Flutter Impeller
scalar.h
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1 // Copyright 2013 The Flutter Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4 
5 #ifndef FLUTTER_IMPELLER_GEOMETRY_SCALAR_H_
6 #define FLUTTER_IMPELLER_GEOMETRY_SCALAR_H_
7 
8 #include <cfloat>
9 #include <type_traits>
10 #include <valarray>
11 
13 
14 namespace impeller {
15 
16 // NOLINTBEGIN(google-explicit-constructor)
17 
18 using Scalar = float;
19 
20 template <class T, class = std::enable_if_t<std::is_arithmetic_v<T>>>
21 constexpr T Absolute(const T& val) {
22  return val >= T{} ? val : -val;
23 }
24 
25 constexpr inline bool ScalarNearlyZero(Scalar x,
26  Scalar tolerance = kEhCloseEnough) {
27  return Absolute(x) <= tolerance;
28 }
29 
30 constexpr inline bool ScalarNearlyEqual(Scalar x,
31  Scalar y,
32  Scalar tolerance = kEhCloseEnough) {
33  return ScalarNearlyZero(x - y, tolerance);
34 }
35 
36 struct Degrees;
37 
38 struct Radians {
39  Scalar radians = 0.0;
40 
41  constexpr Radians() = default;
42 
43  explicit constexpr Radians(Scalar p_radians) : radians(p_radians) {}
44 };
45 
46 struct Degrees {
47  Scalar degrees = 0.0;
48 
49  constexpr Degrees() = default;
50 
51  explicit constexpr Degrees(Scalar p_degrees) : degrees(p_degrees) {}
52 
53  constexpr operator Radians() const {
54  return Radians{degrees * kPi / 180.0f};
55  };
56 };
57 
58 // NOLINTEND(google-explicit-constructor)
59 
60 } // namespace impeller
61 
62 #endif // FLUTTER_IMPELLER_GEOMETRY_SCALAR_H_
impeller::Degrees::Degrees
constexpr Degrees()=default
impeller::Scalar
float Scalar
Definition: scalar.h:18
impeller::Degrees::degrees
Scalar degrees
Definition: scalar.h:47
impeller::kEhCloseEnough
constexpr float kEhCloseEnough
Definition: constants.h:56
impeller::kPi
constexpr float kPi
Definition: constants.h:26
impeller::Radians::radians
Scalar radians
Definition: scalar.h:39
impeller::Radians::Radians
constexpr Radians()=default
impeller::Radians
Definition: scalar.h:38
impeller::ScalarNearlyZero
constexpr bool ScalarNearlyZero(Scalar x, Scalar tolerance=kEhCloseEnough)
Definition: scalar.h:25
impeller::Absolute
constexpr T Absolute(const T &val)
Definition: scalar.h:21
constants.h
impeller::Radians::Radians
constexpr Radians(Scalar p_radians)
Definition: scalar.h:43
impeller::ScalarNearlyEqual
constexpr bool ScalarNearlyEqual(Scalar x, Scalar y, Scalar tolerance=kEhCloseEnough)
Definition: scalar.h:30
impeller::Degrees
Definition: scalar.h:46
impeller
Definition: aiks_blur_unittests.cc:20
impeller::Degrees::Degrees
constexpr Degrees(Scalar p_degrees)
Definition: scalar.h:51