1 /*
2  * Copyright (C) 2016 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 
17 package com.android.internal.widget;
18 
19 import android.compat.annotation.UnsupportedAppUsage;
20 import android.os.Build;
21 
22 public class ScrollBarUtils {
23 
24     @UnsupportedAppUsage(maxTargetSdk = Build.VERSION_CODES.R, trackingBug = 170729553)
getThumbLength(int size, int thickness, int extent, int range)25     public static int getThumbLength(int size, int thickness, int extent, int range) {
26         // Avoid the tiny thumb.
27         final int minLength = thickness * 2;
28         int length = Math.round((float) size * extent / range);
29         if (length < minLength) {
30             length = minLength;
31         }
32         return length;
33     }
34 
getThumbOffset(int size, int thumbLength, int extent, int range, int offset)35     public static int getThumbOffset(int size, int thumbLength, int extent, int range, int offset) {
36         // Avoid the too-big thumb.
37         int thumbOffset = Math.round((float) (size - thumbLength) * offset / (range - extent));
38         if (thumbOffset > size - thumbLength) {
39             thumbOffset = size - thumbLength;
40         }
41         return thumbOffset;
42     }
43 }
44