1 /*
2 * Copyright 2024 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 #include <input/AccelerationCurve.h>
18
19 #include <array>
20 #include <limits>
21
22 #include <log/log_main.h>
23
24 #define LOG_TAG "AccelerationCurve"
25
26 namespace android {
27
28 namespace {
29
30 // The last segment must have an infinite maximum speed, so that all speeds are covered.
31 constexpr std::array<AccelerationCurveSegment, 4> kSegments = {{
32 {32.002, 3.19, 0},
33 {52.83, 4.79, -51.254},
34 {119.124, 7.28, -182.737},
35 {std::numeric_limits<double>::infinity(), 15.04, -1107.556},
36 }};
37
38 static_assert(kSegments.back().maxPointerSpeedMmPerS == std::numeric_limits<double>::infinity());
39
40 constexpr std::array<double, 15> kSensitivityFactors = {1, 2, 4, 6, 7, 8, 9, 10,
41 11, 12, 13, 14, 16, 18, 20};
42
43 } // namespace
44
createAccelerationCurveForPointerSensitivity(int32_t sensitivity)45 std::vector<AccelerationCurveSegment> createAccelerationCurveForPointerSensitivity(
46 int32_t sensitivity) {
47 LOG_ALWAYS_FATAL_IF(sensitivity < -7 || sensitivity > 7, "Invalid pointer sensitivity value");
48 std::vector<AccelerationCurveSegment> output;
49 output.reserve(kSegments.size());
50
51 // The curves we want to produce for different sensitivity values are actually the same curve,
52 // just scaled in the Y (gain) axis by a sensitivity factor and a couple of constants.
53 double commonFactor = 0.64 * kSensitivityFactors[sensitivity + 7] / 10;
54 for (AccelerationCurveSegment seg : kSegments) {
55 output.push_back(AccelerationCurveSegment{seg.maxPointerSpeedMmPerS,
56 commonFactor * seg.baseGain,
57 commonFactor * seg.reciprocal});
58 }
59
60 return output;
61 }
62
63 } // namespace android