1 /*
2 * Copyright (C) 2022 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 // clang-format off
18 #include "../Macros.h"
19 // clang-format on
20 #include "MultiTouchMotionAccumulator.h"
21
22 namespace android {
23
24 // --- MultiTouchMotionAccumulator ---
25
MultiTouchMotionAccumulator()26 MultiTouchMotionAccumulator::MultiTouchMotionAccumulator()
27 : mCurrentSlot(-1), mUsingSlotsProtocol(false) {}
28
configure(const InputDeviceContext & deviceContext,size_t slotCount,bool usingSlotsProtocol)29 void MultiTouchMotionAccumulator::configure(const InputDeviceContext& deviceContext,
30 size_t slotCount, bool usingSlotsProtocol) {
31 mUsingSlotsProtocol = usingSlotsProtocol;
32 mSlots = std::vector<Slot>(slotCount);
33
34 mCurrentSlot = -1;
35 if (mUsingSlotsProtocol) {
36 // Query the driver for the current slot index and use it as the initial slot before we
37 // start reading events from the device. It is possible that the current slot index will
38 // not be the same as it was when the first event was written into the evdev buffer, which
39 // means the input mapper could start out of sync with the initial state of the events in
40 // the evdev buffer. In the extremely unlikely case that this happens, the data from two
41 // slots will be confused until the next ABS_MT_SLOT event is received. This can cause the
42 // touch point to "jump", but at least there will be no stuck touches.
43 int32_t initialSlot;
44 if (const auto status = deviceContext.getAbsoluteAxisValue(ABS_MT_SLOT, &initialSlot);
45 status == OK) {
46 mCurrentSlot = initialSlot;
47 } else {
48 ALOGD("Could not retrieve current multi-touch slot index. status=%d", status);
49 }
50 }
51 }
52
resetSlots()53 void MultiTouchMotionAccumulator::resetSlots() {
54 for (Slot& slot : mSlots) {
55 slot.clear();
56 }
57 mCurrentSlot = -1;
58 }
59
process(const RawEvent * rawEvent)60 void MultiTouchMotionAccumulator::process(const RawEvent* rawEvent) {
61 if (rawEvent->type == EV_ABS) {
62 bool newSlot = false;
63 if (mUsingSlotsProtocol) {
64 if (rawEvent->code == ABS_MT_SLOT) {
65 mCurrentSlot = rawEvent->value;
66 newSlot = true;
67 }
68 } else if (mCurrentSlot < 0) {
69 mCurrentSlot = 0;
70 }
71
72 if (mCurrentSlot < 0 || size_t(mCurrentSlot) >= mSlots.size()) {
73 if (newSlot) {
74 ALOGW_IF(DEBUG_POINTERS,
75 "MultiTouch device emitted invalid slot index %d but it "
76 "should be between 0 and %zd; ignoring this slot.",
77 mCurrentSlot, mSlots.size() - 1);
78 }
79 } else {
80 Slot& slot = mSlots[mCurrentSlot];
81 // If mUsingSlotsProtocol is true, it means the raw pointer has axis info of
82 // ABS_MT_TRACKING_ID and ABS_MT_SLOT, so driver should send a valid trackingId while
83 // updating the slot.
84 if (!mUsingSlotsProtocol) {
85 slot.mInUse = true;
86 }
87
88 switch (rawEvent->code) {
89 case ABS_MT_POSITION_X:
90 slot.mAbsMtPositionX = rawEvent->value;
91 warnIfNotInUse(*rawEvent, slot);
92 break;
93 case ABS_MT_POSITION_Y:
94 slot.mAbsMtPositionY = rawEvent->value;
95 warnIfNotInUse(*rawEvent, slot);
96 break;
97 case ABS_MT_TOUCH_MAJOR:
98 slot.mAbsMtTouchMajor = rawEvent->value;
99 break;
100 case ABS_MT_TOUCH_MINOR:
101 slot.mAbsMtTouchMinor = rawEvent->value;
102 slot.mHaveAbsMtTouchMinor = true;
103 break;
104 case ABS_MT_WIDTH_MAJOR:
105 slot.mAbsMtWidthMajor = rawEvent->value;
106 break;
107 case ABS_MT_WIDTH_MINOR:
108 slot.mAbsMtWidthMinor = rawEvent->value;
109 slot.mHaveAbsMtWidthMinor = true;
110 break;
111 case ABS_MT_ORIENTATION:
112 slot.mAbsMtOrientation = rawEvent->value;
113 break;
114 case ABS_MT_TRACKING_ID:
115 if (mUsingSlotsProtocol && rawEvent->value < 0) {
116 // The slot is no longer in use but it retains its previous contents,
117 // which may be reused for subsequent touches.
118 slot.mInUse = false;
119 } else {
120 slot.mInUse = true;
121 slot.mAbsMtTrackingId = rawEvent->value;
122 }
123 break;
124 case ABS_MT_PRESSURE:
125 slot.mAbsMtPressure = rawEvent->value;
126 break;
127 case ABS_MT_DISTANCE:
128 slot.mAbsMtDistance = rawEvent->value;
129 break;
130 case ABS_MT_TOOL_TYPE:
131 slot.mAbsMtToolType = rawEvent->value;
132 slot.mHaveAbsMtToolType = true;
133 break;
134 }
135 }
136 } else if (rawEvent->type == EV_SYN && rawEvent->code == SYN_MT_REPORT) {
137 // MultiTouch Sync: The driver has returned all data for *one* of the pointers.
138 mCurrentSlot += 1;
139 }
140 }
141
finishSync()142 void MultiTouchMotionAccumulator::finishSync() {
143 if (!mUsingSlotsProtocol) {
144 resetSlots();
145 }
146 }
147
warnIfNotInUse(const RawEvent & event,const Slot & slot)148 void MultiTouchMotionAccumulator::warnIfNotInUse(const RawEvent& event, const Slot& slot) {
149 if (!slot.mInUse) {
150 ALOGW("Received unexpected event (0x%0x, 0x%0x) for slot %i with tracking id %i",
151 event.code, event.value, mCurrentSlot, slot.mAbsMtTrackingId);
152 }
153 }
154
155 // --- MultiTouchMotionAccumulator::Slot ---
156
getToolType() const157 ToolType MultiTouchMotionAccumulator::Slot::getToolType() const {
158 if (mHaveAbsMtToolType) {
159 switch (mAbsMtToolType) {
160 case MT_TOOL_FINGER:
161 return ToolType::FINGER;
162 case MT_TOOL_PEN:
163 return ToolType::STYLUS;
164 case MT_TOOL_PALM:
165 return ToolType::PALM;
166 }
167 }
168 return ToolType::UNKNOWN;
169 }
170
171 } // namespace android
172