1/*
2 * Copyright (C) 2015 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *   http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package android.support.v4.view.animation;
18
19import android.graphics.Path;
20import android.os.Build;
21import android.view.animation.Interpolator;
22import android.view.animation.PathInterpolator;
23
24/**
25 * Helper for creating path-based {@link Interpolator} instances. On API 21 or newer, the
26 * platform implementation will be used and on older platforms a compatible alternative
27 * implementation will be used.
28 */
29public final class PathInterpolatorCompat {
30
31    private PathInterpolatorCompat() {
32        // prevent instantiation
33    }
34
35    /**
36     * Create an {@link Interpolator} for an arbitrary {@link Path}. The {@link Path}
37     * must begin at {@code (0, 0)} and end at {@code (1, 1)}. The x-coordinate along the
38     * {@link Path} is the input value and the output is the y coordinate of the line at that
39     * point. This means that the Path must conform to a function {@code y = f(x)}.
40     * <p/>
41     * The {@link Path} must not have gaps in the x direction and must not
42     * loop back on itself such that there can be two points sharing the same x coordinate.
43     *
44     * @param path the {@link Path} to use to make the line representing the {@link Interpolator}
45     * @return the {@link Interpolator} representing the {@link Path}
46     */
47    public static Interpolator create(Path path) {
48        if (Build.VERSION.SDK_INT >= 21) {
49            return new PathInterpolator(path);
50        }
51        return new PathInterpolatorApi14(path);
52    }
53
54    /**
55     * Create an {@link Interpolator} for a quadratic Bezier curve. The end points
56     * {@code (0, 0)} and {@code (1, 1)} are assumed.
57     *
58     * @param controlX the x coordinate of the quadratic Bezier control point
59     * @param controlY the y coordinate of the quadratic Bezier control point
60     * @return the {@link Interpolator} representing the quadratic Bezier curve
61     */
62    public static Interpolator create(float controlX, float controlY) {
63        if (Build.VERSION.SDK_INT >= 21) {
64            return new PathInterpolator(controlX, controlY);
65        }
66        return new PathInterpolatorApi14(controlX, controlY);
67    }
68
69    /**
70     * Create an {@link Interpolator} for a cubic Bezier curve.  The end points
71     * {@code (0, 0)} and {@code (1, 1)} are assumed.
72     *
73     * @param controlX1 the x coordinate of the first control point of the cubic Bezier
74     * @param controlY1 the y coordinate of the first control point of the cubic Bezier
75     * @param controlX2 the x coordinate of the second control point of the cubic Bezier
76     * @param controlY2 the y coordinate of the second control point of the cubic Bezier
77     * @return the {@link Interpolator} representing the cubic Bezier curve
78     */
79    public static Interpolator create(float controlX1, float controlY1,
80            float controlX2, float controlY2) {
81        if (Build.VERSION.SDK_INT >= 21) {
82            return new PathInterpolator(controlX1, controlY1, controlX2, controlY2);
83        }
84        return new PathInterpolatorApi14(controlX1, controlY1, controlX2, controlY2);
85    }
86}
87