michael@0: 
michael@0: /*
michael@0:  * Copyright 2006 The Android Open Source Project
michael@0:  *
michael@0:  * Use of this source code is governed by a BSD-style license that can be
michael@0:  * found in the LICENSE file.
michael@0:  */
michael@0: 
michael@0: 
michael@0: #ifndef SkInterpolator_DEFINED
michael@0: #define SkInterpolator_DEFINED
michael@0: 
michael@0: #include "SkScalar.h"
michael@0: 
michael@0: class SkInterpolatorBase : SkNoncopyable {
michael@0: public:
michael@0:     enum Result {
michael@0:         kNormal_Result,
michael@0:         kFreezeStart_Result,
michael@0:         kFreezeEnd_Result
michael@0:     };
michael@0: protected:
michael@0:     SkInterpolatorBase();
michael@0:     ~SkInterpolatorBase();
michael@0: public:
michael@0:     void    reset(int elemCount, int frameCount);
michael@0: 
michael@0:     /** Return the start and end time for this interpolator.
michael@0:         If there are no key frames, return false.
michael@0:         @param startTime If not null, returns the time (in milliseconds) of the
michael@0:                          first keyframe. If there are no keyframes, this param
michael@0:                          is ignored (left unchanged).
michael@0:         @param endTime If not null, returns the time (in milliseconds) of the
michael@0:                        last keyframe. If there are no keyframes, this parameter
michael@0:                        is ignored (left unchanged).
michael@0:         @return True if there are key frames, or false if there are none.
michael@0:     */
michael@0:     bool    getDuration(SkMSec* startTime, SkMSec* endTime) const;
michael@0: 
michael@0: 
michael@0:     /** Set the whether the repeat is mirrored.
michael@0:         @param mirror If true, the odd repeats interpolate from the last key
michael@0:                       frame and the first.
michael@0:     */
michael@0:     void setMirror(bool mirror) {
michael@0:         fFlags = SkToU8((fFlags & ~kMirror) | (int)mirror);
michael@0:     }
michael@0: 
michael@0:     /** Set the repeat count. The repeat count may be fractional.
michael@0:         @param repeatCount Multiplies the total time by this scalar.
michael@0:     */
michael@0:     void    setRepeatCount(SkScalar repeatCount) { fRepeat = repeatCount; }
michael@0: 
michael@0:     /** Set the whether the repeat is mirrored.
michael@0:         @param reset If true, the odd repeats interpolate from the last key
michael@0:                      frame and the first.
michael@0:     */
michael@0:     void setReset(bool reset) {
michael@0:         fFlags = SkToU8((fFlags & ~kReset) | (int)reset);
michael@0:     }
michael@0: 
michael@0:     Result  timeToT(SkMSec time, SkScalar* T, int* index, SkBool* exact) const;
michael@0: 
michael@0: protected:
michael@0:     enum Flags {
michael@0:         kMirror = 1,
michael@0:         kReset = 2,
michael@0:         kHasBlend = 4
michael@0:     };
michael@0:     static SkScalar ComputeRelativeT(SkMSec time, SkMSec prevTime,
michael@0:                              SkMSec nextTime, const SkScalar blend[4] = NULL);
michael@0:     int16_t fFrameCount;
michael@0:     uint8_t fElemCount;
michael@0:     uint8_t fFlags;
michael@0:     SkScalar fRepeat;
michael@0:     struct SkTimeCode {
michael@0:         SkMSec  fTime;
michael@0:         SkScalar fBlend[4];
michael@0:     };
michael@0:     SkTimeCode* fTimes;     // pointer into fStorage
michael@0:     void* fStorage;
michael@0: #ifdef SK_DEBUG
michael@0:     SkTimeCode(* fTimesArray)[10];
michael@0: #endif
michael@0: };
michael@0: 
michael@0: class SkInterpolator : public SkInterpolatorBase {
michael@0: public:
michael@0:     SkInterpolator();
michael@0:     SkInterpolator(int elemCount, int frameCount);
michael@0:     void    reset(int elemCount, int frameCount);
michael@0: 
michael@0:     /** Add or replace a key frame, copying the values[] data into the
michael@0:         interpolator.
michael@0:         @param index    The index of this frame (frames must be ordered by time)
michael@0:         @param time The millisecond time for this frame
michael@0:         @param values   The array of values [elemCount] for this frame. The data
michael@0:                         is copied into the interpolator.
michael@0:         @param blend    A positive scalar specifying how to blend between this
michael@0:                         and the next key frame. [0...1) is a cubic lag/log/lag
michael@0:                         blend (slow to change at the beginning and end)
michael@0:                         1 is a linear blend (default)
michael@0:     */
michael@0:     bool setKeyFrame(int index, SkMSec time, const SkScalar values[],
michael@0:                      const SkScalar blend[4] = NULL);
michael@0: 
michael@0:     /** Return the computed values given the specified time. Return whether
michael@0:         those values are the result of pinning to either the first
michael@0:         (kFreezeStart) or last (kFreezeEnd), or from interpolated the two
michael@0:         nearest key values (kNormal).
michael@0:         @param time The time to sample (in milliseconds)
michael@0:         @param (may be null) where to write the computed values.
michael@0:     */
michael@0:     Result timeToValues(SkMSec time, SkScalar values[] = NULL) const;
michael@0: 
michael@0:     SkDEBUGCODE(static void UnitTest();)
michael@0: private:
michael@0:     SkScalar* fValues;  // pointer into fStorage
michael@0: #ifdef SK_DEBUG
michael@0:     SkScalar(* fScalarsArray)[10];
michael@0: #endif
michael@0:     typedef SkInterpolatorBase INHERITED;
michael@0: };
michael@0: 
michael@0: /** Given all the parameters are [0...1], apply the cubic specified by (0,0)
michael@0:     (bx,by) (cx,cy) (1,1) to value, returning the answer, also [0...1].
michael@0: */
michael@0: SkScalar SkUnitCubicInterp(SkScalar value, SkScalar bx, SkScalar by,
michael@0:                            SkScalar cx, SkScalar cy);
michael@0: 
michael@0: #endif