1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/gfx/skia/trunk/include/utils/SkInterpolator.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,131 @@
1.4 +
1.5 +/*
1.6 + * Copyright 2006 The Android Open Source Project
1.7 + *
1.8 + * Use of this source code is governed by a BSD-style license that can be
1.9 + * found in the LICENSE file.
1.10 + */
1.11 +
1.12 +
1.13 +#ifndef SkInterpolator_DEFINED
1.14 +#define SkInterpolator_DEFINED
1.15 +
1.16 +#include "SkScalar.h"
1.17 +
1.18 +class SkInterpolatorBase : SkNoncopyable {
1.19 +public:
1.20 + enum Result {
1.21 + kNormal_Result,
1.22 + kFreezeStart_Result,
1.23 + kFreezeEnd_Result
1.24 + };
1.25 +protected:
1.26 + SkInterpolatorBase();
1.27 + ~SkInterpolatorBase();
1.28 +public:
1.29 + void reset(int elemCount, int frameCount);
1.30 +
1.31 + /** Return the start and end time for this interpolator.
1.32 + If there are no key frames, return false.
1.33 + @param startTime If not null, returns the time (in milliseconds) of the
1.34 + first keyframe. If there are no keyframes, this param
1.35 + is ignored (left unchanged).
1.36 + @param endTime If not null, returns the time (in milliseconds) of the
1.37 + last keyframe. If there are no keyframes, this parameter
1.38 + is ignored (left unchanged).
1.39 + @return True if there are key frames, or false if there are none.
1.40 + */
1.41 + bool getDuration(SkMSec* startTime, SkMSec* endTime) const;
1.42 +
1.43 +
1.44 + /** Set the whether the repeat is mirrored.
1.45 + @param mirror If true, the odd repeats interpolate from the last key
1.46 + frame and the first.
1.47 + */
1.48 + void setMirror(bool mirror) {
1.49 + fFlags = SkToU8((fFlags & ~kMirror) | (int)mirror);
1.50 + }
1.51 +
1.52 + /** Set the repeat count. The repeat count may be fractional.
1.53 + @param repeatCount Multiplies the total time by this scalar.
1.54 + */
1.55 + void setRepeatCount(SkScalar repeatCount) { fRepeat = repeatCount; }
1.56 +
1.57 + /** Set the whether the repeat is mirrored.
1.58 + @param reset If true, the odd repeats interpolate from the last key
1.59 + frame and the first.
1.60 + */
1.61 + void setReset(bool reset) {
1.62 + fFlags = SkToU8((fFlags & ~kReset) | (int)reset);
1.63 + }
1.64 +
1.65 + Result timeToT(SkMSec time, SkScalar* T, int* index, SkBool* exact) const;
1.66 +
1.67 +protected:
1.68 + enum Flags {
1.69 + kMirror = 1,
1.70 + kReset = 2,
1.71 + kHasBlend = 4
1.72 + };
1.73 + static SkScalar ComputeRelativeT(SkMSec time, SkMSec prevTime,
1.74 + SkMSec nextTime, const SkScalar blend[4] = NULL);
1.75 + int16_t fFrameCount;
1.76 + uint8_t fElemCount;
1.77 + uint8_t fFlags;
1.78 + SkScalar fRepeat;
1.79 + struct SkTimeCode {
1.80 + SkMSec fTime;
1.81 + SkScalar fBlend[4];
1.82 + };
1.83 + SkTimeCode* fTimes; // pointer into fStorage
1.84 + void* fStorage;
1.85 +#ifdef SK_DEBUG
1.86 + SkTimeCode(* fTimesArray)[10];
1.87 +#endif
1.88 +};
1.89 +
1.90 +class SkInterpolator : public SkInterpolatorBase {
1.91 +public:
1.92 + SkInterpolator();
1.93 + SkInterpolator(int elemCount, int frameCount);
1.94 + void reset(int elemCount, int frameCount);
1.95 +
1.96 + /** Add or replace a key frame, copying the values[] data into the
1.97 + interpolator.
1.98 + @param index The index of this frame (frames must be ordered by time)
1.99 + @param time The millisecond time for this frame
1.100 + @param values The array of values [elemCount] for this frame. The data
1.101 + is copied into the interpolator.
1.102 + @param blend A positive scalar specifying how to blend between this
1.103 + and the next key frame. [0...1) is a cubic lag/log/lag
1.104 + blend (slow to change at the beginning and end)
1.105 + 1 is a linear blend (default)
1.106 + */
1.107 + bool setKeyFrame(int index, SkMSec time, const SkScalar values[],
1.108 + const SkScalar blend[4] = NULL);
1.109 +
1.110 + /** Return the computed values given the specified time. Return whether
1.111 + those values are the result of pinning to either the first
1.112 + (kFreezeStart) or last (kFreezeEnd), or from interpolated the two
1.113 + nearest key values (kNormal).
1.114 + @param time The time to sample (in milliseconds)
1.115 + @param (may be null) where to write the computed values.
1.116 + */
1.117 + Result timeToValues(SkMSec time, SkScalar values[] = NULL) const;
1.118 +
1.119 + SkDEBUGCODE(static void UnitTest();)
1.120 +private:
1.121 + SkScalar* fValues; // pointer into fStorage
1.122 +#ifdef SK_DEBUG
1.123 + SkScalar(* fScalarsArray)[10];
1.124 +#endif
1.125 + typedef SkInterpolatorBase INHERITED;
1.126 +};
1.127 +
1.128 +/** Given all the parameters are [0...1], apply the cubic specified by (0,0)
1.129 + (bx,by) (cx,cy) (1,1) to value, returning the answer, also [0...1].
1.130 +*/
1.131 +SkScalar SkUnitCubicInterp(SkScalar value, SkScalar bx, SkScalar by,
1.132 + SkScalar cx, SkScalar cy);
1.133 +
1.134 +#endif
