CATextLayer

用于渲染一个无格式或属性文本字符

一、CATextLayer属性

• 1、 @property(copy) id string;
  文本呈现，可以是一个NSString或者NSAttributedString；默认为nil
• 2、 @property CFTypeRef font;
  字体使用，可能是一个CTFontRef，一个CGFontRef或者一个字符串命名体，默认为Helvetica字体；仅当string不是一个NSAttributedString的时候使用；
• 3、 @property CGFloat fontSize;
  字体大小，默认为36；仅当string不是一个NSAttributedString的时候使用；
• 4、 @property CGColorRef foregroundColor;
  用来绘制文本的颜色，默认为不透明的白色；仅当string不是一个NSAttributedString的时候使用；
• 5、 @property(getter=isWrapped) BOOL wrapped;
  文本自适应图层大小，默认是NO；
• 6、 @property(copy) NSString *truncationMode;
  描述如何将字符串截断以适应图层大小，设置缩短的部位，可选择没有，开始，中间，和结束；如下：

/* Truncation modes. */CA_EXTERN NSString * const kCATruncationNone    __OSX_AVAILABLE_STARTING (__MAC_10_5, __IPHONE_3_2);CA_EXTERN NSString * const kCATruncationStart    __OSX_AVAILABLE_STARTING (__MAC_10_5, __IPHONE_3_2);CA_EXTERN NSString * const kCATruncationEnd    __OSX_AVAILABLE_STARTING (__MAC_10_5, __IPHONE_3_2);CA_EXTERN NSString * const kCATruncationMiddle    __OSX_AVAILABLE_STARTING (__MAC_10_5, __IPHONE_3_2);

• 7、 @property(copy) NSString *alignmentMode;
  描述如何在该层中的单行的文本对齐，设置字体的排列格式，可选择自然，左，右，居中和自适应；默认为自然；如下：

/* Alignment modes. */CA_EXTERN NSString * const kCAAlignmentNatural    __OSX_AVAILABLE_STARTING (__MAC_10_5, __IPHONE_3_2);CA_EXTERN NSString * const kCAAlignmentLeft    __OSX_AVAILABLE_STARTING (__MAC_10_5, __IPHONE_3_2);CA_EXTERN NSString * const kCAAlignmentRight    __OSX_AVAILABLE_STARTING (__MAC_10_5, __IPHONE_3_2);CA_EXTERN NSString * const kCAAlignmentCenter    __OSX_AVAILABLE_STARTING (__MAC_10_5, __IPHONE_3_2);CA_EXTERN NSString * const kCAAlignmentJustified    __OSX_AVAILABLE_STARTING (__MAC_10_5, __IPHONE_3_2);

• 8、 @property CGFloat contentsScale;
  使用CATextLayer设置文本，可能会产生模糊状态，因为该默认的分辨率不是retina，设置如下代码即可：

  textLayer.contentsScale = [UIScreen mainScreen].scale;

二、CATextLayer与 CAGradientLayer（会员金闪闪动画字体）

代码如下：

#define UIColorFromRGB(rgbValue) [UIColor colorWithRed:((float)((rgbValue & 0xFF0000) >> 16))/255.0 green:((float)((rgbValue & 0xFF00) >> 8))/255.0 blue:((float)(rgbValue & 0xFF))/255.0 alpha:1.0]@interface ViewController (){    CATextLayer *textLayer;    CAGradientLayer *gradientLayer;    UIView* bgView;}@end@implementation ViewController- (void)viewDidLoad {    [super viewDidLoad];    UIButton* btn = [UIButton buttonWithType:UIButtonTypeCustom];    btn.frame = CGRectMake(0, self.view.frame.size.height - 40, self.view.frame.size.width, 40);    [btn setTitle:@"开始动画" forState:UIControlStateNormal];    [btn addTarget:self action:@selector(clickBtn) forControlEvents:UIControlEventTouchUpInside];    [btn setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];    [self.view addSubview:btn];    bgView = [[UIView alloc]initWithFrame:CGRectMake(0, 40, self.view.frame.size.width, self.view.frame.size.width)];    bgView.backgroundColor = [UIColor brownColor];    [self.view addSubview:bgView];    textLayer = [CATextLayer layer];    textLayer.frame = CGRectMake((bgView.frame.size.width - 200)/2, (bgView.frame.size.width - 200)/2, 200, 200);    textLayer.foregroundColor = [UIColor blackColor].CGColor;    textLayer.alignmentMode =kCAAlignmentJustified;    textLayer.wrapped =YES;    UIFont *font = [UIFont systemFontOfSize:30];    CFStringRef fontName = (__bridge CFStringRef)font.fontName;    CGFontRef fontRef =CGFontCreateWithFontName(fontName);    textLayer.font = fontRef;    textLayer.fontSize = font.pointSize;    CGFontRelease(fontRef);    NSString *text =@"习惯不曾习惯的习惯会习惯 舍得不曾舍得的舍得会舍得";    textLayer.string = text;    textLayer.contentsScale = [UIScreen mainScreen].scale;    [bgView.layer addSublayer:textLayer];    //创建背景图层    gradientLayer =  [CAGradientLayer layer];    [gradientLayer setColors:[NSArray arrayWithObjects:                              (id)[UIColorFromRGB(0x000000) CGColor],                              (id)[UIColorFromRGB(0xFFD700) CGColor],                              (id)[UIColorFromRGB(0x000000) CGColor],                              (id)[UIColorFromRGB(0xFFD700) CGColor],                              (id)[UIColorFromRGB(0x000000) CGColor],                              (id)[UIColorFromRGB(0xFFD700) CGColor],                              (id)[UIColorFromRGB(0x000000) CGColor],                              (id)[UIColorFromRGB(0xFFD700) CGColor],                              (id)[UIColorFromRGB(0x000000) CGColor],                              (id)[UIColorFromRGB(0xFFD700) CGColor],                              (id)[UIColorFromRGB(0x000000) CGColor],                              (id)[[UIColor clearColor] CGColor],                              nil]];    gradientLayer.frame = bgView.bounds;    [gradientLayer setLocations:[NSArray arrayWithObjects:                                 [NSNumber numberWithFloat:0.0],                                 [NSNumber numberWithFloat:0.1],                                 [NSNumber numberWithFloat:0.2],                                 [NSNumber numberWithFloat:0.3],                                 [NSNumber numberWithFloat:0.4],                                 [NSNumber numberWithFloat:0.5],                                 [NSNumber numberWithFloat:0.6],                                 [NSNumber numberWithFloat:0.7],                                 [NSNumber numberWithFloat:0.8],                                 [NSNumber numberWithFloat:0.9],                                 [NSNumber numberWithFloat:1.0],                                 nil]];    [gradientLayer setStartPoint:CGPointMake(0, 0)];    [gradientLayer setEndPoint:CGPointMake(1, 1)];    [gradientLayer setMask:textLayer]; //用progressLayer来截取渐变层    [bgView.layer addSublayer:gradientLayer];}- (void)clickBtn{    //动画    CABasicAnimation *animation = [CABasicAnimation animationWithKeyPath:@"position"];    CGPoint fromPoint = textLayer.position;    CGPoint toPoint = CGPointMake(fromPoint.x + (bgView.frame.size.width - 200)/2, fromPoint.y);    animation.duration = 1;    animation.fromValue = [NSValue valueWithCGPoint:fromPoint];    animation.toValue = [NSValue valueWithCGPoint:toPoint];    animation.autoreverses = YES;    [textLayer addAnimation:animation forKey:nil];    CABasicAnimation *animation2 = [CABasicAnimation animationWithKeyPath:@"position"];    CGPoint fromPoint2 = gradientLayer.position;    CGPoint toPoint2 = CGPointMake(fromPoint.x - (bgView.frame.size.width - 200)/2, fromPoint.y);    animation2.duration = 1;    animation2.fromValue = [NSValue valueWithCGPoint:fromPoint2];    animation2.toValue = [NSValue valueWithCGPoint:toPoint2];    animation2.autoreverses = YES;    [gradientLayer addAnimation:animation2 forKey:nil];}

三、CATextLayer与 CAShapeLayer（波浪）

• 1、 XYWaterWaveView.h文件

#import <UIKit/UIKit.h>@interface XYWaterWaveView : UIView/** *  波纹振幅 默认30 */@property (nonatomic ,assign) CGFloat waveAmplitude;/** *  振幅周期 默认200 */@property (nonatomic ,assign) CGFloat waveCycle;/** *  波纹速度 默认 0.2 */@property (nonatomic ,assign) CGFloat waveSpeed;/** *  波纹高度 默认为300 */@property (nonatomic ,assign) CGFloat waterWaveHeight;/** *  波纹颜色 默认红色 */@property (nonatomic, strong) UIColor* waveColor;/** *  开始 */- (void)startWave;@end

• 2、 XYWaterWaveView.m文件

#import "XYWaterWaveView.h"@interface XYWaterWaveView(){    CGFloat _height;    CGFloat _width;}/** *  波纹偏移 */@property (nonatomic ,assign) CGFloat offsetX;/** *  波纹频率 */@property (nonatomic ,assign) CGFloat waveRate;/** *  定时器 */@property (nonatomic, strong) CADisplayLink *waveDisplaylink;/** *  波纹图层 */@property (nonatomic, strong) CAShapeLayer *waveLayer;/** *  背景图层 */@property (nonatomic, strong) CAShapeLayer *backLayer;/** *  介绍 */@property (nonatomic, strong) CATextLayer *textLayer;@end@implementation XYWaterWaveView#pragma mark -- init- (instancetype)initWithFrame:(CGRect)frame{    self = [super initWithFrame:frame];    if (self) {        [self initData];    }    return self;}- (void)initData{    /**     Asin（rt + x）     A：waveAmplitude     r：waveRate     x：offsetX     */    //振幅    self.waveAmplitude = 30.0f;    //周期    self.waveCycle = 200.0f;    //频率    self.waveRate = 2*M_PI/self.waveCycle;    //偏移    self.offsetX = 0.0f;    //高度    self.waterWaveHeight = 300.0f;    //速度    self.waveSpeed = 0.2f;    //颜色    self.waveColor = [UIColor redColor];    _height = self.frame.size.height;    _width = self.frame.size.width;}#pragma mark - set- (void)setWaveAmplitude:(CGFloat)waveAmplitude{    _waveAmplitude = waveAmplitude;}- (void)setWaveCycle:(CGFloat)waveCycle{    _waveCycle = waveCycle;    _waveRate = 2*M_PI/_waveCycle;}- (void)setWaterWaveHeight:(CGFloat)waterWaveHeight{    _waterWaveHeight = waterWaveHeight;    NSString *text = [NSString stringWithFormat:@"%.2f%@",_waterWaveHeight/_height*100,@"%"];    _textLayer.string = text;}- (void)setWaveSpeed:(CGFloat)waveSpeed{    _waveSpeed = waveSpeed;}#pragma mark -- 开始- (void)startWave{    if (_waveDisplaylink) {        return;    }    if (self.waveLayer == nil) {        // 创建第一个波浪Layer        _waveLayer = [CAShapeLayer layer];        _waveLayer.fillColor = self.waveColor.CGColor;        [self.layer addSublayer:_waveLayer];    }    if (self.backLayer == nil) {        _backLayer = [CAShapeLayer layer];        _backLayer.frame = self.bounds;        _backLayer.fillColor = [UIColor yellowColor].CGColor;        _backLayer.backgroundColor = [UIColor blackColor].CGColor;        [self.layer addSublayer:_backLayer];    }    if (self.textLayer == nil) {        _textLayer = [CATextLayer layer];        _textLayer.foregroundColor = [UIColor blackColor].CGColor;        _textLayer.alignmentMode =kCAAlignmentJustified;        _textLayer.wrapped =YES;        _textLayer.frame = CGRectMake((_width - 150)/2, (_height - 40)/2, 150, 40);        UIFont *font = [UIFont systemFontOfSize:40];        CFStringRef fontName = (__bridge CFStringRef)font.fontName;        CGFontRef fontRef =CGFontCreateWithFontName(fontName);        _textLayer.font = fontRef;        _textLayer.fontSize = font.pointSize;        CGFontRelease(fontRef);        NSString *text = [NSString stringWithFormat:@"%.2f%@",_waterWaveHeight/_height*100,@"%"];        _textLayer.string = text;        _textLayer.contentsScale = [UIScreen mainScreen].scale;        [self.layer addSublayer:_textLayer];        [_backLayer setMask:_textLayer];    }    // 启动定时调用    _waveDisplaylink = [CADisplayLink displayLinkWithTarget:self selector:@selector(getCurrentWave:)];    [_waveDisplaylink addToRunLoop:[NSRunLoop mainRunLoop] forMode:NSRunLoopCommonModes];}- (void)getCurrentWave:(CADisplayLink *)dicplayLink{    // 波浪位移    self.offsetX += self.waveSpeed;    if (self.waterWaveHeight > _height - self.waveAmplitude) {        self.waterWaveHeight = _height - self.waveAmplitude;    }    [self setCurrentWaveLayerPath];}- (void)setCurrentWaveLayerPath{    CGMutablePathRef path = CGPathCreateMutable();    CGFloat currentWavePointY = _height - self.waterWaveHeight;    CGPathMoveToPoint(path, nil, 0, currentWavePointY);    for (float x = 0.0f; x <= _width ; x++) {        // 正弦波浪公式        CGFloat y = self.waveAmplitude * sin(self.waveRate * x + self.offsetX) + currentWavePointY;        CGPathAddLineToPoint(path, nil, x, y);    }    CGPathAddLineToPoint(path, nil, _width, _height);    CGPathAddLineToPoint(path, nil, 0, _height);    CGPathCloseSubpath(path);    self.waveLayer.path = path;    CGMutablePathRef backPath = CGPathCreateMutableCopy(path);    self.backLayer.path = backPath;    CGPathRelease(backPath);    CGPathRelease(path);}#pragma mark -- 停止- (void)reset{    [self stopWave];    [_waveLayer removeFromSuperlayer];    _waveLayer = nil;}- (void)stopWave{    [_waveDisplaylink invalidate];    _waveDisplaylink = nil;}- (void)dealloc{    [self reset];}@end

• 3、 ViewController调用

- (void)viewDidLoad {    [super viewDidLoad];    waterWaveView = [[XYWaterWaveView alloc]initWithFrame:self.view.bounds];    waterWaveView.backgroundColor = [UIColor clearColor];    [self.view addSubview:waterWaveView];    [waterWaveView startWave];    //振幅    UILabel* label1 = [[UILabel alloc]initWithFrame:CGRectMake(0, 20, 60, 40)];    label1.text = @"振幅";    [self.view addSubview:label1];    UISlider* slider1 = [[UISlider alloc]initWithFrame:CGRectMake(40, 20, 280, 40)];    slider1.minimumValue = 20.0;    slider1.maximumValue = 40.0;    slider1.value = 30;    [slider1 addTarget:self action:@selector(slider1:) forControlEvents:UIControlEventValueChanged];    [self.view addSubview:slider1];    //周期    UILabel* label2 = [[UILabel alloc]initWithFrame:CGRectMake(0, 80, 60, 40)];    label2.text = @"周期";    [self.view addSubview:label2];    UISlider* slider2 = [[UISlider alloc]initWithFrame:CGRectMake(40, 80, 280, 40)];    slider2.minimumValue = 100.0;    slider2.maximumValue = 300.0;    slider2.value = 200;    [slider2 addTarget:self action:@selector(slider2:) forControlEvents:UIControlEventValueChanged];    [self.view addSubview:slider2];    //速度    UILabel* label3 = [[UILabel alloc]initWithFrame:CGRectMake(0, 140, 60, 40)];    label3.text = @"速度";    [self.view addSubview:label3];    UISlider* slider3 = [[UISlider alloc]initWithFrame:CGRectMake(40, 140, 280, 40)];    slider3.minimumValue = 0.1f;    slider3.maximumValue = 0.3f;    slider3.value = 0.2f;    [slider3 addTarget:self action:@selector(slider3:) forControlEvents:UIControlEventValueChanged];    [self.view addSubview:slider3];    //高度    UILabel* label4 = [[UILabel alloc]initWithFrame:CGRectMake(0, 200, 60, 40)];    label4.text = @"高度";    [self.view addSubview:label4];    UISlider* slider4 = [[UISlider alloc]initWithFrame:CGRectMake(40, 200, 280, 40)];    slider4.minimumValue = 0;    slider4.maximumValue = self.view.frame.size.height;    slider4.value = 300;    [slider4 addTarget:self action:@selector(slider4:) forControlEvents:UIControlEventValueChanged];    [self.view addSubview:slider4];}- (void)slider1:(UISlider *)slider{    waterWaveView.waveAmplitude = slider.value;}- (void)slider2:(UISlider *)slider{    waterWaveView.waveCycle = slider.value;}- (void)slider3:(UISlider *)slider{    waterWaveView.waveSpeed = slider.value;}- (void)slider4:(UISlider *)slider{    waterWaveView.waterWaveHeight = slider.value;}