usagi 0.2.0

Common algorithms and utilities library for Rust
Documentation 
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#![feature(extern_prelude)]

pub mod math;
pub mod wgs84;
pub mod web_mercator;

#[cfg(test)]
#[test]
fn clamp()
{
  const MIN: i8 = -8;
  const MAX: i8 = 8;
  
  for value in 2 * MIN .. MIN
  { assert_eq!( math::clamp( value, MIN, MAX ), MIN ); }
  
  for value in MIN .. MAX
  { assert_eq!( math::clamp( value, MIN, MAX ), value ); }
  
  for value in MAX .. 2 * MAX
  { assert_eq!( math::clamp( value, MIN, MAX ), MAX ); }
}

#[cfg(test)]
#[test]
fn web_mercator()
{
  let ( lon0, lat0 ) = ( 43.062_083f64, 141.354_389f64 );
  for lod in 0 .. 20
  {
    let angle_error_tolerance = 360.0f64 / ( 1u64 << lod ) as f64 / 256.0;
    let ( px, py ) = web_mercator::angle_to_pixel( lon0, lat0, lod );
    let ( lon1, lat1 ) = web_mercator::pixel_to_angle( px, py, lod );
    assert!( lon1 - lon0 < angle_error_tolerance );
    assert!( lat1 - lat0 < angle_error_tolerance );
    
    let ( tx0, ty0 ) = web_mercator::pixel_to_tile( px, py );
    let uppers = web_mercator::to_upper_tiles( tx0, ty0 );
    for ( utx, uty ) in uppers.iter()
    {
      let ( tx1, ty1 ) = web_mercator::to_lower_tile( *utx, *uty );
      assert_eq!( tx0, tx1 );
      assert_eq!( ty0, ty1 );
    }
  }
}