1/*
2 * Copyright 2006 The Android Open Source Project
3 *
4 * Use of this source code is governed by a BSD-style license that can be
5 * found in the LICENSE file.
6 */
7
8
9#ifndef SkInterpolator_DEFINED
10#define SkInterpolator_DEFINED
11
12#include "include/core/SkScalar.h"
13#include "include/private/SkNoncopyable.h"
14#include "include/private/SkTo.h"
15
16class SK_API SkInterpolatorBase : SkNoncopyable {
17public:
18 enum Result {
19 kNormal_Result,
20 kFreezeStart_Result,
21 kFreezeEnd_Result
22 };
23protected:
24 SkInterpolatorBase();
25 ~SkInterpolatorBase();
26public:
27 void reset(int elemCount, int frameCount);
28
29 /** Return the start and end time for this interpolator.
30 If there are no key frames, return false.
31 @param startTime If not null, returns the time (in milliseconds) of the
32 first keyframe. If there are no keyframes, this param
33 is ignored (left unchanged).
34 @param endTime If not null, returns the time (in milliseconds) of the
35 last keyframe. If there are no keyframes, this parameter
36 is ignored (left unchanged).
37 @return True if there are key frames, or false if there are none.
38 */
39 bool getDuration(SkMSec* startTime, SkMSec* endTime) const;
40
41
42 /** Set the whether the repeat is mirrored.
43 @param mirror If true, the odd repeats interpolate from the last key
44 frame and the first.
45 */
46 void setMirror(bool mirror) {
47 fFlags = SkToU8((fFlags & ~kMirror) | (int)mirror);
48 }
49
50 /** Set the repeat count. The repeat count may be fractional.
51 @param repeatCount Multiplies the total time by this scalar.
52 */
53 void setRepeatCount(SkScalar repeatCount) { fRepeat = repeatCount; }
54
55 /** Set the whether the repeat is mirrored.
56 @param reset If true, the odd repeats interpolate from the last key
57 frame and the first.
58 */
59 void setReset(bool reset) {
60 fFlags = SkToU8((fFlags & ~kReset) | (int)reset);
61 }
62
63 Result timeToT(SkMSec time, SkScalar* T, int* index, bool* exact) const;
64
65protected:
66 enum Flags {
67 kMirror = 1,
68 kReset = 2,
69 kHasBlend = 4
70 };
71 static SkScalar ComputeRelativeT(SkMSec time, SkMSec prevTime, SkMSec nextTime,
72 const SkScalar blend[4] = nullptr);
73 int16_t fFrameCount;
74 uint8_t fElemCount;
75 uint8_t fFlags;
76 SkScalar fRepeat;
77 struct SkTimeCode {
78 SkMSec fTime;
79 SkScalar fBlend[4];
80 };
81 SkTimeCode* fTimes; // pointer into fStorage
82 void* fStorage;
83#ifdef SK_DEBUG
84 SkTimeCode(* fTimesArray)[10];
85#endif
86};
87
88class SK_API SkInterpolator : public SkInterpolatorBase {
89public:
90 SkInterpolator();
91 SkInterpolator(int elemCount, int frameCount);
92 void reset(int elemCount, int frameCount);
93
94 /** Add or replace a key frame, copying the values[] data into the
95 interpolator.
96 @param index The index of this frame (frames must be ordered by time)
97 @param time The millisecond time for this frame
98 @param values The array of values [elemCount] for this frame. The data
99 is copied into the interpolator.
100 @param blend A positive scalar specifying how to blend between this
101 and the next key frame. [0...1) is a cubic lag/log/lag
102 blend (slow to change at the beginning and end)
103 1 is a linear blend (default)
104 */
105 bool setKeyFrame(int index, SkMSec time, const SkScalar values[],
106 const SkScalar blend[4] = nullptr);
107
108 /** Return the computed values given the specified time. Return whether
109 those values are the result of pinning to either the first
110 (kFreezeStart) or last (kFreezeEnd), or from interpolated the two
111 nearest key values (kNormal).
112 @param time The time to sample (in milliseconds)
113 @param (may be null) where to write the computed values.
114 */
115 Result timeToValues(SkMSec time, SkScalar values[] = nullptr) const;
116
117private:
118 SkScalar* fValues; // pointer into fStorage
119#ifdef SK_DEBUG
120 SkScalar(* fScalarsArray)[10];
121#endif
122 typedef SkInterpolatorBase INHERITED;
123};
124
125/** Interpolate a cubic curve, typically to provide an ease-in ease-out transition.
126 All the parameters are in the range of [0...1].
127 The input value is treated as the x-coordinate of the cubic.
128 The output value is the y-coordinate on the cubic at the x-coordinate.
129
130 @param value The x-coordinate pinned between [0..1].
131 @param bx,by,cx,cy The cubic control points where the cubic is specified
132 as (0,0) (bx,by) (cx,cy) (1,1)
133 @return the corresponding y-coordinate value, from [0..1].
134*/
135SkScalar SkUnitCubicInterp(SkScalar value, SkScalar bx, SkScalar by,
136 SkScalar cx, SkScalar cy);
137
138#endif
139