IOS BezierPath 贝塞尔曲线画图详解

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//UIColor *blueColor=[UIColor redColor];

// 画一个矩形

// UIBezierPath *pathRect=[UIBezierPath bezierPathWithRect:CGRectMake(20, 30, 200, 300)];

// UIColor *redColor=[UIColor redColor];

// [redColor set];

// [pathRect stroke];

// 在矩形里面画一个椭圆

// UIBezierPath *pathOval=[UIBezierPath bezierPathWithOvalInRect:CGRectMake(20, 30, 200, 300)];

// [blueColor set];

// [pathOval stroke];

// 画一个圆角矩形

//UIBezierPath *pathRoundCorner=[UIBezierPath bezierPathWithRoundedRect:CGRectMake(20, 30, 200, 300) cornerRadius:5];

// [blueColor set];

// [pathRoundCorner stroke];

// 一个矩形选择其实的几个角是圆角的

// UIBezierPath *pathRoundCorners=[UIBezierPath bezierPathWithRoundedRect:CGRectMake(20, 30, 200, 300) byRoundingCorners:UIRectCornerTopLeft cornerRadii:CGSizeMake(10, 20)];

// [blueColor set];

// [pathRoundCorners stroke];

//画圆弧 0°是水平开始的

// UIBezierPath *pathArc=[UIBezierPath bezierPathWithArcCenter:CGPointMake(150, 300) radius:100 startAngle:0 endAngle:M_PI*2 clockwise:YES];

// [blueColor set];

// [pathArc stroke];

// + (instancetype)bezierPathWithCGPath:(CGPathRef)CGPath; 这个功能没弄明白

//在不同的点之间连线

// UIBezierPath *path=[[UIBezierPath alloc]init];

// path.lineWidth=5;

// path.lineCapStyle=kCGLineCapButt;

// path.lineJoinStyle=kCGLineJoinBevel;

// [path moveToPoint:CGPointMake(20, 20)];

// [path addLineToPoint:CGPointMake(80, 80)];

// [path addLineToPoint:CGPointMake(20, 160)];

// [path closePath];

// [blueColor set];

// [path stroke];

// 三次贝塞尔曲线

// UIBezierPath *path=[[UIBezierPath alloc]init];

// path.lineWidth=5;

// path.lineJoinStyle=kCGLineJoinRound;

// path.lineCapStyle=kCGLineCapButt;

// [path moveToPoint:CGPointMake(20, 100)];

// [path addCurveToPoint:CGPointMake(240, 80) controlPoint1:CGPointMake(80, 40) controlPoint2:CGPointMake(160, 160)];

// [blueColor set];

// [path stroke];

// UIBezierPath *path=[[UIBezierPath alloc]init];

// [path moveToPoint:CGPointMake(20, 100)];

// [path addQuadCurveToPoint:CGPointMake(120, 120) controlPoint:CGPointMake(60, 40)];

// [blueColor set];

// [path stroke];

// UIBezierPath *path=[[UIBezierPath alloc]init];

// //path.flatness=80;

// [path addArcWithCenter:CGPointMake(100, 100) radius:80 startAngle:0 endAngle:M_PI*2 clockwise:YES];

// path.usesEvenOddFillRule=YES;

// [blueColor set];

// [path stroke];

//画虚线

UIBezierPath *path=[[UIBezierPathalloc]init];

[path moveToPoint:CGPointMake(20,100)];

[path addLineToPoint:CGPointMake(180,100)];

CGFloat lengths[] = {20,10,5};

//这是一个C 数组意思就是先画20个像素长度的线段然后空10个像素长度然后再画5个像素长度的线段反复循环下去。

[pathsetLineDash:lengthscount:3 phase:0];

//这里的phase是指位移如果phase的参数是6 那么首先就是画（20-6）个像素长度的线段。

[[UIColorredColor]set];

[pathstroke];

以上贝塞尔曲线需要在view的函数-(void)drawRect:(CGRect)rect里面执行但是也可以在view controller定义CAShapeLayer把画的曲线展现出来。

CAShapeLayer *layer = [[CAShapeLayer alloc]init];

layer.frame=CGRectMake(0, 0, 200, 400);

[self.view.layer addSublayer:layer];

UIBezierPath *bezierPath = [UIBezierPath bezierPath];

UIBezierPath *outerCircle = [UIBezierPath bezierPathWithOvalInRect:CGRectInset(CGRectMake(0, 0, 150, 200), 4, 4)];

[outerCircle setLineWidth:2.0];

[bezierPath appendPath:outerCircle];

UIBezierPath *innerCircle = [UIBezierPath bezierPathWithOvalInRect:CGRectInset(CGRectMake(50, 20, 150, 200), 20, 20)];

[innerCircle setLineWidth:2.0];

[bezierPath appendPath:innerCircle];

bezierPath.usesEvenOddFillRule = YES;

layer.path = bezierPath.CGPath;

layer.fillColor = [UIColor orangeColor].CGColor;

layer.strokeColor = [UIColor redColor].CGColor;

另外函数

- (void)fillWithBlendMode:(CGBlendMode)blendMode alpha:(CGFloat)alpha;

- (void)strokeWithBlendMode:(CGBlendMode)blendMode alpha:(CGFloat)alpha;

可以改变所画出图片的透明度但是不改变当前画布的透明度

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