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 typedef float SkScalar;
15
16 #define SK_Scalar1 1.0f
17 #define SK_ScalarHalf 0.5f
18 #define SK_ScalarSqrt2 SK_FloatSqrt2
19 #define SK_ScalarPI SK_FloatPI
20 #define SK_ScalarTanPIOver8 0.414213562f
21 #define SK_ScalarRoot2Over2 0.707106781f
22 #define SK_ScalarMax 3.402823466e+38f
23 #define SK_ScalarMin (-SK_ScalarMax)
24 #define SK_ScalarInfinity SK_FloatInfinity
25 #define SK_ScalarNegativeInfinity SK_FloatNegativeInfinity
26 #define SK_ScalarNaN SK_FloatNaN
27
28 #define SkScalarFloorToScalar(x) sk_float_floor(x)
29 #define SkScalarCeilToScalar(x) sk_float_ceil(x)
30 #define SkScalarRoundToScalar(x) sk_float_round(x)
31 #define SkScalarTruncToScalar(x) sk_float_trunc(x)
32
33 #define SkScalarFloorToInt(x) sk_float_floor2int(x)
34 #define SkScalarCeilToInt(x) sk_float_ceil2int(x)
35 #define SkScalarRoundToInt(x) sk_float_round2int(x)
36
37 #define SkScalarAbs(x) sk_float_abs(x)
38 #define SkScalarCopySign(x, y) sk_float_copysign(x, y)
39 #define SkScalarMod(x, y) sk_float_mod(x,y)
40 #define SkScalarSqrt(x) sk_float_sqrt(x)
41 #define SkScalarPow(b, e) sk_float_pow(b, e)
42
43 #define SkScalarSin(radians) (float)sk_float_sin(radians)
44 #define SkScalarCos(radians) (float)sk_float_cos(radians)
45 #define SkScalarTan(radians) (float)sk_float_tan(radians)
46 #define SkScalarASin(val) (float)sk_float_asin(val)
47 #define SkScalarACos(val) (float)sk_float_acos(val)
48 #define SkScalarATan2(y, x) (float)sk_float_atan2(y,x)
49 #define SkScalarExp(x) (float)sk_float_exp(x)
50 #define SkScalarLog(x) (float)sk_float_log(x)
51 #define SkScalarLog2(x) (float)sk_float_log2(x)
52
53 //////////////////////////////////////////////////////////////////////////////////////////////////
54
55 #define SkIntToScalar(x) static_cast<SkScalar>(x)
56 #define SkIntToFloat(x) static_cast<float>(x)
57 #define SkScalarTruncToInt(x) sk_float_saturate2int(x)
58
59 #define SkScalarToFloat(x) static_cast<float>(x)
60 #define SkFloatToScalar(x) static_cast<SkScalar>(x)
61 #define SkScalarToDouble(x) static_cast<double>(x)
62 #define SkDoubleToScalar(x) sk_double_to_float(x)
63
SkScalarIsNaN(SkScalar x)64 static inline bool SkScalarIsNaN(SkScalar x) { return x != x; }
65
66 /** Returns true if x is not NaN and not infinite
67 */
SkScalarIsFinite(SkScalar x)68 static inline bool SkScalarIsFinite(SkScalar x) { return sk_float_isfinite(x); }
69
SkScalarsAreFinite(SkScalar a,SkScalar b)70 static inline bool SkScalarsAreFinite(SkScalar a, SkScalar b) {
71 return sk_floats_are_finite(a, b);
72 }
73
SkScalarsAreFinite(const SkScalar array[],int count)74 static inline bool SkScalarsAreFinite(const SkScalar array[], int count) {
75 return sk_floats_are_finite(array, count);
76 }
77
78 /** Returns the fractional part of the scalar. */
SkScalarFraction(SkScalar x)79 static inline SkScalar SkScalarFraction(SkScalar x) {
80 return x - SkScalarTruncToScalar(x);
81 }
82
SkScalarSquare(SkScalar x)83 static inline SkScalar SkScalarSquare(SkScalar x) { return x * x; }
84
85 #define SkScalarInvert(x) sk_ieee_float_divide_TODO_IS_DIVIDE_BY_ZERO_SAFE_HERE(SK_Scalar1, (x))
86 #define SkScalarAve(a, b) (((a) + (b)) * SK_ScalarHalf)
87 #define SkScalarHalf(a) ((a) * SK_ScalarHalf)
88
89 #define SkDegreesToRadians(degrees) ((degrees) * (SK_ScalarPI / 180))
90 #define SkRadiansToDegrees(radians) ((radians) * (180 / SK_ScalarPI))
91
SkScalarIsInt(SkScalar x)92 static inline bool SkScalarIsInt(SkScalar x) {
93 return x == SkScalarFloorToScalar(x);
94 }
95
96 /**
97 * Returns -1 || 0 || 1 depending on the sign of value:
98 * -1 if x < 0
99 * 0 if x == 0
100 * 1 if x > 0
101 */
SkScalarSignAsInt(SkScalar x)102 static inline int SkScalarSignAsInt(SkScalar x) {
103 return x < 0 ? -1 : (x > 0);
104 }
105
106 // Scalar result version of above
SkScalarSignAsScalar(SkScalar x)107 static inline SkScalar SkScalarSignAsScalar(SkScalar x) {
108 return x < 0 ? -SK_Scalar1 : ((x > 0) ? SK_Scalar1 : 0);
109 }
110
111 #define SK_ScalarNearlyZero (SK_Scalar1 / (1 << 12))
112
113 static inline bool SkScalarNearlyZero(SkScalar x,
114 SkScalar tolerance = SK_ScalarNearlyZero) {
115 SkASSERT(tolerance >= 0);
116 return SkScalarAbs(x) <= tolerance;
117 }
118
119 static inline bool SkScalarNearlyEqual(SkScalar x, SkScalar y,
120 SkScalar tolerance = SK_ScalarNearlyZero) {
121 SkASSERT(tolerance >= 0);
122 return SkScalarAbs(x-y) <= tolerance;
123 }
124
125 #define SK_ScalarSinCosNearlyZero (SK_Scalar1 / (1 << 16))
126
SkScalarSinSnapToZero(SkScalar radians)127 static inline float SkScalarSinSnapToZero(SkScalar radians) {
128 float v = SkScalarSin(radians);
129 return SkScalarNearlyZero(v, SK_ScalarSinCosNearlyZero) ? 0.0f : v;
130 }
131
SkScalarCosSnapToZero(SkScalar radians)132 static inline float SkScalarCosSnapToZero(SkScalar radians) {
133 float v = SkScalarCos(radians);
134 return SkScalarNearlyZero(v, SK_ScalarSinCosNearlyZero) ? 0.0f : v;
135 }
136
137 /** Linearly interpolate between A and B, based on t.
138 If t is 0, return A
139 If t is 1, return B
140 else interpolate.
141 t must be [0..SK_Scalar1]
142 */
SkScalarInterp(SkScalar A,SkScalar B,SkScalar t)143 static inline SkScalar SkScalarInterp(SkScalar A, SkScalar B, SkScalar t) {
144 SkASSERT(t >= 0 && t <= SK_Scalar1);
145 return A + (B - A) * t;
146 }
147
148 /** Interpolate along the function described by (keys[length], values[length])
149 for the passed searchKey. SearchKeys outside the range keys[0]-keys[Length]
150 clamp to the min or max value. This function assumes the number of pairs
151 (length) will be small and a linear search is used.
152
153 Repeated keys are allowed for discontinuous functions (so long as keys is
154 monotonically increasing). If key is the value of a repeated scalar in
155 keys the first one will be used.
156 */
157 SkScalar SkScalarInterpFunc(SkScalar searchKey, const SkScalar keys[],
158 const SkScalar values[], int length);
159
160 /*
161 * Helper to compare an array of scalars.
162 */
SkScalarsEqual(const SkScalar a[],const SkScalar b[],int n)163 static inline bool SkScalarsEqual(const SkScalar a[], const SkScalar b[], int n) {
164 SkASSERT(n >= 0);
165 for (int i = 0; i < n; ++i) {
166 if (a[i] != b[i]) {
167 return false;
168 }
169 }
170 return true;
171 }
172
173 #endif
174