. When called on a * non-presentation layer, returns the receiver. The result of calling * this method after the transaction that produced the presentation * layer has completed is undefined. */- (id)modelLayer;/** Property methods. **//* CALayer implements the standard NSKeyValueCoding protocol for all * Objective C properties defined by the class and its subclasses. It * dynamically implements missing accessor methods for properties * declared by subclasses. * * When accessing properties via KVC whose values are not objects, the * standard KVC wrapping conventions are used, with extensions to * support the following types: * *      C Type                  Class *      ------                  ----- *      CGPoint                 NSValue *      CGSize                  NSValue *      CGRect                  NSValue *      CGAffineTransform       NSAffineTransform *      CATransform3D           NSValue  *//* Returns the default value of the named property, or nil if no * default value is known. Subclasses that override this method to * define default values for their own properties should call `super' * for unknown properties. */+ (nullable id)defaultValueForKey:(NSString *)key;/* Method for subclasses to override. Returning true for a given * property causes the layer's contents to be redrawn when the property * is changed (including when changed by an animation attached to the * layer). The default implementation returns NO. Subclasses should * call super for properties defined by the superclass. (For example, * do not try to return YES for properties implemented by CALayer, * doing will have undefined results.) */+ (BOOL)needsDisplayForKey:(NSString *)key;/* Called by the object's implementation of -encodeWithCoder:, returns * false if the named property should not be archived. The base * implementation returns YES. Subclasses should call super for * unknown properties. */- (BOOL)shouldArchiveValueForKey:(NSString *)key;/** Geometry and layer hierarchy properties. **/// layer的范围，默认CGRectZero.Animatable.@property CGRect bounds;/* The position in the superlayer that the anchor point of the layer's * bounds rect is aligned to. Defaults to the zero point. Animatable. */// @property CGPoint position;// 在super layer中layer位置的z成员。默认为zero。可动画。@property CGFloat zPosition;// 定义layer的锚点，坐标系为layer坐标系，可动画。//（0，0）表示layer范围矩形的左下角// (1，1）表示layer范围矩形的右上角// (0.5，0.5）表示layer范围矩形的中心@property CGPoint anchorPoint;// layer锚点坐标的Z值（定位和仿射变换时的参考点）。默认为zero。可动画。@property CGFloat anchorPointZ;// 应用到layer矩形范围内锚点的仿射变换。默认为identity transform。可动画。@property CATransform3D transform;// 获得仿射变化的便利方法。- (CGAffineTransform)affineTransform;- (void)setAffineTransform:(CGAffineTransform)m;// 与NSView不同，在层次结构中的layer有隐式的frame，position功能，bounds，anchorPoint，tansform属性// 当设置好frame时，position和bound.size将随之改变。 @property CGRect frame;// 当layer和它的super layers不显示时为true。默认NO。不可动画。@property(getter=isHidden) BOOL hidden;/* When false layers facing away from the viewer are hidden from view. * Defaults to YES. Animatable. */ * @property(getter=isDoubleSided) BOOL doubleSided;// layer的几何结构是否垂直翻转。默认NO。// 注意即使几何结构翻转了，图片的方向仍然不变。// 存储在contents中的CGImageRef会保持不变，不管为NO或YES，假定在层上没有变换。@property(getter=isGeometryFlipped) BOOL geometryFlipped;/* Returns true if the contents of the contents property of the layer * will be implicitly flipped when rendered in relation to the local * coordinate space (e.g. if there are an odd number of layers with * flippedGeometry=YES from the receiver up to and including the * implicit container of the root layer). Subclasses should not attempt * to redefine this method. When this method returns true the * CGContextRef object passed to -drawInContext: by the default * -display method will have been y- flipped (and rectangles passed to * -setNeedsDisplayInRect: will be similarly flipped). */- (BOOL)contentsAreFlipped;/* The receiver's superlayer object. Implicitly changed to match the * hierarchy described by the `sublayers' properties. */// @property(nullable, readonly) CALayer *superlayer;/* Removes the layer from its superlayer, works both if the receiver is * in its superlayer's `sublayers' array or set as its `mask' value. */// 从surer layer中移除layer，- (void)removeFromSuperlayer;// sublayers数组。layers按从后到前的顺序排列。// 任何新加入的layers的super layers必须为空。否则，结果不能预料。// 返回的数组保证retain它的元素。@property(nullable, copy) NSArray<CALayer *> *sublayers;// 将layer添加到layer's sublayers数组的最后面。// 如果layer已将有super layer，在添加前将会被移除。- (void)addSublayer:(CALayer *)layer;// 将layer添加到layer's sublayers数组中指定的索引处。// 如果layer已将有super layer，在添加前将会被移除。- (void)insertSublayer:(CALayer *)layer atIndex:(unsigned)idx;// 将layer添加到layer's sublayers数组中指定的layer的上面或下面。// 如果layer已将有super layer，在添加前将会被移除。- (void)insertSublayer:(CALayer *)layer below:(nullable CALayer *)sibling;- (void)insertSublayer:(CALayer *)layer above:(nullable CALayer *)sibling;// 将layer从layer's sublayers数组中移除并插入layer2（layer2为non-nil）。// 如果layer的super layer不是接受者，行为不确定。- (void)replaceSublayer:(CALayer *)layer with:(CALayer *)layer2;/* A transform applied to each member of the `sublayers' array while * rendering its contents into the receiver's output. Typically used as * the projection matrix to add perspective and other viewing effects * into the model. Defaults to identity. Animatable. */@property CATransform3D sublayerTransform;/* A layer whose alpha channel is used as a mask to select between the * layer's background and the result of compositing the layer's * contents with its filtered background. Defaults to nil. When used as * a mask the layer's `compositingFilter' and `backgroundFilters' * properties are ignored. When setting the mask to a new layer, the * new layer must have a nil superlayer, otherwise the behavior is * undefined. Nested masks (mask layers with their own masks) are * unsupported. */@property(nullable, strong) CALayer *mask;/* When true an implicit mask matching the layer bounds is applied to * the layer (including the effects of the `cornerRadius' property). If * both `mask' and `masksToBounds' are non-nil the two masks are * multiplied to get the actual mask values. Defaults to NO. * Animatable. */@property BOOL masksToBounds;/** Mapping between layer coordinate and time spaces. **/- (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. **//* Returns the farthest descendant of the layer containing point 'p'. * Siblings are searched in top-to-bottom order. 'p' is defined to be * in the coordinate space of the receiver's nearest ancestor that * isn't a CATransformLayer (transform layers don't have a 2D * coordinate space in which the point could be specified). */- (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. */@property(nullable, strong) id contents;/* A rectangle in normalized image coordinates defining the * subrectangle of the `contents' property that will be drawn into the * layer. If pixels outside the unit rectangles are requested, the edge * pixels of the contents image will be extended outwards. If an empty * rectangle is provided, the results are undefined. Defaults to the * unit rectangle [0 0 1 1]. Animatable. */@property CGRect contentsRect;/* A string defining how the contents of the layer is mapped into its * bounds rect. Options are `center', `top', `bottom', `left', * `right', `topLeft', `topRight', `bottomLeft', `bottomRight', * `resize', `resizeAspect', `resizeAspectFill'. The default value is * `resize'. Note that "bottom" always means "Minimum Y" and "top" * always means "Maximum Y". */@property(copy) NSString *contentsGravity;/* Defines the scale factor applied to the contents of the layer. If * the physical size of the contents is '(w, h)' then the logical size * (i.e. for contentsGravity calculations) is defined as '(w / * contentsScale, h / contentsScale)'. Applies to both images provided * explicitly and content provided via -drawInContext: (i.e. if * contentsScale is two -drawInContext: will draw into a buffer twice * as large as the layer bounds). Defaults to one. Animatable. */@property CGFloat contentsScale  __OSX_AVAILABLE_STARTING (__MAC_10_7, __IPHONE_4_0);/* A rectangle in normalized image coordinates defining the scaled * center part of the `contents' image. * * When an image is resized due to its `contentsGravity' property its * center part implicitly defines the 3x3 grid that controls how the * image is scaled to its drawn size. The center part is stretched in * both dimensions; the top and bottom parts are only stretched * horizontally; the left and right parts are only stretched * vertically; the four corner parts are not stretched at all. (This is * often called "9-slice scaling".) * * The rectangle is interpreted after the effects of the `contentsRect' * property have been applied. It defaults to the unit rectangle [0 0 1 * 1] meaning that the entire image is scaled. As a special case, if * the width or height is zero, it is implicitly adjusted to the width * or height of a single source pixel centered at that position. If the * rectangle extends outside the [0 0 1 1] unit rectangle the result is * undefined. Animatable. */@property CGRect contentsCenter;/* The filter types to use when rendering the `contents' property of * the layer. The minification filter is used when to reduce the size * of image data, the magnification filter to increase the size of * image data. Currently the allowed values are `nearest' and `linear'. * Both properties default to `linear'. */@property(copy) NSString *minificationFilter;@property(copy) NSString *magnificationFilter;/* The bias factor added when determining which levels of detail to use * when minifying using trilinear filtering. The default value is 0. * Animatable. */@property float minificationFilterBias;/* A hint marking that the layer contents provided by -drawInContext: * is completely opaque. Defaults to NO. Note that this does not affect * the interpretation of the `contents' property directly. */@property(getter=isOpaque) BOOL opaque;/* Reload the content of this layer. Calls the -drawInContext: method * then updates the `contents' property of the layer. Typically this is * not called directly. */- (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. */- (void)setNeedsDisplay;- (void)setNeedsDisplayInRect:(CGRect)r;/* Returns true when the layer is marked as needing redrawing. */- (BOOL)needsDisplay;/* Call -display if receiver is marked as needing redrawing. */- (void)displayIfNeeded;/* When true -setNeedsDisplay will automatically be called when the * bounds of the layer changes. Default value is NO. */@property BOOL needsDisplayOnBoundsChange;/* When true, the CGContext object passed to the -drawInContext: method * may queue the drawing commands submitted to it, such that they will * be executed later (i.e. asynchronously to the execution of the * -drawInContext: method). This may allow the layer to complete its * drawing operations sooner than when executing synchronously. The * default value is NO. */@property BOOL drawsAsynchronously  __OSX_AVAILABLE_STARTING (__MAC_10_8, __IPHONE_6_0);/* Called via the -display method when the `contents' property is being * updated. Default implementation does nothing. The context may be * clipped to protect valid layer content. Subclasses that wish to find * the actual region to draw can call CGContextGetClipBoundingBox(). */- (void)drawInContext:(CGContextRef)ctx;/** 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;/* Defines how the edges of the layer are rasterized. For each of the * four edges (left, right, bottom, top) if the corresponding bit is * set the edge will be antialiased. Typically this property is used to * disable antialiasing for edges that abut edges of other layers, to * eliminate the seams that would otherwise occur. The default value is * for all edges to be antialiased. */@property CAEdgeAntialiasingMask edgeAntialiasingMask;/* When true this layer is allowed to antialias its edges, as requested * by the value of the edgeAntialiasingMask property. * * The default value is read from the boolean UIViewEdgeAntialiasing * property in the main bundle's Info.plist. If no value is found in * the Info.plist the default value is NO. */@property BOOL allowsEdgeAntialiasing;/* The background color of the layer. Default value is nil. Colors * created from tiled patterns are supported. Animatable. */@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. */@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. */@property CGFloat borderWidth;/* The color of the layer's border. Defaults to opaque black. Colors * created from tiled patterns are supported. Animatable. */@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. */@property float opacity;/* When true, and the layer's opacity property is less than one, the * layer is allowed to composite itself as a group separate from its * parent. This gives the correct results when the layer contains * multiple opaque components, but may reduce performance. * * The default value of the property is read from the boolean * UIViewGroupOpacity property in the main bundle's Info.plist. If no * value is found in the Info.plist the default value is YES for * applications linked against the iOS 7 SDK or later and NO for * applications linked against an earlier SDK. */@property BOOL allowsGroupOpacity;/* A filter object used to composite the layer with its (possibly * filtered) background. Default value is nil, which implies source- * over compositing. Animatable. * * Note that if the inputs of the filter are modified directly after * the filter is attached to a layer, the behavior is undefined. The * filter must either be reattached to the layer, or filter properties * should be modified by calling -setValue:forKeyPath: on each layer * that the filter is attached to. (This also applies to the `filters' * and `backgroundFilters' properties.) */@property(nullable, strong) id compositingFilter;/* An array of filters that will be applied to the contents of the * layer and its sublayers. Defaults to nil. Animatable. */@property(nullable, copy) NSArray *filters;/* An array of filters that are applied to the background of the layer. * The root layer ignores this property. Animatable. */@property(nullable, copy) NSArray *backgroundFilters;/* When true, the layer is rendered as a bitmap in its local coordinate * space ("rasterized"), then the bitmap is composited into the * destination (with the minificationFilter and magnificationFilter * properties of the layer applied if the bitmap needs scaling). * Rasterization occurs after the layer's filters and shadow effects * are applied, but before the opacity modulation. As an implementation * detail the rendering engine may attempt to cache and reuse the * bitmap from one frame to the next. (Whether it does or not will have * no affect on the rendered output.) * * When false the layer is composited directly into the destination * whenever possible (however, certain features of the compositing * model may force rasterization, e.g. adding filters). * * Defaults to NO. Animatable. */@property BOOL shouldRasterize;/* The scale at which the layer will be rasterized (when the * shouldRasterize property has been set to YES) relative to the * coordinate space of the layer. Defaults to one. Animatable. */@property CGFloat rasterizationScale;/** Shadow properties. **//* The color of the shadow. Defaults to opaque black. Colors created * from patterns are currently NOT supported. Animatable. */@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. */@property float shadowOpacity;/* The shadow offset. Defaults to (0, -3). Animatable. */@property CGSize shadowOffset;/* The blur radius used to create the shadow. Defaults to 3. Animatable. */@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. */@property(nullable) CGPathRef shadowPath;/** Layout methods. **//* Returns the preferred frame size of the layer in the coordinate * space of the superlayer. The default implementation calls the layout * manager if one exists and it implements the -preferredSizeOfLayer: * method, otherwise returns the size of the bounds rect mapped into * the superlayer. */- (CGSize)preferredFrameSize;/* 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. */- (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;@end/** Layer `contentsGravity' values. **/CA_EXTERN NSString * const kCAGravityCenter    __OSX_AVAILABLE_STARTING (__MAC_10_5, __IPHONE_2_0);CA_EXTERN NSString * const kCAGravityTop    __OSX_AVAILABLE_STARTING (__MAC_10_5, __IPHONE_2_0);CA_EXTERN NSString * const kCAGravityBottom    __OSX_AVAILABLE_STARTING (__MAC_10_5, __IPHONE_2_0);CA_EXTERN NSString * const kCAGravityLeft    __OSX_AVAILABLE_STARTING (__MAC_10_5, __IPHONE_2_0);CA_EXTERN NSString * const kCAGravityRight    __OSX_AVAILABLE_STARTING (__MAC_10_5, __IPHONE_2_0);CA_EXTERN NSString * const kCAGravityTopLeft    __OSX_AVAILABLE_STARTING (__MAC_10_5, __IPHONE_2_0);CA_EXTERN NSString * const kCAGravityTopRight    __OSX_AVAILABLE_STARTING (__MAC_10_5, __IPHONE_2_0);CA_EXTERN NSString * const kCAGravityBottomLeft    __OSX_AVAILABLE_STARTING (__MAC_10_5, __IPHONE_2_0);CA_EXTERN NSString * const kCAGravityBottomRight    __OSX_AVAILABLE_STARTING (__MAC_10_5, __IPHONE_2_0);CA_EXTERN NSString * const kCAGravityResize    __OSX_AVAILABLE_STARTING (__MAC_10_5, __IPHONE_2_0);CA_EXTERN NSString * const kCAGravityResizeAspect    __OSX_AVAILABLE_STARTING (__MAC_10_5, __IPHONE_2_0);CA_EXTERN NSString * const kCAGravityResizeAspectFill    __OSX_AVAILABLE_STARTING (__MAC_10_5, __IPHONE_2_0);/** Contents filter names. **/CA_EXTERN NSString * const kCAFilterNearest    __OSX_AVAILABLE_STARTING (__MAC_10_5, __IPHONE_2_0);CA_EXTERN NSString * const kCAFilterLinear    __OSX_AVAILABLE_STARTING (__MAC_10_5, __IPHONE_2_0);/* 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    __OSX_AVAILABLE_STARTING (__MAC_10_6, __IPHONE_3_0);/** Layer event names. **/CA_EXTERN NSString * const kCAOnOrderIn    __OSX_AVAILABLE_STARTING (__MAC_10_5, __IPHONE_2_0);CA_EXTERN NSString * const kCAOnOrderOut    __OSX_AVAILABLE_STARTING (__MAC_10_5, __IPHONE_2_0);/** The animation key used for transitions. **/CA_EXTERN NSString * const kCATransition    __OSX_AVAILABLE_STARTING (__MAC_10_5, __IPHONE_2_0);NS_ASSUME_NONNULL_END

补充

    // 作用：实现透视    UIView *myView = [[self subviews] objectAtIndex:0];    CALayer *layer = myView.layer;    CATransform3D rotationAndPerspectiveTransform = CATransform3DIdentity;    rotationAndPerspectiveTransform.m34 = 1.0 / -500;    rotationAndPerspectiveTransform = CATransform3DRotate(rotationAndPerspectiveTransform, 45.0f * M_PI / 180.0f, 0.0f, 1.0f, 0.0f);    layer.transform = rotationAndPerspectiveTransform;

    // 作用：创建模糊覆盖层    // Object-C    if (!UIAccessibilityIsReduceTransparencyEnabled()) {    self.view.backgroundColor = [UIColor clearColor];    UIBlurEffect *blurEffect = [UIBlurEffect effectWithStyle:UIBlurEffectStyleDark];    UIVisualEffectView *blurEffectView = [[UIVisualEffectView alloc] initWithEffect:blurEffect];    blurEffectView.frame = self.view.bounds;    blurEffectView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;    [self.view addSubview:blurEffectView];} else {    self.view.backgroundColor = [UIColor blackColor];}    // Swift3.0    //only apply the blur if the user hasn't disabled transparency effectsif !UIAccessibilityIsReduceTransparencyEnabled() {    self.view.backgroundColor = UIColor.clear    let blurEffect = UIBlurEffect(style: UIBlurEffectStyle.dark)    let blurEffectView = UIVisualEffectView(effect: blurEffect)    //always fill the view    blurEffectView.frame = self.view.bounds    blurEffectView.autoresizingMask = [.flexibleWidth, .flexibleHeight]    self.view.addSubview(blurEffectView) //if you have more UIViews, use an insertSubview API to place it where needed} else {    self.view.backgroundColor = UIColor.black}

// 作用：给UIImageView设置圆角-(UIImage *)makeRoundedImage:(UIImage *) image                       radius: (float) radius;{  CALayer *imageLayer = [CALayer layer];  imageLayer.frame = CGRectMake(0, 0, image.size.width, image.size.height);  imageLayer.contents = (id) image.CGImage;  imageLayer.masksToBounds = YES;  imageLayer.cornerRadius = radius;  UIGraphicsBeginImageContext(image.size);  [imageLayer renderInContext:UIGraphicsGetCurrentContext()];  UIImage *roundedImage = UIGraphicsGetImageFromCurrentImageContext();  UIGraphicsEndImageContext();  return roundedImage;}}