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Diffstat (limited to 'vendor/github.com/golang/geo/s1/angle.go')
| -rw-r--r-- | vendor/github.com/golang/geo/s1/angle.go | 120 |
1 files changed, 0 insertions, 120 deletions
diff --git a/vendor/github.com/golang/geo/s1/angle.go b/vendor/github.com/golang/geo/s1/angle.go deleted file mode 100644 index 747b23dea..000000000 --- a/vendor/github.com/golang/geo/s1/angle.go +++ /dev/null @@ -1,120 +0,0 @@ -// Copyright 2014 Google Inc. All rights reserved. -// -// Licensed under the Apache License, Version 2.0 (the "License"); -// you may not use this file except in compliance with the License. -// You may obtain a copy of the License at -// -// http://www.apache.org/licenses/LICENSE-2.0 -// -// Unless required by applicable law or agreed to in writing, software -// distributed under the License is distributed on an "AS IS" BASIS, -// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. -// See the License for the specific language governing permissions and -// limitations under the License. - -package s1 - -import ( - "math" - "strconv" -) - -// Angle represents a 1D angle. The internal representation is a double precision -// value in radians, so conversion to and from radians is exact. -// Conversions between E5, E6, E7, and Degrees are not always -// exact. For example, Degrees(3.1) is different from E6(3100000) or E7(31000000). -// -// The following conversions between degrees and radians are exact: -// -// Degree*180 == Radian*math.Pi -// Degree*(180/n) == Radian*(math.Pi/n) for n == 0..8 -// -// These identities hold when the arguments are scaled up or down by any power -// of 2. Some similar identities are also true, for example, -// -// Degree*60 == Radian*(math.Pi/3) -// -// But be aware that this type of identity does not hold in general. For example, -// -// Degree*3 != Radian*(math.Pi/60) -// -// Similarly, the conversion to radians means that (Angle(x)*Degree).Degrees() -// does not always equal x. For example, -// -// (Angle(45*n)*Degree).Degrees() == 45*n for n == 0..8 -// -// but -// -// (60*Degree).Degrees() != 60 -// -// When testing for equality, you should allow for numerical errors (ApproxEqual) -// or convert to discrete E5/E6/E7 values first. -type Angle float64 - -// Angle units. -const ( - Radian Angle = 1 - Degree = (math.Pi / 180) * Radian - - E5 = 1e-5 * Degree - E6 = 1e-6 * Degree - E7 = 1e-7 * Degree -) - -// Radians returns the angle in radians. -func (a Angle) Radians() float64 { return float64(a) } - -// Degrees returns the angle in degrees. -func (a Angle) Degrees() float64 { return float64(a / Degree) } - -// round returns the value rounded to nearest as an int32. -// This does not match C++ exactly for the case of x.5. -func round(val float64) int32 { - if val < 0 { - return int32(val - 0.5) - } - return int32(val + 0.5) -} - -// InfAngle returns an angle larger than any finite angle. -func InfAngle() Angle { - return Angle(math.Inf(1)) -} - -// isInf reports whether this Angle is infinite. -func (a Angle) isInf() bool { - return math.IsInf(float64(a), 0) -} - -// E5 returns the angle in hundred thousandths of degrees. -func (a Angle) E5() int32 { return round(a.Degrees() * 1e5) } - -// E6 returns the angle in millionths of degrees. -func (a Angle) E6() int32 { return round(a.Degrees() * 1e6) } - -// E7 returns the angle in ten millionths of degrees. -func (a Angle) E7() int32 { return round(a.Degrees() * 1e7) } - -// Abs returns the absolute value of the angle. -func (a Angle) Abs() Angle { return Angle(math.Abs(float64(a))) } - -// Normalized returns an equivalent angle in (-π, π]. -func (a Angle) Normalized() Angle { - rad := math.Remainder(float64(a), 2*math.Pi) - if rad <= -math.Pi { - rad = math.Pi - } - return Angle(rad) -} - -func (a Angle) String() string { - return strconv.FormatFloat(a.Degrees(), 'f', 7, 64) // like "%.7f" -} - -// ApproxEqual reports whether the two angles are the same up to a small tolerance. -func (a Angle) ApproxEqual(other Angle) bool { - return math.Abs(float64(a)-float64(other)) <= epsilon -} - -// BUG(dsymonds): The major differences from the C++ version are: -// - no unsigned E5/E6/E7 methods |