CGContext画线

1 前言

得到图形环境,然后用 CGContextMoveToPoint 和 CGContextAddLineToPoint 函数来画线。

2 代码实例

ZYViewControllerView.m

 

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- (void)drawRect:(CGRect)rect{ 

    [self drawRooftopAtTopPointof:CGPointMake(160.0f, 40.0f) textToDisplay:@"Miter" 

                         lineJoin:kCGLineJoinMiter]; 

    [self drawRooftopAtTopPointof:CGPointMake(160.0f, 180.0f) textToDisplay:@"Bevel" 

                         lineJoin:kCGLineJoinBevel]; 

    [self drawRooftopAtTopPointof:CGPointMake(160.0f, 320.0f) textToDisplay:@"Round" 

                        lineJoin:kCGLineJoinRound]; 

} 

/* 

 paramTopPoint:一个点,顶部在这一点 

 textToDisplay:内显示的文字 

 lineJoin:要使用的接合类型 

        kCGLineJoinMiter 

        接合点为尖角。这是默认的接合类型。 

        kCGLineJoinBevel 

        接合点为斜角 

        kCGLineJoinRound 

        接合点为圆角 

 */ 

- (void) drawRooftopAtTopPointof:(CGPoint)paramTopPoint textToDisplay:(NSString *)paramText 

                        lineJoin:(CGLineJoin)paramLineJoin{ 

    /*设置线条颜色*/ 

    [[UIColor brownColor] set]; 

    //获得当前图形上下文 

    CGContextRef currentContext = UIGraphicsGetCurrentContext(); 

    //设置连接类型 

    CGContextSetLineJoin(currentContext, paramLineJoin); 

    //设置线条宽度 

    CGContextSetLineWidth(currentContext,20.0f); 

    //设置开始点位置 

    CGContextMoveToPoint(currentContext,paramTopPoint.x - 140, paramTopPoint.y + 100); 

    //设置终点 

    CGContextAddLineToPoint(currentContext,paramTopPoint.x, paramTopPoint.y); 

    //设置另一个终点 

    CGContextAddLineToPoint(currentContext,paramTopPoint.x + 140, paramTopPoint.y + 100); 

    //画线 

    CGContextStrokePath(currentContext); 

    [[UIColor blackColor] set]; 

    /* 写文字 */ 

    CGPoint drawingPoint = CGPointMake(paramTopPoint.x - 40.0f, 

                                   paramTopPoint.y + 60.0f); 

    [paramText drawAtPoint:drawingPoint withFont:[UIFont boldSystemFontOfSize:30.0f]]; 

}