画虚线

//画虚线

• (UIImage *)drawLineWithView:(UIImageView *)imageView lineColor:(UIColor *)lineColor {
  [imageView layoutIfNeeded];
  // 开始划线 划线的frame
  UIGraphicsBeginImageContext(imageView.frame.size);

  [imageView.image drawInRect:CGRectMake(0, 0, imageView.frame.size.width, imageView.frame.size.height)];

  // 获取上下文
  CGContextRef line = UIGraphicsGetCurrentContext();

  // 设置线条终点的形状
  CGContextSetLineCap(line, kCGLineCapRound);
  // 设置虚线的长度 和 间距
  CGFloat lengths[] = {3,3};

  CGContextSetStrokeColorWithColor(line, lineColor.CGColor);
  // 开始绘制虚线
  CGContextSetLineDash(line, 0, lengths, 2);

  CGContextMoveToPoint(line, 0.0, 2.0);

  CGContextAddLineToPoint(line, 300, 2.0);

  CGContextStrokePath(line);

  // UIGraphicsGetImageFromCurrentImageContext()返回的就是image
  return UIGraphicsGetImageFromCurrentImageContext();
  }