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/*
* Copyright 2011 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#ifndef SkClampRange_DEFINED
#define SkClampRange_DEFINED
#include "SkFixed.h"
#include "SkScalar.h"
#define SkGradFixed SkFixed3232
// We want the largest 32.32 value representable as a float. (float)0x7FFFFFFF
// becomes too big, due to limited mantissa on the float and its rounding rules, so
// we have to manually compute the next smaller value (aka nextafter).
// #define SkGradFixedMaxScalar nextafterf(SkFixed3232ToFloat(SkFixed3232Max), 0)
// #define SkGradFixedMinScalar nextafterf(SkFixed3232ToFloat(SkFixed3232Min), 0)
#define SkGradFixedMaxScalar ( 2147483520.0f)
#define SkGradFixedMinScalar (-2147483520.0f)
#define SkScalarPinToGradFixed(x) SkScalarToFixed3232(SkTPin(x, \
SkGradFixedMinScalar,\
SkGradFixedMaxScalar))
#define SkFixedToGradFixed(x) SkFixedToFixed3232(x)
#define SkGradFixedToFixed(x) (SkFixed)((x) >> 16)
#define kFracMax_SkGradFixed 0xFFFFFFFFLL
/**
* Iteration fixed fx by dx, clamping as you go to [0..kFracMax_SkGradFixed], this class
* computes the (up to) 3 spans there are:
*
* range0: use constant value V0
* range1: iterate as usual fx += dx
* range2: use constant value V1
*/
struct SkClampRange {
int fCount0; // count for fV0
int fCount1; // count for interpolating (fV0...fV1)
int fCount2; // count for fV1
SkGradFixed fFx1; // initial fx value for the fCount1 range.
// only valid if fCount1 > 0
int fV0, fV1;
void init(SkGradFixed fx, SkGradFixed dx, int count, int v0, int v1);
void validate(int count) const {
#ifdef SK_DEBUG
SkASSERT(fCount0 >= 0);
SkASSERT(fCount1 >= 0);
SkASSERT(fCount2 >= 0);
SkASSERT(fCount0 + fCount1 + fCount2 == count);
#endif
}
private:
void initFor1(SkGradFixed fx);
};
#endif
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