/* * Copyright (C) 2006 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ #ifndef SkScalar_DEFINED #define SkScalar_DEFINED #include "SkFixed.h" #include "SkFloatingPoint.h" /** \file SkScalar.h Types and macros for the data type SkScalar. This is the fractional numeric type that, depending on the compile-time flag SK_SCALAR_IS_FLOAT, may be implemented either as an IEEE float, or as a 16.16 SkFixed. The macros in this file are written to allow the calling code to manipulate SkScalar values without knowing which representation is in effect. */ #ifdef SK_SCALAR_IS_FLOAT /** SkScalar is our type for fractional values and coordinates. Depending on compile configurations, it is either represented as an IEEE float, or as a 16.16 fixed point integer. */ typedef float SkScalar; extern const uint32_t gIEEENotANumber; extern const uint32_t gIEEEInfinity; /** SK_Scalar1 is defined to be 1.0 represented as an SkScalar */ #define SK_Scalar1 (1.0f) /** SK_Scalar1 is defined to be 1/2 represented as an SkScalar */ #define SK_ScalarHalf (0.5f) /** SK_ScalarInfinity is defined to be infinity as an SkScalar */ #define SK_ScalarInfinity (*(const float*)&gIEEEInfinity) /** SK_ScalarMax is defined to be the largest value representable as an SkScalar */ #define SK_ScalarMax (3.402823466e+38f) /** SK_ScalarMin is defined to be the smallest value representable as an SkScalar */ #define SK_ScalarMin (-SK_ScalarMax) /** SK_ScalarNaN is defined to be 'Not a Number' as an SkScalar */ #define SK_ScalarNaN (*(const float*)(const void*)&gIEEENotANumber) /** SkScalarIsNaN(n) returns true if argument is not a number */ static inline bool SkScalarIsNaN(float x) { return x != x; } /** Returns true if x is not NaN and not infinite */ static inline bool SkScalarIsFinite(float x) { uint32_t bits = SkFloat2Bits(x); // need unsigned for our shifts int exponent = bits << 1 >> 24; return exponent != 0xFF; } #ifdef SK_DEBUG /** SkIntToScalar(n) returns its integer argument as an SkScalar * * If we're compiling in DEBUG mode, and can thus afford some extra runtime * cycles, check to make sure that the parameter passed in has not already * been converted to SkScalar. (A double conversion like this is harmless * for SK_SCALAR_IS_FLOAT, but for SK_SCALAR_IS_FIXED this causes trouble.) * * Note that we need all of these method signatures to properly handle the * various types that we pass into SkIntToScalar() to date: * int, size_t, U8CPU, etc., even though what we really mean is "anything * but a float". */ static inline float SkIntToScalar(signed int param) { return (float)param; } static inline float SkIntToScalar(unsigned int param) { return (float)param; } static inline float SkIntToScalar(signed long param) { return (float)param; } static inline float SkIntToScalar(unsigned long param) { return (float)param; } static inline float SkIntToScalar(float param) { /* If the parameter passed into SkIntToScalar is a float, * one of two things has happened: * 1. the parameter was an SkScalar (which is typedef'd to float) * 2. the parameter was a float instead of an int * * Either way, it's not good. */ SkASSERT(!"looks like you passed an SkScalar into SkIntToScalar"); return (float)0; } #else // not SK_DEBUG /** SkIntToScalar(n) returns its integer argument as an SkScalar */ #define SkIntToScalar(n) ((float)(n)) #endif // not SK_DEBUG /** SkFixedToScalar(n) returns its SkFixed argument as an SkScalar */ #define SkFixedToScalar(x) SkFixedToFloat(x) /** SkScalarToFixed(n) returns its SkScalar argument as an SkFixed */ #define SkScalarToFixed(x) SkFloatToFixed(x) #define SkScalarToFloat(n) (n) #define SkFloatToScalar(n) (n) #define SkScalarToDouble(n) (double)(n) #define SkDoubleToScalar(n) (float)(n) /** SkScalarFraction(x) returns the signed fractional part of the argument */ #define SkScalarFraction(x) sk_float_mod(x, 1.0f) /** Rounds the SkScalar to the nearest integer value */ #define SkScalarRound(x) sk_float_round2int(x) /** Returns the smallest integer that is >= the specified SkScalar */ #define SkScalarCeil(x) sk_float_ceil2int(x) /** Returns the largest integer that is <= the specified SkScalar */ #define SkScalarFloor(x) sk_float_floor2int(x) /** Returns the absolute value of the specified SkScalar */ #define SkScalarAbs(x) sk_float_abs(x) /** Return x with the sign of y */ #define SkScalarCopySign(x, y) sk_float_copysign(x, y) /** Returns the value pinned between 0 and max inclusive */ inline SkScalar SkScalarClampMax(SkScalar x, SkScalar max) { return x < 0 ? 0 : x > max ? max : x; } /** Returns the value pinned between min and max inclusive */ inline SkScalar SkScalarPin(SkScalar x, SkScalar min, SkScalar max) { return x < min ? min : x > max ? max : x; } /** Returns the specified SkScalar squared (x*x) */ inline SkScalar SkScalarSquare(SkScalar x) { return x * x; } /** Returns the product of two SkScalars */ #define SkScalarMul(a, b) ((float)(a) * (b)) /** Returns the product of two SkScalars plus a third SkScalar */ #define SkScalarMulAdd(a, b, c) ((float)(a) * (b) + (c)) /** Returns the product of a SkScalar and an int rounded to the nearest integer value */ #define SkScalarMulRound(a, b) SkScalarRound((float)(a) * (b)) /** Returns the product of a SkScalar and an int promoted to the next larger int */ #define SkScalarMulCeil(a, b) SkScalarCeil((float)(a) * (b)) /** Returns the product of a SkScalar and an int truncated to the next smaller int */ #define SkScalarMulFloor(a, b) SkScalarFloor((float)(a) * (b)) /** Returns the quotient of two SkScalars (a/b) */ #define SkScalarDiv(a, b) ((float)(a) / (b)) /** Returns the mod of two SkScalars (a mod b) */ #define SkScalarMod(x,y) sk_float_mod(x,y) /** Returns the product of the first two arguments, divided by the third argument */ #define SkScalarMulDiv(a, b, c) ((float)(a) * (b) / (c)) /** Returns the multiplicative inverse of the SkScalar (1/x) */ #define SkScalarInvert(x) (SK_Scalar1 / (x)) #define SkScalarFastInvert(x) (SK_Scalar1 / (x)) /** Returns the square root of the SkScalar */ #define SkScalarSqrt(x) sk_float_sqrt(x) /** Returns the average of two SkScalars (a+b)/2 */ #define SkScalarAve(a, b) (((a) + (b)) * 0.5f) /** Returns the geometric mean of two SkScalars */ #define SkScalarMean(a, b) sk_float_sqrt((float)(a) * (b)) /** Returns one half of the specified SkScalar */ #define SkScalarHalf(a) ((a) * 0.5f) #define SK_ScalarSqrt2 1.41421356f #define SK_ScalarPI 3.14159265f #define SK_ScalarTanPIOver8 0.414213562f #define SK_ScalarRoot2Over2 0.707106781f #define SkDegreesToRadians(degrees) ((degrees) * (SK_ScalarPI / 180)) float SkScalarSinCos(SkScalar radians, SkScalar* cosValue); #define SkScalarSin(radians) (float)sk_float_sin(radians) #define SkScalarCos(radians) (float)sk_float_cos(radians) #define SkScalarTan(radians) (float)sk_float_tan(radians) #define SkScalarASin(val) (float)sk_float_asin(val) #define SkScalarACos(val) (float)sk_float_acos(val) #define SkScalarATan2(y, x) (float)sk_float_atan2(y,x) #define SkScalarExp(x) (float)sk_float_exp(x) #define SkScalarLog(x) (float)sk_float_log(x) inline SkScalar SkMaxScalar(SkScalar a, SkScalar b) { return a > b ? a : b; } inline SkScalar SkMinScalar(SkScalar a, SkScalar b) { return a < b ? a : b; } static inline bool SkScalarIsInt(SkScalar x) { return x == (float)(int)x; } #else typedef SkFixed SkScalar; #define SK_Scalar1 SK_Fixed1 #define SK_ScalarHalf SK_FixedHalf #define SK_ScalarInfinity SK_FixedMax #define SK_ScalarMax SK_FixedMax #define SK_ScalarMin SK_FixedMin #define SK_ScalarNaN SK_FixedNaN #define SkScalarIsNaN(x) ((x) == SK_FixedNaN) #define SkScalarIsFinite(x) ((x) != SK_FixedNaN) #define SkIntToScalar(n) SkIntToFixed(n) #define SkFixedToScalar(x) (x) #define SkScalarToFixed(x) (x) #ifdef SK_CAN_USE_FLOAT #define SkScalarToFloat(n) SkFixedToFloat(n) #define SkFloatToScalar(n) SkFloatToFixed(n) #define SkScalarToDouble(n) SkFixedToDouble(n) #define SkDoubleToScalar(n) SkDoubleToFixed(n) #endif #define SkScalarFraction(x) SkFixedFraction(x) #define SkScalarRound(x) SkFixedRound(x) #define SkScalarCeil(x) SkFixedCeil(x) #define SkScalarFloor(x) SkFixedFloor(x) #define SkScalarAbs(x) SkFixedAbs(x) #define SkScalarCopySign(x, y) SkCopySign32(x, y) #define SkScalarClampMax(x, max) SkClampMax(x, max) #define SkScalarPin(x, min, max) SkPin32(x, min, max) #define SkScalarSquare(x) SkFixedSquare(x) #define SkScalarMul(a, b) SkFixedMul(a, b) #define SkScalarMulAdd(a, b, c) SkFixedMulAdd(a, b, c) #define SkScalarMulRound(a, b) SkFixedMulCommon(a, b, SK_FixedHalf) #define SkScalarMulCeil(a, b) SkFixedMulCommon(a, b, SK_Fixed1 - 1) #define SkScalarMulFloor(a, b) SkFixedMulCommon(a, b, 0) #define SkScalarDiv(a, b) SkFixedDiv(a, b) #define SkScalarMod(a, b) SkFixedMod(a, b) #define SkScalarMulDiv(a, b, c) SkMulDiv(a, b, c) #define SkScalarInvert(x) SkFixedInvert(x) #define SkScalarFastInvert(x) SkFixedFastInvert(x) #define SkScalarSqrt(x) SkFixedSqrt(x) #define SkScalarAve(a, b) SkFixedAve(a, b) #define SkScalarMean(a, b) SkFixedMean(a, b) #define SkScalarHalf(a) ((a) >> 1) #define SK_ScalarSqrt2 SK_FixedSqrt2 #define SK_ScalarPI SK_FixedPI #define SK_ScalarTanPIOver8 SK_FixedTanPIOver8 #define SK_ScalarRoot2Over2 SK_FixedRoot2Over2 #define SkDegreesToRadians(degrees) SkFractMul(degrees, SK_FractPIOver180) #define SkScalarSinCos(radians, cosPtr) SkFixedSinCos(radians, cosPtr) #define SkScalarSin(radians) SkFixedSin(radians) #define SkScalarCos(radians) SkFixedCos(radians) #define SkScalarTan(val) SkFixedTan(val) #define SkScalarASin(val) SkFixedASin(val) #define SkScalarACos(val) SkFixedACos(val) #define SkScalarATan2(y, x) SkFixedATan2(y,x) #define SkScalarExp(x) SkFixedExp(x) #define SkScalarLog(x) SkFixedLog(x) #define SkMaxScalar(a, b) SkMax32(a, b) #define SkMinScalar(a, b) SkMin32(a, b) static inline bool SkScalarIsInt(SkFixed x) { return 0 == (x & 0xffff); } #endif #define SK_ScalarNearlyZero (SK_Scalar1 / (1 << 12)) /* <= is slower than < for floats, so we use < for our tolerance test */ static inline bool SkScalarNearlyZero(SkScalar x, SkScalar tolerance = SK_ScalarNearlyZero) { SkASSERT(tolerance > 0); return SkScalarAbs(x) < tolerance; } static inline bool SkScalarNearlyEqual(SkScalar x, SkScalar y, SkScalar tolerance = SK_ScalarNearlyZero) { SkASSERT(tolerance > 0); return SkScalarAbs(x-y) < tolerance; } /** Linearly interpolate between A and B, based on t. If t is 0, return A If t is 1, return B else interpolate. t must be [0..SK_Scalar1] */ static inline SkScalar SkScalarInterp(SkScalar A, SkScalar B, SkScalar t) { SkASSERT(t >= 0 && t <= SK_Scalar1); return A + SkScalarMul(B - A, t); } /** Interpolate along the function described by (keys[length], values[length]) for the passed searchKey. SearchKeys outside the range keys[0]-keys[Length] clamp to the min or max value. This function was inspired by a desire to change the multiplier for thickness in fakeBold; therefore it assumes the number of pairs (length) will be small, and a linear search is used. Repeated keys are allowed for discontinuous functions (so long as keys is monotonically increasing), and if key is the value of a repeated scalar in keys, the first one will be used. However, that may change if a binary search is used. */ SkScalar SkScalarInterpFunc(SkScalar searchKey, const SkScalar keys[], const SkScalar values[], int length); #endif