077910e20c
git-svn-id: http://skia.googlecode.com/svn/trunk@775 2bbb7eff-a529-9590-31e7-b0007b416f81
279 lines
11 KiB
C
279 lines
11 KiB
C
/*
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* Copyright (C) 2006 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#ifndef SkScalar_DEFINED
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#define SkScalar_DEFINED
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#include "SkFixed.h"
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/** \file SkScalar.h
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Types and macros for the data type SkScalar. This is the fractional numeric type
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that, depending on the compile-time flag SK_SCALAR_IS_FLOAT, may be implemented
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either as an IEEE float, or as a 16.16 SkFixed. The macros in this file are written
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to allow the calling code to manipulate SkScalar values without knowing which representation
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is in effect.
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*/
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#ifdef SK_SCALAR_IS_FLOAT
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#include "SkFloatingPoint.h"
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/** SkScalar is our type for fractional values and coordinates. Depending on
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compile configurations, it is either represented as an IEEE float, or
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as a 16.16 fixed point integer.
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*/
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typedef float SkScalar;
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extern const uint32_t gIEEENotANumber;
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extern const uint32_t gIEEEInfinity;
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/** SK_Scalar1 is defined to be 1.0 represented as an SkScalar
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*/
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#define SK_Scalar1 (1.0f)
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/** SK_Scalar1 is defined to be 1/2 represented as an SkScalar
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*/
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#define SK_ScalarHalf (0.5f)
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/** SK_ScalarInfinity is defined to be infinity as an SkScalar
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*/
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#define SK_ScalarInfinity (*(const float*)&gIEEEInfinity)
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/** SK_ScalarMax is defined to be the largest value representable as an SkScalar
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*/
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#define SK_ScalarMax (3.4028235e+38f)
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/** SK_ScalarMin is defined to be the smallest value representable as an SkScalar
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*/
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#define SK_ScalarMin (1.1754944e-38f)
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/** SK_ScalarNaN is defined to be 'Not a Number' as an SkScalar
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*/
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#define SK_ScalarNaN (*(const float*)(const void*)&gIEEENotANumber)
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/** SkScalarIsNaN(n) returns true if argument is not a number
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*/
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static inline bool SkScalarIsNaN(float x) { return x != x; }
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/** Returns true if x is not NaN and not infinite */
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static inline bool SkScalarIsFinite(float x) {
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uint32_t bits = SkFloat2Bits(x); // need unsigned for our shifts
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int exponent = bits << 1 >> 24;
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return exponent != 0xFF;
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}
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/** SkIntToScalar(n) returns its integer argument as an SkScalar
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*/
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#define SkIntToScalar(n) ((float)(n))
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/** SkFixedToScalar(n) returns its SkFixed argument as an SkScalar
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*/
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#define SkFixedToScalar(x) SkFixedToFloat(x)
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/** SkScalarToFixed(n) returns its SkScalar argument as an SkFixed
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*/
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#define SkScalarToFixed(x) SkFloatToFixed(x)
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#define SkScalarToFloat(n) (n)
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#define SkFloatToScalar(n) (n)
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#define SkScalarToDouble(n) (double)(n)
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#define SkDoubleToScalar(n) (float)(n)
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/** SkScalarFraction(x) returns the signed fractional part of the argument
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*/
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#define SkScalarFraction(x) sk_float_mod(x, 1.0f)
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/** Rounds the SkScalar to the nearest integer value
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*/
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#define SkScalarRound(x) sk_float_round2int(x)
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/** Returns the smallest integer that is >= the specified SkScalar
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*/
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#define SkScalarCeil(x) sk_float_ceil2int(x)
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/** Returns the largest integer that is <= the specified SkScalar
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*/
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#define SkScalarFloor(x) sk_float_floor2int(x)
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/** Returns the absolute value of the specified SkScalar
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*/
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#define SkScalarAbs(x) sk_float_abs(x)
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/** Return x with the sign of y
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*/
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#define SkScalarCopySign(x, y) sk_float_copysign(x, y)
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/** Returns the value pinned between 0 and max inclusive
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*/
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inline SkScalar SkScalarClampMax(SkScalar x, SkScalar max) {
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return x < 0 ? 0 : x > max ? max : x;
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}
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/** Returns the value pinned between min and max inclusive
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*/
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inline SkScalar SkScalarPin(SkScalar x, SkScalar min, SkScalar max) {
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return x < min ? min : x > max ? max : x;
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}
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/** Returns the specified SkScalar squared (x*x)
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*/
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inline SkScalar SkScalarSquare(SkScalar x) { return x * x; }
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/** Returns the product of two SkScalars
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*/
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#define SkScalarMul(a, b) ((float)(a) * (b))
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/** Returns the product of two SkScalars plus a third SkScalar
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*/
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#define SkScalarMulAdd(a, b, c) ((float)(a) * (b) + (c))
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/** Returns the product of a SkScalar and an int rounded to the nearest integer value
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*/
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#define SkScalarMulRound(a, b) SkScalarRound((float)(a) * (b))
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/** Returns the product of a SkScalar and an int promoted to the next larger int
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*/
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#define SkScalarMulCeil(a, b) SkScalarCeil((float)(a) * (b))
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/** Returns the product of a SkScalar and an int truncated to the next smaller int
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*/
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#define SkScalarMulFloor(a, b) SkScalarFloor((float)(a) * (b))
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/** Returns the quotient of two SkScalars (a/b)
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*/
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#define SkScalarDiv(a, b) ((float)(a) / (b))
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/** Returns the mod of two SkScalars (a mod b)
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*/
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#define SkScalarMod(x,y) sk_float_mod(x,y)
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/** Returns the product of the first two arguments, divided by the third argument
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*/
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#define SkScalarMulDiv(a, b, c) ((float)(a) * (b) / (c))
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/** Returns the multiplicative inverse of the SkScalar (1/x)
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*/
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#define SkScalarInvert(x) (SK_Scalar1 / (x))
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#define SkScalarFastInvert(x) (SK_Scalar1 / (x))
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/** Returns the square root of the SkScalar
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*/
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#define SkScalarSqrt(x) sk_float_sqrt(x)
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/** Returns the average of two SkScalars (a+b)/2
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*/
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#define SkScalarAve(a, b) (((a) + (b)) * 0.5f)
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/** Returns the geometric mean of two SkScalars
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*/
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#define SkScalarMean(a, b) sk_float_sqrt((float)(a) * (b))
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/** Returns one half of the specified SkScalar
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*/
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#define SkScalarHalf(a) ((a) * 0.5f)
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#define SK_ScalarSqrt2 1.41421356f
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#define SK_ScalarPI 3.14159265f
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#define SK_ScalarTanPIOver8 0.414213562f
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#define SK_ScalarRoot2Over2 0.707106781f
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#define SkDegreesToRadians(degrees) ((degrees) * (SK_ScalarPI / 180))
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float SkScalarSinCos(SkScalar radians, SkScalar* cosValue);
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#define SkScalarSin(radians) (float)sk_float_sin(radians)
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#define SkScalarCos(radians) (float)sk_float_cos(radians)
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#define SkScalarTan(radians) (float)sk_float_tan(radians)
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#define SkScalarASin(val) (float)sk_float_asin(val)
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#define SkScalarACos(val) (float)sk_float_acos(val)
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#define SkScalarATan2(y, x) (float)sk_float_atan2(y,x)
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#define SkScalarExp(x) (float)sk_float_exp(x)
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#define SkScalarLog(x) (float)sk_float_log(x)
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inline SkScalar SkMaxScalar(SkScalar a, SkScalar b) { return a > b ? a : b; }
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inline SkScalar SkMinScalar(SkScalar a, SkScalar b) { return a < b ? a : b; }
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#else
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typedef SkFixed SkScalar;
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#define SK_Scalar1 SK_Fixed1
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#define SK_ScalarHalf SK_FixedHalf
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#define SK_ScalarInfinity SK_FixedMax
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#define SK_ScalarMax SK_FixedMax
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#define SK_ScalarMin SK_FixedMin
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#define SK_ScalarNaN SK_FixedNaN
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#define SkScalarIsNaN(x) ((x) == SK_FixedNaN)
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#define SkScalarIsFinite(x) ((x) != SK_FixedNaN)
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#define SkIntToScalar(n) SkIntToFixed(n)
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#define SkFixedToScalar(x) (x)
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#define SkScalarToFixed(x) (x)
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#ifdef SK_CAN_USE_FLOAT
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#define SkScalarToFloat(n) SkFixedToFloat(n)
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#define SkFloatToScalar(n) SkFloatToFixed(n)
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#define SkScalarToDouble(n) SkFixedToDouble(n)
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#define SkDoubleToScalar(n) SkDoubleToFixed(n)
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#endif
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#define SkScalarFraction(x) SkFixedFraction(x)
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#define SkScalarRound(x) SkFixedRound(x)
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#define SkScalarCeil(x) SkFixedCeil(x)
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#define SkScalarFloor(x) SkFixedFloor(x)
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#define SkScalarAbs(x) SkFixedAbs(x)
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#define SkScalarCopySign(x, y) SkCopySign32(x, y)
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#define SkScalarClampMax(x, max) SkClampMax(x, max)
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#define SkScalarPin(x, min, max) SkPin32(x, min, max)
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#define SkScalarSquare(x) SkFixedSquare(x)
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#define SkScalarMul(a, b) SkFixedMul(a, b)
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#define SkScalarMulAdd(a, b, c) SkFixedMulAdd(a, b, c)
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#define SkScalarMulRound(a, b) SkFixedMulCommon(a, b, SK_FixedHalf)
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#define SkScalarMulCeil(a, b) SkFixedMulCommon(a, b, SK_Fixed1 - 1)
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#define SkScalarMulFloor(a, b) SkFixedMulCommon(a, b, 0)
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#define SkScalarDiv(a, b) SkFixedDiv(a, b)
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#define SkScalarMod(a, b) SkFixedMod(a, b)
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#define SkScalarMulDiv(a, b, c) SkMulDiv(a, b, c)
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#define SkScalarInvert(x) SkFixedInvert(x)
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#define SkScalarFastInvert(x) SkFixedFastInvert(x)
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#define SkScalarSqrt(x) SkFixedSqrt(x)
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#define SkScalarAve(a, b) SkFixedAve(a, b)
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#define SkScalarMean(a, b) SkFixedMean(a, b)
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#define SkScalarHalf(a) ((a) >> 1)
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#define SK_ScalarSqrt2 SK_FixedSqrt2
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#define SK_ScalarPI SK_FixedPI
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#define SK_ScalarTanPIOver8 SK_FixedTanPIOver8
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#define SK_ScalarRoot2Over2 SK_FixedRoot2Over2
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#define SkDegreesToRadians(degrees) SkFractMul(degrees, SK_FractPIOver180)
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#define SkScalarSinCos(radians, cosPtr) SkFixedSinCos(radians, cosPtr)
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#define SkScalarSin(radians) SkFixedSin(radians)
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#define SkScalarCos(radians) SkFixedCos(radians)
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#define SkScalarTan(val) SkFixedTan(val)
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#define SkScalarASin(val) SkFixedASin(val)
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#define SkScalarACos(val) SkFixedACos(val)
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#define SkScalarATan2(y, x) SkFixedATan2(y,x)
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#define SkScalarExp(x) SkFixedExp(x)
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#define SkScalarLog(x) SkFixedLog(x)
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#define SkMaxScalar(a, b) SkMax32(a, b)
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#define SkMinScalar(a, b) SkMin32(a, b)
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#endif
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#define SK_ScalarNearlyZero (SK_Scalar1 / (1 << 12))
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/* <= is slower than < for floats, so we use < for our tolerance test
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*/
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static inline bool SkScalarNearlyZero(SkScalar x,
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SkScalar tolerance = SK_ScalarNearlyZero) {
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SkASSERT(tolerance > 0);
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return SkScalarAbs(x) < tolerance;
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}
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/** Linearly interpolate between A and B, based on t.
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If t is 0, return A
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If t is 1, return B
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else interpolate.
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t must be [0..SK_Scalar1]
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*/
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static inline SkScalar SkScalarInterp(SkScalar A, SkScalar B, SkScalar t) {
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SkASSERT(t >= 0 && t <= SK_Scalar1);
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return A + SkScalarMul(B - A, t);
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}
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/** Interpolate along the function described by (keys[length], values[length])
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for the passed searchKey. SearchKeys outside the range keys[0]-keys[Length]
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clamp to the min or max value. This function was inspired by a desire
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to change the multiplier for thickness in fakeBold; therefore it assumes
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the number of pairs (length) will be small, and a linear search is used.
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Repeated keys are allowed for discontinuous functions (so long as keys is
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monotonically increasing), and if key is the value of a repeated scalar in
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keys, the first one will be used. However, that may change if a binary
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search is used.
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*/
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SkScalar SkScalarInterpFunc(SkScalar searchKey, const SkScalar keys[],
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const SkScalar values[], int length);
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#endif
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