commit 5b4aaa0510b1c5785982fd2fe8497091b0a4cc4e
Author: Paul Aumann <paul.aumann@gmail.com>
Date:   Mon May 15 14:39:02 2023 +0200

    Initial commit

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..aa724b7
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,15 @@
+*.iml
+.gradle
+/local.properties
+/.idea/caches
+/.idea/libraries
+/.idea/modules.xml
+/.idea/workspace.xml
+/.idea/navEditor.xml
+/.idea/assetWizardSettings.xml
+.DS_Store
+/build
+/captures
+.externalNativeBuild
+.cxx
+local.properties
diff --git a/.idea/.gitignore b/.idea/.gitignore
new file mode 100644
index 0000000..26d3352
--- /dev/null
+++ b/.idea/.gitignore
@@ -0,0 +1,3 @@
+# Default ignored files
+/shelf/
+/workspace.xml
diff --git a/.idea/compiler.xml b/.idea/compiler.xml
new file mode 100644
index 0000000..b589d56
--- /dev/null
+++ b/.idea/compiler.xml
@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="CompilerConfiguration">
+    <bytecodeTargetLevel target="17" />
+  </component>
+</project>
\ No newline at end of file
diff --git a/.idea/gradle.xml b/.idea/gradle.xml
new file mode 100644
index 0000000..a0de2a1
--- /dev/null
+++ b/.idea/gradle.xml
@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="GradleMigrationSettings" migrationVersion="1" />
+  <component name="GradleSettings">
+    <option name="linkedExternalProjectsSettings">
+      <GradleProjectSettings>
+        <option name="testRunner" value="GRADLE" />
+        <option name="distributionType" value="DEFAULT_WRAPPED" />
+        <option name="externalProjectPath" value="$PROJECT_DIR$" />
+        <option name="gradleJvm" value="Embedded JDK" />
+        <option name="modules">
+          <set>
+            <option value="$PROJECT_DIR$" />
+            <option value="$PROJECT_DIR$/app" />
+          </set>
+        </option>
+      </GradleProjectSettings>
+    </option>
+  </component>
+</project>
\ No newline at end of file
diff --git a/.idea/kotlinc.xml b/.idea/kotlinc.xml
new file mode 100644
index 0000000..7e340a7
--- /dev/null
+++ b/.idea/kotlinc.xml
@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="KotlinJpsPluginSettings">
+    <option name="version" value="1.6.21" />
+  </component>
+</project>
\ No newline at end of file
diff --git a/.idea/misc.xml b/.idea/misc.xml
new file mode 100644
index 0000000..0ad17cb
--- /dev/null
+++ b/.idea/misc.xml
@@ -0,0 +1,10 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ExternalStorageConfigurationManager" enabled="true" />
+  <component name="ProjectRootManager" version="2" languageLevel="JDK_17" default="true" project-jdk-name="jbr-17" project-jdk-type="JavaSDK">
+    <output url="file://$PROJECT_DIR$/build/classes" />
+  </component>
+  <component name="ProjectType">
+    <option name="id" value="Android" />
+  </component>
+</project>
\ No newline at end of file
diff --git a/.idea/vcs.xml b/.idea/vcs.xml
new file mode 100644
index 0000000..35eb1dd
--- /dev/null
+++ b/.idea/vcs.xml
@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="VcsDirectoryMappings">
+    <mapping directory="" vcs="Git" />
+  </component>
+</project>
\ No newline at end of file
diff --git a/app/.gitignore b/app/.gitignore
new file mode 100644
index 0000000..42afabf
--- /dev/null
+++ b/app/.gitignore
@@ -0,0 +1 @@
+/build
\ No newline at end of file
diff --git a/app/build.gradle b/app/build.gradle
new file mode 100644
index 0000000..c72f11b
--- /dev/null
+++ b/app/build.gradle
@@ -0,0 +1,43 @@
+plugins {
+    id 'com.android.application'
+    id 'org.jetbrains.kotlin.android'
+}
+
+android {
+    compileSdk 31
+
+    defaultConfig {
+        applicationId "de.luh.hci.mi.protractor"
+        minSdk 23
+        targetSdk 31
+        versionCode 1
+        versionName "1.0"
+
+        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
+    }
+
+    buildTypes {
+        release {
+            minifyEnabled false
+            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
+        }
+    }
+    compileOptions {
+        sourceCompatibility JavaVersion.VERSION_1_8
+        targetCompatibility JavaVersion.VERSION_1_8
+    }
+    kotlinOptions {
+        jvmTarget = '1.8'
+    }
+}
+
+dependencies {
+
+    implementation 'androidx.core:core-ktx:1.7.0'
+    implementation 'androidx.appcompat:appcompat:1.4.1'
+    implementation 'com.google.android.material:material:1.5.0'
+    implementation 'androidx.constraintlayout:constraintlayout:2.1.3'
+    testImplementation 'junit:junit:4.13.2'
+    androidTestImplementation 'androidx.test.ext:junit:1.1.3'
+    androidTestImplementation 'androidx.test.espresso:espresso-core:3.4.0'
+}
\ No newline at end of file
diff --git a/app/proguard-rules.pro b/app/proguard-rules.pro
new file mode 100644
index 0000000..481bb43
--- /dev/null
+++ b/app/proguard-rules.pro
@@ -0,0 +1,21 @@
+# Add project specific ProGuard rules here.
+# You can control the set of applied configuration files using the
+# proguardFiles setting in build.gradle.
+#
+# For more details, see
+#   http://developer.android.com/guide/developing/tools/proguard.html
+
+# If your project uses WebView with JS, uncomment the following
+# and specify the fully qualified class name to the JavaScript interface
+# class:
+#-keepclassmembers class fqcn.of.javascript.interface.for.webview {
+#   public *;
+#}
+
+# Uncomment this to preserve the line number information for
+# debugging stack traces.
+#-keepattributes SourceFile,LineNumberTable
+
+# If you keep the line number information, uncomment this to
+# hide the original source file name.
+#-renamesourcefileattribute SourceFile
\ No newline at end of file
diff --git a/app/src/androidTest/java/de/luh/hci/mi/protractor/ExampleInstrumentedTest.kt b/app/src/androidTest/java/de/luh/hci/mi/protractor/ExampleInstrumentedTest.kt
new file mode 100644
index 0000000..1424b46
--- /dev/null
+++ b/app/src/androidTest/java/de/luh/hci/mi/protractor/ExampleInstrumentedTest.kt
@@ -0,0 +1,24 @@
+package de.luh.hci.mi.protractor
+
+import androidx.test.platform.app.InstrumentationRegistry
+import androidx.test.ext.junit.runners.AndroidJUnit4
+
+import org.junit.Test
+import org.junit.runner.RunWith
+
+import org.junit.Assert.*
+
+/**
+ * Instrumented test, which will execute on an Android device.
+ *
+ * See [testing documentation](http://d.android.com/tools/testing).
+ */
+@RunWith(AndroidJUnit4::class)
+class ExampleInstrumentedTest {
+    @Test
+    fun useAppContext() {
+        // Context of the app under test.
+        val appContext = InstrumentationRegistry.getInstrumentation().targetContext
+        assertEquals("de.luh.hci.mi.protractor", appContext.packageName)
+    }
+}
\ No newline at end of file
diff --git a/app/src/main/AndroidManifest.xml b/app/src/main/AndroidManifest.xml
new file mode 100644
index 0000000..5770dc8
--- /dev/null
+++ b/app/src/main/AndroidManifest.xml
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="de.luh.hci.mi.protractor">
+
+    <uses-permission android:name="android.permission.VIBRATE" />
+    <application
+        android:allowBackup="true"
+        android:icon="@mipmap/ic_launcher"
+        android:label="@string/app_name"
+        android:roundIcon="@mipmap/ic_launcher_round"
+        android:supportsRtl="true"
+        android:theme="@style/Theme.Protractor">
+        <activity
+            android:name=".MainActivity"
+            android:exported="true">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+
+                <category android:name="android.intent.category.LAUNCHER" />
+            </intent-filter>
+        </activity>
+    </application>
+
+</manifest>
\ No newline at end of file
diff --git a/app/src/main/java/de/luh/hci/mi/protractor/GestureRecognizer.kt b/app/src/main/java/de/luh/hci/mi/protractor/GestureRecognizer.kt
new file mode 100644
index 0000000..9e0fdf8
--- /dev/null
+++ b/app/src/main/java/de/luh/hci/mi/protractor/GestureRecognizer.kt
@@ -0,0 +1,200 @@
+package de.luh.hci.mi.protractor
+
+import android.graphics.PointF
+import java.util.*
+import kotlin.math.atan2
+import kotlin.math.cos
+import kotlin.math.sin
+import kotlin.math.sqrt
+
+class GestureRecognizer {
+
+    fun recognize(trace: Vector<PointF>, templates: Vector<Template>): Match? {
+        val resampledTrace = resample(trace, SAMPLE_POINTS_COUNT)
+        val c = centroid(resampledTrace)
+        c.x = -c.x
+        c.y = -c.y
+        translate(resampledTrace, c) // translate to origin
+        normalize(resampledTrace) // not strictly necessary, will be normalized after rotation anyway
+        var bestMatch: Match? = null
+        for (t in templates) {
+            val m = optimalAngle(resampledTrace, t.vector)
+            if (bestMatch == null || m.score > bestMatch.score) {
+                m.template = t
+                bestMatch = m
+            }
+        }
+        return bestMatch
+    }
+
+    /** Resample trace to n points. Linear interpolation.  */
+    fun resample(trace: Vector<PointF>, n: Int): Vector<PointF> {
+        @Suppress("NAME_SHADOWING") var n = n
+        if (n < 0) n = 0
+        val newTrace = Vector<PointF>(n)
+
+        // return empty vector if no points in trace
+        val m = trace.size
+        if (m <= 0) return newTrace
+
+        // trace has only a single point
+        if (m == 1) {
+            val p = trace[0]
+            val i = 0
+            while (i < n) {
+                newTrace.add(p)
+            }
+            return newTrace
+        }
+
+        // at least 2 points in trace
+        val I = pathLength(trace) / (n - 1)
+        var D = 0f
+        var pp = trace[0]
+        newTrace.add(trace[0]) // add first point of original trace
+        var i = 1
+        while (i < m && newTrace.size < n - 1) {
+            var p = trace[i]
+            val d = distance(pp, p)
+            if (d > 0 && D + d > I) {
+                val delta = (I - D) / d
+                p = PointF(pp.x + delta * (p.x - pp.x), pp.y + delta * (p.y - pp.y))
+                newTrace.add(p)
+                D = 0f
+                i--
+            } else {
+                D += d
+            }
+            pp = p
+            i++
+        }
+        newTrace.add(trace[m - 1]) // add last point of original trace
+        return newTrace
+    }
+
+    /**
+     * Length of the trace as sum of distances between points.
+     * @param trace
+     * @return length of the trace
+     */
+    fun pathLength(trace: Vector<PointF>): Float {
+        var length = 0f
+        trace.windowed(2).forEach { (a, b) -> length += distance(a, b) }
+        return length
+    }
+
+    /**
+     * Euclidean distance between points a and b.
+     * @param a
+     * @param b
+     * @return distance between points a and b
+     */
+    fun distance(a: PointF, b: PointF): Float {
+        val dx = a.x - b.x
+        val dy = a.y - b.y
+        return sqrt((dx * dx + dy * dy).toDouble()).toFloat()
+    }
+
+    /**
+     * The centroid is the point (average x-coordinate, average y-coordinate).
+     * @param points
+     * @return centroid of points
+     */
+    fun centroid(points: Vector<PointF>): PointF {
+        val cx = points.sumOf { it.x.toDouble() } / points.size
+        val cy = points.sumOf { it.y.toDouble() } / points.size
+
+        return PointF(cx.toFloat(), cy.toFloat())
+    }
+
+    /**
+     * Move every point by the same amount.
+     * @param points
+     * @param translationVector
+     */
+    fun translate(points: Vector<PointF>, translationVector: PointF) {
+        points.forEach { point -> point.offset(translationVector.x, translationVector.y) }
+    }
+
+    /**
+     * Rotate points around origin by angle theta
+     * @param points
+     * @param theta
+     */
+    fun rotate(points: Vector<PointF>, theta: Float) {
+        points.forEach { point ->
+            point.set(
+                point.x * cos(theta) - point.y * sin(theta),
+                point.y * cos(theta) + point.x * sin(theta)
+            )
+        }
+    }
+
+    /**
+     * Consider the argument vector of n 2D-points as a float vector of 2n floats (R^(2n)).
+     * Normalize the argument vector of 2n floats to a unit vector (of dimension 2n).
+     * @param points
+     */
+    fun normalize(points: Vector<PointF>) {
+        var mag = 0f
+        for (p in points) {
+            mag += p.x * p.x + p.y * p.y
+        }
+        mag = sqrt(mag.toDouble()).toFloat()
+        if (mag.toDouble() != 0.0) mag = 1.0f / mag
+        for (p in points) {
+            p.x *= mag
+            p.y *= mag
+        }
+    }
+
+    /**
+     * Scale by factor. Multiply every point by factor.
+     * @param points
+     * @param factor
+     */
+    fun scale(points: Vector<PointF>, factor: Float) {
+        for (p in points) {
+            p.x *= factor
+            p.y *= factor
+        }
+    }
+
+    /**
+     * Deep copy of a trace.
+     * @param points
+     * @return deep copy of argument
+     */
+    fun copy(points: Vector<PointF>): Vector<PointF> {
+        val n = points.size
+        val c = Vector<PointF>(n)
+        for (p in points) {
+            c.add(PointF(p.x, p.y))
+        }
+        return c
+    }
+
+    /**
+     * Find optimal angle between normalized vectors t and g, both of dimension n.
+     * @param t template vector points, normalized
+     * @param g input gesture vector points, normalized
+     * @return optimal angle (and score) between g and t
+     */
+    fun optimalAngle(g: Vector<PointF>, t: Vector<PointF>): Match {
+
+        // cross product of g and t
+        val a = (g zip t).sumOf { (g, t) -> (g.x * t.x + g.y * t.y).toDouble() }
+
+        // b = sum(x_t * y_g - y_t * x_g)
+        val b = (g zip t).sumOf { (g, t) -> (t.x * g.y - t.y * g.x).toDouble() }
+
+        val theta = atan2(b, a).toFloat()
+        val score = (a * cos(theta) + b * sin(theta)).toFloat()
+        // score is scalar product of g and t(theta)
+        return Match(score, theta)
+    }
+
+    companion object {
+        const val SAMPLE_POINTS_COUNT = 16
+    }
+}
\ No newline at end of file
diff --git a/app/src/main/java/de/luh/hci/mi/protractor/MainActivity.kt b/app/src/main/java/de/luh/hci/mi/protractor/MainActivity.kt
new file mode 100644
index 0000000..847f89e
--- /dev/null
+++ b/app/src/main/java/de/luh/hci/mi/protractor/MainActivity.kt
@@ -0,0 +1,33 @@
+package de.luh.hci.mi.protractor
+
+import android.app.Activity
+import androidx.appcompat.app.AppCompatActivity
+import android.os.Bundle
+import android.view.Menu
+import android.view.MenuItem
+
+class MainActivity : AppCompatActivity() {
+
+    private var sketchView: SketchView? = null
+
+    public override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        sketchView = SketchView(this)
+        setContentView(sketchView)
+        sketchView!!.requestFocus()
+    }
+
+    override fun onCreateOptionsMenu(menu: Menu): Boolean {
+        menu.add(0, 1, 0, "Train gestures") // group, id, order, title
+        menu.add(1, 2, 1, "Test gestures - new Participant")
+        return true // return true to enable menu
+    }
+
+    override fun onOptionsItemSelected(item: MenuItem): Boolean {
+        when (item.itemId) {
+            1 -> sketchView!!.trainGestures()
+            2 -> sketchView!!.testGesturesWithNewParticipant()
+        }
+        return super.onOptionsItemSelected(item)
+    }
+}
\ No newline at end of file
diff --git a/app/src/main/java/de/luh/hci/mi/protractor/Match.kt b/app/src/main/java/de/luh/hci/mi/protractor/Match.kt
new file mode 100644
index 0000000..fe70c93
--- /dev/null
+++ b/app/src/main/java/de/luh/hci/mi/protractor/Match.kt
@@ -0,0 +1,5 @@
+package de.luh.hci.mi.protractor
+
+data class Match(val score: Float, val theta: Float) {
+	var template: Template? = null
+}
\ No newline at end of file
diff --git a/app/src/main/java/de/luh/hci/mi/protractor/SketchView.kt b/app/src/main/java/de/luh/hci/mi/protractor/SketchView.kt
new file mode 100644
index 0000000..5df2545
--- /dev/null
+++ b/app/src/main/java/de/luh/hci/mi/protractor/SketchView.kt
@@ -0,0 +1,425 @@
+package de.luh.hci.mi.protractor
+
+import android.content.Context
+import android.graphics.Bitmap
+import android.graphics.Canvas
+import android.graphics.Paint
+import android.graphics.PointF
+import android.os.Vibrator
+import android.util.Log
+import android.view.MotionEvent
+import android.view.View
+import java.io.DataInputStream
+import java.io.DataOutputStream
+import java.io.EOFException
+import java.io.IOException
+import java.util.*
+
+class SketchView(c: Context) : View(c) {
+    private enum class Modi {
+        TRAINING, EVALUATION, FREERUNNING
+    }
+
+    // @todo: define your own pattern of positive vibration feedback
+    private val positiveVibrationFeedback = longArrayOf(
+        50, 100
+    )
+
+    // @todo: define your own pattern of negative vibration feedback
+    private val negativeVibrationFeedback = longArrayOf(
+        50, 100, 100, 100
+    )
+    private val paint = Paint()
+
+    // will be filled in a method
+    private var evaluationGestures = arrayOf<String?>()
+    private var currentGestureToEvaluate = 0
+    private var bitmap: Bitmap? = null
+    private var canvas: Canvas? = null
+    private var state = Modi.TRAINING
+    private val recognizer = GestureRecognizer()
+    private val trace = Vector<PointF>()
+    private val templates = Vector<Template>()
+    private val gestureFileName = "gestures001.dat"
+    private var dout: DataOutputStream? = null
+    private val vibrator: Vibrator
+
+    private fun clear() {
+        if (canvas != null) {
+            paint.setARGB(255, 255, 255, 255)
+            canvas!!.drawPaint(paint)
+        }
+    }
+
+    override fun onSizeChanged(w: Int, h: Int, oldw: Int, oldh: Int) {
+        bitmap = Bitmap.createBitmap(w, h, Bitmap.Config.RGB_565)
+        canvas = Canvas(bitmap!!)
+        paint.isAntiAlias = false
+        clear()
+        prompt()
+    }
+
+    override fun onDraw(c: Canvas) {
+        if (bitmap != null) {
+            c.drawBitmap(bitmap!!, 0f, 0f, null)
+        }
+    }
+
+    private fun prompt() {
+        if (templates.size < GESTURE_SET.size * EXAMPLES_PER_GESTURE) {
+            val tmod = templates.size % EXAMPLES_PER_GESTURE
+            val tdiv = templates.size / EXAMPLES_PER_GESTURE
+            paint.setARGB(255, 0, 0, 0)
+            canvas!!.drawText(
+                "Draw example " + (tmod + 1) + " of gesture " + GESTURE_SET[tdiv],
+                10f,
+                30f,
+                paint
+            )
+        }
+    }
+
+    private fun promptEvaluation() {
+        paint.setARGB(255, 0, 0, 0)
+        canvas!!.drawText(
+            "Evaluation: Draw gesture " + evaluationGestures[currentGestureToEvaluate] + ". Done " + currentGestureToEvaluate + " of " + evaluationGestures.size,
+            10f,
+            30f,
+            paint
+        )
+    }
+
+    private fun promptEvaluationResult(t: Template?) {
+        paint.setARGB(255, 0, 0, 0)
+        canvas!!.drawText(
+            "Requested: " + evaluationGestures[currentGestureToEvaluate] + " Recognized:  " + t!!.gestureName,
+            10f,
+            60f,
+            paint
+        )
+    }
+
+    override fun onTouchEvent(e: MotionEvent): Boolean {
+        if (e.action == MotionEvent.ACTION_DOWN) {
+            trace.clear()
+            clear()
+        }
+        paint.setARGB(255, 0, 0, 0)
+        val x = e.x.toInt()
+        val y = e.y.toInt()
+        if (e.action == MotionEvent.ACTION_DOWN) {
+            canvas!!.drawCircle(x.toFloat(), y.toFloat(), 6f, paint)
+        } else {
+            canvas!!.drawCircle(x.toFloat(), y.toFloat(), 3f, paint)
+        }
+        if (e.pointerCount > 1) {
+            val x2 = e.getX(1).toInt()
+            val y2 = e.getY(1).toInt()
+            if (e.action == MotionEvent.ACTION_DOWN) {
+                canvas!!.drawCircle(x2.toFloat(), y2.toFloat(), 6f, paint)
+            } else {
+                canvas!!.drawCircle(x2.toFloat(), y2.toFloat(), 3f, paint)
+            }
+        }
+        trace.add(PointF(e.x, e.y))
+
+        // Log.d("SketchView", "up");
+        if (e.action == MotionEvent.ACTION_UP) {
+            clear()
+            val resampledTrace: Vector<PointF> =
+                recognizer.resample(trace, GestureRecognizer.SAMPLE_POINTS_COUNT)
+            if (resampledTrace.size >= 2) {
+                val c = recognizer.centroid(resampledTrace)
+                c.x = -c.x
+                c.y = -c.y
+                recognizer.translate(resampledTrace, c)
+                recognizer.normalize(resampledTrace)
+                paint.setARGB(255, 0, 0, 0)
+                drawTrace(
+                    resampledTrace, 0f, DRAW_SCALE.toFloat(), PointF(
+                        DRAW_SCALE.toFloat(), DRAW_SCALE.toFloat()
+                    )
+                )
+            } else {
+                return true
+            }
+            val n = templates.size
+            if (state == Modi.TRAINING && n >= GESTURE_SET.size * EXAMPLES_PER_GESTURE) {
+                state = Modi.FREERUNNING
+            }
+            if (state == Modi.TRAINING) {
+                // save entered template
+                val id = n / EXAMPLES_PER_GESTURE
+                val t = Template(id, GESTURE_SET[id], resampledTrace)
+                templates.add(t)
+                try {
+                    t.writeTo(dout!!)
+                } catch (ex: IOException) {
+                    Log.d("SketchView", ex.message!!)
+                }
+                prompt()
+            } else {
+                if (dout != null) {
+                    try {
+                        dout!!.close()
+                        dout = null
+                        Log.d("SketchView", "stream closed")
+                    } catch (ex: IOException) {
+                        Log.d("SketchView", ex.message!!)
+                    }
+                }
+                val m = recognizer.recognize(resampledTrace, templates)
+                val t = m!!.template
+
+                // top, left: input gesture (black)
+                paint.setARGB(255, 0, 0, 0)
+                drawTrace(
+                    resampledTrace, 0f, DRAW_SCALE.toFloat(), PointF(
+                        DRAW_SCALE.toFloat(), DRAW_SCALE.toFloat()
+                    )
+                )
+
+                // top, right: template (red)
+                paint.setARGB(255, 255, 0, 0)
+                drawTrace(
+                    t!!.vector,
+                    0f,
+                    DRAW_SCALE.toFloat(),
+                    PointF((2 * DRAW_SCALE).toFloat(), DRAW_SCALE.toFloat())
+                )
+
+                // bottom, left: input gesture (black)
+                paint.setARGB(255, 0, 0, 0)
+                drawTrace(
+                    resampledTrace, 0f, DRAW_SCALE.toFloat(), PointF(
+                        DRAW_SCALE.toFloat(), (2 * DRAW_SCALE).toFloat()
+                    )
+                )
+
+                // bottom, left: rotated template (red)
+                paint.setARGB(255, 255, 0, 0)
+                drawTrace(
+                    t.vector, m.theta, DRAW_SCALE.toFloat(), PointF(
+                        DRAW_SCALE.toFloat(), (2 * DRAW_SCALE).toFloat()
+                    )
+                )
+                if (state == Modi.EVALUATION) {
+                    val correctGesture =
+                        t.gestureName == evaluationGestures[currentGestureToEvaluate]
+                    if (correctGesture) {
+                        playPositiveFeedback()
+                    } else {
+                        playNegativeFeedback()
+                    }
+                    promptEvaluationResult(t)
+                    currentGestureToEvaluate++
+                    if (currentGestureToEvaluate < evaluationGestures.size) {
+                        promptEvaluation()
+                        //go on to evaluate
+                    } else {
+                        state = Modi.FREERUNNING
+                    }
+                } else if (state == Modi.FREERUNNING) {
+                    // text
+                    paint.setARGB(255, 0, 0, 0)
+                    val score = Math.round(1000 * m.score) / 1000.0f
+                    val theta = Math.round(1000 * m.theta) / 1000.0f
+                    val s = "id = " + m.template!!.id + ", score = " + score + ", theta = " + theta
+                    canvas!!.drawText(s, 10f, 30f, paint)
+                    canvas!!.drawText(GESTURE_SET[m.template!!.id], 10f, 60f, paint)
+                }
+            }
+        }
+        invalidate()
+        return true
+    }
+
+    /**
+     * Draw a trace, first rotate, scale, and translate.
+     * @param trace
+     * @param rotate
+     * @param scale
+     * @param translate
+     */
+    fun drawTrace(trace: Vector<PointF>, rotate: Float, scale: Float, translate: PointF?) {
+        val n = trace.size
+        if (n <= 0) return
+        val drawTrace = recognizer.copy(trace)
+        recognizer.rotate(drawTrace, rotate)
+        recognizer.scale(drawTrace, scale)
+        recognizer.translate(drawTrace, translate!!)
+        var x = Math.round(drawTrace[0].x)
+        var y = Math.round(drawTrace[0].y)
+        var xp = x
+        var yp = y
+        canvas!!.drawCircle(x.toFloat(), y.toFloat(), 5f, paint)
+        for (i in 1 until n) {
+            x = Math.round(drawTrace[i].x)
+            y = Math.round(drawTrace[i].y)
+            canvas!!.drawLine(xp.toFloat(), yp.toFloat(), x.toFloat(), y.toFloat(), paint)
+            canvas!!.drawCircle(x.toFloat(), y.toFloat(), 3f, paint)
+            xp = x
+            yp = y
+        }
+    }
+
+    fun testGesturesWithNewParticipant() {
+        if (state == Modi.TRAINING) {
+            return
+        }
+        state = Modi.EVALUATION
+
+        //Gesture Array
+        evaluationGestures = arrayOfNulls(EVALUATIONS_PER_GESTURE * GESTURE_SET.size)
+        currentGestureToEvaluate = 0
+
+        //@todo: fill Array WithGesture Names
+        for (i in evaluationGestures.indices) {
+            evaluationGestures[i] = GESTURE_SET[i % GESTURE_SET.size]
+        }
+
+
+        // end
+        evaluationGestures = randomizeGestureArray(evaluationGestures)
+        clear()
+        promptEvaluation()
+        invalidate()
+    }
+
+    private fun randomizeGestureArray(gesturesToRandomize: Array<String?>): Array<String?> {
+        //@todo: Randomize the order of gestures.
+        gesturesToRandomize.shuffle()
+        return gesturesToRandomize
+    }
+
+    private fun playPositiveFeedback() {
+        // @todo: play Positive Vibration Pattern
+        vibrator.vibrate(positiveVibrationFeedback, -1)
+    }
+
+    private fun playNegativeFeedback() {
+        // @todo: play Negative Vibration Pattern
+        vibrator.vibrate(negativeVibrationFeedback, -1)
+    }
+
+    fun trainGestures() {
+        state = Modi.TRAINING
+        try {
+            if (dout != null) {
+                dout!!.close()
+                dout = null
+            }
+            val fout = context.openFileOutput(gestureFileName, Context.MODE_PRIVATE)
+            dout = DataOutputStream(fout)
+        } catch (ex: IOException) {
+            Log.d("SketchView", ex.message!!)
+        }
+        trace.clear()
+        templates.clear()
+        clear()
+        prompt()
+        invalidate()
+    }
+
+    companion object {
+        // $1 gesture names
+        // http://depts.washington.edu/aimgroup/proj/dollar/
+        private val dollar1WebGestureNames = arrayOf(
+            "triangle",
+            "x",
+            "rectangle",
+            "circle",
+            "check",
+            "caret",
+            "zig-zag",
+            "arrow",
+            "left square bracket",
+            "right square bracket",
+            "v",
+            "delete",
+            "left curly brace",
+            "right curly brace",
+            "star",
+            "pigtail"
+        )
+
+        // $1 gesture names
+        // gesture names from paper (slightly different from above)
+        private val dollar1GestureNames = arrayOf(
+            "triangle",
+            "x",
+            "rectangle",
+            "circle",
+            "check",
+            "caret",
+            "question",
+            "arrow",
+            "left square bracket",
+            "right square bracket",
+            "v",
+            "delete",
+            "left curly brace",
+            "right curly brace",
+            "star",
+            "pigtail"
+        )
+
+        // test gesture names
+        private val testGestureNames = arrayOf(
+            "circle",
+            "check",
+            "triangle"
+        )
+
+        // @todo: new gesture set
+        private val myGestureNames = arrayOf(
+            "...",
+            "...",
+            "...",
+            "...",
+            "..."
+        )
+        private val GESTURE_SET = testGestureNames // @todo: modify, set to your own gesture set
+        private const val EXAMPLES_PER_GESTURE = 3
+        private const val EVALUATIONS_PER_GESTURE = 10
+        private const val DRAW_SCALE = 300
+    }
+
+    init {
+        paint.isAntiAlias = false
+        paint.setARGB(255, 255, 255, 255)
+        paint.textSize = 30f
+        try {
+            val fin = c.openFileInput(gestureFileName)
+            val din = DataInputStream(fin)
+            try {
+                while (true) {
+                    val t = Template.readFrom(din)
+                    templates.add(t)
+                    Log.d("SketchView", "read template: $t")
+                }
+            } catch (exeof: EOFException) {
+                Log.d("SketchView", "EOFException: " + exeof.message)
+                exeof.printStackTrace()
+            }
+            din.close()
+            fin.close()
+        } catch (ex: IOException) {
+            Log.d("SketchView", ex.message!!)
+        }
+        if (templates.size < GESTURE_SET.size * EXAMPLES_PER_GESTURE) {
+            state = Modi.TRAINING
+            try {
+                val fout = c.openFileOutput(gestureFileName, Context.MODE_PRIVATE)
+                dout = DataOutputStream(fout)
+            } catch (ex: IOException) {
+                Log.d("SketchView", ex.message!!)
+            }
+        } else {
+            state = Modi.FREERUNNING
+        }
+
+        //@todo: instantiate Vibrator
+        vibrator = c.getSystemService(Context.VIBRATOR_SERVICE) as Vibrator
+    }
+}
\ No newline at end of file
diff --git a/app/src/main/java/de/luh/hci/mi/protractor/Template.kt b/app/src/main/java/de/luh/hci/mi/protractor/Template.kt
new file mode 100644
index 0000000..65cd238
--- /dev/null
+++ b/app/src/main/java/de/luh/hci/mi/protractor/Template.kt
@@ -0,0 +1,59 @@
+package de.luh.hci.mi.protractor
+
+import android.graphics.PointF
+import java.io.DataInputStream
+import java.io.DataOutputStream
+import java.io.IOException
+import java.util.*
+import kotlin.Throws
+
+class Template(val id: Int, val gestureName: String, var vector: Vector<PointF>) {
+
+    @Throws(IOException::class)
+    fun writeTo(out: DataOutputStream) {
+        out.writeInt(id)
+        out.writeInt(vector.size)
+        for (p in vector) {
+            out.writeFloat(p.x)
+            out.writeFloat(p.y)
+        }
+        out.writeInt(gestureName.toByteArray().size)
+        out.write(gestureName.toByteArray())
+    }
+
+    override fun toString(): String {
+        val sb = StringBuffer()
+        sb.append("[id = $id, name = $gestureName, vector = ")
+        if (vector.size <= 0) {
+            sb.append("(null)")
+        } else {
+            sb.append(vector[0])
+            for (i in 1 until vector.size) {
+                sb.append(", " + vector[i])
+            }
+        }
+        sb.append("]")
+        return sb.toString()
+    }
+
+    companion object {
+        @Throws(IOException::class)
+        fun readFrom(din: DataInputStream): Template {
+            val id = din.readInt()
+            var n = din.readInt()
+            val points = Vector<PointF>()
+            for (i in 0 until n) {
+                val p = PointF()
+                p.x = din.readFloat()
+                p.y = din.readFloat()
+                points.add(p)
+            }
+            n = din.readInt()
+            val gestureName = ByteArray(n)
+            for (i in 0 until n) {
+                gestureName[i] = din.readByte()
+            }
+            return Template(id, String(gestureName), points)
+        }
+    }
+}
\ No newline at end of file
diff --git a/app/src/main/res/drawable-v24/ic_launcher_foreground.xml b/app/src/main/res/drawable-v24/ic_launcher_foreground.xml
new file mode 100644
index 0000000..2b068d1
--- /dev/null
+++ b/app/src/main/res/drawable-v24/ic_launcher_foreground.xml
@@ -0,0 +1,30 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:aapt="http://schemas.android.com/aapt"
+    android:width="108dp"
+    android:height="108dp"
+    android:viewportWidth="108"
+    android:viewportHeight="108">
+    <path android:pathData="M31,63.928c0,0 6.4,-11 12.1,-13.1c7.2,-2.6 26,-1.4 26,-1.4l38.1,38.1L107,108.928l-32,-1L31,63.928z">
+        <aapt:attr name="android:fillColor">
+            <gradient
+                android:endX="85.84757"
+                android:endY="92.4963"
+                android:startX="42.9492"
+                android:startY="49.59793"
+                android:type="linear">
+                <item
+                    android:color="#44000000"
+                    android:offset="0.0" />
+                <item
+                    android:color="#00000000"
+                    android:offset="1.0" />
+            </gradient>
+        </aapt:attr>
+    </path>
+    <path
+        android:fillColor="#FFFFFF"
+        android:fillType="nonZero"
+        android:pathData="M65.3,45.828l3.8,-6.6c0.2,-0.4 0.1,-0.9 -0.3,-1.1c-0.4,-0.2 -0.9,-0.1 -1.1,0.3l-3.9,6.7c-6.3,-2.8 -13.4,-2.8 -19.7,0l-3.9,-6.7c-0.2,-0.4 -0.7,-0.5 -1.1,-0.3C38.8,38.328 38.7,38.828 38.9,39.228l3.8,6.6C36.2,49.428 31.7,56.028 31,63.928h46C76.3,56.028 71.8,49.428 65.3,45.828zM43.4,57.328c-0.8,0 -1.5,-0.5 -1.8,-1.2c-0.3,-0.7 -0.1,-1.5 0.4,-2.1c0.5,-0.5 1.4,-0.7 2.1,-0.4c0.7,0.3 1.2,1 1.2,1.8C45.3,56.528 44.5,57.328 43.4,57.328L43.4,57.328zM64.6,57.328c-0.8,0 -1.5,-0.5 -1.8,-1.2s-0.1,-1.5 0.4,-2.1c0.5,-0.5 1.4,-0.7 2.1,-0.4c0.7,0.3 1.2,1 1.2,1.8C66.5,56.528 65.6,57.328 64.6,57.328L64.6,57.328z"
+        android:strokeWidth="1"
+        android:strokeColor="#00000000" />
+</vector>
\ No newline at end of file
diff --git a/app/src/main/res/drawable/ic_launcher_background.xml b/app/src/main/res/drawable/ic_launcher_background.xml
new file mode 100644
index 0000000..07d5da9
--- /dev/null
+++ b/app/src/main/res/drawable/ic_launcher_background.xml
@@ -0,0 +1,170 @@
+<?xml version="1.0" encoding="utf-8"?>
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+    android:width="108dp"
+    android:height="108dp"
+    android:viewportWidth="108"
+    android:viewportHeight="108">
+    <path
+        android:fillColor="#3DDC84"
+        android:pathData="M0,0h108v108h-108z" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M9,0L9,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M19,0L19,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M29,0L29,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M39,0L39,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M49,0L49,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M59,0L59,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M69,0L69,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M79,0L79,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M89,0L89,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M99,0L99,108"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,9L108,9"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,19L108,19"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,29L108,29"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,39L108,39"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,49L108,49"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,59L108,59"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,69L108,69"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,79L108,79"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,89L108,89"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M0,99L108,99"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M19,29L89,29"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M19,39L89,39"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M19,49L89,49"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M19,59L89,59"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M19,69L89,69"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M19,79L89,79"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M29,19L29,89"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M39,19L39,89"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M49,19L49,89"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M59,19L59,89"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M69,19L69,89"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+    <path
+        android:fillColor="#00000000"
+        android:pathData="M79,19L79,89"
+        android:strokeWidth="0.8"
+        android:strokeColor="#33FFFFFF" />
+</vector>
diff --git a/app/src/main/res/layout/activity_main.xml b/app/src/main/res/layout/activity_main.xml
new file mode 100644
index 0000000..4fc2444
--- /dev/null
+++ b/app/src/main/res/layout/activity_main.xml
@@ -0,0 +1,18 @@
+<?xml version="1.0" encoding="utf-8"?>
+<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    tools:context=".MainActivity">
+
+    <TextView
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:text="Hello World!"
+        app:layout_constraintBottom_toBottomOf="parent"
+        app:layout_constraintLeft_toLeftOf="parent"
+        app:layout_constraintRight_toRightOf="parent"
+        app:layout_constraintTop_toTopOf="parent" />
+
+</androidx.constraintlayout.widget.ConstraintLayout>
\ No newline at end of file
diff --git a/app/src/main/res/mipmap-anydpi-v26/ic_launcher.xml b/app/src/main/res/mipmap-anydpi-v26/ic_launcher.xml
new file mode 100644
index 0000000..eca70cf
--- /dev/null
+++ b/app/src/main/res/mipmap-anydpi-v26/ic_launcher.xml
@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<adaptive-icon xmlns:android="http://schemas.android.com/apk/res/android">
+    <background android:drawable="@drawable/ic_launcher_background" />
+    <foreground android:drawable="@drawable/ic_launcher_foreground" />
+</adaptive-icon>
\ No newline at end of file
diff --git a/app/src/main/res/mipmap-anydpi-v26/ic_launcher_round.xml b/app/src/main/res/mipmap-anydpi-v26/ic_launcher_round.xml
new file mode 100644
index 0000000..eca70cf
--- /dev/null
+++ b/app/src/main/res/mipmap-anydpi-v26/ic_launcher_round.xml
@@ -0,0 +1,5 @@
+<?xml version="1.0" encoding="utf-8"?>
+<adaptive-icon xmlns:android="http://schemas.android.com/apk/res/android">
+    <background android:drawable="@drawable/ic_launcher_background" />
+    <foreground android:drawable="@drawable/ic_launcher_foreground" />
+</adaptive-icon>
\ No newline at end of file
diff --git a/app/src/main/res/mipmap-hdpi/ic_launcher.webp b/app/src/main/res/mipmap-hdpi/ic_launcher.webp
new file mode 100644
index 0000000..c209e78
Binary files /dev/null and b/app/src/main/res/mipmap-hdpi/ic_launcher.webp differ
diff --git a/app/src/main/res/mipmap-hdpi/ic_launcher_round.webp b/app/src/main/res/mipmap-hdpi/ic_launcher_round.webp
new file mode 100644
index 0000000..b2dfe3d
Binary files /dev/null and b/app/src/main/res/mipmap-hdpi/ic_launcher_round.webp differ
diff --git a/app/src/main/res/mipmap-mdpi/ic_launcher.webp b/app/src/main/res/mipmap-mdpi/ic_launcher.webp
new file mode 100644
index 0000000..4f0f1d6
Binary files /dev/null and b/app/src/main/res/mipmap-mdpi/ic_launcher.webp differ
diff --git a/app/src/main/res/mipmap-mdpi/ic_launcher_round.webp b/app/src/main/res/mipmap-mdpi/ic_launcher_round.webp
new file mode 100644
index 0000000..62b611d
Binary files /dev/null and b/app/src/main/res/mipmap-mdpi/ic_launcher_round.webp differ
diff --git a/app/src/main/res/mipmap-xhdpi/ic_launcher.webp b/app/src/main/res/mipmap-xhdpi/ic_launcher.webp
new file mode 100644
index 0000000..948a307
Binary files /dev/null and b/app/src/main/res/mipmap-xhdpi/ic_launcher.webp differ
diff --git a/app/src/main/res/mipmap-xhdpi/ic_launcher_round.webp b/app/src/main/res/mipmap-xhdpi/ic_launcher_round.webp
new file mode 100644
index 0000000..1b9a695
Binary files /dev/null and b/app/src/main/res/mipmap-xhdpi/ic_launcher_round.webp differ
diff --git a/app/src/main/res/mipmap-xxhdpi/ic_launcher.webp b/app/src/main/res/mipmap-xxhdpi/ic_launcher.webp
new file mode 100644
index 0000000..28d4b77
Binary files /dev/null and b/app/src/main/res/mipmap-xxhdpi/ic_launcher.webp differ
diff --git a/app/src/main/res/mipmap-xxhdpi/ic_launcher_round.webp b/app/src/main/res/mipmap-xxhdpi/ic_launcher_round.webp
new file mode 100644
index 0000000..9287f50
Binary files /dev/null and b/app/src/main/res/mipmap-xxhdpi/ic_launcher_round.webp differ
diff --git a/app/src/main/res/mipmap-xxxhdpi/ic_launcher.webp b/app/src/main/res/mipmap-xxxhdpi/ic_launcher.webp
new file mode 100644
index 0000000..aa7d642
Binary files /dev/null and b/app/src/main/res/mipmap-xxxhdpi/ic_launcher.webp differ
diff --git a/app/src/main/res/mipmap-xxxhdpi/ic_launcher_round.webp b/app/src/main/res/mipmap-xxxhdpi/ic_launcher_round.webp
new file mode 100644
index 0000000..9126ae3
Binary files /dev/null and b/app/src/main/res/mipmap-xxxhdpi/ic_launcher_round.webp differ
diff --git a/app/src/main/res/values-night/themes.xml b/app/src/main/res/values-night/themes.xml
new file mode 100644
index 0000000..9b8d837
--- /dev/null
+++ b/app/src/main/res/values-night/themes.xml
@@ -0,0 +1,16 @@
+<resources xmlns:tools="http://schemas.android.com/tools">
+    <!-- Base application theme. -->
+    <style name="Theme.Protractor" parent="Theme.MaterialComponents.DayNight.DarkActionBar">
+        <!-- Primary brand color. -->
+        <item name="colorPrimary">@color/purple_200</item>
+        <item name="colorPrimaryVariant">@color/purple_700</item>
+        <item name="colorOnPrimary">@color/black</item>
+        <!-- Secondary brand color. -->
+        <item name="colorSecondary">@color/teal_200</item>
+        <item name="colorSecondaryVariant">@color/teal_200</item>
+        <item name="colorOnSecondary">@color/black</item>
+        <!-- Status bar color. -->
+        <item name="android:statusBarColor" tools:targetApi="l">?attr/colorPrimaryVariant</item>
+        <!-- Customize your theme here. -->
+    </style>
+</resources>
\ No newline at end of file
diff --git a/app/src/main/res/values/colors.xml b/app/src/main/res/values/colors.xml
new file mode 100644
index 0000000..f8c6127
--- /dev/null
+++ b/app/src/main/res/values/colors.xml
@@ -0,0 +1,10 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <color name="purple_200">#FFBB86FC</color>
+    <color name="purple_500">#FF6200EE</color>
+    <color name="purple_700">#FF3700B3</color>
+    <color name="teal_200">#FF03DAC5</color>
+    <color name="teal_700">#FF018786</color>
+    <color name="black">#FF000000</color>
+    <color name="white">#FFFFFFFF</color>
+</resources>
\ No newline at end of file
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
new file mode 100644
index 0000000..39fbbac
--- /dev/null
+++ b/app/src/main/res/values/strings.xml
@@ -0,0 +1,3 @@
+<resources>
+    <string name="app_name">Protractor</string>
+</resources>
\ No newline at end of file
diff --git a/app/src/main/res/values/themes.xml b/app/src/main/res/values/themes.xml
new file mode 100644
index 0000000..7a3a388
--- /dev/null
+++ b/app/src/main/res/values/themes.xml
@@ -0,0 +1,16 @@
+<resources xmlns:tools="http://schemas.android.com/tools">
+    <!-- Base application theme. -->
+    <style name="Theme.Protractor" parent="Theme.MaterialComponents.DayNight.DarkActionBar">
+        <!-- Primary brand color. -->
+        <item name="colorPrimary">@color/purple_500</item>
+        <item name="colorPrimaryVariant">@color/purple_700</item>
+        <item name="colorOnPrimary">@color/white</item>
+        <!-- Secondary brand color. -->
+        <item name="colorSecondary">@color/teal_200</item>
+        <item name="colorSecondaryVariant">@color/teal_700</item>
+        <item name="colorOnSecondary">@color/black</item>
+        <!-- Status bar color. -->
+        <item name="android:statusBarColor" tools:targetApi="l">?attr/colorPrimaryVariant</item>
+        <!-- Customize your theme here. -->
+    </style>
+</resources>
\ No newline at end of file
diff --git a/app/src/test/java/de/luh/hci/mi/protractor/ExampleUnitTest.kt b/app/src/test/java/de/luh/hci/mi/protractor/ExampleUnitTest.kt
new file mode 100644
index 0000000..f28ff59
--- /dev/null
+++ b/app/src/test/java/de/luh/hci/mi/protractor/ExampleUnitTest.kt
@@ -0,0 +1,17 @@
+package de.luh.hci.mi.protractor
+
+import org.junit.Test
+
+import org.junit.Assert.*
+
+/**
+ * Example local unit test, which will execute on the development machine (host).
+ *
+ * See [testing documentation](http://d.android.com/tools/testing).
+ */
+class ExampleUnitTest {
+    @Test
+    fun addition_isCorrect() {
+        assertEquals(4, 2 + 2)
+    }
+}
\ No newline at end of file
diff --git a/build.gradle b/build.gradle
new file mode 100644
index 0000000..0932efc
--- /dev/null
+++ b/build.gradle
@@ -0,0 +1,10 @@
+// Top-level build file where you can add configuration options common to all sub-projects/modules.
+plugins {
+    id 'com.android.application' version '7.1.2' apply false
+    id 'com.android.library' version '7.1.2' apply false
+    id 'org.jetbrains.kotlin.android' version '1.6.21' apply false
+}
+
+task clean(type: Delete) {
+    delete rootProject.buildDir
+}
\ No newline at end of file
diff --git a/gradle.properties b/gradle.properties
new file mode 100644
index 0000000..cd0519b
--- /dev/null
+++ b/gradle.properties
@@ -0,0 +1,23 @@
+# Project-wide Gradle settings.
+# IDE (e.g. Android Studio) users:
+# Gradle settings configured through the IDE *will override*
+# any settings specified in this file.
+# For more details on how to configure your build environment visit
+# http://www.gradle.org/docs/current/userguide/build_environment.html
+# Specifies the JVM arguments used for the daemon process.
+# The setting is particularly useful for tweaking memory settings.
+org.gradle.jvmargs=-Xmx2048m -Dfile.encoding=UTF-8
+# When configured, Gradle will run in incubating parallel mode.
+# This option should only be used with decoupled projects. More details, visit
+# http://www.gradle.org/docs/current/userguide/multi_project_builds.html#sec:decoupled_projects
+# org.gradle.parallel=true
+# AndroidX package structure to make it clearer which packages are bundled with the
+# Android operating system, and which are packaged with your app"s APK
+# https://developer.android.com/topic/libraries/support-library/androidx-rn
+android.useAndroidX=true
+# Kotlin code style for this project: "official" or "obsolete":
+kotlin.code.style=official
+# Enables namespacing of each library's R class so that its R class includes only the
+# resources declared in the library itself and none from the library's dependencies,
+# thereby reducing the size of the R class for that library
+android.nonTransitiveRClass=true
\ No newline at end of file
diff --git a/gradle/wrapper/gradle-wrapper.jar b/gradle/wrapper/gradle-wrapper.jar
new file mode 100644
index 0000000..e708b1c
Binary files /dev/null and b/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
new file mode 100644
index 0000000..e0894d0
--- /dev/null
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -0,0 +1,6 @@
+#Wed May 11 15:51:36 CEST 2022
+distributionBase=GRADLE_USER_HOME
+distributionUrl=https\://services.gradle.org/distributions/gradle-7.2-bin.zip
+distributionPath=wrapper/dists
+zipStorePath=wrapper/dists
+zipStoreBase=GRADLE_USER_HOME
diff --git a/gradlew b/gradlew
new file mode 100644
index 0000000..4f906e0
--- /dev/null
+++ b/gradlew
@@ -0,0 +1,185 @@
+#!/usr/bin/env sh
+
+#
+# Copyright 2015 the original author or authors.
+#
+# 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
+#
+#      https://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.
+#
+
+##############################################################################
+##
+##  Gradle start up script for UN*X
+##
+##############################################################################
+
+# Attempt to set APP_HOME
+# Resolve links: $0 may be a link
+PRG="$0"
+# Need this for relative symlinks.
+while [ -h "$PRG" ] ; do
+    ls=`ls -ld "$PRG"`
+    link=`expr "$ls" : '.*-> \(.*\)$'`
+    if expr "$link" : '/.*' > /dev/null; then
+        PRG="$link"
+    else
+        PRG=`dirname "$PRG"`"/$link"
+    fi
+done
+SAVED="`pwd`"
+cd "`dirname \"$PRG\"`/" >/dev/null
+APP_HOME="`pwd -P`"
+cd "$SAVED" >/dev/null
+
+APP_NAME="Gradle"
+APP_BASE_NAME=`basename "$0"`
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD="maximum"
+
+warn () {
+    echo "$*"
+}
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+}
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "`uname`" in
+  CYGWIN* )
+    cygwin=true
+    ;;
+  Darwin* )
+    darwin=true
+    ;;
+  MINGW* )
+    msys=true
+    ;;
+  NONSTOP* )
+    nonstop=true
+    ;;
+esac
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD="$JAVA_HOME/jre/sh/java"
+    else
+        JAVACMD="$JAVA_HOME/bin/java"
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD="java"
+    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+
+# Increase the maximum file descriptors if we can.
+if [ "$cygwin" = "false" -a "$darwin" = "false" -a "$nonstop" = "false" ] ; then
+    MAX_FD_LIMIT=`ulimit -H -n`
+    if [ $? -eq 0 ] ; then
+        if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
+            MAX_FD="$MAX_FD_LIMIT"
+        fi
+        ulimit -n $MAX_FD
+        if [ $? -ne 0 ] ; then
+            warn "Could not set maximum file descriptor limit: $MAX_FD"
+        fi
+    else
+        warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT"
+    fi
+fi
+
+# For Darwin, add options to specify how the application appears in the dock
+if $darwin; then
+    GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
+fi
+
+# For Cygwin or MSYS, switch paths to Windows format before running java
+if [ "$cygwin" = "true" -o "$msys" = "true" ] ; then
+    APP_HOME=`cygpath --path --mixed "$APP_HOME"`
+    CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
+
+    JAVACMD=`cygpath --unix "$JAVACMD"`
+
+    # We build the pattern for arguments to be converted via cygpath
+    ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
+    SEP=""
+    for dir in $ROOTDIRSRAW ; do
+        ROOTDIRS="$ROOTDIRS$SEP$dir"
+        SEP="|"
+    done
+    OURCYGPATTERN="(^($ROOTDIRS))"
+    # Add a user-defined pattern to the cygpath arguments
+    if [ "$GRADLE_CYGPATTERN" != "" ] ; then
+        OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)"
+    fi
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    i=0
+    for arg in "$@" ; do
+        CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -`
+        CHECK2=`echo "$arg"|egrep -c "^-"`                                 ### Determine if an option
+
+        if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then                    ### Added a condition
+            eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"`
+        else
+            eval `echo args$i`="\"$arg\""
+        fi
+        i=`expr $i + 1`
+    done
+    case $i in
+        0) set -- ;;
+        1) set -- "$args0" ;;
+        2) set -- "$args0" "$args1" ;;
+        3) set -- "$args0" "$args1" "$args2" ;;
+        4) set -- "$args0" "$args1" "$args2" "$args3" ;;
+        5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
+        6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
+        7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
+        8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
+        9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
+    esac
+fi
+
+# Escape application args
+save () {
+    for i do printf %s\\n "$i" | sed "s/'/'\\\\''/g;1s/^/'/;\$s/\$/' \\\\/" ; done
+    echo " "
+}
+APP_ARGS=`save "$@"`
+
+# Collect all arguments for the java command, following the shell quoting and substitution rules
+eval set -- $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS "\"-Dorg.gradle.appname=$APP_BASE_NAME\"" -classpath "\"$CLASSPATH\"" org.gradle.wrapper.GradleWrapperMain "$APP_ARGS"
+
+exec "$JAVACMD" "$@"
diff --git a/gradlew.bat b/gradlew.bat
new file mode 100644
index 0000000..107acd3
--- /dev/null
+++ b/gradlew.bat
@@ -0,0 +1,89 @@
+@rem
+@rem Copyright 2015 the original author or authors.
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem      https://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+@rem
+
+@if "%DEBUG%" == "" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+set DIRNAME=%~dp0
+if "%DIRNAME%" == "" set DIRNAME=.
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Resolve any "." and ".." in APP_HOME to make it shorter.
+for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if "%ERRORLEVEL%" == "0" goto execute
+
+echo.
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto execute
+
+echo.
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %*
+
+:end
+@rem End local scope for the variables with windows NT shell
+if "%ERRORLEVEL%"=="0" goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
+exit /b 1
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega
diff --git a/settings.gradle b/settings.gradle
new file mode 100644
index 0000000..4a140bc
--- /dev/null
+++ b/settings.gradle
@@ -0,0 +1,16 @@
+pluginManagement {
+    repositories {
+        gradlePluginPortal()
+        google()
+        mavenCentral()
+    }
+}
+dependencyResolutionManagement {
+    repositoriesMode.set(RepositoriesMode.FAIL_ON_PROJECT_REPOS)
+    repositories {
+        google()
+        mavenCentral()
+    }
+}
+rootProject.name = "Protractor"
+include ':app'