167eb17cd6
This changes SkScalarClampMax and SkScalarPin to use SkTMin and SkTMax. This change allows compilers to more easily transform these operations into fast max/min operarations as opposed to conditional branches. Review URL: https://codereview.chromium.org/993593002
273 lines
9.3 KiB
C
273 lines
9.3 KiB
C
/*
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* Copyright 2006 The Android Open Source Project
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*
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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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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#include "SkFloatingPoint.h"
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// TODO: move this sort of check into SkPostConfig.h
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#define SK_SCALAR_IS_DOUBLE 0
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#undef SK_SCALAR_IS_FLOAT
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#define SK_SCALAR_IS_FLOAT 1
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#if SK_SCALAR_IS_FLOAT
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typedef float SkScalar;
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#define SK_Scalar1 1.0f
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#define SK_ScalarHalf 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 SK_ScalarMax 3.402823466e+38f
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#define SK_ScalarInfinity SK_FloatInfinity
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#define SK_ScalarNegativeInfinity SK_FloatNegativeInfinity
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#define SK_ScalarNaN SK_FloatNaN
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#define SkFixedToScalar(x) SkFixedToFloat(x)
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#define SkScalarToFixed(x) SkFloatToFixed(x)
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#define SkScalarFloorToScalar(x) sk_float_floor(x)
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#define SkScalarCeilToScalar(x) sk_float_ceil(x)
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#define SkScalarRoundToScalar(x) sk_float_floor((x) + 0.5f)
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#define SkScalarFloorToInt(x) sk_float_floor2int(x)
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#define SkScalarCeilToInt(x) sk_float_ceil2int(x)
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#define SkScalarRoundToInt(x) sk_float_round2int(x)
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#define SkScalarAbs(x) sk_float_abs(x)
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#define SkScalarCopySign(x, y) sk_float_copysign(x, y)
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#define SkScalarMod(x, y) sk_float_mod(x,y)
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#define SkScalarFraction(x) sk_float_mod(x, 1.0f)
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#define SkScalarSqrt(x) sk_float_sqrt(x)
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#define SkScalarPow(b, e) sk_float_pow(b, e)
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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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#define SkScalarLog2(x) (float)sk_float_log2(x)
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#else // SK_SCALAR_IS_DOUBLE
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typedef double SkScalar;
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#define SK_Scalar1 1.0
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#define SK_ScalarHalf 0.5
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#define SK_ScalarSqrt2 1.414213562373095
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#define SK_ScalarPI 3.141592653589793
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#define SK_ScalarTanPIOver8 0.4142135623731
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#define SK_ScalarRoot2Over2 0.70710678118655
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#define SK_ScalarMax 1.7976931348623157+308
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#define SK_ScalarInfinity SK_DoubleInfinity
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#define SK_ScalarNegativeInfinity SK_DoubleNegativeInfinity
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#define SK_ScalarNaN SK_DoubleNaN
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#define SkFixedToScalar(x) SkFixedToDouble(x)
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#define SkScalarToFixed(x) SkDoubleToFixed(x)
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#define SkScalarFloorToScalar(x) floor(x)
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#define SkScalarCeilToScalar(x) ceil(x)
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#define SkScalarRoundToScalar(x) floor((x) + 0.5)
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#define SkScalarFloorToInt(x) (int)floor(x)
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#define SkScalarCeilToInt(x) (int)ceil(x)
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#define SkScalarRoundToInt(x) (int)floor((x) + 0.5)
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#define SkScalarAbs(x) abs(x)
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#define SkScalarCopySign(x, y) copysign(x, y)
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#define SkScalarMod(x, y) fmod(x,y)
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#define SkScalarFraction(x) fmod(x, 1.0)
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#define SkScalarSqrt(x) sqrt(x)
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#define SkScalarPow(b, e) pow(b, e)
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#define SkScalarSin(radians) sin(radians)
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#define SkScalarCos(radians) cos(radians)
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#define SkScalarTan(radians) tan(radians)
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#define SkScalarASin(val) asin(val)
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#define SkScalarACos(val) acos(val)
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#define SkScalarATan2(y, x) atan2(y,x)
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#define SkScalarExp(x) exp(x)
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#define SkScalarLog(x) log(x)
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#define SkScalarLog2(x) log2(x)
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#endif
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//////////////////////////////////////////////////////////////////////////////////////////////////
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#define SkIntToScalar(x) static_cast<SkScalar>(x)
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#define SkScalarTruncToInt(x) static_cast<int>(x)
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#define SkScalarToFloat(x) static_cast<float>(x)
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#define SkFloatToScalar(x) static_cast<SkScalar>(x)
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#define SkScalarToDouble(x) static_cast<double>(x)
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#define SkDoubleToScalar(x) static_cast<SkScalar>(x)
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#define SK_ScalarMin (-SK_ScalarMax)
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static inline bool SkScalarIsNaN(SkScalar x) { return x != x; }
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/** Returns true if x is not NaN and not infinite
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*/
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static inline bool SkScalarIsFinite(SkScalar x) {
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// We rely on the following behavior of infinities and nans
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// 0 * finite --> 0
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// 0 * infinity --> NaN
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// 0 * NaN --> NaN
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SkScalar prod = x * 0;
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// At this point, prod will either be NaN or 0
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return !SkScalarIsNaN(prod);
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}
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static inline bool SkScalarsAreFinite(SkScalar a, SkScalar b) {
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SkScalar prod = 0;
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prod *= a;
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prod *= b;
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// At this point, prod will either be NaN or 0
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return !SkScalarIsNaN(prod);
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}
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static inline bool SkScalarsAreFinite(const SkScalar array[], int count) {
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SkScalar prod = 0;
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for (int i = 0; i < count; ++i) {
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prod *= array[i];
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}
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// At this point, prod will either be NaN or 0
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return !SkScalarIsNaN(prod);
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}
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/**
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* Variant of SkScalarRoundToInt, that performs the rounding step (adding 0.5) explicitly using
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* double, to avoid possibly losing the low bit(s) of the answer before calling floor().
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*
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* This routine will likely be slower than SkScalarRoundToInt(), and should only be used when the
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* extra precision is known to be valuable.
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*
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* In particular, this catches the following case:
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* SkScalar x = 0.49999997;
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* int ix = SkScalarRoundToInt(x);
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* SkASSERT(0 == ix); // <--- fails
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* ix = SkDScalarRoundToInt(x);
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* SkASSERT(0 == ix); // <--- succeeds
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*/
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static inline int SkDScalarRoundToInt(SkScalar x) {
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double xx = x;
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xx += 0.5;
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return (int)floor(xx);
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}
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static inline SkScalar SkScalarClampMax(SkScalar x, SkScalar max) {
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x = SkTMin(x, max);
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x = SkTMax<SkScalar>(x, 0);
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return x;
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}
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static inline SkScalar SkScalarPin(SkScalar x, SkScalar min, SkScalar max) {
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x = SkTMin(x, max);
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x = SkTMax(x, min);
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return x;
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}
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SkScalar SkScalarSinCos(SkScalar radians, SkScalar* cosValue);
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static inline SkScalar SkScalarSquare(SkScalar x) { return x * x; }
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#define SkScalarMul(a, b) ((SkScalar)(a) * (b))
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#define SkScalarMulAdd(a, b, c) ((SkScalar)(a) * (b) + (c))
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#define SkScalarDiv(a, b) ((SkScalar)(a) / (b))
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#define SkScalarMulDiv(a, b, c) ((SkScalar)(a) * (b) / (c))
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#define SkScalarInvert(x) (SK_Scalar1 / (x))
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#define SkScalarFastInvert(x) (SK_Scalar1 / (x))
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#define SkScalarAve(a, b) (((a) + (b)) * SK_ScalarHalf)
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#define SkScalarHalf(a) ((a) * SK_ScalarHalf)
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#define SkDegreesToRadians(degrees) ((degrees) * (SK_ScalarPI / 180))
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#define SkRadiansToDegrees(radians) ((radians) * (180 / SK_ScalarPI))
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static inline SkScalar SkMaxScalar(SkScalar a, SkScalar b) { return a > b ? a : b; }
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static inline SkScalar SkMinScalar(SkScalar a, SkScalar b) { return a < b ? a : b; }
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static inline bool SkScalarIsInt(SkScalar x) {
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return x == (SkScalar)(int)x;
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}
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/**
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* Returns -1 || 0 || 1 depending on the sign of value:
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* -1 if x < 0
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* 0 if x == 0
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* 1 if x > 0
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*/
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static inline int SkScalarSignAsInt(SkScalar x) {
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return x < 0 ? -1 : (x > 0);
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}
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// Scalar result version of above
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static inline SkScalar SkScalarSignAsScalar(SkScalar x) {
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return x < 0 ? -SK_Scalar1 : ((x > 0) ? SK_Scalar1 : 0);
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}
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#define SK_ScalarNearlyZero (SK_Scalar1 / (1 << 12))
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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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static inline bool SkScalarNearlyEqual(SkScalar x, SkScalar y,
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SkScalar tolerance = SK_ScalarNearlyZero) {
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SkASSERT(tolerance >= 0);
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return SkScalarAbs(x-y) <= 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 + (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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/*
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* Helper to compare an array of scalars.
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*/
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static inline bool SkScalarsEqual(const SkScalar a[], const SkScalar b[], int n) {
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SkASSERT(n >= 0);
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for (int i = 0; i < n; ++i) {
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if (a[i] != b[i]) {
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return false;
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}
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}
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return true;
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}
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#endif
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