ruler,尺子，刻度尺

使用

WXScrollRulerView * aview = [[WXScrollRulerView alloc] initWithFrame:CGRectMake(0, 150, self.view.bounds.size.width, 70) minValue:30 maxValue:180 initialValue:200];

aview.rulerColor = [UIColor colorWithWhite:0.0 alpha:0.5];

aview.backgroundColor = [UIColor yellowColor];

[self.view addSubview:aview];

aview.currentValueChanged = ^(float value) {   

    showLabel.text = [NSString stringWithFormat:@"%d",(int)value];
};

效果图