Jeff Brown | 5912f95 | 2013-07-01 19:10:31 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2012 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 | |
Prabir Pradhan | c08b0db | 2022-09-10 00:57:15 +0000 | [diff] [blame] | 17 | #pragma once |
Jeff Brown | 5912f95 | 2013-07-01 19:10:31 -0700 | [diff] [blame] | 18 | |
Zixuan Qu | 79b76d1 | 2022-11-11 04:47:51 +0000 | [diff] [blame] | 19 | #include <android-base/stringprintf.h> |
Jeff Brown | 5912f95 | 2013-07-01 19:10:31 -0700 | [diff] [blame] | 20 | #include <input/Input.h> |
| 21 | #include <input/VelocityTracker.h> |
| 22 | #include <utils/Timers.h> |
| 23 | |
Zixuan Qu | 79b76d1 | 2022-11-11 04:47:51 +0000 | [diff] [blame] | 24 | using android::base::StringPrintf; |
| 25 | |
Jeff Brown | 5912f95 | 2013-07-01 19:10:31 -0700 | [diff] [blame] | 26 | namespace android { |
| 27 | |
| 28 | /* |
| 29 | * Specifies parameters that govern pointer or wheel acceleration. |
| 30 | */ |
| 31 | struct VelocityControlParameters { |
| 32 | // A scale factor that is multiplied with the raw velocity deltas |
| 33 | // prior to applying any other velocity control factors. The scale |
| 34 | // factor should be used to adapt the input device resolution |
| 35 | // (eg. counts per inch) to the output device resolution (eg. pixels per inch). |
| 36 | // |
| 37 | // Must be a positive value. |
| 38 | // Default is 1.0 (no scaling). |
| 39 | float scale; |
| 40 | |
| 41 | // The scaled speed at which acceleration begins to be applied. |
| 42 | // This value establishes the upper bound of a low speed regime for |
| 43 | // small precise motions that are performed without any acceleration. |
| 44 | // |
| 45 | // Must be a non-negative value. |
| 46 | // Default is 0.0 (no low threshold). |
| 47 | float lowThreshold; |
| 48 | |
| 49 | // The scaled speed at which maximum acceleration is applied. |
| 50 | // The difference between highThreshold and lowThreshold controls |
| 51 | // the range of speeds over which the acceleration factor is interpolated. |
| 52 | // The wider the range, the smoother the acceleration. |
| 53 | // |
| 54 | // Must be a non-negative value greater than or equal to lowThreshold. |
| 55 | // Default is 0.0 (no high threshold). |
| 56 | float highThreshold; |
| 57 | |
| 58 | // The acceleration factor. |
| 59 | // When the speed is above the low speed threshold, the velocity will scaled |
| 60 | // by an interpolated value between 1.0 and this amount. |
| 61 | // |
| 62 | // Must be a positive greater than or equal to 1.0. |
| 63 | // Default is 1.0 (no acceleration). |
| 64 | float acceleration; |
| 65 | |
| 66 | VelocityControlParameters() : |
| 67 | scale(1.0f), lowThreshold(0.0f), highThreshold(0.0f), acceleration(1.0f) { |
| 68 | } |
| 69 | |
| 70 | VelocityControlParameters(float scale, float lowThreshold, |
| 71 | float highThreshold, float acceleration) : |
| 72 | scale(scale), lowThreshold(lowThreshold), |
| 73 | highThreshold(highThreshold), acceleration(acceleration) { |
| 74 | } |
Zixuan Qu | 79b76d1 | 2022-11-11 04:47:51 +0000 | [diff] [blame] | 75 | |
| 76 | std::string dump() const { |
| 77 | return StringPrintf("scale=%0.3f, lowThreshold=%0.3f, highThreshold=%0.3f, " |
| 78 | "acceleration=%0.3f\n", |
| 79 | scale, lowThreshold, highThreshold, acceleration); |
| 80 | } |
Jeff Brown | 5912f95 | 2013-07-01 19:10:31 -0700 | [diff] [blame] | 81 | }; |
| 82 | |
| 83 | /* |
| 84 | * Implements mouse pointer and wheel speed control and acceleration. |
| 85 | */ |
| 86 | class VelocityControl { |
| 87 | public: |
| 88 | VelocityControl(); |
| 89 | |
Zixuan Qu | 79b76d1 | 2022-11-11 04:47:51 +0000 | [diff] [blame] | 90 | /* Gets the various parameters. */ |
Zixuan Qu | ad07441 | 2022-11-23 19:20:58 +0000 | [diff] [blame] | 91 | const VelocityControlParameters& getParameters() const; |
Zixuan Qu | 79b76d1 | 2022-11-11 04:47:51 +0000 | [diff] [blame] | 92 | |
Jeff Brown | 5912f95 | 2013-07-01 19:10:31 -0700 | [diff] [blame] | 93 | /* Sets the various parameters. */ |
| 94 | void setParameters(const VelocityControlParameters& parameters); |
| 95 | |
| 96 | /* Resets the current movement counters to zero. |
| 97 | * This has the effect of nullifying any acceleration. */ |
| 98 | void reset(); |
| 99 | |
| 100 | /* Translates a raw movement delta into an appropriately |
| 101 | * scaled / accelerated delta based on the current velocity. */ |
| 102 | void move(nsecs_t eventTime, float* deltaX, float* deltaY); |
| 103 | |
| 104 | private: |
| 105 | // If no movements are received within this amount of time, |
| 106 | // we assume the movement has stopped and reset the movement counters. |
| 107 | static const nsecs_t STOP_TIME = 500 * 1000000; // 500 ms |
| 108 | |
| 109 | VelocityControlParameters mParameters; |
| 110 | |
| 111 | nsecs_t mLastMovementTime; |
Yeabkal Wubshit | 37acf6e | 2022-08-27 05:48:51 +0000 | [diff] [blame] | 112 | float mRawPositionX, mRawPositionY; |
Jeff Brown | 5912f95 | 2013-07-01 19:10:31 -0700 | [diff] [blame] | 113 | VelocityTracker mVelocityTracker; |
| 114 | }; |
| 115 | |
| 116 | } // namespace android |