Line data Source code
1 : /*
2 : * Copyright 2006 The Android Open Source Project
3 : *
4 : * Use of this source code is governed by a BSD-style license that can be
5 : * found in the LICENSE file.
6 : */
7 :
8 : #ifndef SkScalar_DEFINED
9 : #define SkScalar_DEFINED
10 :
11 : #include "../private/SkFloatingPoint.h"
12 :
13 : #undef SK_SCALAR_IS_FLOAT
14 : #define SK_SCALAR_IS_FLOAT 1
15 :
16 : typedef float SkScalar;
17 :
18 : #define SK_Scalar1 1.0f
19 : #define SK_ScalarHalf 0.5f
20 : #define SK_ScalarSqrt2 1.41421356f
21 : #define SK_ScalarPI 3.14159265f
22 : #define SK_ScalarTanPIOver8 0.414213562f
23 : #define SK_ScalarRoot2Over2 0.707106781f
24 : #define SK_ScalarMax 3.402823466e+38f
25 : #define SK_ScalarInfinity SK_FloatInfinity
26 : #define SK_ScalarNegativeInfinity SK_FloatNegativeInfinity
27 : #define SK_ScalarNaN SK_FloatNaN
28 :
29 : #define SkScalarFloorToScalar(x) sk_float_floor(x)
30 : #define SkScalarCeilToScalar(x) sk_float_ceil(x)
31 : #define SkScalarRoundToScalar(x) sk_float_floor((x) + 0.5f)
32 : #define SkScalarTruncToScalar(x) sk_float_trunc(x)
33 :
34 : #define SkScalarFloorToInt(x) sk_float_floor2int(x)
35 : #define SkScalarCeilToInt(x) sk_float_ceil2int(x)
36 : #define SkScalarRoundToInt(x) sk_float_round2int(x)
37 :
38 : #define SkScalarAbs(x) sk_float_abs(x)
39 : #define SkScalarCopySign(x, y) sk_float_copysign(x, y)
40 : #define SkScalarMod(x, y) sk_float_mod(x,y)
41 : #define SkScalarSqrt(x) sk_float_sqrt(x)
42 : #define SkScalarPow(b, e) sk_float_pow(b, e)
43 :
44 : #define SkScalarSin(radians) (float)sk_float_sin(radians)
45 : #define SkScalarCos(radians) (float)sk_float_cos(radians)
46 : #define SkScalarTan(radians) (float)sk_float_tan(radians)
47 : #define SkScalarASin(val) (float)sk_float_asin(val)
48 : #define SkScalarACos(val) (float)sk_float_acos(val)
49 : #define SkScalarATan2(y, x) (float)sk_float_atan2(y,x)
50 : #define SkScalarExp(x) (float)sk_float_exp(x)
51 : #define SkScalarLog(x) (float)sk_float_log(x)
52 : #define SkScalarLog2(x) (float)sk_float_log2(x)
53 :
54 : //////////////////////////////////////////////////////////////////////////////////////////////////
55 :
56 : #define SkIntToScalar(x) static_cast<SkScalar>(x)
57 : #define SkIntToFloat(x) static_cast<float>(x)
58 : #define SkScalarTruncToInt(x) static_cast<int>(x)
59 :
60 : #define SkScalarToFloat(x) static_cast<float>(x)
61 : #define SkFloatToScalar(x) static_cast<SkScalar>(x)
62 : #define SkScalarToDouble(x) static_cast<double>(x)
63 : #define SkDoubleToScalar(x) static_cast<SkScalar>(x)
64 :
65 : #define SK_ScalarMin (-SK_ScalarMax)
66 :
67 158276 : static inline bool SkScalarIsNaN(SkScalar x) { return x != x; }
68 :
69 : /** Returns true if x is not NaN and not infinite
70 : */
71 4576 : static inline bool SkScalarIsFinite(SkScalar x) {
72 : // We rely on the following behavior of infinities and nans
73 : // 0 * finite --> 0
74 : // 0 * infinity --> NaN
75 : // 0 * NaN --> NaN
76 4576 : SkScalar prod = x * 0;
77 : // At this point, prod will either be NaN or 0
78 4576 : return !SkScalarIsNaN(prod);
79 : }
80 :
81 15 : static inline bool SkScalarsAreFinite(SkScalar a, SkScalar b) {
82 15 : SkScalar prod = 0;
83 15 : prod *= a;
84 15 : prod *= b;
85 : // At this point, prod will either be NaN or 0
86 15 : return !SkScalarIsNaN(prod);
87 : }
88 :
89 25 : static inline bool SkScalarsAreFinite(const SkScalar array[], int count) {
90 25 : SkScalar prod = 0;
91 250 : for (int i = 0; i < count; ++i) {
92 225 : prod *= array[i];
93 : }
94 : // At this point, prod will either be NaN or 0
95 25 : return !SkScalarIsNaN(prod);
96 : }
97 :
98 : /**
99 : * Variant of SkScalarRoundToInt, that performs the rounding step (adding 0.5) explicitly using
100 : * double, to avoid possibly losing the low bit(s) of the answer before calling floor().
101 : *
102 : * This routine will likely be slower than SkScalarRoundToInt(), and should only be used when the
103 : * extra precision is known to be valuable.
104 : *
105 : * In particular, this catches the following case:
106 : * SkScalar x = 0.49999997;
107 : * int ix = SkScalarRoundToInt(x);
108 : * SkASSERT(0 == ix); // <--- fails
109 : * ix = SkDScalarRoundToInt(x);
110 : * SkASSERT(0 == ix); // <--- succeeds
111 : */
112 : static inline int SkDScalarRoundToInt(SkScalar x) {
113 : double xx = x;
114 : xx += 0.5;
115 : return (int)floor(xx);
116 : }
117 :
118 : /** Returns the fractional part of the scalar. */
119 0 : static inline SkScalar SkScalarFraction(SkScalar x) {
120 0 : return x - SkScalarTruncToScalar(x);
121 : }
122 :
123 0 : static inline SkScalar SkScalarClampMax(SkScalar x, SkScalar max) {
124 0 : x = SkTMin(x, max);
125 0 : x = SkTMax<SkScalar>(x, 0);
126 0 : return x;
127 : }
128 :
129 66 : static inline SkScalar SkScalarPin(SkScalar x, SkScalar min, SkScalar max) {
130 66 : return SkTPin(x, min, max);
131 : }
132 :
133 : SkScalar SkScalarSinCos(SkScalar radians, SkScalar* cosValue);
134 :
135 0 : static inline SkScalar SkScalarSquare(SkScalar x) { return x * x; }
136 :
137 : #define SkScalarInvert(x) (SK_Scalar1 / (x))
138 : #define SkScalarFastInvert(x) (SK_Scalar1 / (x))
139 : #define SkScalarAve(a, b) (((a) + (b)) * SK_ScalarHalf)
140 : #define SkScalarHalf(a) ((a) * SK_ScalarHalf)
141 :
142 : #define SkDegreesToRadians(degrees) ((degrees) * (SK_ScalarPI / 180))
143 : #define SkRadiansToDegrees(radians) ((radians) * (180 / SK_ScalarPI))
144 :
145 926 : static inline SkScalar SkMaxScalar(SkScalar a, SkScalar b) { return a > b ? a : b; }
146 926 : static inline SkScalar SkMinScalar(SkScalar a, SkScalar b) { return a < b ? a : b; }
147 :
148 0 : static inline bool SkScalarIsInt(SkScalar x) {
149 0 : return x == (SkScalar)(int)x;
150 : }
151 :
152 : /**
153 : * Returns -1 || 0 || 1 depending on the sign of value:
154 : * -1 if x < 0
155 : * 0 if x == 0
156 : * 1 if x > 0
157 : */
158 619 : static inline int SkScalarSignAsInt(SkScalar x) {
159 619 : return x < 0 ? -1 : (x > 0);
160 : }
161 :
162 : // Scalar result version of above
163 : static inline SkScalar SkScalarSignAsScalar(SkScalar x) {
164 : return x < 0 ? -SK_Scalar1 : ((x > 0) ? SK_Scalar1 : 0);
165 : }
166 :
167 : #define SK_ScalarNearlyZero (SK_Scalar1 / (1 << 12))
168 :
169 1396 : static inline bool SkScalarNearlyZero(SkScalar x,
170 : SkScalar tolerance = SK_ScalarNearlyZero) {
171 1396 : SkASSERT(tolerance >= 0);
172 1396 : return SkScalarAbs(x) <= tolerance;
173 : }
174 :
175 8 : static inline bool SkScalarNearlyEqual(SkScalar x, SkScalar y,
176 : SkScalar tolerance = SK_ScalarNearlyZero) {
177 8 : SkASSERT(tolerance >= 0);
178 8 : return SkScalarAbs(x-y) <= tolerance;
179 : }
180 :
181 : /** Linearly interpolate between A and B, based on t.
182 : If t is 0, return A
183 : If t is 1, return B
184 : else interpolate.
185 : t must be [0..SK_Scalar1]
186 : */
187 0 : static inline SkScalar SkScalarInterp(SkScalar A, SkScalar B, SkScalar t) {
188 0 : SkASSERT(t >= 0 && t <= SK_Scalar1);
189 0 : return A + (B - A) * t;
190 : }
191 :
192 : /** Interpolate along the function described by (keys[length], values[length])
193 : for the passed searchKey. SearchKeys outside the range keys[0]-keys[Length]
194 : clamp to the min or max value. This function was inspired by a desire
195 : to change the multiplier for thickness in fakeBold; therefore it assumes
196 : the number of pairs (length) will be small, and a linear search is used.
197 : Repeated keys are allowed for discontinuous functions (so long as keys is
198 : monotonically increasing), and if key is the value of a repeated scalar in
199 : keys, the first one will be used. However, that may change if a binary
200 : search is used.
201 : */
202 : SkScalar SkScalarInterpFunc(SkScalar searchKey, const SkScalar keys[],
203 : const SkScalar values[], int length);
204 :
205 : /*
206 : * Helper to compare an array of scalars.
207 : */
208 539 : static inline bool SkScalarsEqual(const SkScalar a[], const SkScalar b[], int n) {
209 539 : SkASSERT(n >= 0);
210 2641 : for (int i = 0; i < n; ++i) {
211 2116 : if (a[i] != b[i]) {
212 14 : return false;
213 : }
214 : }
215 525 : return true;
216 : }
217 :
218 : #endif
|
