绘制移动正弦波抗锯齿

Question

我要绘制在一个清晰和消除锯齿方式可变频率和可变幅度的移动正弦波。这怎么可能？

Answer 1

好，我实现正弦波入的UIView的drawRect方法如下：

float x=75; 
float yc=50; 
float w=0; 
    while (w<=rect.frame.size.width) { 
    CGPathMoveToPoint(path, nil, w,y/2); 
    CGPathAddQuadCurveToPoint(path, nil, w+x/4, -yc,w+ x/2, y/2); 
    CGPathMoveToPoint(path, nil, w+x/2,y/2); 
    CGPathAddQuadCurveToPoint(path, nil, w+3*x/4, y+yc, w+x, y/2); 
    CGContextAddPath(context, path); 
    CGContextDrawPath(context, kCGPathStroke); 
    w+=x; 
    } 

在此，x是每个正弦波的宽度，而y是所述框架的高度。这将绘制数量的正弦波以适应整个UIViewFrame。它会产生清脆的正弦波，并且yc是控制手柄。尝试一下，你可能会喜欢它。

如果宽度ie。 x与框架的宽度相似，则会产生单个正弦波。完整的正弦波的

数=（帧的宽度）/（“x”的每个正弦波的宽度）

Answer 2

制成的GeneratorOfOne的版本更完整，并迅速版本。这一个也用选定的颜色填充波浪的底部：

class WaveView: UIView { 

    private var maskPath: UIBezierPath! 
    @IBInspectable var fillColor: UIColor = UIColor.blueColor() 
    @IBInspectable var cycles: CGFloat = 7 

    override func drawRect(rect: CGRect) { 

     var w: CGFloat = 0    // Starting position 
     let width = rect.width 
     let y: CGFloat = rect.height 
     let yc: CGFloat = rect.height/2 
     let x = width/cycles 

     let context = UIGraphicsGetCurrentContext(); 
     CGContextSetFillColorWithColor(context, UIColor.greenColor().CGColor); 
     let path = CGPathCreateMutable(); 

     CGPathMoveToPoint(path, nil, 0, 0) 

     while (w<=rect.width) { 
      CGPathMoveToPoint(path, nil, w,y/2); 
      CGPathAddQuadCurveToPoint(path, nil, w+x/4, -yc, (w+x/2), y/2); 
      CGPathMoveToPoint(path, nil, w+x/2,y/2); 
      CGPathAddQuadCurveToPoint(path, nil, w+3*x/4, y+yc, w+x, y/2); 
      w+=x; 
     } 

     CGPathAddLineToPoint(path, nil, rect.width, rect.height) 
     CGPathAddLineToPoint(path, nil, 0, rect.height) 
     CGPathAddLineToPoint(path, nil, 0, y/2); 
     CGPathCloseSubpath(path) 

     maskPath = UIBezierPath(CGPath: path) 
     maskPath.lineCapStyle = CGLineCap.Square 
     maskPath.lineJoinStyle = CGLineJoin.Miter 

     CGContextAddPath(context, path); 
     CGContextSetFillColorWithColor(context, fillColor.CGColor) 
     CGContextFillPath(context) 
    } 

}