gecko/gfx/skia/include/core/SkClampRange.h
2011-10-28 20:05:31 +13:00

40 lines
947 B
C++

/*
* 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"
/**
* Iteration fixed fx by dx, clamping as you go to [0..0xFFFF], 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
SkFixed fFx1; // initial fx value for the fCount1 range.
// only valid if fCount1 > 0
int fV0, fV1;
bool fOverflowed; // true if we had to clamp due to numerical overflow
void init(SkFixed fx, SkFixed dx, int count, int v0, int v1);
private:
void initFor1(SkFixed fx);
};
#endif