The Tor Browser / file comparison
comparison: widget/gonk/libui/VelocityControl.h
widget/gonk/libui/VelocityControl.h
- branch
- TOR_BUG_3246
- changeset 4
- fc2d59ddac77
equal
deleted
inserted
replaced
| -1:000000000000 | 0:2d675a14f4f5 |
|---|---|
| 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 | |
| 17 #ifndef _ANDROIDFW_VELOCITY_CONTROL_H | |
| 18 #define _ANDROIDFW_VELOCITY_CONTROL_H | |
| 19 | |
| 20 #include "Input.h" | |
| 21 #include "VelocityTracker.h" | |
| 22 #include <utils/Timers.h> | |
| 23 | |
| 24 namespace android { | |
| 25 | |
| 26 /* | |
| 27 * Specifies parameters that govern pointer or wheel acceleration. | |
| 28 */ | |
| 29 struct VelocityControlParameters { | |
| 30 // A scale factor that is multiplied with the raw velocity deltas | |
| 31 // prior to applying any other velocity control factors. The scale | |
| 32 // factor should be used to adapt the input device resolution | |
| 33 // (eg. counts per inch) to the output device resolution (eg. pixels per inch). | |
| 34 // | |
| 35 // Must be a positive value. | |
| 36 // Default is 1.0 (no scaling). | |
| 37 float scale; | |
| 38 | |
| 39 // The scaled speed at which acceleration begins to be applied. | |
| 40 // This value establishes the upper bound of a low speed regime for | |
| 41 // small precise motions that are performed without any acceleration. | |
| 42 // | |
| 43 // Must be a non-negative value. | |
| 44 // Default is 0.0 (no low threshold). | |
| 45 float lowThreshold; | |
| 46 | |
| 47 // The scaled speed at which maximum acceleration is applied. | |
| 48 // The difference between highThreshold and lowThreshold controls | |
| 49 // the range of speeds over which the acceleration factor is interpolated. | |
| 50 // The wider the range, the smoother the acceleration. | |
| 51 // | |
| 52 // Must be a non-negative value greater than or equal to lowThreshold. | |
| 53 // Default is 0.0 (no high threshold). | |
| 54 float highThreshold; | |
| 55 | |
| 56 // The acceleration factor. | |
| 57 // When the speed is above the low speed threshold, the velocity will scaled | |
| 58 // by an interpolated value between 1.0 and this amount. | |
| 59 // | |
| 60 // Must be a positive greater than or equal to 1.0. | |
| 61 // Default is 1.0 (no acceleration). | |
| 62 float acceleration; | |
| 63 | |
| 64 VelocityControlParameters() : | |
| 65 scale(1.0f), lowThreshold(0.0f), highThreshold(0.0f), acceleration(1.0f) { | |
| 66 } | |
| 67 | |
| 68 VelocityControlParameters(float scale, float lowThreshold, | |
| 69 float highThreshold, float acceleration) : | |
| 70 scale(scale), lowThreshold(lowThreshold), | |
| 71 highThreshold(highThreshold), acceleration(acceleration) { | |
| 72 } | |
| 73 }; | |
| 74 | |
| 75 /* | |
| 76 * Implements mouse pointer and wheel speed control and acceleration. | |
| 77 */ | |
| 78 class VelocityControl { | |
| 79 public: | |
| 80 VelocityControl(); | |
| 81 | |
| 82 /* Sets the various parameters. */ | |
| 83 void setParameters(const VelocityControlParameters& parameters); | |
| 84 | |
| 85 /* Resets the current movement counters to zero. | |
| 86 * This has the effect of nullifying any acceleration. */ | |
| 87 void reset(); | |
| 88 | |
| 89 /* Translates a raw movement delta into an appropriately | |
| 90 * scaled / accelerated delta based on the current velocity. */ | |
| 91 void move(nsecs_t eventTime, float* deltaX, float* deltaY); | |
| 92 | |
| 93 private: | |
| 94 // If no movements are received within this amount of time, | |
| 95 // we assume the movement has stopped and reset the movement counters. | |
| 96 static const nsecs_t STOP_TIME = 500 * 1000000; // 500 ms | |
| 97 | |
| 98 VelocityControlParameters mParameters; | |
| 99 | |
| 100 nsecs_t mLastMovementTime; | |
| 101 VelocityTracker::Position mRawPosition; | |
| 102 VelocityTracker mVelocityTracker; | |
| 103 }; | |
| 104 | |
| 105 } // namespace android | |
| 106 | |
| 107 #endif // _ANDROIDFW_VELOCITY_CONTROL_H |
