SkScalar.h revision cf4335ca4a35a9d1ff9fba0482f32a9a85474b97
1e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng 2e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng/* 3e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng * Copyright 2006 The Android Open Source Project 4e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng * 5e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng * Use of this source code is governed by a BSD-style license that can be 6e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng * found in the LICENSE file. 7e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng */ 8e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng 9e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng 10e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng#ifndef SkScalar_DEFINED 11e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng#define SkScalar_DEFINED 12e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng 13e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng#include "SkFixed.h" 14e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng#include "SkFloatingPoint.h" 15e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng 16e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng/** \file SkScalar.h 17e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng 18e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng Types and macros for the data type SkScalar. This is the fractional numeric type 19e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng that, depending on the compile-time flag SK_SCALAR_IS_FLOAT, may be implemented 20e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng either as an IEEE float, or as a 16.16 SkFixed. The macros in this file are written 21e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng to allow the calling code to manipulate SkScalar values without knowing which representation 22e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng is in effect. 23e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng*/ 24e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng 25e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng#ifdef SK_SCALAR_IS_FLOAT 26e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng 27e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng /** SkScalar is our type for fractional values and coordinates. Depending on 28e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng compile configurations, it is either represented as an IEEE float, or 29e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng as a 16.16 fixed point integer. 30e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng */ 31e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng typedef float SkScalar; 32e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng extern const uint32_t gIEEENotANumber; 33e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng extern const uint32_t gIEEEInfinity; 34e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng 35e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng /** SK_Scalar1 is defined to be 1.0 represented as an SkScalar 36e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng */ 37e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng #define SK_Scalar1 (1.0f) 38e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng /** SK_Scalar1 is defined to be 1/2 represented as an SkScalar 39e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng */ 40e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng #define SK_ScalarHalf (0.5f) 41e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng /** SK_ScalarInfinity is defined to be infinity as an SkScalar 42e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng */ 43e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng #define SK_ScalarInfinity (*(const float*)&gIEEEInfinity) 44e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng /** SK_ScalarMax is defined to be the largest value representable as an SkScalar 45e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng */ 46e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng #define SK_ScalarMax (3.402823466e+38f) 47e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng /** SK_ScalarMin is defined to be the smallest value representable as an SkScalar 48e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng */ 49e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng #define SK_ScalarMin (-SK_ScalarMax) 50e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng /** SK_ScalarNaN is defined to be 'Not a Number' as an SkScalar 51e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng */ 52e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng #define SK_ScalarNaN (*(const float*)(const void*)&gIEEENotANumber) 53e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng /** SkScalarIsNaN(n) returns true if argument is not a number 54e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng */ 55e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng static inline bool SkScalarIsNaN(float x) { return x != x; } 56e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng 57e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng /** Returns true if x is not NaN and not infinite */ 58e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng static inline bool SkScalarIsFinite(float x) { 59e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng // We rely on the following behavior of infinities and nans 60e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng // 0 * finite --> 0 61e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng // 0 * infinity --> NaN 62e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng // 0 * NaN --> NaN 63e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng float prod = x * 0; 64e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng // At this point, prod will either be NaN or 0 65e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng // Therefore we can return (prod == prod) or (0 == prod). 66e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng return prod == prod; 67e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng } 68e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng 69e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng#ifdef SK_DEBUG 70e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng /** SkIntToScalar(n) returns its integer argument as an SkScalar 71e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng * 72e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng * If we're compiling in DEBUG mode, and can thus afford some extra runtime 73e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng * cycles, check to make sure that the parameter passed in has not already 74e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng * been converted to SkScalar. (A double conversion like this is harmless 75e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng * for SK_SCALAR_IS_FLOAT, but for SK_SCALAR_IS_FIXED this causes trouble.) 76e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng * 77e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng * Note that we need all of these method signatures to properly handle the 78e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng * various types that we pass into SkIntToScalar() to date: 79e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng * int, size_t, U8CPU, etc., even though what we really mean is "anything 80e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng * but a float". 81e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng */ 82e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng static inline float SkIntToScalar(int param) { 83e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng return (float)param; 84e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng } 85e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng static inline float SkIntToScalar(unsigned int param) { 86e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng return (float)param; 87e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng } 88e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng static inline float SkIntToScalar(long param) { 89e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng return (float)param; 90e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng } 91e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng static inline float SkIntToScalar(unsigned long param) { 92e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng return (float)param; 93e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng } 94e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng static inline float SkIntToScalar(int64_t param) { 95e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng return (float)param; 96e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng } 97e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng static inline float SkIntToScalar(uint64_t param) { 98e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng return (float)param; 99e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng } 100e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng static inline float SkIntToScalar(float /* param */) { 101e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng /* If the parameter passed into SkIntToScalar is a float, 102e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng * one of two things has happened: 103e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng * 1. the parameter was an SkScalar (which is typedef'd to float) 104e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng * 2. the parameter was a float instead of an int 105e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng * 106e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng * Either way, it's not good. 107e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng */ 108e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng SkDEBUGFAIL("looks like you passed an SkScalar into SkIntToScalar"); 109e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng return (float)0; 110e6e8a0bd7cffcc9ae2e0e75546fb12a19213d4aeBen Cheng } 111#else // not SK_DEBUG 112 /** SkIntToScalar(n) returns its integer argument as an SkScalar 113 */ 114 #define SkIntToScalar(n) ((float)(n)) 115#endif // not SK_DEBUG 116 /** SkFixedToScalar(n) returns its SkFixed argument as an SkScalar 117 */ 118 #define SkFixedToScalar(x) SkFixedToFloat(x) 119 /** SkScalarToFixed(n) returns its SkScalar argument as an SkFixed 120 */ 121 #define SkScalarToFixed(x) SkFloatToFixed(x) 122 123 #define SkScalarToFloat(n) (n) 124 #define SkFloatToScalar(n) (n) 125 126 #define SkScalarToDouble(n) (double)(n) 127 #define SkDoubleToScalar(n) (float)(n) 128 129 /** SkScalarFraction(x) returns the signed fractional part of the argument 130 */ 131 #define SkScalarFraction(x) sk_float_mod(x, 1.0f) 132 133 #define SkScalarFloorToScalar(x) sk_float_floor(x) 134 #define SkScalarCeilToScalar(x) sk_float_ceil(x) 135 #define SkScalarRoundToScalar(x) sk_float_floor((x) + 0.5f) 136 137 #define SkScalarFloorToInt(x) sk_float_floor2int(x) 138 #define SkScalarCeilToInt(x) sk_float_ceil2int(x) 139 #define SkScalarRoundToInt(x) sk_float_round2int(x) 140 141 /** Returns the absolute value of the specified SkScalar 142 */ 143 #define SkScalarAbs(x) sk_float_abs(x) 144 /** Return x with the sign of y 145 */ 146 #define SkScalarCopySign(x, y) sk_float_copysign(x, y) 147 /** Returns the value pinned between 0 and max inclusive 148 */ 149 inline SkScalar SkScalarClampMax(SkScalar x, SkScalar max) { 150 return x < 0 ? 0 : x > max ? max : x; 151 } 152 /** Returns the value pinned between min and max inclusive 153 */ 154 inline SkScalar SkScalarPin(SkScalar x, SkScalar min, SkScalar max) { 155 return x < min ? min : x > max ? max : x; 156 } 157 /** Returns the specified SkScalar squared (x*x) 158 */ 159 inline SkScalar SkScalarSquare(SkScalar x) { return x * x; } 160 /** Returns the product of two SkScalars 161 */ 162 #define SkScalarMul(a, b) ((float)(a) * (b)) 163 /** Returns the product of two SkScalars plus a third SkScalar 164 */ 165 #define SkScalarMulAdd(a, b, c) ((float)(a) * (b) + (c)) 166 /** Returns the product of a SkScalar and an int rounded to the nearest integer value 167 */ 168 #define SkScalarMulRound(a, b) SkScalarRound((float)(a) * (b)) 169 /** Returns the product of a SkScalar and an int promoted to the next larger int 170 */ 171 #define SkScalarMulCeil(a, b) SkScalarCeil((float)(a) * (b)) 172 /** Returns the product of a SkScalar and an int truncated to the next smaller int 173 */ 174 #define SkScalarMulFloor(a, b) SkScalarFloor((float)(a) * (b)) 175 /** Returns the quotient of two SkScalars (a/b) 176 */ 177 #define SkScalarDiv(a, b) ((float)(a) / (b)) 178 /** Returns the mod of two SkScalars (a mod b) 179 */ 180 #define SkScalarMod(x,y) sk_float_mod(x,y) 181 /** Returns the product of the first two arguments, divided by the third argument 182 */ 183 #define SkScalarMulDiv(a, b, c) ((float)(a) * (b) / (c)) 184 /** Returns the multiplicative inverse of the SkScalar (1/x) 185 */ 186 #define SkScalarInvert(x) (SK_Scalar1 / (x)) 187 #define SkScalarFastInvert(x) (SK_Scalar1 / (x)) 188 /** Returns the square root of the SkScalar 189 */ 190 #define SkScalarSqrt(x) sk_float_sqrt(x) 191 /** Returns b to the e 192 */ 193 #define SkScalarPow(b, e) sk_float_pow(b, e) 194 /** Returns the average of two SkScalars (a+b)/2 195 */ 196 #define SkScalarAve(a, b) (((a) + (b)) * 0.5f) 197 /** Returns the geometric mean of two SkScalars 198 */ 199 #define SkScalarMean(a, b) sk_float_sqrt((float)(a) * (b)) 200 /** Returns one half of the specified SkScalar 201 */ 202 #define SkScalarHalf(a) ((a) * 0.5f) 203 204 #define SK_ScalarSqrt2 1.41421356f 205 #define SK_ScalarPI 3.14159265f 206 #define SK_ScalarTanPIOver8 0.414213562f 207 #define SK_ScalarRoot2Over2 0.707106781f 208 209 #define SkDegreesToRadians(degrees) ((degrees) * (SK_ScalarPI / 180)) 210 float SkScalarSinCos(SkScalar radians, SkScalar* cosValue); 211 #define SkScalarSin(radians) (float)sk_float_sin(radians) 212 #define SkScalarCos(radians) (float)sk_float_cos(radians) 213 #define SkScalarTan(radians) (float)sk_float_tan(radians) 214 #define SkScalarASin(val) (float)sk_float_asin(val) 215 #define SkScalarACos(val) (float)sk_float_acos(val) 216 #define SkScalarATan2(y, x) (float)sk_float_atan2(y,x) 217 #define SkScalarExp(x) (float)sk_float_exp(x) 218 #define SkScalarLog(x) (float)sk_float_log(x) 219 220 inline SkScalar SkMaxScalar(SkScalar a, SkScalar b) { return a > b ? a : b; } 221 inline SkScalar SkMinScalar(SkScalar a, SkScalar b) { return a < b ? a : b; } 222 223 static inline bool SkScalarIsInt(SkScalar x) { 224 return x == (float)(int)x; 225 } 226#else 227 typedef SkFixed SkScalar; 228 229 #define SK_Scalar1 SK_Fixed1 230 #define SK_ScalarHalf SK_FixedHalf 231 #define SK_ScalarInfinity SK_FixedMax 232 #define SK_ScalarMax SK_FixedMax 233 #define SK_ScalarMin SK_FixedMin 234 #define SK_ScalarNaN SK_FixedNaN 235 #define SkScalarIsNaN(x) ((x) == SK_FixedNaN) 236 #define SkScalarIsFinite(x) ((x) != SK_FixedNaN) 237 238 #define SkIntToScalar(n) SkIntToFixed(n) 239 #define SkFixedToScalar(x) (x) 240 #define SkScalarToFixed(x) (x) 241 #define SkScalarToFloat(n) SkFixedToFloat(n) 242 #define SkFloatToScalar(n) SkFloatToFixed(n) 243 244 #define SkScalarToDouble(n) SkFixedToDouble(n) 245 #define SkDoubleToScalar(n) SkDoubleToFixed(n) 246 #define SkScalarFraction(x) SkFixedFraction(x) 247 248 #define SkScalarFloorToScalar(x) SkFixedFloorToFixed(x) 249 #define SkScalarCeilToScalar(x) SkFixedCeilToFixed(x) 250 #define SkScalarRoundToScalar(x) SkFixedRoundToFixed(x) 251 252 #define SkScalarFloorToInt(x) SkFixedFloorToInt(x) 253 #define SkScalarCeilToInt(x) SkFixedCeilToInt(x) 254 #define SkScalarRoundToInt(x) SkFixedRoundToInt(x) 255 256 #define SkScalarAbs(x) SkFixedAbs(x) 257 #define SkScalarCopySign(x, y) SkCopySign32(x, y) 258 #define SkScalarClampMax(x, max) SkClampMax(x, max) 259 #define SkScalarPin(x, min, max) SkPin32(x, min, max) 260 #define SkScalarSquare(x) SkFixedSquare(x) 261 #define SkScalarMul(a, b) SkFixedMul(a, b) 262 #define SkScalarMulAdd(a, b, c) SkFixedMulAdd(a, b, c) 263 #define SkScalarMulRound(a, b) SkFixedMulCommon(a, b, SK_FixedHalf) 264 #define SkScalarMulCeil(a, b) SkFixedMulCommon(a, b, SK_Fixed1 - 1) 265 #define SkScalarMulFloor(a, b) SkFixedMulCommon(a, b, 0) 266 #define SkScalarDiv(a, b) SkFixedDiv(a, b) 267 #define SkScalarMod(a, b) SkFixedMod(a, b) 268 #define SkScalarMulDiv(a, b, c) SkMulDiv(a, b, c) 269 #define SkScalarInvert(x) SkFixedInvert(x) 270 #define SkScalarFastInvert(x) SkFixedFastInvert(x) 271 #define SkScalarSqrt(x) SkFixedSqrt(x) 272 #define SkScalarAve(a, b) SkFixedAve(a, b) 273 #define SkScalarMean(a, b) SkFixedMean(a, b) 274 #define SkScalarHalf(a) ((a) >> 1) 275 276 #define SK_ScalarSqrt2 SK_FixedSqrt2 277 #define SK_ScalarPI SK_FixedPI 278 #define SK_ScalarTanPIOver8 SK_FixedTanPIOver8 279 #define SK_ScalarRoot2Over2 SK_FixedRoot2Over2 280 281 #define SkDegreesToRadians(degrees) SkFractMul(degrees, SK_FractPIOver180) 282 #define SkScalarSinCos(radians, cosPtr) SkFixedSinCos(radians, cosPtr) 283 #define SkScalarSin(radians) SkFixedSin(radians) 284 #define SkScalarCos(radians) SkFixedCos(radians) 285 #define SkScalarTan(val) SkFixedTan(val) 286 #define SkScalarASin(val) SkFixedASin(val) 287 #define SkScalarACos(val) SkFixedACos(val) 288 #define SkScalarATan2(y, x) SkFixedATan2(y,x) 289 #define SkScalarExp(x) SkFixedExp(x) 290 #define SkScalarLog(x) SkFixedLog(x) 291 292 #define SkMaxScalar(a, b) SkMax32(a, b) 293 #define SkMinScalar(a, b) SkMin32(a, b) 294 295 static inline bool SkScalarIsInt(SkFixed x) { 296 return 0 == (x & 0xffff); 297 } 298#endif 299 300// DEPRECATED : use ToInt or ToScalar variant 301#define SkScalarFloor(x) SkScalarFloorToInt(x) 302#define SkScalarCeil(x) SkScalarCeilToInt(x) 303#define SkScalarRound(x) SkScalarRoundToInt(x) 304 305/** 306 * Returns -1 || 0 || 1 depending on the sign of value: 307 * -1 if x < 0 308 * 0 if x == 0 309 * 1 if x > 0 310 */ 311static inline int SkScalarSignAsInt(SkScalar x) { 312 return x < 0 ? -1 : (x > 0); 313} 314 315// Scalar result version of above 316static inline SkScalar SkScalarSignAsScalar(SkScalar x) { 317 return x < 0 ? -SK_Scalar1 : ((x > 0) ? SK_Scalar1 : 0); 318} 319 320#define SK_ScalarNearlyZero (SK_Scalar1 / (1 << 12)) 321 322static inline bool SkScalarNearlyZero(SkScalar x, 323 SkScalar tolerance = SK_ScalarNearlyZero) { 324 SkASSERT(tolerance >= 0); 325 return SkScalarAbs(x) <= tolerance; 326} 327 328static inline bool SkScalarNearlyEqual(SkScalar x, SkScalar y, 329 SkScalar tolerance = SK_ScalarNearlyZero) { 330 SkASSERT(tolerance >= 0); 331 return SkScalarAbs(x-y) <= tolerance; 332} 333 334/** Linearly interpolate between A and B, based on t. 335 If t is 0, return A 336 If t is 1, return B 337 else interpolate. 338 t must be [0..SK_Scalar1] 339*/ 340static inline SkScalar SkScalarInterp(SkScalar A, SkScalar B, SkScalar t) { 341 SkASSERT(t >= 0 && t <= SK_Scalar1); 342 return A + SkScalarMul(B - A, t); 343} 344 345/** Interpolate along the function described by (keys[length], values[length]) 346 for the passed searchKey. SearchKeys outside the range keys[0]-keys[Length] 347 clamp to the min or max value. This function was inspired by a desire 348 to change the multiplier for thickness in fakeBold; therefore it assumes 349 the number of pairs (length) will be small, and a linear search is used. 350 Repeated keys are allowed for discontinuous functions (so long as keys is 351 monotonically increasing), and if key is the value of a repeated scalar in 352 keys, the first one will be used. However, that may change if a binary 353 search is used. 354*/ 355SkScalar SkScalarInterpFunc(SkScalar searchKey, const SkScalar keys[], 356 const SkScalar values[], int length); 357 358#endif 359