reed@android.com | 8a1c16f | 2008-12-17 15:59:43 +0000 | [diff] [blame^] | 1 | /* |
| 2 | * Copyright (C) 2006 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | #ifndef SkScalar_DEFINED |
| 18 | #define SkScalar_DEFINED |
| 19 | |
| 20 | #include "SkFixed.h" |
| 21 | |
| 22 | /** \file SkScalar.h |
| 23 | |
| 24 | Types and macros for the data type SkScalar. This is the fractional numeric type |
| 25 | that, depending on the compile-time flag SK_SCALAR_IS_FLOAT, may be implemented |
| 26 | either as an IEEE float, or as a 16.16 SkFixed. The macros in this file are written |
| 27 | to allow the calling code to manipulate SkScalar values without knowing which representation |
| 28 | is in effect. |
| 29 | */ |
| 30 | |
| 31 | #ifdef SK_SCALAR_IS_FLOAT |
| 32 | #include "SkFloatingPoint.h" |
| 33 | |
| 34 | /** SkScalar is our type for fractional values and coordinates. Depending on |
| 35 | compile configurations, it is either represented as an IEEE float, or |
| 36 | as a 16.16 fixed point integer. |
| 37 | */ |
| 38 | typedef float SkScalar; |
| 39 | extern const uint32_t gIEEENotANumber; |
| 40 | extern const uint32_t gIEEEInfinity; |
| 41 | |
| 42 | /** SK_Scalar1 is defined to be 1.0 represented as an SkScalar |
| 43 | */ |
| 44 | #define SK_Scalar1 (1.0f) |
| 45 | /** SK_Scalar1 is defined to be 1/2 represented as an SkScalar |
| 46 | */ |
| 47 | #define SK_ScalarHalf (0.5f) |
| 48 | /** SK_ScalarInfinity is defined to be infinity as an SkScalar |
| 49 | */ |
| 50 | #define SK_ScalarInfinity (*(const float*)&gIEEEInfinity) |
| 51 | /** SK_ScalarMax is defined to be the largest value representable as an SkScalar |
| 52 | */ |
| 53 | #define SK_ScalarMax (3.4028235e+38f) |
| 54 | /** SK_ScalarMin is defined to be the smallest value representable as an SkScalar |
| 55 | */ |
| 56 | #define SK_ScalarMin (1.1754944e-38f) |
| 57 | /** SK_ScalarNaN is defined to be 'Not a Number' as an SkScalar |
| 58 | */ |
| 59 | #define SK_ScalarNaN (*(const float*)(const void*)&gIEEENotANumber) |
| 60 | /** SkScalarIsNaN(n) returns true if argument is not a number |
| 61 | */ |
| 62 | static inline bool SkScalarIsNaN(float x) { return x != x; } |
| 63 | /** SkIntToScalar(n) returns its integer argument as an SkScalar |
| 64 | */ |
| 65 | #define SkIntToScalar(n) ((float)(n)) |
| 66 | /** SkFixedToScalar(n) returns its SkFixed argument as an SkScalar |
| 67 | */ |
| 68 | #define SkFixedToScalar(x) SkFixedToFloat(x) |
| 69 | /** SkScalarToFixed(n) returns its SkScalar argument as an SkFixed |
| 70 | */ |
| 71 | #define SkScalarToFixed(x) SkFloatToFixed(x) |
| 72 | |
| 73 | #define SkScalarToFloat(n) (n) |
| 74 | #define SkFloatToScalar(n) (n) |
| 75 | |
| 76 | #define SkScalarToDouble(n) (double)(n) |
| 77 | #define SkDoubleToScalar(n) (float)(n) |
| 78 | |
| 79 | /** SkScalarFraction(x) returns the signed fractional part of the argument |
| 80 | */ |
| 81 | #define SkScalarFraction(x) sk_float_mod(x, 1.0f) |
| 82 | /** Rounds the SkScalar to the nearest integer value |
| 83 | */ |
| 84 | #define SkScalarRound(x) sk_float_round2int(x) |
| 85 | /** Returns the smallest integer that is >= the specified SkScalar |
| 86 | */ |
| 87 | #define SkScalarCeil(x) sk_float_ceil2int(x) |
| 88 | /** Returns the largest integer that is <= the specified SkScalar |
| 89 | */ |
| 90 | #define SkScalarFloor(x) sk_float_floor2int(x) |
| 91 | /** Returns the absolute value of the specified SkScalar |
| 92 | */ |
| 93 | #define SkScalarAbs(x) sk_float_abs(x) |
| 94 | /** Returns the value pinned between 0 and max inclusive |
| 95 | */ |
| 96 | inline SkScalar SkScalarClampMax(SkScalar x, SkScalar max) { |
| 97 | return x < 0 ? 0 : x > max ? max : x; |
| 98 | } |
| 99 | /** Returns the value pinned between min and max inclusive |
| 100 | */ |
| 101 | inline SkScalar SkScalarPin(SkScalar x, SkScalar min, SkScalar max) { |
| 102 | return x < min ? min : x > max ? max : x; |
| 103 | } |
| 104 | /** Returns the specified SkScalar squared (x*x) |
| 105 | */ |
| 106 | inline SkScalar SkScalarSquare(SkScalar x) { return x * x; } |
| 107 | /** Returns the product of two SkScalars |
| 108 | */ |
| 109 | #define SkScalarMul(a, b) ((float)(a) * (b)) |
| 110 | /** Returns the product of two SkScalars plus a third SkScalar |
| 111 | */ |
| 112 | #define SkScalarMulAdd(a, b, c) ((float)(a) * (b) + (c)) |
| 113 | /** Returns the product of a SkScalar and an int rounded to the nearest integer value |
| 114 | */ |
| 115 | #define SkScalarMulRound(a, b) SkScalarRound((float)(a) * (b)) |
| 116 | /** Returns the product of a SkScalar and an int promoted to the next larger int |
| 117 | */ |
| 118 | #define SkScalarMulCeil(a, b) SkScalarCeil((float)(a) * (b)) |
| 119 | /** Returns the product of a SkScalar and an int truncated to the next smaller int |
| 120 | */ |
| 121 | #define SkScalarMulFloor(a, b) SkScalarFloor((float)(a) * (b)) |
| 122 | /** Returns the quotient of two SkScalars (a/b) |
| 123 | */ |
| 124 | #define SkScalarDiv(a, b) ((float)(a) / (b)) |
| 125 | /** Returns the mod of two SkScalars (a mod b) |
| 126 | */ |
| 127 | #define SkScalarMod(x,y) sk_float_mod(x,y) |
| 128 | /** Returns the product of the first two arguments, divided by the third argument |
| 129 | */ |
| 130 | #define SkScalarMulDiv(a, b, c) ((float)(a) * (b) / (c)) |
| 131 | /** Returns the multiplicative inverse of the SkScalar (1/x) |
| 132 | */ |
| 133 | #define SkScalarInvert(x) (SK_Scalar1 / (x)) |
| 134 | #define SkScalarFastInvert(x) (SK_Scalar1 / (x)) |
| 135 | /** Returns the square root of the SkScalar |
| 136 | */ |
| 137 | #define SkScalarSqrt(x) sk_float_sqrt(x) |
| 138 | /** Returns the average of two SkScalars (a+b)/2 |
| 139 | */ |
| 140 | #define SkScalarAve(a, b) (((a) + (b)) * 0.5f) |
| 141 | /** Returns the geometric mean of two SkScalars |
| 142 | */ |
| 143 | #define SkScalarMean(a, b) sk_float_sqrt((float)(a) * (b)) |
| 144 | /** Returns one half of the specified SkScalar |
| 145 | */ |
| 146 | #define SkScalarHalf(a) ((a) * 0.5f) |
| 147 | |
| 148 | #define SK_ScalarSqrt2 1.41421356f |
| 149 | #define SK_ScalarPI 3.14159265f |
| 150 | #define SK_ScalarTanPIOver8 0.414213562f |
| 151 | #define SK_ScalarRoot2Over2 0.707106781f |
| 152 | |
| 153 | #define SkDegreesToRadians(degrees) ((degrees) * (SK_ScalarPI / 180)) |
| 154 | float SkScalarSinCos(SkScalar radians, SkScalar* cosValue); |
| 155 | #define SkScalarSin(radians) (float)sk_float_sin(radians) |
| 156 | #define SkScalarCos(radians) (float)sk_float_cos(radians) |
| 157 | #define SkScalarTan(radians) (float)sk_float_tan(radians) |
| 158 | #define SkScalarASin(val) (float)sk_float_asin(val) |
| 159 | #define SkScalarACos(val) (float)sk_float_acos(val) |
| 160 | #define SkScalarATan2(y, x) (float)sk_float_atan2(y,x) |
| 161 | #define SkScalarExp(x) (float)sk_float_exp(x) |
| 162 | #define SkScalarLog(x) (float)sk_float_log(x) |
| 163 | |
| 164 | inline SkScalar SkMaxScalar(SkScalar a, SkScalar b) { return a > b ? a : b; } |
| 165 | inline SkScalar SkMinScalar(SkScalar a, SkScalar b) { return a < b ? a : b; } |
| 166 | |
| 167 | #else |
| 168 | typedef SkFixed SkScalar; |
| 169 | |
| 170 | #define SK_Scalar1 SK_Fixed1 |
| 171 | #define SK_ScalarHalf SK_FixedHalf |
| 172 | #define SK_ScalarInfinity SK_FixedMax |
| 173 | #define SK_ScalarMax SK_FixedMax |
| 174 | #define SK_ScalarMin SK_FixedMin |
| 175 | #define SK_ScalarNaN SK_FixedNaN |
| 176 | #define SkScalarIsNaN(x) ((x) == SK_FixedNaN) |
| 177 | #define SkIntToScalar(n) SkIntToFixed(n) |
| 178 | #define SkFixedToScalar(x) (x) |
| 179 | #define SkScalarToFixed(x) (x) |
| 180 | #ifdef SK_CAN_USE_FLOAT |
| 181 | #define SkScalarToFloat(n) SkFixedToFloat(n) |
| 182 | #define SkFloatToScalar(n) SkFloatToFixed(n) |
| 183 | |
| 184 | #define SkScalarToDouble(n) SkFixedToDouble(n) |
| 185 | #define SkDoubleToScalar(n) SkDoubleToFixed(n) |
| 186 | #endif |
| 187 | #define SkScalarFraction(x) SkFixedFraction(x) |
| 188 | #define SkScalarRound(x) SkFixedRound(x) |
| 189 | #define SkScalarCeil(x) SkFixedCeil(x) |
| 190 | #define SkScalarFloor(x) SkFixedFloor(x) |
| 191 | #define SkScalarAbs(x) SkFixedAbs(x) |
| 192 | #define SkScalarClampMax(x, max) SkClampMax(x, max) |
| 193 | #define SkScalarPin(x, min, max) SkPin32(x, min, max) |
| 194 | #define SkScalarSquare(x) SkFixedSquare(x) |
| 195 | #define SkScalarMul(a, b) SkFixedMul(a, b) |
| 196 | #define SkScalarMulAdd(a, b, c) SkFixedMulAdd(a, b, c) |
| 197 | #define SkScalarMulRound(a, b) SkFixedMulCommon(a, b, SK_FixedHalf) |
| 198 | #define SkScalarMulCeil(a, b) SkFixedMulCommon(a, b, SK_Fixed1 - 1) |
| 199 | #define SkScalarMulFloor(a, b) SkFixedMulCommon(a, b, 0) |
| 200 | #define SkScalarDiv(a, b) SkFixedDiv(a, b) |
| 201 | #define SkScalarMod(a, b) SkFixedMod(a, b) |
| 202 | #define SkScalarMulDiv(a, b, c) SkMulDiv(a, b, c) |
| 203 | #define SkScalarInvert(x) SkFixedInvert(x) |
| 204 | #define SkScalarFastInvert(x) SkFixedFastInvert(x) |
| 205 | #define SkScalarSqrt(x) SkFixedSqrt(x) |
| 206 | #define SkScalarAve(a, b) SkFixedAve(a, b) |
| 207 | #define SkScalarMean(a, b) SkFixedMean(a, b) |
| 208 | #define SkScalarHalf(a) ((a) >> 1) |
| 209 | |
| 210 | #define SK_ScalarSqrt2 SK_FixedSqrt2 |
| 211 | #define SK_ScalarPI SK_FixedPI |
| 212 | #define SK_ScalarTanPIOver8 SK_FixedTanPIOver8 |
| 213 | #define SK_ScalarRoot2Over2 SK_FixedRoot2Over2 |
| 214 | |
| 215 | #define SkDegreesToRadians(degrees) SkFractMul(degrees, SK_FractPIOver180) |
| 216 | #define SkScalarSinCos(radians, cosPtr) SkFixedSinCos(radians, cosPtr) |
| 217 | #define SkScalarSin(radians) SkFixedSin(radians) |
| 218 | #define SkScalarCos(radians) SkFixedCos(radians) |
| 219 | #define SkScalarTan(val) SkFixedTan(val) |
| 220 | #define SkScalarASin(val) SkFixedASin(val) |
| 221 | #define SkScalarACos(val) SkFixedACos(val) |
| 222 | #define SkScalarATan2(y, x) SkFixedATan2(y,x) |
| 223 | #define SkScalarExp(x) SkFixedExp(x) |
| 224 | #define SkScalarLog(x) SkFixedLog(x) |
| 225 | |
| 226 | #define SkMaxScalar(a, b) SkMax32(a, b) |
| 227 | #define SkMinScalar(a, b) SkMin32(a, b) |
| 228 | #endif |
| 229 | |
| 230 | #define SK_ScalarNearlyZero (SK_Scalar1 / (1 << 12)) |
| 231 | |
| 232 | /* <= is slower than < for floats, so we use < for our tolerance test |
| 233 | */ |
| 234 | |
| 235 | inline bool SkScalarNearlyZero(SkScalar x, SkScalar tolerance = SK_ScalarNearlyZero) |
| 236 | { |
| 237 | SkASSERT(tolerance > 0); |
| 238 | return SkScalarAbs(x) < tolerance; |
| 239 | } |
| 240 | |
| 241 | /** Linearly interpolate between A and B, based on t. |
| 242 | If t is 0, return A |
| 243 | If t is 1, return B |
| 244 | else interpolate. |
| 245 | t must be [0..SK_Scalar1] |
| 246 | */ |
| 247 | inline SkScalar SkScalarInterp(SkScalar A, SkScalar B, SkScalar t) |
| 248 | { |
| 249 | SkASSERT(t >= 0 && t <= SK_Scalar1); |
| 250 | return A + SkScalarMul(B - A, t); |
| 251 | } |
| 252 | |
| 253 | #endif |
| 254 | |