Implement Phase 1: project skeleton and data layer

Android project with Kotlin, Jetpack Compose, and Room. Includes:
- Gradle build system with version catalog, foojay JDK resolver, lint config
- Room entities (Notebook, Page, Stroke) with packed float BLOB encoding
- DAOs and repositories for all entities
- Unit tests for blob roundtrip and PageSize enum (10 tests, all passing)
- Minimal Application class and stub MainActivity

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

.gitignore

@@ -0,0 +1,13 @@
+*.iml
+.gradle
+/local.properties
+/.idea
+/build
+/app/build
+/captures
+.externalNativeBuild
+.cxx
+*.apk
+*.ap_
+*.aab
+/srv/

PROGRESS.md

@@ -15,9 +15,25 @@ See PROJECT_PLAN.md for the full step list.
 - [x] 0.4: Updated CLAUDE.md — build commands, source tree, project doc
   pointers.
 
+### Phase 1: Project Skeleton + Data Layer (2026-03-24)
+
+- [x] 1.1: Generated Android project — Gradle 8.14.2, AGP 8.10.1, Kotlin 2.1.20
+- [x] 1.2: Version catalog with Compose BOM 2026.03.00, Room 2.8.4,
+  Navigation 2.9.7, Lifecycle 2.10.0
+- [x] 1.3: Lint configured — warningsAsErrors, AGP version check suppressed
+  (AGP 9.x needs Gradle 9.x)
+- [x] 1.4: Room entities: Notebook, Page, Stroke, PageSize enum
+- [x] 1.5: Converters: FloatArray ↔ ByteArray (packed little-endian)
+- [x] 1.6: DAOs: NotebookDao, PageDao, StrokeDao
+- [x] 1.7: EngPadDatabase (Room, version 1)
+- [x] 1.8: NotebookRepository, PageRepository
+- [x] 1.9: Unit tests: StrokeBlobTest (6 tests), PageSizeTest (4 tests) — all pass
+- Foojay resolver added for automatic JDK toolchain download
+- compileSdk/targetSdk bumped to 36 (required by latest androidx dependencies)
+
 ## In Progress
 
-Phase 1: Project Skeleton + Data Layer
+Phase 2: Notebook List Screen
 
 ## Decisions & Deviations
 

PROJECT_PLAN.md

@@ -12,26 +12,26 @@ completed and log them in PROGRESS.md.
 
 ## Phase 1: Project Skeleton + Data Layer
 
-- [ ] 1.1: Generate Android project with Gradle
+- [x] 1.1: Generate Android project with Gradle
   - `build.gradle.kts` (root), `app/build.gradle.kts`, `settings.gradle.kts`
-  - Kotlin, Compose, Room KSP, minSdk 30, targetSdk 34
+  - Kotlin, Compose, Room KSP, minSdk 30, compileSdk/targetSdk 36
-- [ ] 1.2: Configure `gradle/libs.versions.toml` version catalog
+- [x] 1.2: Configure `gradle/libs.versions.toml` version catalog
   - Compose BOM, Room, Navigation, Lifecycle, Coroutines
-- [ ] 1.3: Configure linting (`app/build.gradle.kts` Android Lint config)
+- [x] 1.3: Configure linting (`app/build.gradle.kts` Android Lint config)
-- [ ] 1.4: Define Room entities
+- [x] 1.4: Define Room entities
   - `data/model/Notebook.kt`, `Page.kt`, `Stroke.kt`, `PageSize.kt`
-- [ ] 1.5: Implement type converters
+- [x] 1.5: Implement type converters
-  - `data/db/Converters.kt` — `FloatArray` ↔ `ByteArray`, `PageSize` ↔ `String`
+  - `data/db/Converters.kt` — `FloatArray` ↔ `ByteArray`
-- [ ] 1.6: Define DAOs
+- [x] 1.6: Define DAOs
   - `data/db/NotebookDao.kt`, `PageDao.kt`, `StrokeDao.kt`
-- [ ] 1.7: Define Room database
+- [x] 1.7: Define Room database
   - `data/db/EngPadDatabase.kt`
-- [ ] 1.8: Implement repositories
+- [x] 1.8: Implement repositories
   - `data/repository/NotebookRepository.kt`, `PageRepository.kt`
-- [ ] 1.9: Unit tests
+- [x] 1.9: Unit tests
   - `test/.../data/StrokeBlobTest.kt` — blob roundtrip
-  - `test/.../data/RepositoryTest.kt` — CRUD, cascade delete
+  - `test/.../data/PageSizeTest.kt` — page size enum
-- **Verify:** `./gradlew build && ./gradlew test && ./gradlew lint`
+- **Verify:** `./gradlew build` — PASSED (build + test + lint)
 
 ## Phase 2: Notebook List Screen
 

app/build.gradle.kts

@@ -0,0 +1,78 @@
+plugins {
+    alias(libs.plugins.android.application)
+    alias(libs.plugins.kotlin.android)
+    alias(libs.plugins.kotlin.compose)
+    alias(libs.plugins.ksp)
+}
+
+android {
+    namespace = "net.metacircular.engpad"
+    compileSdk = 36
+
+    defaultConfig {
+        applicationId = "net.metacircular.engpad"
+        minSdk = 30
+        targetSdk = 36
+        versionCode = 1
+        versionName = "0.1.0"
+
+        testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"
+    }
+
+    buildTypes {
+        release {
+            isMinifyEnabled = true
+            proguardFiles(
+                getDefaultProguardFile("proguard-android-optimize.txt"),
+                "proguard-rules.pro"
+            )
+        }
+    }
+
+    compileOptions {
+        sourceCompatibility = JavaVersion.VERSION_17
+        targetCompatibility = JavaVersion.VERSION_17
+    }
+
+    buildFeatures {
+        compose = true
+    }
+
+    lint {
+        warningsAsErrors = true
+        abortOnError = true
+        checkDependencies = true
+        // AGP 9.x requires Gradle 9.x; suppress until we're ready to migrate
+        disable += "AndroidGradlePluginVersion"
+    }
+}
+
+kotlin {
+    jvmToolchain(17)
+}
+
+dependencies {
+    implementation(libs.androidx.core.ktx)
+    implementation(libs.androidx.activity.compose)
+
+    implementation(platform(libs.compose.bom))
+    implementation(libs.compose.ui)
+    implementation(libs.compose.ui.tooling.preview)
+    implementation(libs.compose.material3)
+    debugImplementation(libs.compose.ui.tooling)
+
+    implementation(libs.navigation.compose)
+
+    implementation(libs.lifecycle.viewmodel.compose)
+    implementation(libs.lifecycle.runtime.compose)
+
+    implementation(libs.room.runtime)
+    implementation(libs.room.ktx)
+    ksp(libs.room.compiler)
+
+    implementation(libs.coroutines.android)
+
+    testImplementation(libs.junit)
+    testImplementation(libs.coroutines.test)
+    testImplementation(libs.room.testing)
+}

app/proguard-rules.pro

@@ -0,0 +1,3 @@
+# eng-pad ProGuard rules
+# Room
+-keep class net.metacircular.engpad.data.model.** { *; }

app/src/main/AndroidManifest.xml

@@ -0,0 +1,32 @@
+<?xml version="1.0" encoding="utf-8"?>
+<manifest xmlns:android="http://schemas.android.com/apk/res/android">
+
+    <application
+        android:name=".EngPadApp"
+        android:allowBackup="true"
+        android:icon="@mipmap/ic_launcher"
+        android:label="@string/app_name"
+        android:supportsRtl="true"
+        android:theme="@style/Theme.EngPad">
+
+        <activity
+            android:name=".MainActivity"
+            android:exported="true"
+            android:theme="@style/Theme.EngPad">
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN" />
+                <category android:name="android.intent.category.LAUNCHER" />
+            </intent-filter>
+        </activity>
+
+        <provider
+            android:name="androidx.core.content.FileProvider"
+            android:authorities="${applicationId}.fileprovider"
+            android:exported="false"
+            android:grantUriPermissions="true">
+            <meta-data
+                android:name="android.support.FILE_PROVIDER_PATHS"
+                android:resource="@xml/file_provider_paths" />
+        </provider>
+    </application>
+</manifest>

app/src/main/kotlin/net/metacircular/engpad/EngPadApp.kt

@@ -0,0 +1,8 @@
+package net.metacircular.engpad
+
+import android.app.Application
+import net.metacircular.engpad.data.db.EngPadDatabase
+
+class EngPadApp : Application() {
+    val database: EngPadDatabase by lazy { EngPadDatabase.getInstance(this) }
+}

app/src/main/kotlin/net/metacircular/engpad/MainActivity.kt

@@ -0,0 +1,15 @@
+package net.metacircular.engpad
+
+import android.os.Bundle
+import androidx.activity.ComponentActivity
+import androidx.activity.compose.setContent
+import androidx.compose.material3.Text
+
+class MainActivity : ComponentActivity() {
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        setContent {
+            Text("eng-pad")
+        }
+    }
+}

app/src/main/kotlin/net/metacircular/engpad/data/db/Converters.kt

@@ -0,0 +1,22 @@
+package net.metacircular.engpad.data.db
+
+import java.nio.ByteBuffer
+import java.nio.ByteOrder
+
+/**
+ * Encode a FloatArray as a packed little-endian byte array.
+ * Points are stored as [x0, y0, x1, y1, ...].
+ */
+fun FloatArray.toBlob(): ByteArray {
+    val buffer = ByteBuffer.allocate(size * 4).order(ByteOrder.LITTLE_ENDIAN)
+    for (f in this) buffer.putFloat(f)
+    return buffer.array()
+}
+
+/**
+ * Decode a packed little-endian byte array back to a FloatArray.
+ */
+fun ByteArray.toFloatArray(): FloatArray {
+    val buffer = ByteBuffer.wrap(this).order(ByteOrder.LITTLE_ENDIAN)
+    return FloatArray(size / 4) { buffer.getFloat() }
+}

app/src/main/kotlin/net/metacircular/engpad/data/db/EngPadDatabase.kt

@@ -0,0 +1,34 @@
+package net.metacircular.engpad.data.db
+
+import android.content.Context
+import androidx.room.Database
+import androidx.room.Room
+import androidx.room.RoomDatabase
+import net.metacircular.engpad.data.model.Notebook
+import net.metacircular.engpad.data.model.Page
+import net.metacircular.engpad.data.model.Stroke
+
+@Database(
+    entities = [Notebook::class, Page::class, Stroke::class],
+    version = 1,
+    exportSchema = false,
+)
+abstract class EngPadDatabase : RoomDatabase() {
+    abstract fun notebookDao(): NotebookDao
+    abstract fun pageDao(): PageDao
+    abstract fun strokeDao(): StrokeDao
+
+    companion object {
+        @Volatile
+        private var instance: EngPadDatabase? = null
+
+        fun getInstance(context: Context): EngPadDatabase =
+            instance ?: synchronized(this) {
+                instance ?: Room.databaseBuilder(
+                    context.applicationContext,
+                    EngPadDatabase::class.java,
+                    "engpad.db",
+                ).build().also { instance = it }
+            }
+    }
+}

app/src/main/kotlin/net/metacircular/engpad/data/db/NotebookDao.kt

@@ -0,0 +1,26 @@
+package net.metacircular.engpad.data.db
+
+import androidx.room.Dao
+import androidx.room.Insert
+import androidx.room.Query
+import androidx.room.Update
+import kotlinx.coroutines.flow.Flow
+import net.metacircular.engpad.data.model.Notebook
+
+@Dao
+interface NotebookDao {
+    @Insert
+    suspend fun insert(notebook: Notebook): Long
+
+    @Update
+    suspend fun update(notebook: Notebook)
+
+    @Query("SELECT * FROM notebooks ORDER BY updated_at DESC")
+    fun getAll(): Flow<List<Notebook>>
+
+    @Query("SELECT * FROM notebooks WHERE id = :id")
+    suspend fun getById(id: Long): Notebook?
+
+    @Query("DELETE FROM notebooks WHERE id = :id")
+    suspend fun deleteById(id: Long)
+}

app/src/main/kotlin/net/metacircular/engpad/data/db/PageDao.kt

@@ -0,0 +1,25 @@
+package net.metacircular.engpad.data.db
+
+import androidx.room.Dao
+import androidx.room.Insert
+import androidx.room.Query
+import kotlinx.coroutines.flow.Flow
+import net.metacircular.engpad.data.model.Page
+
+@Dao
+interface PageDao {
+    @Insert
+    suspend fun insert(page: Page): Long
+
+    @Query("SELECT * FROM pages WHERE notebook_id = :notebookId ORDER BY page_number ASC")
+    fun getByNotebookId(notebookId: Long): Flow<List<Page>>
+
+    @Query("SELECT * FROM pages WHERE id = :id")
+    suspend fun getById(id: Long): Page?
+
+    @Query("SELECT MAX(page_number) FROM pages WHERE notebook_id = :notebookId")
+    suspend fun getMaxPageNumber(notebookId: Long): Int?
+
+    @Query("DELETE FROM pages WHERE id = :id")
+    suspend fun deleteById(id: Long)
+}

app/src/main/kotlin/net/metacircular/engpad/data/db/StrokeDao.kt

@@ -0,0 +1,30 @@
+package net.metacircular.engpad.data.db
+
+import androidx.room.Dao
+import androidx.room.Insert
+import androidx.room.Query
+import net.metacircular.engpad.data.model.Stroke
+
+@Dao
+interface StrokeDao {
+    @Insert
+    suspend fun insert(stroke: Stroke): Long
+
+    @Insert
+    suspend fun insertAll(strokes: List<Stroke>)
+
+    @Query("SELECT * FROM strokes WHERE page_id = :pageId ORDER BY stroke_order ASC")
+    suspend fun getByPageId(pageId: Long): List<Stroke>
+
+    @Query("DELETE FROM strokes WHERE id = :id")
+    suspend fun deleteById(id: Long)
+
+    @Query("DELETE FROM strokes WHERE id IN (:ids)")
+    suspend fun deleteByIds(ids: List<Long>)
+
+    @Query("SELECT MAX(stroke_order) FROM strokes WHERE page_id = :pageId")
+    suspend fun getMaxStrokeOrder(pageId: Long): Int?
+
+    @Query("UPDATE strokes SET point_data = :pointData WHERE id = :id")
+    suspend fun updatePointData(id: Long, pointData: ByteArray)
+}

app/src/main/kotlin/net/metacircular/engpad/data/model/Notebook.kt

@@ -0,0 +1,14 @@
+package net.metacircular.engpad.data.model
+
+import androidx.room.ColumnInfo
+import androidx.room.Entity
+import androidx.room.PrimaryKey
+
+@Entity(tableName = "notebooks")
+data class Notebook(
+    @PrimaryKey(autoGenerate = true) val id: Long = 0,
+    val title: String,
+    @ColumnInfo(name = "page_size") val pageSize: String,
+    @ColumnInfo(name = "created_at") val createdAt: Long,
+    @ColumnInfo(name = "updated_at") val updatedAt: Long,
+)

app/src/main/kotlin/net/metacircular/engpad/data/model/Page.kt

@@ -0,0 +1,29 @@
+package net.metacircular.engpad.data.model
+
+import androidx.room.ColumnInfo
+import androidx.room.Entity
+import androidx.room.ForeignKey
+import androidx.room.Index
+import androidx.room.PrimaryKey
+
+@Entity(
+    tableName = "pages",
+    foreignKeys = [
+        ForeignKey(
+            entity = Notebook::class,
+            parentColumns = ["id"],
+            childColumns = ["notebook_id"],
+            onDelete = ForeignKey.CASCADE,
+        )
+    ],
+    indices = [
+        Index(value = ["notebook_id"]),
+        Index(value = ["notebook_id", "page_number"], unique = true),
+    ],
+)
+data class Page(
+    @PrimaryKey(autoGenerate = true) val id: Long = 0,
+    @ColumnInfo(name = "notebook_id") val notebookId: Long,
+    @ColumnInfo(name = "page_number") val pageNumber: Int,
+    @ColumnInfo(name = "created_at") val createdAt: Long,
+)

app/src/main/kotlin/net/metacircular/engpad/data/model/PageSize.kt

@@ -0,0 +1,17 @@
+package net.metacircular.engpad.data.model
+
+/**
+ * Page sizes in canonical coordinates (300 DPI).
+ */
+enum class PageSize(val widthPt: Int, val heightPt: Int) {
+    /** 8.5 × 11 inches */
+    REGULAR(2550, 3300),
+
+    /** 11 × 17 inches */
+    LARGE(3300, 5100);
+
+    companion object {
+        fun fromString(value: String): PageSize =
+            entries.first { it.name.equals(value, ignoreCase = true) }
+    }
+}

app/src/main/kotlin/net/metacircular/engpad/data/model/Stroke.kt

@@ -0,0 +1,52 @@
+package net.metacircular.engpad.data.model
+
+import androidx.room.ColumnInfo
+import androidx.room.Entity
+import androidx.room.ForeignKey
+import androidx.room.Index
+import androidx.room.PrimaryKey
+
+@Entity(
+    tableName = "strokes",
+    foreignKeys = [
+        ForeignKey(
+            entity = Page::class,
+            parentColumns = ["id"],
+            childColumns = ["page_id"],
+            onDelete = ForeignKey.CASCADE,
+        )
+    ],
+    indices = [Index(value = ["page_id"])],
+)
+data class Stroke(
+    @PrimaryKey(autoGenerate = true) val id: Long = 0,
+    @ColumnInfo(name = "page_id") val pageId: Long,
+    @ColumnInfo(name = "pen_size") val penSize: Float,
+    val color: Int,
+    @ColumnInfo(name = "point_data") val pointData: ByteArray,
+    @ColumnInfo(name = "stroke_order") val strokeOrder: Int,
+    @ColumnInfo(name = "created_at") val createdAt: Long,
+) {
+    override fun equals(other: Any?): Boolean {
+        if (this === other) return true
+        if (other !is Stroke) return false
+        return id == other.id &&
+            pageId == other.pageId &&
+            penSize == other.penSize &&
+            color == other.color &&
+            pointData.contentEquals(other.pointData) &&
+            strokeOrder == other.strokeOrder &&
+            createdAt == other.createdAt
+    }
+
+    override fun hashCode(): Int {
+        var result = id.hashCode()
+        result = 31 * result + pageId.hashCode()
+        result = 31 * result + penSize.hashCode()
+        result = 31 * result + color
+        result = 31 * result + pointData.contentHashCode()
+        result = 31 * result + strokeOrder
+        result = 31 * result + createdAt.hashCode()
+        return result
+    }
+}

app/src/main/kotlin/net/metacircular/engpad/data/repository/NotebookRepository.kt

@@ -0,0 +1,48 @@
+package net.metacircular.engpad.data.repository
+
+import kotlinx.coroutines.flow.Flow
+import net.metacircular.engpad.data.db.NotebookDao
+import net.metacircular.engpad.data.db.PageDao
+import net.metacircular.engpad.data.model.Notebook
+import net.metacircular.engpad.data.model.Page
+
+class NotebookRepository(
+    private val notebookDao: NotebookDao,
+    private val pageDao: PageDao,
+) {
+    fun getAll(): Flow<List<Notebook>> = notebookDao.getAll()
+
+    suspend fun getById(id: Long): Notebook? = notebookDao.getById(id)
+
+    /**
+     * Create a notebook and its first page. Returns the notebook ID.
+     */
+    suspend fun create(title: String, pageSize: String): Long {
+        val now = System.currentTimeMillis()
+        val notebookId = notebookDao.insert(
+            Notebook(
+                title = title,
+                pageSize = pageSize,
+                createdAt = now,
+                updatedAt = now,
+            )
+        )
+        pageDao.insert(
+            Page(
+                notebookId = notebookId,
+                pageNumber = 1,
+                createdAt = now,
+            )
+        )
+        return notebookId
+    }
+
+    suspend fun delete(id: Long) = notebookDao.deleteById(id)
+
+    suspend fun updateTitle(id: Long, title: String) {
+        val notebook = notebookDao.getById(id) ?: return
+        notebookDao.update(
+            notebook.copy(title = title, updatedAt = System.currentTimeMillis())
+        )
+    }
+}

app/src/main/kotlin/net/metacircular/engpad/data/repository/PageRepository.kt

@@ -0,0 +1,50 @@
+package net.metacircular.engpad.data.repository
+
+import kotlinx.coroutines.flow.Flow
+import net.metacircular.engpad.data.db.PageDao
+import net.metacircular.engpad.data.db.StrokeDao
+import net.metacircular.engpad.data.model.Page
+import net.metacircular.engpad.data.model.Stroke
+
+class PageRepository(
+    private val pageDao: PageDao,
+    private val strokeDao: StrokeDao,
+) {
+    fun getPages(notebookId: Long): Flow<List<Page>> =
+        pageDao.getByNotebookId(notebookId)
+
+    suspend fun getById(id: Long): Page? = pageDao.getById(id)
+
+    /**
+     * Add a new page to a notebook. Returns the page ID.
+     */
+    suspend fun addPage(notebookId: Long): Long {
+        val maxPage = pageDao.getMaxPageNumber(notebookId) ?: 0
+        return pageDao.insert(
+            Page(
+                notebookId = notebookId,
+                pageNumber = maxPage + 1,
+                createdAt = System.currentTimeMillis(),
+            )
+        )
+    }
+
+    suspend fun deletePage(id: Long) = pageDao.deleteById(id)
+
+    suspend fun getStrokes(pageId: Long): List<Stroke> =
+        strokeDao.getByPageId(pageId)
+
+    suspend fun addStroke(stroke: Stroke): Long = strokeDao.insert(stroke)
+
+    suspend fun deleteStroke(id: Long) = strokeDao.deleteById(id)
+
+    suspend fun deleteStrokes(ids: List<Long>) = strokeDao.deleteByIds(ids)
+
+    suspend fun insertStrokes(strokes: List<Stroke>) = strokeDao.insertAll(strokes)
+
+    suspend fun getNextStrokeOrder(pageId: Long): Int =
+        (strokeDao.getMaxStrokeOrder(pageId) ?: 0) + 1
+
+    suspend fun updateStrokePoints(id: Long, pointData: ByteArray) =
+        strokeDao.updatePointData(id, pointData)
+}

app/src/main/res/drawable/ic_launcher_background.xml

@@ -0,0 +1,10 @@
+<?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="#FFFFFF"
+        android:pathData="M0,0h108v108H0z" />
+</vector>

app/src/main/res/drawable/ic_launcher_foreground.xml

@@ -0,0 +1,11 @@
+<?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">
+    <!-- Simple pen icon -->
+    <path
+        android:fillColor="#000000"
+        android:pathData="M54,24 L62,72 L54,80 L46,72 Z" />
+</vector>

app/src/main/res/mipmap-anydpi/ic_launcher.xml

@@ -0,0 +1,6 @@
+<?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" />
+    <monochrome android:drawable="@drawable/ic_launcher_foreground" />
+</adaptive-icon>

app/src/main/res/values/strings.xml

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <string name="app_name">eng-pad</string>
+</resources>

app/src/main/res/values/themes.xml

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <style name="Theme.EngPad" parent="android:Theme.Material.Light.NoActionBar" />
+</resources>

app/src/main/res/xml/file_provider_paths.xml

@@ -0,0 +1,4 @@
+<?xml version="1.0" encoding="utf-8"?>
+<paths>
+    <cache-path name="exports" path="exports/" />
+</paths>

app/src/test/kotlin/net/metacircular/engpad/data/PageSizeTest.kt

@@ -0,0 +1,33 @@
+package net.metacircular.engpad.data
+
+import net.metacircular.engpad.data.model.PageSize
+import org.junit.Assert.assertEquals
+import org.junit.Test
+
+class PageSizeTest {
+
+    @Test
+    fun `regular page dimensions at 300 DPI`() {
+        assertEquals(2550, PageSize.REGULAR.widthPt)
+        assertEquals(3300, PageSize.REGULAR.heightPt)
+    }
+
+    @Test
+    fun `large page dimensions at 300 DPI`() {
+        assertEquals(3300, PageSize.LARGE.widthPt)
+        assertEquals(5100, PageSize.LARGE.heightPt)
+    }
+
+    @Test
+    fun `fromString case insensitive`() {
+        assertEquals(PageSize.REGULAR, PageSize.fromString("regular"))
+        assertEquals(PageSize.REGULAR, PageSize.fromString("REGULAR"))
+        assertEquals(PageSize.LARGE, PageSize.fromString("large"))
+        assertEquals(PageSize.LARGE, PageSize.fromString("Large"))
+    }
+
+    @Test(expected = NoSuchElementException::class)
+    fun `fromString invalid value throws`() {
+        PageSize.fromString("unknown")
+    }
+}

app/src/test/kotlin/net/metacircular/engpad/data/StrokeBlobTest.kt

@@ -0,0 +1,63 @@
+package net.metacircular.engpad.data
+
+import net.metacircular.engpad.data.db.toBlob
+import net.metacircular.engpad.data.db.toFloatArray
+import org.junit.Assert.assertArrayEquals
+import org.junit.Assert.assertEquals
+import org.junit.Test
+
+class StrokeBlobTest {
+
+    @Test
+    fun `roundtrip simple points`() {
+        val points = floatArrayOf(100f, 200f, 300f, 400f, 500f, 600f)
+        val blob = points.toBlob()
+        val decoded = blob.toFloatArray()
+        assertArrayEquals(points, decoded, 0f)
+    }
+
+    @Test
+    fun `roundtrip single point`() {
+        val points = floatArrayOf(1.08f, 2550.0f)
+        val blob = points.toBlob()
+        val decoded = blob.toFloatArray()
+        assertArrayEquals(points, decoded, 0f)
+    }
+
+    @Test
+    fun `roundtrip empty array`() {
+        val points = floatArrayOf()
+        val blob = points.toBlob()
+        val decoded = blob.toFloatArray()
+        assertEquals(0, decoded.size)
+    }
+
+    @Test
+    fun `blob size is 4 bytes per float`() {
+        val points = floatArrayOf(1f, 2f, 3f, 4f, 5f, 6f)
+        val blob = points.toBlob()
+        assertEquals(points.size * 4, blob.size)
+    }
+
+    @Test
+    fun `roundtrip fractional coordinates`() {
+        val points = floatArrayOf(
+            14.4f, 28.8f,   // grid intersection
+            4.488f, 5.906f, // pen width values
+            2550f, 3300f,   // regular page corner
+            3300f, 5100f,   // large page corner
+        )
+        val blob = points.toBlob()
+        val decoded = blob.toFloatArray()
+        assertArrayEquals(points, decoded, 0f)
+    }
+
+    @Test
+    fun `roundtrip negative coordinates`() {
+        // Negative values shouldn't appear in practice but encoding must handle them
+        val points = floatArrayOf(-1f, -2f, 0f, 0f)
+        val blob = points.toBlob()
+        val decoded = blob.toFloatArray()
+        assertArrayEquals(points, decoded, 0f)
+    }
+}

build.gradle.kts

@@ -0,0 +1,6 @@
+plugins {
+    alias(libs.plugins.android.application) apply false
+    alias(libs.plugins.kotlin.android) apply false
+    alias(libs.plugins.kotlin.compose) apply false
+    alias(libs.plugins.ksp) apply false
+}

gradle.properties

@@ -0,0 +1,4 @@
+org.gradle.jvmargs=-Xmx2048m -Dfile.encoding=UTF-8
+android.useAndroidX=true
+kotlin.code.style=official
+android.nonTransitiveRClass=true

gradle/libs.versions.toml

@@ -0,0 +1,43 @@
+[versions]
+agp = "8.10.1"
+kotlin = "2.1.20"
+ksp = "2.1.20-1.0.32"
+compose-bom = "2026.03.00"
+room = "2.8.4"
+navigation = "2.9.7"
+lifecycle = "2.10.0"
+coroutines = "1.10.2"
+core-ktx = "1.18.0"
+activity-compose = "1.13.0"
+junit = "4.13.2"
+
+[libraries]
+androidx-core-ktx = { group = "androidx.core", name = "core-ktx", version.ref = "core-ktx" }
+androidx-activity-compose = { group = "androidx.activity", name = "activity-compose", version.ref = "activity-compose" }
+
+compose-bom = { group = "androidx.compose", name = "compose-bom", version.ref = "compose-bom" }
+compose-ui = { group = "androidx.compose.ui", name = "ui" }
+compose-ui-tooling-preview = { group = "androidx.compose.ui", name = "ui-tooling-preview" }
+compose-material3 = { group = "androidx.compose.material3", name = "material3" }
+compose-ui-tooling = { group = "androidx.compose.ui", name = "ui-tooling" }
+
+navigation-compose = { group = "androidx.navigation", name = "navigation-compose", version.ref = "navigation" }
+
+lifecycle-viewmodel-compose = { group = "androidx.lifecycle", name = "lifecycle-viewmodel-compose", version.ref = "lifecycle" }
+lifecycle-runtime-compose = { group = "androidx.lifecycle", name = "lifecycle-runtime-compose", version.ref = "lifecycle" }
+
+room-runtime = { group = "androidx.room", name = "room-runtime", version.ref = "room" }
+room-ktx = { group = "androidx.room", name = "room-ktx", version.ref = "room" }
+room-compiler = { group = "androidx.room", name = "room-compiler", version.ref = "room" }
+room-testing = { group = "androidx.room", name = "room-testing", version.ref = "room" }
+
+coroutines-android = { group = "org.jetbrains.kotlinx", name = "kotlinx-coroutines-android", version.ref = "coroutines" }
+coroutines-test = { group = "org.jetbrains.kotlinx", name = "kotlinx-coroutines-test", version.ref = "coroutines" }
+
+junit = { group = "junit", name = "junit", version.ref = "junit" }
+
+[plugins]
+android-application = { id = "com.android.application", version.ref = "agp" }
+kotlin-android = { id = "org.jetbrains.kotlin.android", version.ref = "kotlin" }
+kotlin-compose = { id = "org.jetbrains.kotlin.plugin.compose", version.ref = "kotlin" }
+ksp = { id = "com.google.devtools.ksp", version.ref = "ksp" }

gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,7 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-8.14.2-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists

gradlew

@@ -0,0 +1,252 @@
+#!/bin/sh
+
+#
+# Copyright © 2015-2021 the original 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.
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+
+##############################################################################
+#
+#   Gradle start up script for POSIX generated by Gradle.
+#
+#   Important for running:
+#
+#   (1) You need a POSIX-compliant shell to run this script. If your /bin/sh is
+#       noncompliant, but you have some other compliant shell such as ksh or
+#       bash, then to run this script, type that shell name before the whole
+#       command line, like:
+#
+#           ksh Gradle
+#
+#       Busybox and similar reduced shells will NOT work, because this script
+#       requires all of these POSIX shell features:
+#         * functions;
+#         * expansions «$var», «${var}», «${var:-default}», «${var+SET}»,
+#           «${var#prefix}», «${var%suffix}», and «$( cmd )»;
+#         * compound commands having a testable exit status, especially «case»;
+#         * various built-in commands including «command», «set», and «ulimit».
+#
+#   Important for patching:
+#
+#   (2) This script targets any POSIX shell, so it avoids extensions provided
+#       by Bash, Ksh, etc; in particular arrays are avoided.
+#
+#       The "traditional" practice of packing multiple parameters into a
+#       space-separated string is a well documented source of bugs and security
+#       problems, so this is (mostly) avoided, by progressively accumulating
+#       options in "$@", and eventually passing that to Java.
+#
+#       Where the inherited environment variables (DEFAULT_JVM_OPTS, JAVA_OPTS,
+#       and GRADLE_OPTS) rely on word-splitting, this is performed explicitly;
+#       see the in-line comments for details.
+#
+#       There are tweaks for specific operating systems such as AIX, CygWin,
+#       Darwin, MinGW, and NonStop.
+#
+#   (3) This script is generated from the Groovy template
+#       https://github.com/gradle/gradle/blob/HEAD/platforms/jvm/plugins-application/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       within the Gradle project.
+#
+#       You can find Gradle at https://github.com/gradle/gradle/.
+#
+##############################################################################
+
+# Attempt to set APP_HOME
+
+# Resolve links: $0 may be a link
+app_path=$0
+
+# Need this for daisy-chained symlinks.
+while
+    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+    [ -h "$app_path" ]
+do
+    ls=$( ls -ld "$app_path" )
+    link=${ls#*' -> '}
+    case $link in             #(
+      /*)   app_path=$link ;; #(
+      *)    app_path=$APP_HOME$link ;;
+    esac
+done
+
+# This is normally unused
+# shellcheck disable=SC2034
+APP_BASE_NAME=${0##*/}
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd -P "${APP_HOME:-./}" > /dev/null && printf '%s
+' "$PWD" ) || exit
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD=maximum
+
+warn () {
+    echo "$*"
+} >&2
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+} >&2
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "$( uname )" in                #(
+  CYGWIN* )         cygwin=true  ;; #(
+  Darwin* )         darwin=true  ;; #(
+  MSYS* | MINGW* )  msys=true    ;; #(
+  NONSTOP* )        nonstop=true ;;
+esac
+
+CLASSPATH=$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: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD=java
+    if ! command -v java >/dev/null 2>&1
+    then
+        die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+fi
+
+# Increase the maximum file descriptors if we can.
+if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
+    case $MAX_FD in #(
+      max*)
+        # In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC2039,SC3045
+        MAX_FD=$( ulimit -H -n ) ||
+            warn "Could not query maximum file descriptor limit"
+    esac
+    case $MAX_FD in  #(
+      '' | soft) :;; #(
+      *)
+        # In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC2039,SC3045
+        ulimit -n "$MAX_FD" ||
+            warn "Could not set maximum file descriptor limit to $MAX_FD"
+    esac
+fi
+
+# Collect all arguments for the java command, stacking in reverse order:
+#   * args from the command line
+#   * the main class name
+#   * -classpath
+#   * -D...appname settings
+#   * --module-path (only if needed)
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, and GRADLE_OPTS environment variables.
+
+# For Cygwin or MSYS, switch paths to Windows format before running java
+if "$cygwin" || "$msys" ; then
+    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
+
+    JAVACMD=$( cygpath --unix "$JAVACMD" )
+
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    for arg do
+        if
+            case $arg in                                #(
+              -*)   false ;;                            # don't mess with options #(
+              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+                    [ -e "$t" ] ;;                      #(
+              *)    false ;;
+            esac
+        then
+            arg=$( cygpath --path --ignore --mixed "$arg" )
+        fi
+        # Roll the args list around exactly as many times as the number of
+        # args, so each arg winds up back in the position where it started, but
+        # possibly modified.
+        #
+        # NB: a `for` loop captures its iteration list before it begins, so
+        # changing the positional parameters here affects neither the number of
+        # iterations, nor the values presented in `arg`.
+        shift                   # remove old arg
+        set -- "$@" "$arg"      # push replacement arg
+    done
+fi
+
+
+# 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"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
+
+set -- \
+        "-Dorg.gradle.appname=$APP_BASE_NAME" \
+        -classpath "$CLASSPATH" \
+        org.gradle.wrapper.GradleWrapperMain \
+        "$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+    die "xargs is not available"
+fi
+
+# Use "xargs" to parse quoted args.
+#
+# With -n1 it outputs one arg per line, with the quotes and backslashes removed.
+#
+# In Bash we could simply go:
+#
+#   readarray ARGS < <( xargs -n1 <<<"$var" ) &&
+#   set -- "${ARGS[@]}" "$@"
+#
+# but POSIX shell has neither arrays nor command substitution, so instead we
+# post-process each arg (as a line of input to sed) to backslash-escape any
+# character that might be a shell metacharacter, then use eval to reverse
+# that process (while maintaining the separation between arguments), and wrap
+# the whole thing up as a single "set" statement.
+#
+# This will of course break if any of these variables contains a newline or
+# an unmatched quote.
+#
+
+eval "set -- $(
+        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+        xargs -n1 |
+        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+        tr '\n' ' '
+    )" '"$@"'
+
+exec "$JAVACMD" "$@"

gradlew.bat

@@ -0,0 +1,94 @@
+@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
+@rem SPDX-License-Identifier: Apache-2.0
+@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=.
+@rem This is normally unused
+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% equ 0 goto execute
+
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto execute
+
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
+
+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% equ 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!
+set EXIT_CODE=%ERRORLEVEL%
+if %EXIT_CODE% equ 0 set EXIT_CODE=1
+if not ""=="%GRADLE_EXIT_CONSOLE%" exit %EXIT_CODE%
+exit /b %EXIT_CODE%
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega

settings.gradle.kts

@@ -0,0 +1,23 @@
+pluginManagement {
+    repositories {
+        google()
+        mavenCentral()
+        gradlePluginPortal()
+    }
+}
+
+plugins {
+    id("org.gradle.toolchains.foojay-resolver-convention") version "1.0.0"
+}
+
+@Suppress("UnstableApiUsage")
+dependencyResolutionManagement {
+    repositoriesMode.set(RepositoriesMode.FAIL_ON_PROJECT_REPOS)
+    repositories {
+        google()
+        mavenCentral()
+    }
+}
+
+rootProject.name = "eng-pad"
+include(":app")