| |
| /* |
| * Copyright 2006 The Android Open Source Project |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| |
| #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; |
| |
| /** 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 SK_FloatInfinity |
| /** SK_ScalarNegativeInfinity is defined to be negative infinity as an SkScalar |
| */ |
| #define SK_ScalarNegativeInfinity SK_FloatNegativeInfinity |
| /** 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 SK_FloatNaN |
| /** 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) { |
| // We rely on the following behavior of infinities and nans |
| // 0 * finite --> 0 |
| // 0 * infinity --> NaN |
| // 0 * NaN --> NaN |
| float prod = x * 0; |
| // At this point, prod will either be NaN or 0 |
| // Therefore we can return (prod == prod) or (0 == prod). |
| return prod == prod; |
| } |
| |
| #if defined(SK_DEBUG) && !defined(SK_BUILD_FOR_ANDROID) |
| /** 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. |
| */ |
| SkDEBUGFAIL("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) |
| |
| #define SkScalarFloorToScalar(x) sk_float_floor(x) |
| #define SkScalarCeilToScalar(x) sk_float_ceil(x) |
| #define SkScalarRoundToScalar(x) sk_float_floor((x) + 0.5f) |
| |
| #define SkScalarFloorToInt(x) sk_float_floor2int(x) |
| #define SkScalarCeilToInt(x) sk_float_ceil2int(x) |
| #define SkScalarRoundToInt(x) sk_float_round2int(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 b to the e |
| */ |
| #define SkScalarPow(b, e) sk_float_pow(b, e) |
| /** 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_ScalarNegativeInfinity SK_FixedMin |
| #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) |
| #define SkScalarToFloat(n) SkFixedToFloat(n) |
| #define SkFloatToScalar(n) SkFloatToFixed(n) |
| |
| #define SkScalarToDouble(n) SkFixedToDouble(n) |
| #define SkDoubleToScalar(n) SkDoubleToFixed(n) |
| #define SkScalarFraction(x) SkFixedFraction(x) |
| |
| #define SkScalarFloorToScalar(x) SkFixedFloorToFixed(x) |
| #define SkScalarCeilToScalar(x) SkFixedCeilToFixed(x) |
| #define SkScalarRoundToScalar(x) SkFixedRoundToFixed(x) |
| |
| #define SkScalarFloorToInt(x) SkFixedFloorToInt(x) |
| #define SkScalarCeilToInt(x) SkFixedCeilToInt(x) |
| #define SkScalarRoundToInt(x) SkFixedRoundToInt(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 |
| |
| // DEPRECATED : use ToInt or ToScalar variant |
| #define SkScalarFloor(x) SkScalarFloorToInt(x) |
| #define SkScalarCeil(x) SkScalarCeilToInt(x) |
| #define SkScalarRound(x) SkScalarRoundToInt(x) |
| |
| /** |
| * Returns -1 || 0 || 1 depending on the sign of value: |
| * -1 if x < 0 |
| * 0 if x == 0 |
| * 1 if x > 0 |
| */ |
| static inline int SkScalarSignAsInt(SkScalar x) { |
| return x < 0 ? -1 : (x > 0); |
| } |
| |
| // Scalar result version of above |
| static inline SkScalar SkScalarSignAsScalar(SkScalar x) { |
| return x < 0 ? -SK_Scalar1 : ((x > 0) ? SK_Scalar1 : 0); |
| } |
| |
| #define SK_ScalarNearlyZero (SK_Scalar1 / (1 << 12)) |
| |
| 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); |
| } |
| |
| static inline SkScalar SkScalarLog2(SkScalar x) { |
| static const SkScalar log2_conversion_factor = SkScalarDiv(1, SkScalarLog(2)); |
| |
| return SkScalarMul(SkScalarLog(x), log2_conversion_factor); |
| } |
| |
| /** 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); |
| |
| /* |
| * Helper to compare an array of scalars. |
| */ |
| static inline bool SkScalarsEqual(const SkScalar a[], const SkScalar b[], int n) { |
| #ifdef SK_SCALAR_IS_FLOAT |
| SkASSERT(n >= 0); |
| for (int i = 0; i < n; ++i) { |
| if (a[i] != b[i]) { |
| return false; |
| } |
| } |
| return true; |
| #else |
| return 0 == memcmp(a, b, n * sizeof(SkScalar)); |
| #endif |
| } |
| |
| #endif |
