Add support to disable touchpad acceleration

Bug: 387184135
Test: atest TouchpadInputMapperUnitTest
Flag: com.android.hardware.input.pointer_acceleration
Change-Id: I4e2c8a1fa79c680573ed5632965093c8ad7a478d

4 files changed, 88 insertions, 2 deletions

diff --git a/services/inputflinger/include/InputReaderBase.h b/services/inputflinger/include/InputReaderBase.h
index 404a509247..0eef14f309 100644
--- a/services/inputflinger/include/InputReaderBase.h
+++ b/services/inputflinger/include/InputReaderBase.h
@@ -150,6 +150,11 @@ struct InputReaderConfiguration {
     // speed setting still affects the scaling factor.
     bool mousePointerAccelerationEnabled;
 
+    // True if the touchpad should exhibit pointer acceleration. If false,
+    // a flat acceleration curve (linear scaling) is used, but the user's pointer
+    // speed setting still affects the scaling factor.
+    bool touchpadAccelerationEnabled;
+
     // Velocity control parameters for touchpad pointer movements on the old touchpad stack (based
     // on TouchInputMapper).
     //
@@ -284,6 +289,7 @@ struct InputReaderConfiguration {
             mousePointerSpeed(0),
             displaysWithMousePointerAccelerationDisabled(),
             mousePointerAccelerationEnabled(true),
+            touchpadAccelerationEnabled(true),
             pointerVelocityControlParameters(1.0f, 500.0f, 3000.0f,
                                              static_cast<float>(
                                                      android::os::IInputConstants::
diff --git a/services/inputflinger/reader/mapper/TouchpadInputMapper.cpp b/services/inputflinger/reader/mapper/TouchpadInputMapper.cpp
index 0c094e6cce..0df3364644 100644
--- a/services/inputflinger/reader/mapper/TouchpadInputMapper.cpp
+++ b/services/inputflinger/reader/mapper/TouchpadInputMapper.cpp
@@ -59,9 +59,11 @@ const bool DEBUG_TOUCHPAD_GESTURES =
                                   ANDROID_LOG_INFO);
 
 std::vector<double> createAccelerationCurveForSensitivity(int32_t sensitivity,
+                                                          bool accelerationEnabled,
                                                           size_t propertySize) {
-    std::vector<AccelerationCurveSegment> segments =
-            createAccelerationCurveForPointerSensitivity(sensitivity);
+    std::vector<AccelerationCurveSegment> segments = accelerationEnabled
+            ? createAccelerationCurveForPointerSensitivity(sensitivity)
+            : createFlatAccelerationCurve(sensitivity);
     LOG_ALWAYS_FATAL_IF(propertySize < 4 * segments.size());
     std::vector<double> output(propertySize, 0);
 
@@ -358,12 +360,14 @@ std::list<NotifyArgs> TouchpadInputMapper::reconfigure(nsecs_t when,
         GesturesProp accelCurveProp = mPropertyProvider.getProperty("Pointer Accel Curve");
         accelCurveProp.setRealValues(
                 createAccelerationCurveForSensitivity(config.touchpadPointerSpeed,
+                                                      config.touchpadAccelerationEnabled,
                                                       accelCurveProp.getCount()));
         mPropertyProvider.getProperty("Use Custom Touchpad Scroll Accel Curve")
                 .setBoolValues({true});
         GesturesProp scrollCurveProp = mPropertyProvider.getProperty("Scroll Accel Curve");
         scrollCurveProp.setRealValues(
                 createAccelerationCurveForSensitivity(config.touchpadPointerSpeed,
+                                                      config.touchpadAccelerationEnabled,
                                                       scrollCurveProp.getCount()));
         mPropertyProvider.getProperty("Scroll X Out Scale").setRealValues({1.0});
         mPropertyProvider.getProperty("Scroll Y Out Scale").setRealValues({1.0});
@@ -510,4 +514,12 @@ std::optional<HardwareProperties> TouchpadInputMapper::getTouchpadHardwareProper
     return mHardwareProperties;
 }
 
+std::optional<GesturesProp> TouchpadInputMapper::getGesturePropertyForTesting(
+        const std::string& name) {
+    if (!mPropertyProvider.hasProperty(name)) {
+        return std::nullopt;
+    }
+    return mPropertyProvider.getProperty(name);
+}
+
 } // namespace android
diff --git a/services/inputflinger/reader/mapper/TouchpadInputMapper.h b/services/inputflinger/reader/mapper/TouchpadInputMapper.h
index a2c4be9e50..56553c9eea 100644
--- a/services/inputflinger/reader/mapper/TouchpadInputMapper.h
+++ b/services/inputflinger/reader/mapper/TouchpadInputMapper.h
@@ -70,6 +70,8 @@ public:
 
     std::optional<HardwareProperties> getTouchpadHardwareProperties() override;
 
+    std::optional<GesturesProp> getGesturePropertyForTesting(const std::string& name);
+
 private:
     void resetGestureInterpreter(nsecs_t when);
     explicit TouchpadInputMapper(InputDeviceContext& deviceContext,
diff --git a/services/inputflinger/tests/TouchpadInputMapper_test.cpp b/services/inputflinger/tests/TouchpadInputMapper_test.cpp
index ea69fffeaa..07891145bf 100644
--- a/services/inputflinger/tests/TouchpadInputMapper_test.cpp
+++ b/services/inputflinger/tests/TouchpadInputMapper_test.cpp
@@ -18,10 +18,13 @@
 
 #include <android-base/logging.h>
 #include <gtest/gtest.h>
+#include <input/AccelerationCurve.h>
 
+#include <log/log.h>
 #include <thread>
 #include "InputMapperTest.h"
 #include "InterfaceMocks.h"
+#include "TestConstants.h"
 #include "TestEventMatchers.h"
 
 #define TAG "TouchpadInputMapper_test"
@@ -190,4 +193,67 @@ TEST_F(TouchpadInputMapperTest, TouchpadHardwareState) {
     mFakePolicy->assertTouchpadHardwareStateNotified();
 }
 
+TEST_F(TouchpadInputMapperTest, TouchpadAccelerationDisabled) {
+    mReaderConfiguration.touchpadAccelerationEnabled = false;
+    mReaderConfiguration.touchpadPointerSpeed = 3;
+
+    std::list<NotifyArgs> args =
+            mMapper->reconfigure(ARBITRARY_TIME, mReaderConfiguration,
+                                 InputReaderConfiguration::Change::TOUCHPAD_SETTINGS);
+    auto* touchpadMapper = static_cast<TouchpadInputMapper*>(mMapper.get());
+
+    const auto accelCurvePropsDisabled =
+            touchpadMapper->getGesturePropertyForTesting("Pointer Accel Curve");
+    ASSERT_TRUE(accelCurvePropsDisabled.has_value());
+    std::vector<double> curveValuesDisabled = accelCurvePropsDisabled.value().getRealValues();
+    std::vector<AccelerationCurveSegment> curve =
+            createFlatAccelerationCurve(mReaderConfiguration.touchpadPointerSpeed);
+    double expectedBaseGain = curve[0].baseGain;
+    ASSERT_EQ(curveValuesDisabled[0], std::numeric_limits<double>::infinity());
+    ASSERT_EQ(curveValuesDisabled[1], 0);
+    ASSERT_NEAR(curveValuesDisabled[2], expectedBaseGain, EPSILON);
+    ASSERT_EQ(curveValuesDisabled[3], 0);
+}
+
+TEST_F(TouchpadInputMapperTest, TouchpadAccelerationEnabled) {
+    // Enable touchpad acceleration.
+    mReaderConfiguration.touchpadAccelerationEnabled = true;
+    mReaderConfiguration.touchpadPointerSpeed = 3;
+
+    std::list<NotifyArgs> args =
+            mMapper->reconfigure(ARBITRARY_TIME, mReaderConfiguration,
+                                 InputReaderConfiguration::Change::TOUCHPAD_SETTINGS);
+    ASSERT_THAT(args, testing::IsEmpty());
+
+    auto* touchpadMapper = static_cast<TouchpadInputMapper*>(mMapper.get());
+
+    // Get the acceleration curve properties when acceleration is enabled.
+    const auto accelCurvePropsEnabled =
+            touchpadMapper->getGesturePropertyForTesting("Pointer Accel Curve");
+    ASSERT_TRUE(accelCurvePropsEnabled.has_value());
+
+    // Get the curve values.
+    std::vector<double> curveValuesEnabled = accelCurvePropsEnabled.value().getRealValues();
+
+    // Use createAccelerationCurveForPointerSensitivity to get expected curve segments.
+    std::vector<AccelerationCurveSegment> expectedCurveSegments =
+            createAccelerationCurveForPointerSensitivity(mReaderConfiguration.touchpadPointerSpeed);
+
+    // Iterate through the segments and compare the values.
+    for (size_t i = 0; i < expectedCurveSegments.size(); ++i) {
+        // Check max speed.
+        if (std::isinf(expectedCurveSegments[i].maxPointerSpeedMmPerS)) {
+            ASSERT_TRUE(std::isinf(curveValuesEnabled[i * 4 + 0]));
+        } else {
+            ASSERT_NEAR(curveValuesEnabled[i * 4 + 0],
+                        expectedCurveSegments[i].maxPointerSpeedMmPerS, EPSILON);
+        }
+
+        // Check that the x^2 term is zero.
+        ASSERT_NEAR(curveValuesEnabled[i * 4 + 1], 0, EPSILON);
+        ASSERT_NEAR(curveValuesEnabled[i * 4 + 2], expectedCurveSegments[i].baseGain, EPSILON);
+        ASSERT_NEAR(curveValuesEnabled[i * 4 + 3], expectedCurveSegments[i].reciprocal, EPSILON);
+    }
+}
+
 } // namespace android