VirtualTouchpadEvdev.cpp revision 89af70bce420f011adfeb0f80984b3895c4d7d9b 
1#include "VirtualTouchpadEvdev.h"
2
3#include <android/input.h>
4#include <inttypes.h>
5#include <linux/input.h>
6#include <log/log.h>
7
8// References:
9//  [0] Multi-touch (MT) Protocol,
10//      https://www.kernel.org/doc/Documentation/input/multi-touch-protocol.txt
11
12namespace android {
13namespace dvr {
14
15namespace {
16
17// Virtual evdev device properties. The name is arbitrary, but Android can
18// use it to look up device configuration, so it must be unique. Vendor and
19// product values must be 0 to indicate an internal device and prevent a
20// similar lookup that could conflict with a physical device.
21static const char* const kDeviceName = "vr window manager virtual touchpad";
22static constexpr int16_t kDeviceBusType = BUS_VIRTUAL;
23static constexpr int16_t kDeviceVendor = 0;
24static constexpr int16_t kDeviceProduct = 0;
25static constexpr int16_t kDeviceVersion = 0x0001;
26
27static constexpr int32_t kWidth = 0x10000;
28static constexpr int32_t kHeight = 0x10000;
29static constexpr int32_t kSlots = 2;
30
31}  // anonymous namespace
32
33sp<VirtualTouchpad> VirtualTouchpadEvdev::Create() {
34  VirtualTouchpadEvdev* const touchpad = new VirtualTouchpadEvdev();
35  const status_t status = touchpad->Initialize();
36  if (status) {
37    ALOGE("initialization failed: %d", status);
38    return sp<VirtualTouchpad>();
39  }
40  return sp<VirtualTouchpad>(touchpad);
41}
42
43int VirtualTouchpadEvdev::Initialize() {
44  if (!injector_) {
45    owned_injector_.reset(new EvdevInjector());
46    injector_ = owned_injector_.get();
47  }
48  injector_->ConfigureBegin(kDeviceName, kDeviceBusType, kDeviceVendor,
49                            kDeviceProduct, kDeviceVersion);
50  injector_->ConfigureInputProperty(INPUT_PROP_DIRECT);
51  injector_->ConfigureMultiTouchXY(0, 0, kWidth - 1, kHeight - 1);
52  injector_->ConfigureAbsSlots(kSlots);
53  injector_->ConfigureKey(BTN_TOUCH);
54  injector_->ConfigureKey(BTN_BACK);
55  injector_->ConfigureEnd();
56  return injector_->GetError();
57}
58
59int VirtualTouchpadEvdev::Touch(float x, float y, float pressure) {
60  if ((x < 0.0f) || (x >= 1.0f) || (y < 0.0f) || (y >= 1.0f)) {
61    return EINVAL;
62  }
63  int32_t device_x = x * kWidth;
64  int32_t device_y = y * kHeight;
65  touches_ = ((touches_ & 1) << 1) | (pressure > 0);
66  ALOGV("(%f,%f) %f -> (%" PRId32 ",%" PRId32 ") %d",
67        x, y, pressure, device_x, device_y, touches_);
68
69  if (!injector_) {
70    return EvdevInjector::ERROR_SEQUENCING;
71  }
72  injector_->ResetError();
73  switch (touches_) {
74    case 0b00:  // Hover continues.
75      if (device_x != last_device_x_ || device_y != last_device_y_) {
76        injector_->SendMultiTouchXY(0, 0, device_x, device_y);
77        injector_->SendSynReport();
78      }
79      break;
80    case 0b01:  // Touch begins.
81      // Press.
82      injector_->SendMultiTouchXY(0, 0, device_x, device_y);
83      injector_->SendKey(BTN_TOUCH, EvdevInjector::KEY_PRESS);
84      injector_->SendSynReport();
85      break;
86    case 0b10:  // Touch ends.
87      injector_->SendKey(BTN_TOUCH, EvdevInjector::KEY_RELEASE);
88      injector_->SendMultiTouchLift(0);
89      injector_->SendSynReport();
90      break;
91    case 0b11:  // Touch continues.
92      if (device_x != last_device_x_ || device_y != last_device_y_) {
93        injector_->SendMultiTouchXY(0, 0, device_x, device_y);
94        injector_->SendSynReport();
95      }
96      break;
97  }
98  last_device_x_ = device_x;
99  last_device_y_ = device_y;
100
101  return injector_->GetError();
102}
103
104int VirtualTouchpadEvdev::ButtonState(int buttons) {
105  const int changes = last_motion_event_buttons_ ^ buttons;
106  if (!changes) {
107    return 0;
108  }
109  if (buttons & ~AMOTION_EVENT_BUTTON_BACK) {
110    return ENOTSUP;
111  }
112  ALOGV("change %X from %X to %X", changes, last_motion_event_buttons_,
113        buttons);
114
115  if (!injector_) {
116    return EvdevInjector::ERROR_SEQUENCING;
117  }
118  injector_->ResetError();
119  if (changes & AMOTION_EVENT_BUTTON_BACK) {
120    injector_->SendKey(BTN_BACK,
121                       (buttons & AMOTION_EVENT_BUTTON_BACK)
122                           ? EvdevInjector::KEY_PRESS
123                           : EvdevInjector::KEY_RELEASE);
124  }
125  last_motion_event_buttons_ = buttons;
126  return injector_->GetError();
127}
128
129}  // namespace dvr
130}  // namespace android
131