CGContext画线

来源：互联网发布：mysql trigger 编辑：程序博客网时间：2024/06/07 19:30

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

[plain]
- (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]];
}

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