QQ20170816-103932.gif
整体思路
1.创建路径（path），使用正弦函数计算一点坐标（x，y），将所有的点连接成线，绘画出路径。
2.创建CAShapeLayer图层，根据路径绘画出波形效果。
3.使用CADispalyLink定时器，改变路径，做出动画效果。
代码说明
效果的实现主要是路径的绘制。理解正弦和余弦函数最为关键。可以参考iOS水波纹动画详解
代码来源iOS 水波表现进度的动画效果实现以及demo
注意问题
需要注意的问题ios坐标系x左边是正方向，y下边是正方向。绘画出的路径需要填充的区域如图所示：
屏幕快照 2017-08-16 上午11.29.58.png
单个波形，有渐变效果
//
// YSWaterWaveView.m
// Wave
//
// Created by moshuqi on 16/1/7.
// Copyright © 2016年 msq. All rights reserved.
//
#import "YSWaterWaveView.h"
@interface YSWaterWaveView ()
@property (nonatomic, strong) CADisplayLink *displayLink;
@property (nonatomic, strong) CAShapeLayer *waveLayer; // 绘制波形
@property (nonatomic, strong) CAGradientLayer *gradientLayer; // 绘制渐变
@property (nonatomic, strong) NSArray *colors; // 渐变的颜色数组
@property (nonatomic, assign) CGFloat percent; // 波浪上升的比例
// 绘制波形的变量定义，使用波形曲线y=Asin(ωx+φ)+k进行绘制
@property (nonatomic, assign) CGFloat waveAmplitude; // 波纹振幅，A
@property (nonatomic, assign) CGFloat waveCycle; // 波纹周期，T = 2π/ω
@property (nonatomic, assign) CGFloat offsetX; // 波浪x位移，φ
@property (nonatomic, assign) CGFloat waveSpeed; // 波纹速度，用来累加到相位φ上，达到波纹水平移动的效果
@property (nonatomic, assign) CGFloat currentWavePointY; // 当前波浪高度，k
@property (nonatomic, assign) CGFloat waveGrowth; // 波纹上升速度，累加到k上，达到波浪高度上升的效果
@property (nonatomic, assign) BOOL bWaveFinished; // 上升完成
// 用来计算波峰一定范围内的波动值
@property (nonatomic, assign) BOOL increase;
@property (nonatomic, assign) CGFloat variable;
@end
@implementation YSWaterWaveView
static const CGFloat kExtraHeight = 20; // 保证水波波峰不被裁剪，增加部分额外的高度
- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self)
{
[self defaultConfig];
self.backgroundColor = [UIColor colorWithRed:4 / 255.0 green:181 / 255.0 blue:108 / 255.0 alpha:1];
}
return self;
}
- (void)setGrowthSpeed:(CGFloat)growthSpeed
{
self.waveGrowth = growthSpeed;
}
- (void)setGradientColors:(NSArray *)colors
{
// 必须保证传进来的参数为UIColor*的数组
NSMutableArray *array = [NSMutableArray array];
for (UIColor *color in colors)
{
[array addObject:(__bridge id)color.CGColor];
}
self.colors = array;
}
- (void)setColorsWithArray:(NSArray *)colors
{
self.colors = colors;
}
- (void)defaultConfig
{
// 默认设置一些属性
self.waveCycle = 1.66 * M_PI / CGRectGetWidth(self.frame); // 影响波长
self.currentWavePointY = CGRectGetHeight(self.frame) * self.percent; // 波纹从下往上升起
self.waveGrowth = 1.0;
self.waveSpeed = 0.4 / M_PI;
self.offsetX = 0;
}
- (void)resetProperty
{
// 重置属性
self.currentWavePointY = CGRectGetHeight(self.frame) * self.percent;
self.offsetX = 0;
self.variable = 1.6;
self.increase = NO;
}
- (void)resetLayer
{
// 动画开始之前重置layer
if (self.waveLayer)
{
[self.waveLayer removeFromSuperlayer];
self.waveLayer = nil;
}
self.waveLayer = [CAShapeLayer layer];
// 设置渐变
if (self.gradientLayer)
{
[self.gradientLayer removeFromSuperlayer];
self.gradientLayer = nil;
}
self.gradientLayer = [CAGradientLayer layer];
self.gradientLayer.frame = [self gradientLayerFrame];
[self setupGradientColor];
[self.gradientLayer setMask:self.waveLayer];
[self.layer addSublayer:self.gradientLayer];
}
- (void)setupGradientColor
{
// gradientLayer设置渐变色
if ([self.colors count] < 1)
{
self.colors = [self defaultColors];
}
self.gradientLayer.colors = self.colors;
//设定颜色分割点
NSInteger count = [self.colors count];
CGFloat d = 1.0 / count;
NSMutableArray *locations = [NSMutableArray array];
for (NSInteger i = 0; i < count; i++)
{
NSNumber *num = @(d + d * i);
[locations addObject:num];
}
NSNumber *lastNum = @(1.0f);
[locations addObject:lastNum];
self.gradientLayer.locations = locations;
// 设置渐变方向，从上往下
self.gradientLayer.startPoint = CGPointMake(0, 0);
self.gradientLayer.endPoint = CGPointMake(0, 1);
}
- (CGRect)gradientLayerFrame
{
// gradientLayer在上升完成之后的frame值，如果gradientLayer在上升过程中不断变化frame值会导致一开始绘制卡顿，所以只进行一次赋值
CGFloat gradientLayerHeight = CGRectGetHeight(self.frame) * self.percent + kExtraHeight;
if (gradientLayerHeight > CGRectGetHeight(self.frame))
{
gradientLayerHeight = CGRectGetHeight(self.frame);
}
CGRect frame = CGRectMake(0, CGRectGetHeight(self.frame) - gradientLayerHeight, CGRectGetWidth(self.frame), gradientLayerHeight);
return frame;
}
- (NSArray *)defaultColors
{
// 默认的渐变色
UIColor *color0 = [UIColor colorWithRed:164 / 255.0 green:216 / 255.0 blue:222 / 255.0 alpha:1];
UIColor *color1 = [UIColor colorWithRed:105 / 255.0 green:192 / 255.0 blue:154 / 255.0 alpha:1];
NSArray *colors = @[(__bridge id)color0.CGColor, (__bridge id)color1.CGColor];
return colors;
}
- (void)startWaveToPercent:(CGFloat)percent
{
self.percent = percent;
[self resetProperty];
[self resetLayer];
if (self.displayLink)
{
[self.displayLink invalidate];
self.displayLink = nil;
}
self.bWaveFinished = NO;
// 启动同步渲染绘制波纹
self.displayLink = [CADisplayLink displayLinkWithTarget:self selector:@selector(setCurrentWave:)];
[self.displayLink addToRunLoop:[NSRunLoop mainRunLoop] forMode:NSRunLoopCommonModes];
}
- (void)stopWave
{
[self.displayLink invalidate];
self.displayLink = nil;
}
- (void)setCurrentWave:(CADisplayLink *)displayLink
{
if ([self waveFinished])
{
self.bWaveFinished = YES;
[self amplitudeReduce];
// 减小到0之后动画停止。
NSLog(@"完成amplitude = %lf",self.waveAmplitude);
if (self.waveAmplitude <= 0)
{
[self stopWave];
return;
}
}
else
{
// 波浪高度未到指定高度 继续上涨
[self amplitudeChanged];
self.currentWavePointY -= self.waveGrowth;
}
self.offsetX += self.waveSpeed;
[self setCurrentWaveLayerPath];
}
- (BOOL)waveFinished
{
// 波浪上升动画是否完成
CGFloat d = CGRectGetHeight(self.frame) - CGRectGetHeight(self.gradientLayer.frame);
CGFloat extraH = MIN(d, kExtraHeight);
BOOL bFinished = self.currentWavePointY <= extraH;
return bFinished;
}
- (void)setCurrentWaveLayerPath
{
// 通过正弦曲线来绘制波浪形状
CGMutablePathRef path = CGPathCreateMutable();
CGFloat y = self.currentWavePointY;
CGPathMoveToPoint(path, nil, 0, y);
CGFloat width = CGRectGetWidth(self.frame);
NSLog(@"k == %lf",self.currentWavePointY);
for (float x = 0.0f; x <= width; x++)
{
// 正弦波浪公式
y = self.waveAmplitude * sin(self.waveCycle * x + self.offsetX) + self.currentWavePointY;
//坐标系决定的 x和y的正方向向下。
CGPathAddLineToPoint(path, nil, x, y);
}
//path 路径封好
CGPathAddLineToPoint(path, nil, width, CGRectGetHeight(self.frame));
CGPathAddLineToPoint(path, nil, 0, CGRectGetHeight(self.frame));
CGPathCloseSubpath(path);
self.waveLayer.path = path;
CGPathRelease(path);
}
- (void)amplitudeChanged
{
// 波峰在一定范围之内进行轻微波动
// 波峰该继续增大或减小
if (self.increase)
{
self.variable += 0.01;
}
else
{
self.variable -= 0.01;
}
// 变化的范围
if (self.variable <= 1)
{
self.increase = YES;
}
if (self.variable >= 1.6)
{
self.increase = NO;
}
NSLog(@"variable = %lf",self.variable);
// 根据variable值来决定波峰
self.waveAmplitude = self.variable * 5;
NSLog(@"amplitude = %lf",self.waveAmplitude);
}
- (void)amplitudeReduce
{
// 波浪上升完成后，波峰开始逐渐降低
self.waveAmplitude -= 0.066;
}
@end
单个波形，无渐变效果
//
// YSWaterWaveView.m
// Wave
//
// Created by moshuqi on 16/1/7.
// Copyright © 2016年 msq. All rights reserved.
//
#import "YSWaterWaveView.h"
@interface YSWaterWaveView ()
@property (nonatomic, strong) CADisplayLink *displayLink;
@property (nonatomic, strong) CAShapeLayer *waveLayer; // 绘制波形
@property (nonatomic, strong) CAShapeLayer *waveLayerCos; // 绘制余弦波形
@property (nonatomic, strong) CAGradientLayer *gradientLayer; // 绘制渐变
@property (nonatomic, strong) NSArray *colors; // 渐变的颜色数组
@property (nonatomic, assign) CGFloat percent; // 波浪上升的比例
// 绘制波形的变量定义，使用波形曲线y=Asin(ωx+φ)+k进行绘制
@property (nonatomic, assign) CGFloat waveAmplitude; // 波纹振幅，A
@property (nonatomic, assign) CGFloat waveCycle; // 波纹周期，T = 2π/ω
@property (nonatomic, assign) CGFloat offsetX; // 波浪x位移，φ
@property (nonatomic, assign) CGFloat waveSpeed; // 波纹速度，用来累加到相位φ上，达到波纹水平移动的效果
@property (nonatomic, assign) CGFloat currentWavePointY; // 当前波浪高度，k
@property (nonatomic, assign) CGFloat waveGrowth; // 波纹上升速度，累加到k上，达到波浪高度上升的效果
@property (nonatomic, assign) BOOL bWaveFinished; // 上升完成
// 用来计算波峰一定范围内的波动值
@property (nonatomic, assign) BOOL increase;
@property (nonatomic, assign) CGFloat variable;
@end
@implementation YSWaterWaveView
static const CGFloat kExtraHeight = 20; // 保证水波波峰不被裁剪，增加部分额外的高度
- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self)
{
[self defaultConfig];
self.backgroundColor = [UIColor colorWithRed:4 / 255.0 green:181 / 255.0 blue:108 / 255.0 alpha:1];
}
return self;
}
- (void)setGrowthSpeed:(CGFloat)growthSpeed
{
self.waveGrowth = growthSpeed;
}
- (void)setGradientColors:(NSArray *)colors
{
// 必须保证传进来的参数为UIColor*的数组
NSMutableArray *array = [NSMutableArray array];
for (UIColor *color in colors)
{
[array addObject:(__bridge id)color.CGColor];
}
self.colors = array;
}
- (void)setColorsWithArray:(NSArray *)colors
{
self.colors = colors;
}
- (void)defaultConfig
{
// 默认设置一些属性
self.waveCycle = 1.66 * M_PI / CGRectGetWidth(self.frame); // 影响波长
self.currentWavePointY = CGRectGetHeight(self.frame) * self.percent; // 波纹从下往上升起
self.waveGrowth = 1.0;
self.waveSpeed = 0.4 / M_PI;
self.offsetX = 0;
}
- (void)resetProperty
{
// 重置属性
self.currentWavePointY = CGRectGetHeight(self.frame);
self.offsetX = 0;
self.variable = 1.6;
self.increase = NO;
}
- (void)resetLayer
{
// 动画开始之前重置layer
if (self.waveLayer)
{
[self.waveLayer removeFromSuperlayer];
self.waveLayer = nil;
}
self.waveLayer = [CAShapeLayer layer];
self.waveLayer.frame = CGRectMake(0, 0, self.frame.size.width, self.frame.size.width);
self.waveLayer.backgroundColor = [UIColor orangeColor].CGColor;
[self.layer addSublayer:self.waveLayer];
}
- (void)startWaveToPercent:(CGFloat)percent
{
self.percent = percent;
[self resetProperty];
[self resetLayer];
if (self.displayLink)
{
[self.displayLink invalidate];
self.displayLink = nil;
}
self.bWaveFinished = NO;
// 启动同步渲染绘制波纹
self.displayLink = [CADisplayLink displayLinkWithTarget:self selector:@selector(setCurrentWave:)];
[self.displayLink addToRunLoop:[NSRunLoop mainRunLoop] forMode:NSRunLoopCommonModes];
}
- (void)stopWave
{
[self.displayLink invalidate];
self.displayLink = nil;
}
- (void)setCurrentWave:(CADisplayLink *)displayLink
{
if ([self waveFinished])
{
self.bWaveFinished = YES;
[self amplitudeReduce];
// 减小到0之后动画停止。
NSLog(@"完成amplitude = %lf",self.waveAmplitude);
if (self.waveAmplitude <= 0)
{
[self stopWave];
return;
}
}
else
{
// 波浪高度未到指定高度 继续上涨
[self amplitudeChanged];
self.currentWavePointY -= self.waveGrowth;
}
self.offsetX += self.waveSpeed;
[self setCurrentWaveLayerPath];
}
- (BOOL)waveFinished
{
// 波浪上升动画是否完成
CGFloat d = CGRectGetHeight(self.frame) - CGRectGetHeight(self.waveLayer.frame)*self.percent;
BOOL bFinished = self.currentWavePointY <= d;
return bFinished;
}
- (void)setCurrentWaveLayerPath
{
// 通过正弦曲线来绘制波浪形状
CGMutablePathRef path = CGPathCreateMutable();
CGFloat y = self.currentWavePointY;
CGPathMoveToPoint(path, nil, 0, y);
CGFloat width = CGRectGetWidth(self.frame);
NSLog(@"k == %lf",self.currentWavePointY);
for (float x = 0.0f; x <= width; x++)
{
// 正弦波浪公式
y = self.waveAmplitude * sin(self.waveCycle * x + self.offsetX) + self.currentWavePointY;
//坐标系决定的 x和y的正方向向下。
CGPathAddLineToPoint(path, nil, x, y);
}
//path 路径封好
CGPathAddLineToPoint(path, nil, width, CGRectGetHeight(self.frame));
CGPathAddLineToPoint(path, nil, 0, CGRectGetHeight(self.frame));
CGPathCloseSubpath(path);
self.waveLayer.path = path;
self.waveLayer.fillColor = [UIColor cyanColor].CGColor;
CGPathRelease(path);
}
- (void)amplitudeChanged
{
// 波峰在一定范围之内进行轻微波动
// 波峰该继续增大或减小
if (self.increase)
{
self.variable += 0.01;
}
else
{
self.variable -= 0.01;
}
// 变化的范围
if (self.variable <= 1)
{
self.increase = YES;
}
if (self.variable >= 1.6)
{
self.increase = NO;
}
NSLog(@"variable = %lf",self.variable);
// 根据variable值来决定波峰
self.waveAmplitude = self.variable * 5;
NSLog(@"amplitude = %lf",self.waveAmplitude);
}
- (void)amplitudeReduce
{
// 波浪上升完成后，波峰开始逐渐降低
self.waveAmplitude -= 0.066;
}
@end
双波形，无渐变效果
//
// YSWaterWaveView.m
// Wave
//
// Created by moshuqi on 16/1/7.
// Copyright © 2016年 msq. All rights reserved.
//
#import "YSWaterWaveView.h"
@interface YSWaterWaveView ()
@property (nonatomic, strong) CADisplayLink *displayLink;
@property (nonatomic, strong) CAShapeLayer *waveLayer; // 绘制波形
@property (nonatomic, strong) CAShapeLayer *waveLayerCos; // 绘制余弦波形
@property (nonatomic, strong) CAGradientLayer *gradientLayer; // 绘制渐变
@property (nonatomic, strong) NSArray *colors; // 渐变的颜色数组
@property (nonatomic, assign) CGFloat percent; // 波浪上升的比例
// 绘制波形的变量定义，使用波形曲线y=Asin(ωx+φ)+k进行绘制
@property (nonatomic, assign) CGFloat waveAmplitude; // 波纹振幅，A
@property (nonatomic, assign) CGFloat waveCycle; // 波纹周期，T = 2π/ω
@property (nonatomic, assign) CGFloat offsetX; // 波浪x位移，φ
@property (nonatomic, assign) CGFloat waveSpeed; // 波纹速度，用来累加到相位φ上，达到波纹水平移动的效果
@property (nonatomic, assign) CGFloat currentWavePointY; // 当前波浪高度，k
@property (nonatomic, assign) CGFloat waveGrowth; // 波纹上升速度，累加到k上，达到波浪高度上升的效果
@property (nonatomic, assign) BOOL bWaveFinished; // 上升完成
// 用来计算波峰一定范围内的波动值
@property (nonatomic, assign) BOOL increase;
@property (nonatomic, assign) CGFloat variable;
@end
@implementation YSWaterWaveView
static const CGFloat kExtraHeight = 20; // 保证水波波峰不被裁剪，增加部分额外的高度
- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];
if (self)
{
[self defaultConfig];
self.backgroundColor = [UIColor colorWithRed:4 / 255.0 green:181 / 255.0 blue:108 / 255.0 alpha:1];
}
return self;
}
- (void)setGrowthSpeed:(CGFloat)growthSpeed
{
self.waveGrowth = growthSpeed;
}
- (void)setGradientColors:(NSArray *)colors
{
// 必须保证传进来的参数为UIColor*的数组
NSMutableArray *array = [NSMutableArray array];
for (UIColor *color in colors)
{
[array addObject:(__bridge id)color.CGColor];
}
self.colors = array;
}
- (void)setColorsWithArray:(NSArray *)colors
{
self.colors = colors;
}
- (void)defaultConfig
{
// 默认设置一些属性
self.waveCycle = 1.66 * M_PI / CGRectGetWidth(self.frame); // 影响波长
self.currentWavePointY = CGRectGetHeight(self.frame) * self.percent; // 波纹从下往上升起
self.waveGrowth = 1.0;
self.waveSpeed = 0.4 / M_PI;
self.offsetX = 0;
}
- (void)resetProperty
{
// 重置属性
self.currentWavePointY = CGRectGetHeight(self.frame);
self.offsetX = 0;
self.variable = 1.6;
self.increase = NO;
}
- (void)resetLayer
{
// 动画开始之前重置layer
if (self.waveLayer)
{
[self.waveLayer removeFromSuperlayer];
self.waveLayer = nil;
}
self.waveLayer = [CAShapeLayer layer];
self.waveLayer.frame = CGRectMake(0, 0, self.frame.size.width, self.frame.size.width);
self.waveLayer.backgroundColor = [UIColor orangeColor].CGColor;
self.waveLayer.fillColor = [[UIColor cyanColor] colorWithAlphaComponent:0.3f].CGColor;
[self.layer addSublayer:self.waveLayer];
if (self.waveLayerCos)
{
[self.waveLayerCos removeFromSuperlayer];
self.waveLayerCos = nil;
}
self.waveLayerCos = [CAShapeLayer layer];
self.waveLayerCos.frame = CGRectMake(0, 0, self.frame.size.width, self.frame.size.width);
self.waveLayerCos.backgroundColor = [UIColor clearColor].CGColor;
self.waveLayerCos.fillColor = [[UIColor cyanColor] colorWithAlphaComponent:0.3f].CGColor;
// self.waveLayerCos.opacity = 0.5;
[self.layer addSublayer:self.waveLayerCos];
}
- (void)startWaveToPercent:(CGFloat)percent
{
self.percent = percent;
[self resetProperty];
[self resetLayer];
if (self.displayLink)
{
[self.displayLink invalidate];
self.displayLink = nil;
}
self.bWaveFinished = NO;
// 启动同步渲染绘制波纹
self.displayLink = [CADisplayLink displayLinkWithTarget:self selector:@selector(setCurrentWave:)];
[self.displayLink addToRunLoop:[NSRunLoop mainRunLoop] forMode:NSRunLoopCommonModes];
}
- (void)stopWave
{
[self.displayLink invalidate];
self.displayLink = nil;
}
- (void)setCurrentWave:(CADisplayLink *)displayLink
{
if ([self waveFinished])
{
self.bWaveFinished = YES;
[self amplitudeReduce];
// 减小到0之后动画停止。
NSLog(@"完成amplitude = %lf",self.waveAmplitude);
if (self.waveAmplitude <= 0)
{
[self stopWave];
return;
}
}
else
{
// 波浪高度未到指定高度 继续上涨
[self amplitudeChanged];
self.currentWavePointY -= self.waveGrowth;
}
self.offsetX += self.waveSpeed;
[self setCurrentWaveLayerPath];
}
- (BOOL)waveFinished
{
// 波浪上升动画是否完成
CGFloat d = CGRectGetHeight(self.frame) - CGRectGetHeight(self.waveLayer.frame)*self.percent;
BOOL bFinished = self.currentWavePointY <= d;
return bFinished;
}
- (void)setCurrentWaveLayerPath
{
// 通过正弦曲线来绘制波浪形状
CGMutablePathRef path = CGPathCreateMutable();
CGFloat y = self.currentWavePointY;
CGPathMoveToPoint(path, nil, 0, y);
CGFloat width = CGRectGetWidth(self.frame);
NSLog(@"k == %lf",self.currentWavePointY);
for (float x = 0.0f; x <= width; x++)
{
// 正弦波浪公式
y = self.waveAmplitude * sin(self.waveCycle * x + self.offsetX) + self.currentWavePointY;
//坐标系决定的 x和y的正方向向下。
CGPathAddLineToPoint(path, nil, x, y);
}
//path 路径封好
CGPathAddLineToPoint(path, nil, width, CGRectGetHeight(self.frame));
CGPathAddLineToPoint(path, nil, 0, CGRectGetHeight(self.frame));
CGPathCloseSubpath(path);
self.waveLayer.path = path;
CGPathRelease(path);
CGMutablePathRef pathCos = CGPathCreateMutable();
CGPathMoveToPoint(pathCos, nil, 0, y);
for (float x = 0.0f; x <= width; x++)
{
// 正弦波浪公式
y = self.waveAmplitude * cos(self.waveCycle * x + self.offsetX) + self.currentWavePointY;
//坐标系决定的 x和y的正方向向下。
CGPathAddLineToPoint(pathCos, nil, x, y);
}
//path 路径封好
CGPathAddLineToPoint(pathCos, nil, width, CGRectGetHeight(self.frame));
CGPathAddLineToPoint(pathCos, nil, 0, CGRectGetHeight(self.frame));
CGPathCloseSubpath(pathCos);
self.waveLayerCos.path = pathCos;
CGPathRelease(pathCos);
}
- (void)amplitudeChanged
{
// 波峰在一定范围之内进行轻微波动
// 波峰该继续增大或减小
if (self.increase)
{
self.variable += 0.01;
}
else
{
self.variable -= 0.01;
}
// 变化的范围
if (self.variable <= 1)
{
self.increase = YES;
}
if (self.variable >= 1.6)
{
self.increase = NO;
}
NSLog(@"variable = %lf",self.variable);
// 根据variable值来决定波峰
self.waveAmplitude = self.variable * 5;
NSLog(@"amplitude = %lf",self.waveAmplitude);
}
- (void)amplitudeReduce
{
// 波浪上升完成后，波峰开始逐渐降低
self.waveAmplitude -= 0.066;
}
@end
头文件
//
// YSWaterWaveView.h
// Wave
//
// Created by moshuqi on 16/1/7.
// Copyright © 2016年 msq. All rights reserved.
//
#import <UIKit/UIKit.h>
@interface YSWaterWaveView : UIView
- (void)startWaveToPercent:(CGFloat)percent;
- (void)setGrowthSpeed:(CGFloat)growthSpeed; // 设置上升速度
- (void)setGradientColors:(NSArray *)colors; // 设置渐变色
@end
调用方法
CGFloat d = 160;
CGRect rect = CGRectMake(0, 0, d, d);
YSWaterWaveView *waterWaveView = [[YSWaterWaveView alloc] initWithFrame:rect];
waterWaveView.center = self.view.center;
waterWaveView.layer.cornerRadius = d / 2;
waterWaveView.clipsToBounds = YES;
[self.view addSubview:waterWaveView];
[waterWaveView startWaveToPercent:0.8];
正弦型函数解析式：y=Asin（ωx+φ）+k在本文中的使用
*A：振幅，振幅决定了波纹起伏的大小，是一个一直变化的值，而且当波纹达到想要的高度后振幅会逐渐减小至零，当振幅小于零时，波纹已经成一条直线，在这里需要将定时器关闭。代码中使用两个变量（self.increase和self.variable）改变振幅的大小。
*w：角速度，和波长有关系，其他情况不变的情况下，角速度越大，单个波长的周
期（T = 2 *M_PI/W）越短，波长越短。代码中角速度（self.waveCycle）是一个定值。
*x：点在x方向的位置。
*φ：初相位，代码中使用self.offsetX来表示，通过self.waveSpeed改变self.offsetX大小。
*k：正弦函数在坐标系Y上的偏移量，想要达到的高度由它来控制，因为Y坐标正方向向下，所以代码中控制它的变量（self.currentWavePointY）是递减的，递减变量用self.waveGrowth控制。
