1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/gfx/skia/trunk/include/core/SkScalar.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,234 @@
1.4 +/*
1.5 + * Copyright 2006 The Android Open Source Project
1.6 + *
1.7 + * Use of this source code is governed by a BSD-style license that can be
1.8 + * found in the LICENSE file.
1.9 + */
1.10 +
1.11 +#ifndef SkScalar_DEFINED
1.12 +#define SkScalar_DEFINED
1.13 +
1.14 +#include "SkFixed.h"
1.15 +#include "SkFloatingPoint.h"
1.16 +
1.17 +//#define SK_SUPPORT_DEPRECATED_SCALARROUND
1.18 +
1.19 +typedef float SkScalar;
1.20 +
1.21 +/** SK_Scalar1 is defined to be 1.0 represented as an SkScalar
1.22 +*/
1.23 +#define SK_Scalar1 (1.0f)
1.24 +/** SK_Scalar1 is defined to be 1/2 represented as an SkScalar
1.25 +*/
1.26 +#define SK_ScalarHalf (0.5f)
1.27 +/** SK_ScalarInfinity is defined to be infinity as an SkScalar
1.28 +*/
1.29 +#define SK_ScalarInfinity SK_FloatInfinity
1.30 +/** SK_ScalarNegativeInfinity is defined to be negative infinity as an SkScalar
1.31 +*/
1.32 +#define SK_ScalarNegativeInfinity SK_FloatNegativeInfinity
1.33 +/** SK_ScalarMax is defined to be the largest value representable as an SkScalar
1.34 +*/
1.35 +#define SK_ScalarMax (3.402823466e+38f)
1.36 +/** SK_ScalarMin is defined to be the smallest value representable as an SkScalar
1.37 +*/
1.38 +#define SK_ScalarMin (-SK_ScalarMax)
1.39 +/** SK_ScalarNaN is defined to be 'Not a Number' as an SkScalar
1.40 +*/
1.41 +#define SK_ScalarNaN SK_FloatNaN
1.42 +/** SkScalarIsNaN(n) returns true if argument is not a number
1.43 +*/
1.44 +static inline bool SkScalarIsNaN(float x) { return x != x; }
1.45 +
1.46 +/** Returns true if x is not NaN and not infinite */
1.47 +static inline bool SkScalarIsFinite(float x) {
1.48 + // We rely on the following behavior of infinities and nans
1.49 + // 0 * finite --> 0
1.50 + // 0 * infinity --> NaN
1.51 + // 0 * NaN --> NaN
1.52 + float prod = x * 0;
1.53 + // At this point, prod will either be NaN or 0
1.54 + // Therefore we can return (prod == prod) or (0 == prod).
1.55 + return prod == prod;
1.56 +}
1.57 +
1.58 +/** SkIntToScalar(n) returns its integer argument as an SkScalar
1.59 +*/
1.60 +#define SkIntToScalar(n) ((float)(n))
1.61 +/** SkFixedToScalar(n) returns its SkFixed argument as an SkScalar
1.62 +*/
1.63 +#define SkFixedToScalar(x) SkFixedToFloat(x)
1.64 +/** SkScalarToFixed(n) returns its SkScalar argument as an SkFixed
1.65 +*/
1.66 +#define SkScalarToFixed(x) SkFloatToFixed(x)
1.67 +
1.68 +#define SkScalarToFloat(n) (n)
1.69 +#ifndef SK_SCALAR_TO_FLOAT_EXCLUDED
1.70 +#define SkFloatToScalar(n) (n)
1.71 +#endif
1.72 +
1.73 +#define SkScalarToDouble(n) (double)(n)
1.74 +#define SkDoubleToScalar(n) (float)(n)
1.75 +
1.76 +/** SkScalarFraction(x) returns the signed fractional part of the argument
1.77 +*/
1.78 +#define SkScalarFraction(x) sk_float_mod(x, 1.0f)
1.79 +
1.80 +#define SkScalarFloorToScalar(x) sk_float_floor(x)
1.81 +#define SkScalarCeilToScalar(x) sk_float_ceil(x)
1.82 +#define SkScalarRoundToScalar(x) sk_float_floor((x) + 0.5f)
1.83 +
1.84 +#define SkScalarFloorToInt(x) sk_float_floor2int(x)
1.85 +#define SkScalarCeilToInt(x) sk_float_ceil2int(x)
1.86 +#define SkScalarRoundToInt(x) sk_float_round2int(x)
1.87 +#define SkScalarTruncToInt(x) static_cast<int>(x)
1.88 +
1.89 +/** Returns the absolute value of the specified SkScalar
1.90 +*/
1.91 +#define SkScalarAbs(x) sk_float_abs(x)
1.92 +/** Return x with the sign of y
1.93 + */
1.94 +#define SkScalarCopySign(x, y) sk_float_copysign(x, y)
1.95 +/** Returns the value pinned between 0 and max inclusive
1.96 +*/
1.97 +inline SkScalar SkScalarClampMax(SkScalar x, SkScalar max) {
1.98 + return x < 0 ? 0 : x > max ? max : x;
1.99 +}
1.100 +/** Returns the value pinned between min and max inclusive
1.101 +*/
1.102 +inline SkScalar SkScalarPin(SkScalar x, SkScalar min, SkScalar max) {
1.103 + return x < min ? min : x > max ? max : x;
1.104 +}
1.105 +/** Returns the specified SkScalar squared (x*x)
1.106 +*/
1.107 +inline SkScalar SkScalarSquare(SkScalar x) { return x * x; }
1.108 +/** Returns the product of two SkScalars
1.109 +*/
1.110 +#define SkScalarMul(a, b) ((float)(a) * (b))
1.111 +/** Returns the product of two SkScalars plus a third SkScalar
1.112 +*/
1.113 +#define SkScalarMulAdd(a, b, c) ((float)(a) * (b) + (c))
1.114 +/** Returns the quotient of two SkScalars (a/b)
1.115 +*/
1.116 +#define SkScalarDiv(a, b) ((float)(a) / (b))
1.117 +/** Returns the mod of two SkScalars (a mod b)
1.118 +*/
1.119 +#define SkScalarMod(x,y) sk_float_mod(x,y)
1.120 +/** Returns the product of the first two arguments, divided by the third argument
1.121 +*/
1.122 +#define SkScalarMulDiv(a, b, c) ((float)(a) * (b) / (c))
1.123 +/** Returns the multiplicative inverse of the SkScalar (1/x)
1.124 +*/
1.125 +#define SkScalarInvert(x) (SK_Scalar1 / (x))
1.126 +#define SkScalarFastInvert(x) (SK_Scalar1 / (x))
1.127 +/** Returns the square root of the SkScalar
1.128 +*/
1.129 +#define SkScalarSqrt(x) sk_float_sqrt(x)
1.130 +/** Returns b to the e
1.131 +*/
1.132 +#define SkScalarPow(b, e) sk_float_pow(b, e)
1.133 +/** Returns the average of two SkScalars (a+b)/2
1.134 +*/
1.135 +#define SkScalarAve(a, b) (((a) + (b)) * 0.5f)
1.136 +/** Returns one half of the specified SkScalar
1.137 +*/
1.138 +#define SkScalarHalf(a) ((a) * 0.5f)
1.139 +
1.140 +#define SK_ScalarSqrt2 1.41421356f
1.141 +#define SK_ScalarPI 3.14159265f
1.142 +#define SK_ScalarTanPIOver8 0.414213562f
1.143 +#define SK_ScalarRoot2Over2 0.707106781f
1.144 +
1.145 +#define SkDegreesToRadians(degrees) ((degrees) * (SK_ScalarPI / 180))
1.146 +#define SkRadiansToDegrees(radians) ((radians) * (180 / SK_ScalarPI))
1.147 +float SkScalarSinCos(SkScalar radians, SkScalar* cosValue);
1.148 +#define SkScalarSin(radians) (float)sk_float_sin(radians)
1.149 +#define SkScalarCos(radians) (float)sk_float_cos(radians)
1.150 +#define SkScalarTan(radians) (float)sk_float_tan(radians)
1.151 +#define SkScalarASin(val) (float)sk_float_asin(val)
1.152 +#define SkScalarACos(val) (float)sk_float_acos(val)
1.153 +#define SkScalarATan2(y, x) (float)sk_float_atan2(y,x)
1.154 +#define SkScalarExp(x) (float)sk_float_exp(x)
1.155 +#define SkScalarLog(x) (float)sk_float_log(x)
1.156 +
1.157 +inline SkScalar SkMaxScalar(SkScalar a, SkScalar b) { return a > b ? a : b; }
1.158 +inline SkScalar SkMinScalar(SkScalar a, SkScalar b) { return a < b ? a : b; }
1.159 +
1.160 +static inline bool SkScalarIsInt(SkScalar x) {
1.161 + return x == (float)(int)x;
1.162 +}
1.163 +
1.164 +// DEPRECATED : use ToInt or ToScalar variant
1.165 +#ifdef SK_SUPPORT_DEPRECATED_SCALARROUND
1.166 +# define SkScalarFloor(x) SkScalarFloorToInt(x)
1.167 +# define SkScalarCeil(x) SkScalarCeilToInt(x)
1.168 +# define SkScalarRound(x) SkScalarRoundToInt(x)
1.169 +#endif
1.170 +
1.171 +/**
1.172 + * Returns -1 || 0 || 1 depending on the sign of value:
1.173 + * -1 if x < 0
1.174 + * 0 if x == 0
1.175 + * 1 if x > 0
1.176 + */
1.177 +static inline int SkScalarSignAsInt(SkScalar x) {
1.178 + return x < 0 ? -1 : (x > 0);
1.179 +}
1.180 +
1.181 +// Scalar result version of above
1.182 +static inline SkScalar SkScalarSignAsScalar(SkScalar x) {
1.183 + return x < 0 ? -SK_Scalar1 : ((x > 0) ? SK_Scalar1 : 0);
1.184 +}
1.185 +
1.186 +#define SK_ScalarNearlyZero (SK_Scalar1 / (1 << 12))
1.187 +
1.188 +static inline bool SkScalarNearlyZero(SkScalar x,
1.189 + SkScalar tolerance = SK_ScalarNearlyZero) {
1.190 + SkASSERT(tolerance >= 0);
1.191 + return SkScalarAbs(x) <= tolerance;
1.192 +}
1.193 +
1.194 +static inline bool SkScalarNearlyEqual(SkScalar x, SkScalar y,
1.195 + SkScalar tolerance = SK_ScalarNearlyZero) {
1.196 + SkASSERT(tolerance >= 0);
1.197 + return SkScalarAbs(x-y) <= tolerance;
1.198 +}
1.199 +
1.200 +/** Linearly interpolate between A and B, based on t.
1.201 + If t is 0, return A
1.202 + If t is 1, return B
1.203 + else interpolate.
1.204 + t must be [0..SK_Scalar1]
1.205 +*/
1.206 +static inline SkScalar SkScalarInterp(SkScalar A, SkScalar B, SkScalar t) {
1.207 + SkASSERT(t >= 0 && t <= SK_Scalar1);
1.208 + return A + (B - A) * t;
1.209 +}
1.210 +
1.211 +/** Interpolate along the function described by (keys[length], values[length])
1.212 + for the passed searchKey. SearchKeys outside the range keys[0]-keys[Length]
1.213 + clamp to the min or max value. This function was inspired by a desire
1.214 + to change the multiplier for thickness in fakeBold; therefore it assumes
1.215 + the number of pairs (length) will be small, and a linear search is used.
1.216 + Repeated keys are allowed for discontinuous functions (so long as keys is
1.217 + monotonically increasing), and if key is the value of a repeated scalar in
1.218 + keys, the first one will be used. However, that may change if a binary
1.219 + search is used.
1.220 +*/
1.221 +SkScalar SkScalarInterpFunc(SkScalar searchKey, const SkScalar keys[],
1.222 + const SkScalar values[], int length);
1.223 +
1.224 +/*
1.225 + * Helper to compare an array of scalars.
1.226 + */
1.227 +static inline bool SkScalarsEqual(const SkScalar a[], const SkScalar b[], int n) {
1.228 + SkASSERT(n >= 0);
1.229 + for (int i = 0; i < n; ++i) {
1.230 + if (a[i] != b[i]) {
1.231 + return false;
1.232 + }
1.233 + }
1.234 + return true;
1.235 +}
1.236 +
1.237 +#endif
