Question

我有两个角度a和b，我想计算两个角度之间的绝对差值。实例

>> absDiffDeg(360,5)
ans = 5
>> absDiffDeg(-5,5)
ans = 10
>> absDiffDeg(5,-5)
ans = 10

Answer 1

归一化差值，不需要abs运算，因为mod（x，y）取y的符号。

func scrollViewDidScroll(scrollView: UIScrollView) {
  // Work out which view is showing on the left. 0 to N-1
  // Based on each being 320 wide.
  CGFloat offset=scrollView.contentOffset.x;
  NSUInteger leftHandSideViewIndex=(NSUInteger)offset.x/320;

  // Left hand side alpha is 1 minus percentage (as a fraction) off screen
  self.coloredViews[leftHandSide].alpha = 
    1.0 - (offset - (320.0 * leftHandSideViewIndex))/320.0;

  // Right hand side alpha is 1 - percentage (as a fraction) on screen
  // Only do this if there is a right hand side.
  if (leftHandSideViewIndex < self.coloredViews.count-1){
    self.coloredViews[leftHandSide+1].alpha = 
      1.0 - ((320.0 * leftHandSizeViewIndex+1)-offset)/320.0;
  }
}

这是0-360之间的数字，但我们想要的最小角度在0-180之间。最简单的方法是

normDeg = mod(a-b,360);

Answer 2

使用角度进行数学运算时，首先将它们标准化很有用。此功能将所有角度标准化为（-180,180）范围：

 normalizeDeg=@(x)(-mod(-x+180,360)+180)

现在可以使用此函数进行标准化，可以计算绝对差值：

absDiffDeg=@(a,b)abs(normalizeDeg(normalizeDeg(a)-normalizeDeg(b)))

Answer 3

uning unwrap怎么样？这是一个尝试：

absDiffDeg = @(a,b) abs(diff(unwrap([a,b]/180*pi)*180/pi));

最佳，

计算两个角度之间的绝对差异

3 个答案: