Virtual rotary encoder native support

 - detect rotary encoder input devices if they have a single scroll
   axis and nothing else

 - make the rotary mapper display-aware as the virtual rotary is
   constrained to a single virtual display, just like the other
   virtual input devices

Fix: 320328752
Test: atest inputflinger_tests
Test: see CTS in topic
Flag: android.companion.virtualdevice.flags.virtual_rotary

Change-Id: I5581013d06708cbcc2c3ac8a622cd259aea8a9b4

1 files changed, 11 insertions, 0 deletions

diff --git a/libs/input/VirtualInputDevice.cpp b/libs/input/VirtualInputDevice.cpp
index eea06f1720..b73ee65504 100644
--- a/libs/input/VirtualInputDevice.cpp
+++ b/libs/input/VirtualInputDevice.cpp
@@ -509,4 +509,15 @@ bool VirtualStylus::handleStylusUp(uint16_t tool, std::chrono::nanoseconds event
     return true;
 }
 
+// --- VirtualRotaryEncoder ---
+VirtualRotaryEncoder::VirtualRotaryEncoder(unique_fd fd) : VirtualInputDevice(std::move(fd)) {}
+
+VirtualRotaryEncoder::~VirtualRotaryEncoder() {}
+
+bool VirtualRotaryEncoder::writeScrollEvent(float scrollAmount,
+                                            std::chrono::nanoseconds eventTime) {
+    return writeInputEvent(EV_REL, REL_WHEEL, static_cast<int32_t>(scrollAmount), eventTime) &&
+            writeInputEvent(EV_SYN, SYN_REPORT, 0, eventTime);
+}
+
 } // namespace android