     1
     2
     3
     4
     5
     6
     7
     8
     9
    10
    11
    12
    13
    14
    15
    16
    17
    18
    19
    20
    21
    22
    23
    24
    25
    26
    27
    28
    29
    30
    31
    32
    33
    34
    35
    36
    37
    38
    39
    40
    41
    42
    43
    44
    45
    46
    47
    48
    49
    50
    51
    52
    53
    54
    55
    56
    57
    58
    59
    60
    61
    62
    63
    64
    65
    66
    67
    68
    69
    70
    71
    72
    73
    74

    //! A simple octant struct for transforming line points.

    use Point;
    use std::ops::{Neg, Sub};
    use num_traits::Zero;

    /// A simple octant struct for transforming line points.
    pub struct Octant {
        value: u8,
    }

    impl Octant {
        #[inline]
        /// Get the relevant octant from a start and end point.
        pub fn new<T>(start: Point<T>, end: Point<T>) -> Self
        where
            T: Sub<Output = T> + Neg<Output = T> + PartialOrd + Zero,
        {
            let mut value = 0;
            let mut dx = end.0 - start.0;
            let mut dy = end.1 - start.1;

            if dy < T::zero() {
                dx = -dx;
                dy = -dy;
                value += 4;
            }

            if dx < T::zero() {
                let tmp = dx;
                dx = dy;
                dy = -tmp;
                value += 2
            }

            if dx < dy {
                value += 1
            }

            Self { value }
        }

        /// Convert a point to its position in the octant.
        #[inline]
        pub fn to<T: Neg<Output = T>>(&self, point: Point<T>) -> Point<T> {
            match self.value {
                0 => (point.0, point.1),
                1 => (point.1, point.0),
                2 => (point.1, -point.0),
                3 => (-point.0, point.1),
                4 => (-point.0, -point.1),
                5 => (-point.1, -point.0),
                6 => (-point.1, point.0),
                7 => (point.0, -point.1),
                _ => unreachable!(),
            }
        }

        /// Convert a point from its position in the octant.
        #[inline]
        pub fn from<T: Neg<Output = T>>(&self, point: Point<T>) -> Point<T> {
            match self.value {
                0 => (point.0, point.1),
                1 => (point.1, point.0),
                2 => (-point.1, point.0),
                3 => (-point.0, point.1),
                4 => (-point.0, -point.1),
                5 => (-point.1, -point.0),
                6 => (point.1, -point.0),
                7 => (point.0, -point.1),
                _ => unreachable!(),
            }
        }
    }

# Help

## Keyboard Shortcuts

`?`
  Show this help dialog
`S`
  Focus the search field
`↑`
  Move up in search results
`↓`
  Move down in search results
`↹`
  Switch tab
`⏎`
  Go to active search result
`+`
  Expand all sections
`-`
  Collapse all sections

## Search Tricks

Prefix searches with a type followed by a colon (e.g., `fn:`) to restrict the search to a given type.

Accepted types are: `fn`, `mod`, `struct`, `enum`, `trait`, `type`, `macro`, and `const`.

Search functions by type signature (e.g., `vec -> usize` or `* -> vec`)

Search multiple things at once by splitting your query with comma (e.g., `str,u8` or `String,struct:Vec,test`)