Introduce testable UDFPS touch architecture

Bug: 218388821
Bug: 218374828
Test: atest SinglePointerUdfpsTouchProcessorTest
Change-Id: I5654550873f580db07d708e3de1a13e45f70b052

packages/SystemUI/src/com/android/systemui/biometrics/udfps/InteractionEvent.kt

@@ -0,0 +1,50 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.systemui.biometrics.udfps
+
+import android.view.MotionEvent
+
+/** Interaction event between a finger and the under-display fingerprint sensor (UDFPS). */
+enum class InteractionEvent {
+    /**
+     * A finger entered the sensor area. This can originate from either [MotionEvent.ACTION_DOWN] or
+     * [MotionEvent.ACTION_MOVE].
+     */
+    DOWN,
+
+    /**
+     * A finger left the sensor area. This can originate from either [MotionEvent.ACTION_UP] or
+     * [MotionEvent.ACTION_MOVE].
+     */
+    UP,
+
+    /**
+     * The touch reporting has stopped. This corresponds to [MotionEvent.ACTION_CANCEL]. This should
+     * not be confused with [UP]. If there was a finger on the sensor, it may or may not still be on
+     * the sensor.
+     */
+    CANCEL,
+
+    /**
+     * The interaction hasn't changed since the previous event. The can originate from any of
+     * [MotionEvent.ACTION_DOWN], [MotionEvent.ACTION_MOVE], or [MotionEvent.ACTION_UP] if one of
+     * these is true:
+     * - There was previously a finger on the sensor, and that finger is still on the sensor.
+     * - There was previously no finger on the sensor, and there still isn't.
+     */
+    UNCHANGED,
+}

packages/SystemUI/src/com/android/systemui/biometrics/udfps/NormalizedTouchData.kt

@@ -0,0 +1,64 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.systemui.biometrics.udfps
+
+import android.graphics.RectF
+import android.view.MotionEvent
+import com.android.systemui.biometrics.UdfpsOverlayParams
+
+/** Touch data in natural orientation and native resolution. */
+data class NormalizedTouchData(
+
+    /**
+     * Value obtained from [MotionEvent.getPointerId], or [MotionEvent.INVALID_POINTER_ID] if the ID
+     * is not available.
+     */
+    val pointerId: Int,
+
+    /** [MotionEvent.getRawX] mapped to natural orientation and native resolution. */
+    val x: Float,
+
+    /** [MotionEvent.getRawY] mapped to natural orientation and native resolution. */
+    val y: Float,
+
+    /** [MotionEvent.getTouchMinor] mapped to natural orientation and native resolution. */
+    val minor: Float,
+
+    /** [MotionEvent.getTouchMajor] mapped to natural orientation and native resolution. */
+    val major: Float,
+
+    /** [MotionEvent.getOrientation] mapped to natural orientation. */
+    val orientation: Float,
+
+    /** [MotionEvent.getEventTime]. */
+    val time: Long,
+
+    /** [MotionEvent.getDownTime]. */
+    val gestureStart: Long,
+) {
+
+    /**
+     * [overlayParams] contains the location and dimensions of the sensor area, as well as the scale
+     * factor and orientation of the overlay. See [UdfpsOverlayParams].
+     *
+     * Returns whether the given pointer is within the sensor's bounding box.
+     */
+    fun isWithinSensor(overlayParams: UdfpsOverlayParams): Boolean {
+        val r = RectF(overlayParams.sensorBounds).apply { scale(1f / overlayParams.scaleFactor) }
+        return r.left <= x && r.right >= x && r.top <= y && r.bottom >= y
+    }
+}

packages/SystemUI/src/com/android/systemui/biometrics/udfps/SinglePointerTouchProcessor.kt

@@ -0,0 +1,168 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.systemui.biometrics.udfps
+
+import android.graphics.PointF
+import android.util.RotationUtils
+import android.view.MotionEvent
+import android.view.MotionEvent.INVALID_POINTER_ID
+import android.view.Surface
+import com.android.systemui.biometrics.UdfpsOverlayParams
+import com.android.systemui.biometrics.udfps.TouchProcessorResult.Failure
+import com.android.systemui.biometrics.udfps.TouchProcessorResult.ProcessedTouch
+
+// TODO(b/259140693): Consider using an object pool of TouchProcessorResult to avoid allocations.
+class SinglePointerTouchProcessor : TouchProcessor {
+
+    override fun processTouch(
+        event: MotionEvent,
+        previousPointerOnSensorId: Int,
+        overlayParams: UdfpsOverlayParams,
+    ): TouchProcessorResult {
+
+        return when (event.actionMasked) {
+            MotionEvent.ACTION_DOWN ->
+                processActionDown(event.preprocess(previousPointerOnSensorId, overlayParams))
+            MotionEvent.ACTION_MOVE ->
+                processActionMove(event.preprocess(previousPointerOnSensorId, overlayParams))
+            MotionEvent.ACTION_UP ->
+                processActionUp(event.preprocess(previousPointerOnSensorId, overlayParams))
+            MotionEvent.ACTION_CANCEL ->
+                processActionCancel(event.preprocess(previousPointerOnSensorId, overlayParams))
+            else ->
+                Failure("Unsupported MotionEvent." + MotionEvent.actionToString(event.actionMasked))
+        }
+    }
+}
+
+private data class PreprocessedTouch(
+    val data: NormalizedTouchData,
+    val previousPointerOnSensorId: Int,
+    val isWithinSensor: Boolean,
+)
+
+private fun processActionDown(touch: PreprocessedTouch): TouchProcessorResult {
+    return if (touch.isWithinSensor) {
+        ProcessedTouch(InteractionEvent.DOWN, pointerOnSensorId = touch.data.pointerId, touch.data)
+    } else {
+        val event =
+            if (touch.data.pointerId == touch.previousPointerOnSensorId) {
+                InteractionEvent.UP
+            } else {
+                InteractionEvent.UNCHANGED
+            }
+        ProcessedTouch(event, pointerOnSensorId = INVALID_POINTER_ID, touch.data)
+    }
+}
+
+private fun processActionMove(touch: PreprocessedTouch): TouchProcessorResult {
+    val hadPointerOnSensor = touch.previousPointerOnSensorId != INVALID_POINTER_ID
+    val interactionEvent =
+        when {
+            touch.isWithinSensor && !hadPointerOnSensor -> InteractionEvent.DOWN
+            !touch.isWithinSensor && hadPointerOnSensor -> InteractionEvent.UP
+            else -> InteractionEvent.UNCHANGED
+        }
+    val pointerOnSensorId =
+        when (interactionEvent) {
+            InteractionEvent.UNCHANGED -> touch.previousPointerOnSensorId
+            InteractionEvent.DOWN -> touch.data.pointerId
+            else -> INVALID_POINTER_ID
+        }
+    return ProcessedTouch(interactionEvent, pointerOnSensorId, touch.data)
+}
+
+private fun processActionUp(touch: PreprocessedTouch): TouchProcessorResult {
+    return if (touch.isWithinSensor) {
+        ProcessedTouch(InteractionEvent.UP, pointerOnSensorId = INVALID_POINTER_ID, touch.data)
+    } else {
+        val event =
+            if (touch.previousPointerOnSensorId != INVALID_POINTER_ID) {
+                InteractionEvent.UP
+            } else {
+                InteractionEvent.UNCHANGED
+            }
+        ProcessedTouch(event, pointerOnSensorId = INVALID_POINTER_ID, touch.data)
+    }
+}
+
+private fun processActionCancel(touch: PreprocessedTouch): TouchProcessorResult {
+    return ProcessedTouch(
+        InteractionEvent.CANCEL,
+        pointerOnSensorId = INVALID_POINTER_ID,
+        touch.data
+    )
+}
+
+/** Returns [PreprocessedTouch], which is an input to all the action-specific functions. */
+private fun MotionEvent.preprocess(
+    previousPointerOnSensorId: Int,
+    overlayParams: UdfpsOverlayParams
+): PreprocessedTouch {
+    // TODO(b/253085297): Add multitouch support. pointerIndex can be > 0 for ACTION_MOVE.
+    val pointerIndex = 0
+    val touchData = normalize(pointerIndex, overlayParams)
+    val isWithinSensor = touchData.isWithinSensor(overlayParams)
+    return PreprocessedTouch(touchData, previousPointerOnSensorId, isWithinSensor)
+}
+
+/**
+ * Returns the touch information from the given [MotionEvent] with the relevant fields mapped to
+ * natural orientation and native resolution.
+ */
+private fun MotionEvent.normalize(
+    pointerIndex: Int,
+    overlayParams: UdfpsOverlayParams
+): NormalizedTouchData {
+    val naturalTouch: PointF = rotateToNaturalOrientation(pointerIndex, overlayParams)
+    val nativeX = naturalTouch.x / overlayParams.scaleFactor
+    val nativeY = naturalTouch.y / overlayParams.scaleFactor
+    val nativeMinor: Float = getTouchMinor(pointerIndex) / overlayParams.scaleFactor
+    val nativeMajor: Float = getTouchMajor(pointerIndex) / overlayParams.scaleFactor
+    return NormalizedTouchData(
+        pointerId = getPointerId(pointerIndex),
+        x = nativeX,
+        y = nativeY,
+        minor = nativeMinor,
+        major = nativeMajor,
+        // TODO(b/259311354): touch orientation should be reported relative to Surface.ROTATION_O.
+        orientation = getOrientation(pointerIndex),
+        time = eventTime,
+        gestureStart = downTime,
+    )
+}
+
+/**
+ * Returns the [MotionEvent.getRawX] and [MotionEvent.getRawY] of the given pointer as if the device
+ * is in the [Surface.ROTATION_0] orientation.
+ */
+private fun MotionEvent.rotateToNaturalOrientation(
+    pointerIndex: Int,
+    overlayParams: UdfpsOverlayParams
+): PointF {
+    val touchPoint = PointF(getRawX(pointerIndex), getRawY(pointerIndex))
+    val rot = overlayParams.rotation
+    if (rot == Surface.ROTATION_90 || rot == Surface.ROTATION_270) {
+        RotationUtils.rotatePointF(
+            touchPoint,
+            RotationUtils.deltaRotation(rot, Surface.ROTATION_0),
+            overlayParams.logicalDisplayWidth.toFloat(),
+            overlayParams.logicalDisplayHeight.toFloat()
+        )
+    }
+    return touchPoint
+}

packages/SystemUI/src/com/android/systemui/biometrics/udfps/TouchProcessor.kt

@@ -0,0 +1,47 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.systemui.biometrics.udfps
+
+import android.view.MotionEvent
+import com.android.systemui.biometrics.UdfpsOverlayParams
+
+/**
+ * Determines whether a finger entered or left the area of the under-display fingerprint sensor
+ * (UDFPS). Maps the touch information from a [MotionEvent] to the orientation and scale independent
+ * [NormalizedTouchData].
+ */
+interface TouchProcessor {
+
+    /**
+     * [event] touch event to be processed.
+     *
+     * [previousPointerOnSensorId] pointerId for the finger that was on the sensor prior to this
+     * event. See [MotionEvent.getPointerId]. If there was no finger on the sensor, this should be
+     * set to [MotionEvent.INVALID_POINTER_ID].
+     *
+     * [overlayParams] contains the location and dimensions of the sensor area, as well as the scale
+     * factor and orientation of the overlay. See [UdfpsOverlayParams].
+     *
+     * Returns [TouchProcessorResult.ProcessedTouch] on success, and [TouchProcessorResult.Failure]
+     * on failure.
+     */
+    fun processTouch(
+        event: MotionEvent,
+        previousPointerOnSensorId: Int,
+        overlayParams: UdfpsOverlayParams,
+    ): TouchProcessorResult
+}

packages/SystemUI/src/com/android/systemui/biometrics/udfps/TouchProcessorResult.kt

@@ -0,0 +1,42 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.systemui.biometrics.udfps
+
+import android.view.MotionEvent
+
+/** Contains all the possible returns types for [TouchProcessor.processTouch] */
+sealed class TouchProcessorResult {
+
+    /**
+     * [event] whether a finger entered or left the sensor area. See [InteractionEvent].
+     *
+     * [pointerOnSensorId] pointerId fof the finger that's currently on the sensor. See
+     * [MotionEvent.getPointerId]. If there is no finger on the sensor, the value is set to
+     * [MotionEvent.INVALID_POINTER_ID].
+     *
+     * [touchData] relevant data from the MotionEvent, mapped to natural orientation and native
+     * resolution. See [NormalizedTouchData].
+     */
+    data class ProcessedTouch(
+        val event: InteractionEvent,
+        val pointerOnSensorId: Int,
+        val touchData: NormalizedTouchData
+    ) : TouchProcessorResult()
+
+    /** [reason] the reason for the failure. */
+    data class Failure(val reason: String = "") : TouchProcessorResult()
+}

packages/SystemUI/tests/src/com/android/systemui/biometrics/udfps/NormalizedTouchDataTest.kt

@@ -0,0 +1,92 @@
+package com.android.systemui.biometrics.udfps
+
+import android.graphics.Rect
+import androidx.test.filters.SmallTest
+import com.android.systemui.SysuiTestCase
+import com.android.systemui.biometrics.UdfpsOverlayParams
+import com.google.common.truth.Truth.assertThat
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.junit.runners.Parameterized
+import org.junit.runners.Parameterized.Parameters
+
+@SmallTest
+@RunWith(Parameterized::class)
+class NormalizedTouchDataTest(val testCase: TestCase) : SysuiTestCase() {
+
+    @Test
+    fun isWithinSensor() {
+        val touchData = TOUCH_DATA.copy(x = testCase.x.toFloat(), y = testCase.y.toFloat())
+        val actual = touchData.isWithinSensor(OVERLAY_PARAMS)
+
+        assertThat(actual).isEqualTo(testCase.expected)
+    }
+
+    data class TestCase(val x: Int, val y: Int, val expected: Boolean)
+
+    companion object {
+        @Parameters(name = "{0}")
+        @JvmStatic
+        fun data(): List<TestCase> =
+            listOf(
+                    genPositiveTestCases(
+                        validXs = listOf(SENSOR.left, SENSOR.right, SENSOR.centerX()),
+                        validYs = listOf(SENSOR.top, SENSOR.bottom, SENSOR.centerY())
+                    ),
+                    genNegativeTestCases(
+                        invalidXs = listOf(SENSOR.left - 1, SENSOR.right + 1),
+                        invalidYs = listOf(SENSOR.top - 1, SENSOR.bottom + 1),
+                        validXs = listOf(SENSOR.left, SENSOR.right, SENSOR.centerX()),
+                        validYs = listOf(SENSOR.top, SENSOR.bottom, SENSOR.centerY())
+                    )
+                )
+                .flatten()
+    }
+}
+
+/* Placeholder touch parameters. */
+private const val POINTER_ID = 42
+private const val NATIVE_MINOR = 2.71828f
+private const val NATIVE_MAJOR = 3.14f
+private const val ORIENTATION = 1.23f
+private const val TIME = 12345699L
+private const val GESTURE_START = 12345600L
+
+/* Template [NormalizedTouchData]. */
+private val TOUCH_DATA =
+    NormalizedTouchData(
+        POINTER_ID,
+        x = 0f,
+        y = 0f,
+        NATIVE_MINOR,
+        NATIVE_MAJOR,
+        ORIENTATION,
+        TIME,
+        GESTURE_START
+    )
+
+private val SENSOR = Rect(100 /* left */, 200 /* top */, 300 /* right */, 500 /* bottom */)
+private val OVERLAY_PARAMS = UdfpsOverlayParams(sensorBounds = SENSOR)
+
+private fun genTestCases(
+    xs: List<Int>,
+    ys: List<Int>,
+    expected: Boolean
+): List<NormalizedTouchDataTest.TestCase> {
+    return xs.flatMap { x -> ys.map { y -> NormalizedTouchDataTest.TestCase(x, y, expected) } }
+}
+
+private fun genPositiveTestCases(
+    validXs: List<Int>,
+    validYs: List<Int>,
+) = genTestCases(validXs, validYs, expected = true)
+
+private fun genNegativeTestCases(
+    invalidXs: List<Int>,
+    invalidYs: List<Int>,
+    validXs: List<Int>,
+    validYs: List<Int>,
+): List<NormalizedTouchDataTest.TestCase> {
+    return genTestCases(invalidXs, validYs, expected = false) +
+        genTestCases(validXs, invalidYs, expected = false)
+}

packages/SystemUI/tests/src/com/android/systemui/biometrics/udfps/SinglePointerTouchProcessorTest.kt

@@ -0,0 +1,500 @@
+/*
+ * Copyright (C) 2022 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.systemui.biometrics.udfps
+
+import android.graphics.Rect
+import android.view.MotionEvent
+import android.view.MotionEvent.INVALID_POINTER_ID
+import android.view.MotionEvent.PointerProperties
+import android.view.Surface
+import android.view.Surface.Rotation
+import androidx.test.filters.SmallTest
+import com.android.systemui.SysuiTestCase
+import com.android.systemui.biometrics.UdfpsOverlayParams
+import com.google.common.truth.Truth.assertThat
+import org.junit.Test
+import org.junit.runner.RunWith
+import org.junit.runners.Parameterized
+import org.junit.runners.Parameterized.Parameters
+
+@SmallTest
+@RunWith(Parameterized::class)
+class SinglePointerTouchProcessorTest(val testCase: TestCase) : SysuiTestCase() {
+    private val underTest = SinglePointerTouchProcessor()
+
+    @Test
+    fun processTouch() {
+        val actual =
+            underTest.processTouch(
+                testCase.event,
+                testCase.previousPointerOnSensorId,
+                testCase.overlayParams,
+            )
+
+        assertThat(actual).isInstanceOf(testCase.expected.javaClass)
+        if (actual is TouchProcessorResult.ProcessedTouch) {
+            assertThat(actual).isEqualTo(testCase.expected)
+        }
+    }
+
+    data class TestCase(
+        val event: MotionEvent,
+        val previousPointerOnSensorId: Int,
+        val overlayParams: UdfpsOverlayParams,
+        val expected: TouchProcessorResult,
+    ) {
+        override fun toString(): String {
+            val expectedOutput =
+                if (expected is TouchProcessorResult.ProcessedTouch) {
+                    expected.event.toString() +
+                        ", (x: ${expected.touchData.x}, y: ${expected.touchData.y})" +
+                        ", pointerOnSensorId: ${expected.pointerOnSensorId}" +
+                        ", ..."
+                } else {
+                    TouchProcessorResult.Failure().toString()
+                }
+            return "{" +
+                MotionEvent.actionToString(event.action) +
+                ", (x: ${event.x}, y: ${event.y})" +
+                ", scale: ${overlayParams.scaleFactor}" +
+                ", rotation: " +
+                Surface.rotationToString(overlayParams.rotation) +
+                ", previousPointerOnSensorId: $previousPointerOnSensorId" +
+                ", ...} expected: {$expectedOutput}"
+        }
+    }
+
+    companion object {
+        @Parameters(name = "{0}")
+        @JvmStatic
+        fun data(): List<TestCase> =
+            listOf(
+                    // MotionEvent.ACTION_DOWN
+                    genPositiveTestCases(
+                        motionEventAction = MotionEvent.ACTION_DOWN,
+                        previousPointerOnSensorId = INVALID_POINTER_ID,
+                        isWithinSensor = true,
+                        expectedInteractionEvent = InteractionEvent.DOWN,
+                        expectedPointerOnSensorId = POINTER_ID,
+                    ),
+                    genPositiveTestCases(
+                        motionEventAction = MotionEvent.ACTION_DOWN,
+                        previousPointerOnSensorId = POINTER_ID,
+                        isWithinSensor = true,
+                        expectedInteractionEvent = InteractionEvent.DOWN,
+                        expectedPointerOnSensorId = POINTER_ID,
+                    ),
+                    genPositiveTestCases(
+                        motionEventAction = MotionEvent.ACTION_DOWN,
+                        previousPointerOnSensorId = INVALID_POINTER_ID,
+                        isWithinSensor = false,
+                        expectedInteractionEvent = InteractionEvent.UNCHANGED,
+                        expectedPointerOnSensorId = INVALID_POINTER_ID,
+                    ),
+                    genPositiveTestCases(
+                        motionEventAction = MotionEvent.ACTION_DOWN,
+                        previousPointerOnSensorId = POINTER_ID,
+                        isWithinSensor = false,
+                        expectedInteractionEvent = InteractionEvent.UP,
+                        expectedPointerOnSensorId = INVALID_POINTER_ID,
+                    ),
+                    // MotionEvent.ACTION_MOVE
+                    genPositiveTestCases(
+                        motionEventAction = MotionEvent.ACTION_MOVE,
+                        previousPointerOnSensorId = INVALID_POINTER_ID,
+                        isWithinSensor = true,
+                        expectedInteractionEvent = InteractionEvent.DOWN,
+                        expectedPointerOnSensorId = POINTER_ID,
+                    ),
+                    genPositiveTestCases(
+                        motionEventAction = MotionEvent.ACTION_MOVE,
+                        previousPointerOnSensorId = POINTER_ID,
+                        isWithinSensor = true,
+                        expectedInteractionEvent = InteractionEvent.UNCHANGED,
+                        expectedPointerOnSensorId = POINTER_ID,
+                    ),
+                    genPositiveTestCases(
+                        motionEventAction = MotionEvent.ACTION_MOVE,
+                        previousPointerOnSensorId = INVALID_POINTER_ID,
+                        isWithinSensor = false,
+                        expectedInteractionEvent = InteractionEvent.UNCHANGED,
+                        expectedPointerOnSensorId = INVALID_POINTER_ID,
+                    ),
+                    genPositiveTestCases(
+                        motionEventAction = MotionEvent.ACTION_MOVE,
+                        previousPointerOnSensorId = POINTER_ID,
+                        isWithinSensor = false,
+                        expectedInteractionEvent = InteractionEvent.UP,
+                        expectedPointerOnSensorId = INVALID_POINTER_ID,
+                    ),
+                    // MotionEvent.ACTION_UP
+                    genPositiveTestCases(
+                        motionEventAction = MotionEvent.ACTION_UP,
+                        previousPointerOnSensorId = INVALID_POINTER_ID,
+                        isWithinSensor = true,
+                        expectedInteractionEvent = InteractionEvent.UP,
+                        expectedPointerOnSensorId = INVALID_POINTER_ID,
+                    ),
+                    genPositiveTestCases(
+                        motionEventAction = MotionEvent.ACTION_UP,
+                        previousPointerOnSensorId = POINTER_ID,
+                        isWithinSensor = true,
+                        expectedInteractionEvent = InteractionEvent.UP,
+                        expectedPointerOnSensorId = INVALID_POINTER_ID,
+                    ),
+                    genPositiveTestCases(
+                        motionEventAction = MotionEvent.ACTION_UP,
+                        previousPointerOnSensorId = INVALID_POINTER_ID,
+                        isWithinSensor = false,
+                        expectedInteractionEvent = InteractionEvent.UNCHANGED,
+                        expectedPointerOnSensorId = INVALID_POINTER_ID,
+                    ),
+                    genPositiveTestCases(
+                        motionEventAction = MotionEvent.ACTION_UP,
+                        previousPointerOnSensorId = POINTER_ID,
+                        isWithinSensor = false,
+                        expectedInteractionEvent = InteractionEvent.UP,
+                        expectedPointerOnSensorId = INVALID_POINTER_ID,
+                    ),
+                    // MotionEvent.ACTION_CANCEL
+                    genPositiveTestCases(
+                        motionEventAction = MotionEvent.ACTION_CANCEL,
+                        previousPointerOnSensorId = INVALID_POINTER_ID,
+                        isWithinSensor = true,
+                        expectedInteractionEvent = InteractionEvent.CANCEL,
+                        expectedPointerOnSensorId = INVALID_POINTER_ID,
+                    ),
+                    genPositiveTestCases(
+                        motionEventAction = MotionEvent.ACTION_CANCEL,
+                        previousPointerOnSensorId = POINTER_ID,
+                        isWithinSensor = true,
+                        expectedInteractionEvent = InteractionEvent.CANCEL,
+                        expectedPointerOnSensorId = INVALID_POINTER_ID,
+                    ),
+                    genPositiveTestCases(
+                        motionEventAction = MotionEvent.ACTION_CANCEL,
+                        previousPointerOnSensorId = INVALID_POINTER_ID,
+                        isWithinSensor = false,
+                        expectedInteractionEvent = InteractionEvent.CANCEL,
+                        expectedPointerOnSensorId = INVALID_POINTER_ID,
+                    ),
+                    genPositiveTestCases(
+                        motionEventAction = MotionEvent.ACTION_CANCEL,
+                        previousPointerOnSensorId = POINTER_ID,
+                        isWithinSensor = false,
+                        expectedInteractionEvent = InteractionEvent.CANCEL,
+                        expectedPointerOnSensorId = INVALID_POINTER_ID,
+                    ),
+                )
+                .flatten() +
+                listOf(
+                        // Unsupported MotionEvent actions.
+                        genTestCasesForUnsupportedAction(MotionEvent.ACTION_POINTER_DOWN),
+                        genTestCasesForUnsupportedAction(MotionEvent.ACTION_POINTER_UP),
+                        genTestCasesForUnsupportedAction(MotionEvent.ACTION_HOVER_ENTER),
+                        genTestCasesForUnsupportedAction(MotionEvent.ACTION_HOVER_MOVE),
+                        genTestCasesForUnsupportedAction(MotionEvent.ACTION_HOVER_EXIT),
+                    )
+                    .flatten()
+    }
+}
+
+/* Display dimensions in native resolution and natural orientation. */
+private const val ROTATION_0_NATIVE_DISPLAY_WIDTH = 400
+private const val ROTATION_0_NATIVE_DISPLAY_HEIGHT = 600
+
+/*
+ * ROTATION_0 map:
+ * _ _ _ _
+ * _ _ O _
+ * _ _ _ _
+ * _ S _ _
+ * _ S _ _
+ * _ _ _ _
+ *
+ * (_) empty space
+ * (S) sensor
+ * (O) touch outside of the sensor
+ */
+private val ROTATION_0_NATIVE_SENSOR_BOUNDS =
+    Rect(
+        100, /* left */
+        300, /* top */
+        200, /* right */
+        500, /* bottom */
+    )
+private val ROTATION_0_INPUTS =
+    OrientationBasedInputs(
+        rotation = Surface.ROTATION_0,
+        nativeXWithinSensor = ROTATION_0_NATIVE_SENSOR_BOUNDS.exactCenterX(),
+        nativeYWithinSensor = ROTATION_0_NATIVE_SENSOR_BOUNDS.exactCenterY(),
+        nativeXOutsideSensor = 250f,
+        nativeYOutsideSensor = 150f,
+    )
+
+/*
+ * ROTATION_90 map:
+ * _ _ _ _ _ _
+ * _ O _ _ _ _
+ * _ _ _ S S _
+ * _ _ _ _ _ _
+ *
+ * (_) empty space
+ * (S) sensor
+ * (O) touch outside of the sensor
+ */
+private val ROTATION_90_NATIVE_SENSOR_BOUNDS =
+    Rect(
+        300, /* left */
+        200, /* top */
+        500, /* right */
+        300, /* bottom */
+    )
+private val ROTATION_90_INPUTS =
+    OrientationBasedInputs(
+        rotation = Surface.ROTATION_90,
+        nativeXWithinSensor = ROTATION_90_NATIVE_SENSOR_BOUNDS.exactCenterX(),
+        nativeYWithinSensor = ROTATION_90_NATIVE_SENSOR_BOUNDS.exactCenterY(),
+        nativeXOutsideSensor = 150f,
+        nativeYOutsideSensor = 150f,
+    )
+
+/* ROTATION_180 is not supported. It's treated the same as ROTATION_0. */
+private val ROTATION_180_INPUTS =
+    ROTATION_0_INPUTS.copy(
+        rotation = Surface.ROTATION_180,
+    )
+
+/*
+ * ROTATION_270 map:
+ * _ _ _ _ _ _
+ * _ S S _ _ _
+ * _ _ _ _ O _
+ * _ _ _ _ _ _
+ *
+ * (_) empty space
+ * (S) sensor
+ * (O) touch outside of the sensor
+ */
+private val ROTATION_270_NATIVE_SENSOR_BOUNDS =
+    Rect(
+        100, /* left */
+        100, /* top */
+        300, /* right */
+        200, /* bottom */
+    )
+private val ROTATION_270_INPUTS =
+    OrientationBasedInputs(
+        rotation = Surface.ROTATION_270,
+        nativeXWithinSensor = ROTATION_270_NATIVE_SENSOR_BOUNDS.exactCenterX(),
+        nativeYWithinSensor = ROTATION_270_NATIVE_SENSOR_BOUNDS.exactCenterY(),
+        nativeXOutsideSensor = 450f,
+        nativeYOutsideSensor = 250f,
+    )
+
+/* Placeholder touch parameters. */
+private const val POINTER_ID = 42
+private const val NATIVE_MINOR = 2.71828f
+private const val NATIVE_MAJOR = 3.14f
+private const val ORIENTATION = 1.23f
+private const val TIME = 12345699L
+private const val GESTURE_START = 12345600L
+
+/* Template [MotionEvent]. */
+private val MOTION_EVENT =
+    obtainMotionEvent(
+        action = 0,
+        pointerId = POINTER_ID,
+        x = 0f,
+        y = 0f,
+        minor = 0f,
+        major = 0f,
+        orientation = ORIENTATION,
+        time = TIME,
+        gestureStart = GESTURE_START,
+    )
+
+/* Template [NormalizedTouchData]. */
+private val NORMALIZED_TOUCH_DATA =
+    NormalizedTouchData(
+        POINTER_ID,
+        x = 0f,
+        y = 0f,
+        NATIVE_MINOR,
+        NATIVE_MAJOR,
+        ORIENTATION,
+        TIME,
+        GESTURE_START
+    )
+
+/*
+ * Contains test inputs that are tied to a particular device orientation.
+ *
+ * "native" means in native resolution (not scaled).
+ */
+private data class OrientationBasedInputs(
+    @Rotation val rotation: Int,
+    val nativeXWithinSensor: Float,
+    val nativeYWithinSensor: Float,
+    val nativeXOutsideSensor: Float,
+    val nativeYOutsideSensor: Float,
+) {
+
+    fun toOverlayParams(scaleFactor: Float): UdfpsOverlayParams =
+        UdfpsOverlayParams(
+            sensorBounds = ROTATION_0_NATIVE_SENSOR_BOUNDS.scaled(scaleFactor),
+            overlayBounds = ROTATION_0_NATIVE_SENSOR_BOUNDS.scaled(scaleFactor),
+            naturalDisplayHeight = (ROTATION_0_NATIVE_DISPLAY_HEIGHT * scaleFactor).toInt(),
+            naturalDisplayWidth = (ROTATION_0_NATIVE_DISPLAY_WIDTH * scaleFactor).toInt(),
+            scaleFactor = scaleFactor,
+            rotation = rotation
+        )
+
+    fun getNativeX(isWithinSensor: Boolean): Float {
+        return if (isWithinSensor) nativeXWithinSensor else nativeXOutsideSensor
+    }
+
+    fun getNativeY(isWithinSensor: Boolean): Float {
+        return if (isWithinSensor) nativeYWithinSensor else nativeYOutsideSensor
+    }
+}
+
+private fun genPositiveTestCases(
+    motionEventAction: Int,
+    previousPointerOnSensorId: Int,
+    isWithinSensor: Boolean,
+    expectedInteractionEvent: InteractionEvent,
+    expectedPointerOnSensorId: Int
+): List<SinglePointerTouchProcessorTest.TestCase> {
+    val scaleFactors = listOf(0.75f, 1f, 1.5f)
+    val orientations =
+        listOf(
+            ROTATION_0_INPUTS,
+            ROTATION_90_INPUTS,
+            ROTATION_180_INPUTS,
+            ROTATION_270_INPUTS,
+        )
+    return scaleFactors.flatMap { scaleFactor ->
+        orientations.map { orientation ->
+            val overlayParams = orientation.toOverlayParams(scaleFactor)
+            val nativeX = orientation.getNativeX(isWithinSensor)
+            val nativeY = orientation.getNativeY(isWithinSensor)
+            val event =
+                MOTION_EVENT.copy(
+                    action = motionEventAction,
+                    x = nativeX * scaleFactor,
+                    y = nativeY * scaleFactor,
+                    minor = NATIVE_MINOR * scaleFactor,
+                    major = NATIVE_MAJOR * scaleFactor,
+                )
+            val expectedTouchData =
+                NORMALIZED_TOUCH_DATA.copy(
+                    x = ROTATION_0_INPUTS.getNativeX(isWithinSensor),
+                    y = ROTATION_0_INPUTS.getNativeY(isWithinSensor),
+                )
+            val expected =
+                TouchProcessorResult.ProcessedTouch(
+                    event = expectedInteractionEvent,
+                    pointerOnSensorId = expectedPointerOnSensorId,
+                    touchData = expectedTouchData,
+                )
+            SinglePointerTouchProcessorTest.TestCase(
+                event = event,
+                previousPointerOnSensorId = previousPointerOnSensorId,
+                overlayParams = overlayParams,
+                expected = expected,
+            )
+        }
+    }
+}
+
+private fun genTestCasesForUnsupportedAction(
+    motionEventAction: Int
+): List<SinglePointerTouchProcessorTest.TestCase> {
+    val isWithinSensor = true
+    val previousPointerOnSensorIds = listOf(INVALID_POINTER_ID, POINTER_ID)
+    return previousPointerOnSensorIds.map { previousPointerOnSensorId ->
+        val overlayParams = ROTATION_0_INPUTS.toOverlayParams(scaleFactor = 1f)
+        val nativeX = ROTATION_0_INPUTS.getNativeX(isWithinSensor)
+        val nativeY = ROTATION_0_INPUTS.getNativeY(isWithinSensor)
+        val event =
+            MOTION_EVENT.copy(
+                action = motionEventAction,
+                x = nativeX,
+                y = nativeY,
+                minor = NATIVE_MINOR,
+                major = NATIVE_MAJOR,
+            )
+        SinglePointerTouchProcessorTest.TestCase(
+            event = event,
+            previousPointerOnSensorId = previousPointerOnSensorId,
+            overlayParams = overlayParams,
+            expected = TouchProcessorResult.Failure(),
+        )
+    }
+}
+
+private fun obtainMotionEvent(
+    action: Int,
+    pointerId: Int,
+    x: Float,
+    y: Float,
+    minor: Float,
+    major: Float,
+    orientation: Float,
+    time: Long,
+    gestureStart: Long,
+): MotionEvent {
+    val pp = PointerProperties()
+    pp.id = pointerId
+    val pc = MotionEvent.PointerCoords()
+    pc.x = x
+    pc.y = y
+    pc.touchMinor = minor
+    pc.touchMajor = major
+    pc.orientation = orientation
+    return MotionEvent.obtain(
+        gestureStart /* downTime */,
+        time /* eventTime */,
+        action /* action */,
+        1 /* pointerCount */,
+        arrayOf(pp) /* pointerProperties */,
+        arrayOf(pc) /* pointerCoords */,
+        0 /* metaState */,
+        0 /* buttonState */,
+        1f /* xPrecision */,
+        1f /* yPrecision */,
+        0 /* deviceId */,
+        0 /* edgeFlags */,
+        0 /* source */,
+        0 /* flags */
+    )
+}
+
+private fun MotionEvent.copy(
+    action: Int = this.action,
+    pointerId: Int = this.getPointerId(0),
+    x: Float = this.rawX,
+    y: Float = this.rawY,
+    minor: Float = this.touchMinor,
+    major: Float = this.touchMajor,
+    orientation: Float = this.orientation,
+    time: Long = this.eventTime,
+    gestureStart: Long = this.downTime,
+) = obtainMotionEvent(action, pointerId, x, y, minor, major, orientation, time, gestureStart)
+
+private fun Rect.scaled(scaleFactor: Float) = Rect(this).apply { scale(scaleFactor) }