diff -r 000000000000 -r 6474c204b198 gfx/skia/trunk/include/utils/SkInterpolator.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/gfx/skia/trunk/include/utils/SkInterpolator.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,131 @@
+
+/*
+ * Copyright 2006 The Android Open Source Project
+ *
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+
+#ifndef SkInterpolator_DEFINED
+#define SkInterpolator_DEFINED
+
+#include "SkScalar.h"
+
+class SkInterpolatorBase : SkNoncopyable {
+public:
+    enum Result {
+        kNormal_Result,
+        kFreezeStart_Result,
+        kFreezeEnd_Result
+    };
+protected:
+    SkInterpolatorBase();
+    ~SkInterpolatorBase();
+public:
+    void    reset(int elemCount, int frameCount);
+
+    /** Return the start and end time for this interpolator.
+        If there are no key frames, return false.
+        @param startTime If not null, returns the time (in milliseconds) of the
+                         first keyframe. If there are no keyframes, this param
+                         is ignored (left unchanged).
+        @param endTime If not null, returns the time (in milliseconds) of the
+                       last keyframe. If there are no keyframes, this parameter
+                       is ignored (left unchanged).
+        @return True if there are key frames, or false if there are none.
+    */
+    bool    getDuration(SkMSec* startTime, SkMSec* endTime) const;
+
+
+    /** Set the whether the repeat is mirrored.
+        @param mirror If true, the odd repeats interpolate from the last key
+                      frame and the first.
+    */
+    void setMirror(bool mirror) {
+        fFlags = SkToU8((fFlags & ~kMirror) | (int)mirror);
+    }
+
+    /** Set the repeat count. The repeat count may be fractional.
+        @param repeatCount Multiplies the total time by this scalar.
+    */
+    void    setRepeatCount(SkScalar repeatCount) { fRepeat = repeatCount; }
+
+    /** Set the whether the repeat is mirrored.
+        @param reset If true, the odd repeats interpolate from the last key
+                     frame and the first.
+    */
+    void setReset(bool reset) {
+        fFlags = SkToU8((fFlags & ~kReset) | (int)reset);
+    }
+
+    Result  timeToT(SkMSec time, SkScalar* T, int* index, SkBool* exact) const;
+
+protected:
+    enum Flags {
+        kMirror = 1,
+        kReset = 2,
+        kHasBlend = 4
+    };
+    static SkScalar ComputeRelativeT(SkMSec time, SkMSec prevTime,
+                             SkMSec nextTime, const SkScalar blend[4] = NULL);
+    int16_t fFrameCount;
+    uint8_t fElemCount;
+    uint8_t fFlags;
+    SkScalar fRepeat;
+    struct SkTimeCode {
+        SkMSec  fTime;
+        SkScalar fBlend[4];
+    };
+    SkTimeCode* fTimes;     // pointer into fStorage
+    void* fStorage;
+#ifdef SK_DEBUG
+    SkTimeCode(* fTimesArray)[10];
+#endif
+};
+
+class SkInterpolator : public SkInterpolatorBase {
+public:
+    SkInterpolator();
+    SkInterpolator(int elemCount, int frameCount);
+    void    reset(int elemCount, int frameCount);
+
+    /** Add or replace a key frame, copying the values[] data into the
+        interpolator.
+        @param index    The index of this frame (frames must be ordered by time)
+        @param time The millisecond time for this frame
+        @param values   The array of values [elemCount] for this frame. The data
+                        is copied into the interpolator.
+        @param blend    A positive scalar specifying how to blend between this
+                        and the next key frame. [0...1) is a cubic lag/log/lag
+                        blend (slow to change at the beginning and end)
+                        1 is a linear blend (default)
+    */
+    bool setKeyFrame(int index, SkMSec time, const SkScalar values[],
+                     const SkScalar blend[4] = NULL);
+
+    /** Return the computed values given the specified time. Return whether
+        those values are the result of pinning to either the first
+        (kFreezeStart) or last (kFreezeEnd), or from interpolated the two
+        nearest key values (kNormal).
+        @param time The time to sample (in milliseconds)
+        @param (may be null) where to write the computed values.
+    */
+    Result timeToValues(SkMSec time, SkScalar values[] = NULL) const;
+
+    SkDEBUGCODE(static void UnitTest();)
+private:
+    SkScalar* fValues;  // pointer into fStorage
+#ifdef SK_DEBUG
+    SkScalar(* fScalarsArray)[10];
+#endif
+    typedef SkInterpolatorBase INHERITED;
+};
+
+/** Given all the parameters are [0...1], apply the cubic specified by (0,0)
+    (bx,by) (cx,cy) (1,1) to value, returning the answer, also [0...1].
+*/
+SkScalar SkUnitCubicInterp(SkScalar value, SkScalar bx, SkScalar by,
+                           SkScalar cx, SkScalar cy);
+
+#endif