IOS 绘制三角形的实例详解

 - (void)ljTestView { CGPoint piont1; piont1.x = 170; piont1.y = 100; CGPoint piont2; piont2.x = 50; piont2.y = 200; CGPoint piont3; piont3.x = 220; piont3.y = 200; ljDrawRect *_ljView = [[ljDrawRect alloc]initStartPoint:piont1 middlePoint:piont2 endPoint:piont3 color:[UIColor redColor]]; _ljView.frame = CGRectMake(0, 64, kDEVICEWIDTH, kDEVICEHEIGHT - 64); _ljView.backgroundColor = [UIColor yellowColor]; [self.view addSubview:_ljView]; } 

 #import "ljDrawRect.h" @interface ljDrawRect () { CGPoint _startPoint; CGPoint _middlePoint; CGPoint _endPoint; UIColor *_color; } @end @implementation ljDrawRect #pragma mark - #pragma mark - method - (instancetype)initStartPoint:(CGPoint)startPoint middlePoint:(CGPoint)middlePoint endPoint:(CGPoint)endPoint color:(UIColor*)color { self = [super init]; if (self) { _startPoint = startPoint; _middlePoint = middlePoint; _endPoint = endPoint; _color = color; self.backgroundColor = [UIColor clearColor]; } return self; } - (void)drawRect:(CGRect)rect { CGContextRef context = UIGraphicsGetCurrentContext(); CGContextBeginPath(context);//标记 CGContextMoveToPoint(context, _startPoint.x, _startPoint.y); CGContextAddLineToPoint(context,_middlePoint.x, _middlePoint.y); CGContextAddLineToPoint(context,_endPoint.x, _endPoint.y); CGContextClosePath(context);//路径结束标志，不写默认封闭 [_color setFill]; //设置填充色 [_color setStroke];//边框也设置为_color，否则为默认的黑色 CGContextDrawPath(context, kCGPathFillStroke);//绘制路径path } @end