vector.go

Documentation: oss.terrastruct.com/d2/lib/geo

     1  package geo
     2  
     3  import (
     4  	"math"
     5  )
     6  
     7  // A N-Dimensional Vector with components (x, y, z, ...) based on the origin
     8  type Vector []float64
     9  
    10  // New Vector from components
    11  func NewVector(components ...float64) Vector {
    12  	return components
    13  }
    14  
    15  // New Vector of length and pointing in the direction of angle
    16  func NewVectorFromProperties(length float64, angleInRadians float64) Vector {
    17  	return NewVector(
    18  		length*math.Sin(angleInRadians),
    19  		length*math.Cos(angleInRadians),
    20  	)
    21  }
    22  
    23  // Creates a Vector by extending the length of the current one by length
    24  func (a Vector) AddLength(length float64) Vector {
    25  	return a.Unit().Multiply(a.Length() + length)
    26  }
    27  
    28  func (a Vector) Add(b Vector) Vector {
    29  	c := []float64{}
    30  	for i := 0; i < len(a); i++ {
    31  		c = append(c, a[i]+b[i])
    32  	}
    33  	return c
    34  }
    35  
    36  func (a Vector) Minus(b Vector) Vector {
    37  	c := []float64{}
    38  	for i := 0; i < len(a); i++ {
    39  		c = append(c, a[i]-b[i])
    40  	}
    41  	return c
    42  }
    43  
    44  func (a Vector) Multiply(v float64) Vector {
    45  	c := []float64{}
    46  	for i := 0; i < len(a); i++ {
    47  		c = append(c, a[i]*v)
    48  	}
    49  	return c
    50  }
    51  
    52  func (a Vector) Length() float64 {
    53  	sum := 0.0
    54  	for _, comp := range a {
    55  		sum += comp * comp
    56  	}
    57  	return math.Sqrt(sum)
    58  }
    59  
    60  // Creates an unit Vector pointing in the same direction of this Vector
    61  func (a Vector) Unit() Vector {
    62  	return a.Multiply(1 / a.Length())
    63  }
    64  
    65  func (a Vector) ToPoint() *Point {
    66  	return &Point{a[0], a[1]}
    67  }
    68  
    69  // return the line (x1,y1) -> (x2,y2) rotated 90% counter-clockwise (left)
    70  func getNormalVector(x1, y1, x2, y2 float64) (float64, float64) {
    71  	return y1 - y2, x2 - x1
    72  }
    73  
    74  func GetUnitNormalVector(x1, y1, x2, y2 float64) (float64, float64) {
    75  	normalX, normalY := getNormalVector(x1, y1, x2, y2)
    76  	length := EuclideanDistance(x1, y1, x2, y2)
    77  	return normalX / length, normalY / length
    78  }
    79  
    80  func (a Vector) Radians() float64 {
    81  	return float64(float32(math.Atan2(a[1], a[0])))
    82  }
    83  
    84  func (a Vector) Degrees() float64 {
    85  	return a.Radians() * 180 / math.Pi
    86  }
    87  
    88  func (a Vector) Reverse() Vector {
    89  	return a.Multiply(-1)
    90  }
    91
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