1 /*
2 * Copyright 2006 The Android Open Source Project
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7
8 #ifndef SkScalar_DEFINED
9 #define SkScalar_DEFINED
10
11 #include "include/private/base/SkAssert.h"
12 #include "include/private/base/SkFloatingPoint.h"
13
14 #include <cmath>
15
16 typedef float SkScalar;
17
18 #define SK_Scalar1 1.0f
19 #define SK_ScalarHalf 0.5f
20 #define SK_ScalarSqrt2 SK_FloatSqrt2
21 #define SK_ScalarPI SK_FloatPI
22 #define SK_ScalarTanPIOver8 0.414213562f
23 #define SK_ScalarRoot2Over2 0.707106781f
24 #define SK_ScalarMax 3.402823466e+38f
25 #define SK_ScalarMin (-SK_ScalarMax)
26 #define SK_ScalarInfinity SK_FloatInfinity
27 #define SK_ScalarNegativeInfinity SK_FloatNegativeInfinity
28 #define SK_ScalarNaN SK_FloatNaN
29
30 #define SkScalarFloorToScalar(x) std::floor(x)
31 #define SkScalarCeilToScalar(x) std::ceil(x)
32 #define SkScalarRoundToScalar(x) sk_float_round(x)
33 #define SkScalarTruncToScalar(x) std::trunc(x)
34
35 #define SkScalarFloorToInt(x) sk_float_floor2int(x)
36 #define SkScalarCeilToInt(x) sk_float_ceil2int(x)
37 #define SkScalarRoundToInt(x) sk_float_round2int(x)
38
39 #define SkScalarAbs(x) std::fabs(x)
40 #define SkScalarCopySign(x, y) std::copysign(x, y)
41 #define SkScalarMod(x, y) std::fmod(x,y)
42 #define SkScalarSqrt(x) std::sqrt(x)
43 #define SkScalarPow(b, e) std::pow(b, e)
44
45 #define SkScalarSin(radians) ((float)std::sin(radians))
46 #define SkScalarCos(radians) ((float)std::cos(radians))
47 #define SkScalarTan(radians) ((float)std::tan(radians))
48 #define SkScalarASin(val) ((float)std::asin(val))
49 #define SkScalarACos(val) ((float)std::acos(val))
50 #define SkScalarATan2(y, x) ((float)std::atan2(y,x))
51 #define SkScalarExp(x) ((float)std::exp(x))
52 #define SkScalarLog(x) ((float)std::log(x))
53 #define SkScalarLog2(x) ((float)std::log2(x))
54
55 //////////////////////////////////////////////////////////////////////////////////////////////////
56
57 #define SkIntToScalar(x) static_cast<SkScalar>(x)
58 #define SkIntToFloat(x) static_cast<float>(x)
59 #define SkScalarTruncToInt(x) sk_float_saturate2int(x)
60
61 #define SkScalarToFloat(x) static_cast<float>(x)
62 #define SkFloatToScalar(x) static_cast<SkScalar>(x)
63 #define SkScalarToDouble(x) static_cast<double>(x)
64 #define SkDoubleToScalar(x) sk_double_to_float(x)
65
66 /** Returns the fractional part of the scalar. */
SkScalarFraction(SkScalar x)67 static inline SkScalar SkScalarFraction(SkScalar x) {
68 return x - SkScalarTruncToScalar(x);
69 }
70
SkScalarSquare(SkScalar x)71 static inline SkScalar SkScalarSquare(SkScalar x) { return x * x; }
72
73 #define SkScalarInvert(x) (SK_Scalar1 / (x))
74 #define SkScalarAve(a, b) (((a) + (b)) * SK_ScalarHalf)
75 #define SkScalarHalf(a) ((a) * SK_ScalarHalf)
76
77 #define SkDegreesToRadians(degrees) ((degrees) * (SK_ScalarPI / 180))
78 #define SkRadiansToDegrees(radians) ((radians) * (180 / SK_ScalarPI))
79
SkScalarIsInt(SkScalar x)80 static inline bool SkScalarIsInt(SkScalar x) {
81 return x == SkScalarFloorToScalar(x);
82 }
83
84 /**
85 * Returns -1 || 0 || 1 depending on the sign of value:
86 * -1 if x < 0
87 * 0 if x == 0
88 * 1 if x > 0
89 */
SkScalarSignAsInt(SkScalar x)90 static inline int SkScalarSignAsInt(SkScalar x) {
91 return x < 0 ? -1 : (x > 0);
92 }
93
94 // Scalar result version of above
SkScalarSignAsScalar(SkScalar x)95 static inline SkScalar SkScalarSignAsScalar(SkScalar x) {
96 return x < 0 ? -SK_Scalar1 : ((x > 0) ? SK_Scalar1 : 0);
97 }
98
99 #define SK_ScalarNearlyZero (SK_Scalar1 / (1 << 12))
100
101 static inline bool SkScalarNearlyZero(SkScalar x,
102 SkScalar tolerance = SK_ScalarNearlyZero) {
103 SkASSERT(tolerance >= 0);
104 return SkScalarAbs(x) <= tolerance;
105 }
106
107 static inline bool SkScalarNearlyEqual(SkScalar x, SkScalar y,
108 SkScalar tolerance = SK_ScalarNearlyZero) {
109 SkASSERT(tolerance >= 0);
110 return SkScalarAbs(x-y) <= tolerance;
111 }
112
113 #define SK_ScalarSinCosNearlyZero (SK_Scalar1 / (1 << 16))
114
SkScalarSinSnapToZero(SkScalar radians)115 static inline float SkScalarSinSnapToZero(SkScalar radians) {
116 float v = SkScalarSin(radians);
117 return SkScalarNearlyZero(v, SK_ScalarSinCosNearlyZero) ? 0.0f : v;
118 }
119
SkScalarCosSnapToZero(SkScalar radians)120 static inline float SkScalarCosSnapToZero(SkScalar radians) {
121 float v = SkScalarCos(radians);
122 return SkScalarNearlyZero(v, SK_ScalarSinCosNearlyZero) ? 0.0f : v;
123 }
124
125 /** Linearly interpolate between A and B, based on t.
126 If t is 0, return A
127 If t is 1, return B
128 else interpolate.
129 t must be [0..SK_Scalar1]
130 */
SkScalarInterp(SkScalar A,SkScalar B,SkScalar t)131 static inline SkScalar SkScalarInterp(SkScalar A, SkScalar B, SkScalar t) {
132 SkASSERT(t >= 0 && t <= SK_Scalar1);
133 return A + (B - A) * t;
134 }
135
136 /** Interpolate along the function described by (keys[length], values[length])
137 for the passed searchKey. SearchKeys outside the range keys[0]-keys[Length]
138 clamp to the min or max value. This function assumes the number of pairs
139 (length) will be small and a linear search is used.
140
141 Repeated keys are allowed for discontinuous functions (so long as keys is
142 monotonically increasing). If key is the value of a repeated scalar in
143 keys the first one will be used.
144 */
145 SkScalar SkScalarInterpFunc(SkScalar searchKey, const SkScalar keys[],
146 const SkScalar values[], int length);
147
148 /*
149 * Helper to compare an array of scalars.
150 */
SkScalarsEqual(const SkScalar a[],const SkScalar b[],int n)151 static inline bool SkScalarsEqual(const SkScalar a[], const SkScalar b[], int n) {
152 SkASSERT(n >= 0);
153 for (int i = 0; i < n; ++i) {
154 if (a[i] != b[i]) {
155 return false;
156 }
157 }
158 return true;
159 }
160
161 #endif
162