iOS 画一个不规则的图形

- (void)drawRect:(CGRect)rect {

CGContextRef context = UIGraphicsGetCurrentContext();

    CGContextSetLineCap(context, kCGLineCapRound);

    CGContextSetLineWidth(context, 3);  //线宽

    CGContextSetAllowsAntialiasing(context, true);

    CGContextSetRGBStrokeColor(context,70.0/255.0,241.0/255.0,241.0/255.0,1.0);  //线的颜色

    CGContextBeginPath(context);

    CGContextMoveToPoint(context, 100, 100);  //起点坐标

    CGContextAddLineToPoint(context, 100, 300);  //终点坐标

    CGContextAddLineToPoint(context, 200, 300);

    CGContextAddLineToPoint(context, 200, 160);

    CGContextAddLineToPoint(context, 230, 145);

    CGContextAddLineToPoint(context, 200, 130);

    CGContextAddLineToPoint(context, 200, 100);

    CGContextAddLineToPoint(context, 100, 100);

    CGContextClosePath(context);

    CGContextSetFillColorWithColor(context, [UIColor yellowColor].CGColor);//填充颜色

    CGContextDrawPath(context,kCGPathEOFill);//根据坐标绘制路径

}

//也可以用这种方法

- (CAShapeLayer*)creatMaskLayerWithView:(UIView*)view

{

    CGFloatviewWidth =CGRectGetWidth(view.frame);

    CGFloatviewHeight =CGRectGetHeight(view.frame);

    CGFloatrightSpace =10;

    CGFloattopSpace =15;

    CGPointpoint1 =CGPointMake(0,0);

    CGPointpoint2 =CGPointMake(viewWidth - rightSpace,0);

    CGPointpoint3 =CGPointMake(viewWidth - rightSpace, topSpace);

    CGPointpoint4 =CGPointMake(viewWidth, topSpace);

    CGPointpoint5 =CGPointMake(viewWidth - rightSpace, topSpace +10);

    CGPointpoint6 =CGPointMake(viewWidth - rightSpace, viewHeight);

    CGPointpoint7 =CGPointMake(0, viewHeight);

    UIBezierPath * path = [UIBezierPath bezierPath];

    [pathmoveToPoint:point1];

    [pathaddLineToPoint:point2];

    [pathaddLineToPoint:point3];

    [pathaddLineToPoint:point4];

    [pathaddLineToPoint:point5];

    [pathaddLineToPoint:point6];

    [pathaddLineToPoint:point7];

    [pathclosePath];

    CAShapeLayer * layer = [CAShapeLayer layer];

    layer.path= path.CGPath;

    returnlayer;

}

这样调用

  UIView * view = [[UIView alloc] initWithFrame:CGRectMake(40, 50, 80, 100)];

    view.backgroundColor = [UIColor orangeColor];

    [self.view addSubview:view];

    view.layer.mask = [self creatMaskLayerWithView:view];