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/SkFloatingPoint.h"
12
13#undef SK_SCALAR_IS_FLOAT
14#define SK_SCALAR_IS_FLOAT 1
15
16typedef 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_ScalarInfinity SK_FloatInfinity
26#define SK_ScalarNegativeInfinity SK_FloatNegativeInfinity
27#define SK_ScalarNaN SK_FloatNaN
28
29#define SkScalarFloorToScalar(x) sk_float_floor(x)
30#define SkScalarCeilToScalar(x) sk_float_ceil(x)
31#define SkScalarRoundToScalar(x) sk_float_floor((x) + 0.5f)
32#define SkScalarTruncToScalar(x) sk_float_trunc(x)
33
34#define SkScalarFloorToInt(x) sk_float_floor2int(x)
35#define SkScalarCeilToInt(x) sk_float_ceil2int(x)
36#define SkScalarRoundToInt(x) sk_float_round2int(x)
37
38#define SkScalarAbs(x) sk_float_abs(x)
39#define SkScalarCopySign(x, y) sk_float_copysign(x, y)
40#define SkScalarMod(x, y) sk_float_mod(x,y)
41#define SkScalarSqrt(x) sk_float_sqrt(x)
42#define SkScalarPow(b, e) sk_float_pow(b, e)
43
44#define SkScalarSin(radians) (float)sk_float_sin(radians)
45#define SkScalarCos(radians) (float)sk_float_cos(radians)
46#define SkScalarTan(radians) (float)sk_float_tan(radians)
47#define SkScalarASin(val) (float)sk_float_asin(val)
48#define SkScalarACos(val) (float)sk_float_acos(val)
49#define SkScalarATan2(y, x) (float)sk_float_atan2(y,x)
50#define SkScalarExp(x) (float)sk_float_exp(x)
51#define SkScalarLog(x) (float)sk_float_log(x)
52#define SkScalarLog2(x) (float)sk_float_log2(x)
53
54//////////////////////////////////////////////////////////////////////////////////////////////////
55
56#define SkIntToScalar(x) static_cast<SkScalar>(x)
57#define SkIntToFloat(x) static_cast<float>(x)
58#define SkScalarTruncToInt(x) sk_float_saturate2int(x)
59
60#define SkScalarToFloat(x) static_cast<float>(x)
61#define SkFloatToScalar(x) static_cast<SkScalar>(x)
62#define SkScalarToDouble(x) static_cast<double>(x)
63#define SkDoubleToScalar(x) sk_double_to_float(x)
64
65#define SK_ScalarMin (-SK_ScalarMax)
66
67static inline bool SkScalarIsNaN(SkScalar x) { return x != x; }
68
69/** Returns true if x is not NaN and not infinite
70 */
71static inline bool SkScalarIsFinite(SkScalar x) { return sk_float_isfinite(x); }
72
73static inline bool SkScalarsAreFinite(SkScalar a, SkScalar b) {
74 return sk_floats_are_finite(a, b);
75}
76
77static inline bool SkScalarsAreFinite(const SkScalar array[], int count) {
78 return sk_floats_are_finite(array, count);
79}
80
81/**
82 * Variant of SkScalarRoundToInt, that performs the rounding step (adding 0.5) explicitly using
83 * double, to avoid possibly losing the low bit(s) of the answer before calling floor().
84 *
85 * This routine will likely be slower than SkScalarRoundToInt(), and should only be used when the
86 * extra precision is known to be valuable.
87 *
88 * In particular, this catches the following case:
89 * SkScalar x = 0.49999997;
90 * int ix = SkScalarRoundToInt(x);
91 * SkASSERT(0 == ix); // <--- fails
92 * ix = SkDScalarRoundToInt(x);
93 * SkASSERT(0 == ix); // <--- succeeds
94 */
95static inline int SkDScalarRoundToInt(SkScalar x) {
96 double xx = x;
97 xx += 0.5;
98 return (int)floor(xx);
99}
100
101/** Returns the fractional part of the scalar. */
102static inline SkScalar SkScalarFraction(SkScalar x) {
103 return x - SkScalarTruncToScalar(x);
104}
105
106static inline SkScalar SkScalarSquare(SkScalar x) { return x * x; }
107
108#define SkScalarInvert(x) sk_ieee_float_divide_TODO_IS_DIVIDE_BY_ZERO_SAFE_HERE(SK_Scalar1, (x))
109#define SkScalarAve(a, b) (((a) + (b)) * SK_ScalarHalf)
110#define SkScalarHalf(a) ((a) * SK_ScalarHalf)
111
112#define SkDegreesToRadians(degrees) ((degrees) * (SK_ScalarPI / 180))
113#define SkRadiansToDegrees(radians) ((radians) * (180 / SK_ScalarPI))
114
115static inline bool SkScalarIsInt(SkScalar x) {
116 return x == SkScalarFloorToScalar(x);
117}
118
119/**
120 * Returns -1 || 0 || 1 depending on the sign of value:
121 * -1 if x < 0
122 * 0 if x == 0
123 * 1 if x > 0
124 */
125static inline int SkScalarSignAsInt(SkScalar x) {
126 return x < 0 ? -1 : (x > 0);
127}
128
129// Scalar result version of above
130static inline SkScalar SkScalarSignAsScalar(SkScalar x) {
131 return x < 0 ? -SK_Scalar1 : ((x > 0) ? SK_Scalar1 : 0);
132}
133
134#define SK_ScalarNearlyZero (SK_Scalar1 / (1 << 12))
135
136static inline bool SkScalarNearlyZero(SkScalar x,
137 SkScalar tolerance = SK_ScalarNearlyZero) {
138 SkASSERT(tolerance >= 0);
139 return SkScalarAbs(x) <= tolerance;
140}
141
142static inline bool SkScalarNearlyEqual(SkScalar x, SkScalar y,
143 SkScalar tolerance = SK_ScalarNearlyZero) {
144 SkASSERT(tolerance >= 0);
145 return SkScalarAbs(x-y) <= tolerance;
146}
147
148static inline float SkScalarSinSnapToZero(SkScalar radians) {
149 float v = SkScalarSin(radians);
150 return SkScalarNearlyZero(v) ? 0.0f : v;
151}
152
153static inline float SkScalarCosSnapToZero(SkScalar radians) {
154 float v = SkScalarCos(radians);
155 return SkScalarNearlyZero(v) ? 0.0f : v;
156}
157
158/** Linearly interpolate between A and B, based on t.
159 If t is 0, return A
160 If t is 1, return B
161 else interpolate.
162 t must be [0..SK_Scalar1]
163*/
164static inline SkScalar SkScalarInterp(SkScalar A, SkScalar B, SkScalar t) {
165 SkASSERT(t >= 0 && t <= SK_Scalar1);
166 return A + (B - A) * t;
167}
168
169/** Interpolate along the function described by (keys[length], values[length])
170 for the passed searchKey. SearchKeys outside the range keys[0]-keys[Length]
171 clamp to the min or max value. This function was inspired by a desire
172 to change the multiplier for thickness in fakeBold; therefore it assumes
173 the number of pairs (length) will be small, and a linear search is used.
174 Repeated keys are allowed for discontinuous functions (so long as keys is
175 monotonically increasing), and if key is the value of a repeated scalar in
176 keys, the first one will be used. However, that may change if a binary
177 search is used.
178*/
179SkScalar SkScalarInterpFunc(SkScalar searchKey, const SkScalar keys[],
180 const SkScalar values[], int length);
181
182/*
183 * Helper to compare an array of scalars.
184 */
185static inline bool SkScalarsEqual(const SkScalar a[], const SkScalar b[], int n) {
186 SkASSERT(n >= 0);
187 for (int i = 0; i < n; ++i) {
188 if (a[i] != b[i]) {
189 return false;
190 }
191 }
192 return true;
193}
194
195#endif
196