commit e1a41a84725af9321ee12dabd1b14310dd70ac89
author Prabir Pradhan <prabirmsp@google.com> Fri Oct 14 18:06:50 2022 +0000
committer Prabir Pradhan <prabirmsp@google.com> Thu Oct 27 18:11:53 2022 +0000
tree b6b18ecb83bf638322fd46054660f8dfbf04ec3a
parent 2197cb4c1bf6ec84ceccc79ae20b690f214acc34

Generate key events for stylus button presses

Ensure all devices that report stylus buttons are categorized as a
keyboard. This means that KeyboardInputMapper will get a chance to
handle the events from these devices.

Then, we allow KeyboardInputMapper to process stylus button events.
Since stylus button (e.g. BTN_STYLUS) are mapped to Android key codes in
the Generic.kl file, KeyEvents with the appropriate key codes will be
generated for these button presses.

Bug: 246394583
Test: atest inputflinger_tests
Change-Id: I92d4a60f23f98f9d239edf1f4dd400e6e528e350

services/inputflinger/reader/EventHub.cpp

diff --git a/services/inputflinger/reader/EventHub.cpp b/services/inputflinger/reader/EventHub.cpp
index 18d03f8..eaa6f5c 100644
--- a/services/inputflinger/reader/EventHub.cpp
+++ b/services/inputflinger/reader/EventHub.cpp
@@ -2171,13 +2171,15 @@
     device->readDeviceBitMask(EVIOCGBIT(EV_MSC, 0), device->mscBitmask);
     device->readDeviceBitMask(EVIOCGPROP(0), device->propBitmask);
 
-    // See if this is a keyboard.  Ignore everything in the button range except for
-    // joystick and gamepad buttons which are handled like keyboards for the most part.
+    // See if this is a device with keys. This could be full keyboard, or other devices like
+    // gamepads, joysticks, and styluses with buttons that should generate key presses.
     bool haveKeyboardKeys =
             device->keyBitmask.any(0, BTN_MISC) || device->keyBitmask.any(BTN_WHEEL, KEY_MAX + 1);
     bool haveGamepadButtons = device->keyBitmask.any(BTN_MISC, BTN_MOUSE) ||
             device->keyBitmask.any(BTN_JOYSTICK, BTN_DIGI);
-    if (haveKeyboardKeys || haveGamepadButtons) {
+    bool haveStylusButtons = device->keyBitmask.test(BTN_STYLUS) ||
+            device->keyBitmask.test(BTN_STYLUS2) || device->keyBitmask.test(BTN_STYLUS3);
+    if (haveKeyboardKeys || haveGamepadButtons || haveStylusButtons) {
         device->classes |= InputDeviceClass::KEYBOARD;
     }
 
@@ -2208,14 +2210,10 @@
     } else if (device->keyBitmask.test(BTN_TOUCH) && device->absBitmask.test(ABS_X) &&
                device->absBitmask.test(ABS_Y)) {
         device->classes |= InputDeviceClass::TOUCH;
-        // Is this a BT stylus?
+        // Is this a stylus that reports contact/pressure independently of touch coordinates?
     } else if ((device->absBitmask.test(ABS_PRESSURE) || device->keyBitmask.test(BTN_TOUCH)) &&
                !device->absBitmask.test(ABS_X) && !device->absBitmask.test(ABS_Y)) {
         device->classes |= InputDeviceClass::EXTERNAL_STYLUS;
-        // Keyboard will try to claim some of the buttons but we really want to reserve those so we
-        // can fuse it with the touch screen data, so just take them back. Note this means an
-        // external stylus cannot also be a keyboard device.
-        device->classes &= ~InputDeviceClass::KEYBOARD;
     }
 
     // See if this device is a joystick.

services/inputflinger/reader/mapper/KeyboardInputMapper.cpp

diff --git a/services/inputflinger/reader/mapper/KeyboardInputMapper.cpp b/services/inputflinger/reader/mapper/KeyboardInputMapper.cpp
index fa38186..33b8a1b 100644
--- a/services/inputflinger/reader/mapper/KeyboardInputMapper.cpp
+++ b/services/inputflinger/reader/mapper/KeyboardInputMapper.cpp
@@ -53,10 +53,11 @@
     return keyCode;
 }
 
-static bool isKeyboardOrGamepadKey(int32_t scanCode) {
-    return scanCode < BTN_MOUSE || scanCode >= BTN_WHEEL ||
-            (scanCode >= BTN_MISC && scanCode < BTN_MOUSE) ||
-            (scanCode >= BTN_JOYSTICK && scanCode < BTN_DIGI);
+static bool isSupportedScanCode(int32_t scanCode) {
+    // KeyboardInputMapper handles keys from keyboards, gamepads, and styluses.
+    return scanCode < BTN_MOUSE || (scanCode >= BTN_JOYSTICK && scanCode < BTN_DIGI) ||
+            scanCode == BTN_STYLUS || scanCode == BTN_STYLUS2 || scanCode == BTN_STYLUS3 ||
+            scanCode >= BTN_WHEEL;
 }
 
 static bool isMediaKey(int32_t keyCode) {
@@ -195,7 +196,7 @@
             int32_t usageCode = mCurrentHidUsage;
             mCurrentHidUsage = 0;
 
-            if (isKeyboardOrGamepadKey(scanCode)) {
+            if (isSupportedScanCode(scanCode)) {
                 out += processKey(rawEvent->when, rawEvent->readTime, rawEvent->value != 0,
                                   scanCode, usageCode);
             }