include/core/SkClampRange.h

/*
 * 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