ios 绘制三角形

先上效果图

上面三角形的代码

- (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];
}

画三角形的类

#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