docs: update CLAUDE.md to reflect current codebase

Add ForewordParser pipeline step, document all Song/SongLine fields,
Foreword type, ForewordPage variant, BookConfig subtypes, all ChordPro
directives, and new Configuration section for songbook.yaml options.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

CLAUDE.md

@@ -35,16 +35,17 @@ Requires Java 21 (configured in `gradle.properties`). Kotlin 2.1.10, Gradle 9.3.
 
 ## Architecture
 
-**Pipeline:** Parse → Measure → Paginate → Render
+**Pipeline:** Parse → Validate → Measure → Paginate → Render
 
 `SongbookPipeline` (in `app`) orchestrates the full flow:
 1. `ConfigParser` reads `songbook.yaml` → `BookConfig`
-2. `ChordProParser` reads `.chopro` files → `Song` objects
-3. `Validator` checks config and songs
-4. `MeasurementEngine` calculates each song's height in mm using `FontMetrics`
-5. `TocGenerator` estimates TOC page count and creates entries
-6. `PaginationEngine` arranges songs into pages (greedy spread packing)
-7. `PdfBookRenderer` generates the PDF via OpenPDF
+2. `ChordProParser` reads `.chopro`/`.cho`/`.crd` files → `Song` objects
+3. `ForewordParser` reads optional `foreword.txt` → `Foreword` (if configured)
+4. `Validator` checks config and songs
+5. `MeasurementEngine` calculates each song's height in mm using `FontMetrics`
+6. `TocGenerator` estimates TOC page count and creates entries
+7. `PaginationEngine` arranges songs into pages (greedy spread packing)
+8. `PdfBookRenderer` generates the PDF via OpenPDF
 
 **Module dependency graph:**
 ```
@@ -62,14 +63,39 @@ app, parser ← gui (Compose Desktop)
 
 ## Key Types
 
-- `Song` → sections → `SongLine` → `LineSegment(chord?, text)` — chord is placed above the text segment
-- `PageContent` — sealed class: `SongPage`, `FillerImage`, `BlankPage`
+- `Song` → sections → `SongLine` → `LineSegment(chord?, text)` — chord is placed above the text segment. Also has `aliases`, `lyricist`, `composer`, `key`, `tags`, `notes: List<String>`, `references: Map<String, Int>` (bookId → page), `capo`
+- `SongLine` — holds `segments` plus optional `imagePath` (when set, the line is an inline image)
+- `Foreword` — `quote`, `paragraphs`, `signatures` — parsed from a plain-text file
+- `PageContent` — sealed class: `SongPage`, `FillerImage`, `BlankPage`, `ForewordPage`
 - `SectionType` — enum: `VERSE`, `CHORUS`, `BRIDGE`, `REPEAT`
+- `BookConfig` — top-level config with `FontsConfig`, `LayoutConfig`, `TocConfig`, `ForewordConfig`, `ReferenceBook` list. `FontSpec.file` supports custom font files. `LayoutConfig.metadataLabels` (`"abbreviated"` or `"german"`) and `metadataPosition` (`"top"` or `"bottom"`) control metadata rendering
 - `BuildResult` — returned by `SongbookPipeline.build()` with success/errors/counts
 
 ## Song Format
 
-ChordPro-compatible `.chopro` files: directives in `{braces}`, chords in `[brackets]` inline with lyrics, comments with `#`. See `songs/` for examples.
+ChordPro-compatible `.chopro`/`.cho`/`.crd` files: directives in `{braces}`, chords in `[brackets]` inline with lyrics, comments with `#`. See `songs/` for examples.
+
+**Metadata directives:** `{title: }` / `{t: }`, `{alias: }`, `{lyricist: }`, `{composer: }`, `{key: }`, `{tags: }`, `{note: }`, `{capo: }`
+
+**Section directives:** `{start_of_verse}` / `{sov}`, `{end_of_verse}` / `{eov}`, `{start_of_chorus}` / `{soc}`, `{end_of_chorus}` / `{eoc}`, `{start_of_repeat}` / `{sor}`, `{end_of_repeat}` / `{eor}`. Section starts accept an optional label. `{chorus}` inserts a chorus reference, `{repeat}` sets a repeat label.
+
+**Notes block:** `{start_of_notes}` / `{son}` … `{end_of_notes}` / `{eon}` — multi-paragraph rich-text notes rendered at the end of a song.
+
+**Inline image:** `{image: path}` — embeds an image within a song section.
+
+**Reference:** `{ref: bookId pageNumber}` — cross-reference to a page in another songbook (configured in `reference_books`).
+
+## Configuration
+
+`songbook.yaml` at the project root. Key options beyond the basics:
+
+- `fonts.<role>.file` — path to a custom font file (TTF/OTF) for any font role (`lyrics`, `chords`, `title`, `metadata`, `toc`)
+- `layout.metadata_labels` — `"abbreviated"` (M:/T:) or `"german"` (Worte:/Weise:)
+- `layout.metadata_position` — `"top"` (after title) or `"bottom"` (bottom of last page)
+- `toc.highlight_column` — abbreviation of the reference-book column to highlight (e.g. `"CL"`)
+- `foreword.file` — path to a foreword text file (default `./foreword.txt`)
+- `reference_books` — list of `{id, name, abbreviation}` for cross-reference columns in the TOC
+- `songs.order` — `"alphabetical"` or `"manual"` (file-system order)
 
 ## Test Patterns
 

app/src/main/kotlin/de/pfadfinder/songbook/app/SongbookPipeline.kt

@@ -28,9 +28,12 @@ class SongbookPipeline(private val projectDir: File) {
             return BuildResult(false, errors = listOf(ValidationError(configFile.name, null, "songbook.yaml not found")))
         }
         logger.info { "Parsing config: ${configFile.absolutePath}" }
-        val config = ConfigParser.parse(configFile)
+        val rawConfig = ConfigParser.parse(configFile)
 
-        // Validate config
+        // Resolve font file paths relative to the project directory
+        val config = resolveFontPaths(rawConfig)
+
+        // Validate config (including font file existence)
         val configErrors = Validator.validateConfig(config)
         if (configErrors.isNotEmpty()) {
             return BuildResult(false, errors = configErrors)
@@ -149,13 +152,39 @@ class SongbookPipeline(private val projectDir: File) {
         )
     }
 
+    /**
+     * Resolves font file paths relative to the project directory.
+     * If a FontSpec has a `file` property, it is resolved against projectDir
+     * to produce an absolute path.
+     */
+    private fun resolveFontPaths(config: BookConfig): BookConfig {
+        fun FontSpec.resolveFile(): FontSpec {
+            val fontFile = this.file ?: return this
+            val fontFileObj = File(fontFile)
+            // Only resolve relative paths; absolute paths are left as-is
+            if (fontFileObj.isAbsolute) return this
+            val resolved = File(projectDir, fontFile)
+            return this.copy(file = resolved.absolutePath)
+        }
+
+        val resolvedFonts = config.fonts.copy(
+            lyrics = config.fonts.lyrics.resolveFile(),
+            chords = config.fonts.chords.resolveFile(),
+            title = config.fonts.title.resolveFile(),
+            metadata = config.fonts.metadata.resolveFile(),
+            toc = config.fonts.toc.resolveFile()
+        )
+        return config.copy(fonts = resolvedFonts)
+    }
+
     fun validate(): List<ValidationError> {
         val configFile = File(projectDir, "songbook.yaml")
         if (!configFile.exists()) {
             return listOf(ValidationError(configFile.name, null, "songbook.yaml not found"))
         }
 
-        val config = ConfigParser.parse(configFile)
+        val rawConfig = ConfigParser.parse(configFile)
+        val config = resolveFontPaths(rawConfig)
         val errors = mutableListOf<ValidationError>()
         errors.addAll(Validator.validateConfig(config))
 

layout/src/main/kotlin/de/pfadfinder/songbook/layout/MeasurementEngine.kt

@@ -15,9 +15,16 @@ class MeasurementEngine(
         // Title height
         heightMm += fontMetrics.measureLineHeight(config.fonts.title, config.fonts.title.size) * 1.5f
 
-        // Metadata line (composer/lyricist)
+        // Metadata lines (composer/lyricist) - may be 1 or 2 lines depending on label style
         if (song.composer != null || song.lyricist != null) {
-            heightMm += fontMetrics.measureLineHeight(config.fonts.metadata, config.fonts.metadata.size) * 1.8f
+            val metaLineHeight = fontMetrics.measureLineHeight(config.fonts.metadata, config.fonts.metadata.size) * 1.8f
+            val useGerman = config.layout.metadataLabels == "german"
+            if (useGerman && song.lyricist != null && song.composer != null && song.lyricist != song.composer) {
+                // Two separate lines: "Worte: ..." and "Weise: ..."
+                heightMm += metaLineHeight * 2
+            } else {
+                heightMm += metaLineHeight
+            }
         }
 
         // Key/capo line
@@ -43,6 +50,11 @@ class MeasurementEngine(
 
             // Lines in section
             for (line in section.lines) {
+                if (line.imagePath != null) {
+                    // Inline image: estimate height as 40mm (default image block height)
+                    heightMm += 40f
+                    heightMm += 2f  // gap around image
+                } else {
                     val hasChords = line.segments.any { it.chord != null }
                     val lyricHeight = fontMetrics.measureLineHeight(config.fonts.lyrics, config.fonts.lyrics.size)
                     if (hasChords) {
@@ -53,16 +65,29 @@ class MeasurementEngine(
                     }
                     heightMm += 0.35f  // ~1pt gap between lines
                 }
+            }
 
             // Verse spacing
             heightMm += config.layout.verseSpacing
         }
 
-        // Notes at bottom
+        // Notes at bottom (with word-wrap estimation for multi-paragraph notes)
         if (song.notes.isNotEmpty()) {
-            heightMm += 1.5f  // gap
-            for (note in song.notes) {
-                heightMm += fontMetrics.measureLineHeight(config.fonts.metadata, config.fonts.metadata.size) * 1.5f
+            heightMm += 1.5f  // gap before notes
+            val metaLineHeight = fontMetrics.measureLineHeight(config.fonts.metadata, config.fonts.metadata.size) * 1.5f
+            // A5 content width in mm = 148 - inner margin - outer margin
+            val contentWidthMm = 148f - config.layout.margins.inner - config.layout.margins.outer
+
+            for ((idx, note) in song.notes.withIndex()) {
+                // Estimate how many wrapped lines this note paragraph needs
+                val noteWidthMm = fontMetrics.measureTextWidth(note, config.fonts.metadata, config.fonts.metadata.size)
+                val estimatedLines = maxOf(1, kotlin.math.ceil((noteWidthMm / contentWidthMm).toDouble()).toInt())
+                heightMm += metaLineHeight * estimatedLines
+
+                // Paragraph spacing between note paragraphs
+                if (idx < song.notes.size - 1) {
+                    heightMm += metaLineHeight * 0.3f
+                }
             }
         }
 

layout/src/test/kotlin/de/pfadfinder/songbook/layout/MeasurementEngineTest.kt

@@ -324,4 +324,40 @@ class MeasurementEngineTest {
         // Should be the same since no reference books are configured
         heightWith shouldBe heightWithout
     }
+
+    @Test
+    fun `inline image adds significant height`() {
+        val songWithImage = Song(
+            title = "With Image",
+            sections = listOf(
+                SongSection(
+                    type = SectionType.VERSE,
+                    lines = listOf(
+                        SongLine(listOf(LineSegment(text = "Line before"))),
+                        SongLine(imagePath = "images/test.png"),
+                        SongLine(listOf(LineSegment(text = "Line after")))
+                    )
+                )
+            )
+        )
+        val songWithoutImage = Song(
+            title = "No Image",
+            sections = listOf(
+                SongSection(
+                    type = SectionType.VERSE,
+                    lines = listOf(
+                        SongLine(listOf(LineSegment(text = "Line before"))),
+                        SongLine(listOf(LineSegment(text = "Line after")))
+                    )
+                )
+            )
+        )
+
+        val heightWith = engine.measure(songWithImage).totalHeightMm
+        val heightWithout = engine.measure(songWithoutImage).totalHeightMm
+
+        // Inline image adds ~42mm (40mm image + 2mm gap)
+        val diff = heightWith - heightWithout
+        diff shouldBeGreaterThan 30f  // should be substantial
+    }
 }

model/src/main/kotlin/de/pfadfinder/songbook/model/BookConfig.kt

@@ -8,7 +8,12 @@ data class BookConfig(
     val images: ImagesConfig = ImagesConfig(),
     val referenceBooks: List<ReferenceBook> = emptyList(),
     val output: OutputConfig = OutputConfig(),
-    val foreword: ForewordConfig? = null
+    val foreword: ForewordConfig? = null,
+    val toc: TocConfig = TocConfig()
+)
+
+data class TocConfig(
+    val highlightColumn: String? = null  // abbreviation of the column to highlight (e.g. "CL")
 )
 
 data class ForewordConfig(
@@ -46,7 +51,9 @@ data class LayoutConfig(
     val margins: Margins = Margins(),
     val chordLineSpacing: Float = 3f,    // mm
     val verseSpacing: Float = 4f,         // mm
-    val pageNumberPosition: String = "bottom-outer"
+    val pageNumberPosition: String = "bottom-outer",
+    val metadataLabels: String = "abbreviated",  // "abbreviated" (M:/T:) or "german" (Worte:/Weise:)
+    val metadataPosition: String = "top"  // "top" (after title) or "bottom" (bottom of last page)
 )
 
 data class Margins(

model/src/main/kotlin/de/pfadfinder/songbook/model/Song.kt

@@ -23,7 +23,10 @@ enum class SectionType {
     VERSE, CHORUS, BRIDGE, REPEAT
 }
 
-data class SongLine(val segments: List<LineSegment>)
+data class SongLine(
+    val segments: List<LineSegment> = emptyList(),
+    val imagePath: String? = null  // when non-null, this "line" is an inline image (segments ignored)
+)
 
 data class LineSegment(
     val chord: String? = null,  // null = no chord above this segment

parser/src/main/kotlin/de/pfadfinder/songbook/parser/ChordProParser.kt

@@ -25,6 +25,17 @@ object ChordProParser {
         var currentLabel: String? = null
         var currentLines = mutableListOf<SongLine>()
 
+        // Notes block state
+        var inNotesBlock = false
+        var currentNoteParagraph = StringBuilder()
+
+        fun flushNoteParagraph() {
+            if (currentNoteParagraph.isNotEmpty()) {
+                notes.add(currentNoteParagraph.toString().trim())
+                currentNoteParagraph = StringBuilder()
+            }
+        }
+
         fun flushSection() {
             if (currentType != null) {
                 sections.add(SongSection(type = currentType!!, label = currentLabel, lines = currentLines.toList()))
@@ -37,6 +48,27 @@ object ChordProParser {
         for (rawLine in lines) {
             val line = rawLine.trimEnd()
 
+            // Inside a notes block: collect lines as paragraphs
+            if (inNotesBlock) {
+                if (line.trimStart().startsWith("{") && line.trimEnd().endsWith("}")) {
+                    val inner = line.trim().removePrefix("{").removeSuffix("}").trim().lowercase()
+                    if (inner == "end_of_notes" || inner == "eon") {
+                        flushNoteParagraph()
+                        inNotesBlock = false
+                        continue
+                    }
+                }
+                if (line.isBlank()) {
+                    flushNoteParagraph()
+                } else {
+                    if (currentNoteParagraph.isNotEmpty()) {
+                        currentNoteParagraph.append(" ")
+                    }
+                    currentNoteParagraph.append(line.trim())
+                }
+                continue
+            }
+
             // Skip comments
             if (line.trimStart().startsWith("#")) continue
 
@@ -97,6 +129,21 @@ object ChordProParser {
                     "end_of_repeat", "eor" -> {
                         flushSection()
                     }
+                    "image" -> if (value != null) {
+                        // Inline image within a song section
+                        if (currentType == null) {
+                            currentType = SectionType.VERSE
+                        }
+                        currentLines.add(SongLine(imagePath = value.trim()))
+                    }
+                    "start_of_notes", "son" -> {
+                        inNotesBlock = true
+                    }
+                    "end_of_notes", "eon" -> {
+                        // Should have been handled in the notes block above
+                        flushNoteParagraph()
+                        inNotesBlock = false
+                    }
                     "chorus" -> {
                         flushSection()
                         sections.add(SongSection(type = SectionType.CHORUS))

parser/src/main/kotlin/de/pfadfinder/songbook/parser/Validator.kt

@@ -1,7 +1,9 @@
 package de.pfadfinder.songbook.parser
 
 import de.pfadfinder.songbook.model.BookConfig
+import de.pfadfinder.songbook.model.FontSpec
 import de.pfadfinder.songbook.model.Song
+import java.io.File
 
 data class ValidationError(val file: String?, val line: Int?, val message: String)
 
@@ -50,6 +52,27 @@ object Validator {
             if (outer <= 0) errors.add(ValidationError(file = null, line = null, message = "Outer margin must be greater than 0"))
         }
 
+        // Validate font files exist (paths should already be resolved to absolute by the pipeline)
+        validateFontFile(config.fonts.lyrics, "lyrics", errors)
+        validateFontFile(config.fonts.chords, "chords", errors)
+        validateFontFile(config.fonts.title, "title", errors)
+        validateFontFile(config.fonts.metadata, "metadata", errors)
+        validateFontFile(config.fonts.toc, "toc", errors)
+
         return errors
     }
+
+    private fun validateFontFile(font: FontSpec, fontRole: String, errors: MutableList<ValidationError>) {
+        val fontFile = font.file ?: return
+        val file = File(fontFile)
+        if (!file.exists()) {
+            errors.add(
+                ValidationError(
+                    file = null,
+                    line = null,
+                    message = "Font file for '$fontRole' not found: $fontFile"
+                )
+            )
+        }
+    }
 }

parser/src/test/kotlin/de/pfadfinder/songbook/parser/ChordProParserTest.kt

@@ -485,4 +485,147 @@ class ChordProParserTest {
         line.segments[2].chord shouldBe "G"
         line.segments[2].text shouldBe "End"
     }
+
+    @Test
+    fun `parse notes block with multiple paragraphs`() {
+        val input = """
+            {title: Song}
+            {start_of_notes}
+            First paragraph of the notes.
+            It continues on the next line.
+
+            Second paragraph with different content.
+            {end_of_notes}
+            {start_of_verse}
+            text
+            {end_of_verse}
+        """.trimIndent()
+        val song = ChordProParser.parse(input)
+        song.notes shouldHaveSize 2
+        song.notes[0] shouldBe "First paragraph of the notes. It continues on the next line."
+        song.notes[1] shouldBe "Second paragraph with different content."
+    }
+
+    @Test
+    fun `parse notes block with single paragraph`() {
+        val input = """
+            {title: Song}
+            {start_of_notes}
+            A single note paragraph.
+            {end_of_notes}
+            {start_of_verse}
+            text
+            {end_of_verse}
+        """.trimIndent()
+        val song = ChordProParser.parse(input)
+        song.notes shouldHaveSize 1
+        song.notes[0] shouldBe "A single note paragraph."
+    }
+
+    @Test
+    fun `parse notes block with short directives son eon`() {
+        val input = """
+            {title: Song}
+            {son}
+            Short form notes.
+            {eon}
+            {start_of_verse}
+            text
+            {end_of_verse}
+        """.trimIndent()
+        val song = ChordProParser.parse(input)
+        song.notes shouldHaveSize 1
+        song.notes[0] shouldBe "Short form notes."
+    }
+
+    @Test
+    fun `notes block and single note directives combine`() {
+        val input = """
+            {title: Song}
+            {note: Single line note}
+            {start_of_notes}
+            Block note paragraph.
+            {end_of_notes}
+            {start_of_verse}
+            text
+            {end_of_verse}
+        """.trimIndent()
+        val song = ChordProParser.parse(input)
+        song.notes shouldHaveSize 2
+        song.notes[0] shouldBe "Single line note"
+        song.notes[1] shouldBe "Block note paragraph."
+    }
+
+    @Test
+    fun `parse notes block with three paragraphs`() {
+        val input = """
+            {title: Song}
+            {start_of_notes}
+            Paragraph one.
+
+            Paragraph two.
+
+            Paragraph three.
+            {end_of_notes}
+            {start_of_verse}
+            text
+            {end_of_verse}
+        """.trimIndent()
+        val song = ChordProParser.parse(input)
+        song.notes shouldHaveSize 3
+        song.notes[0] shouldBe "Paragraph one."
+        song.notes[1] shouldBe "Paragraph two."
+        song.notes[2] shouldBe "Paragraph three."
+    }
+
+    @Test
+    fun `parse image directive within song section`() {
+        val input = """
+            {title: Song}
+            {start_of_verse}
+            [Am]Hello world
+            {image: images/drawing.png}
+            [C]Goodbye world
+            {end_of_verse}
+        """.trimIndent()
+        val song = ChordProParser.parse(input)
+        song.sections shouldHaveSize 1
+        song.sections[0].lines shouldHaveSize 3
+        song.sections[0].lines[0].segments[0].chord shouldBe "Am"
+        song.sections[0].lines[1].imagePath shouldBe "images/drawing.png"
+        song.sections[0].lines[1].segments.shouldBeEmpty()
+        song.sections[0].lines[2].segments[0].chord shouldBe "C"
+    }
+
+    @Test
+    fun `parse image directive outside section creates implicit verse`() {
+        val input = """
+            {title: Song}
+            {image: images/landscape.jpg}
+        """.trimIndent()
+        val song = ChordProParser.parse(input)
+        song.sections shouldHaveSize 1
+        song.sections[0].type shouldBe SectionType.VERSE
+        song.sections[0].lines shouldHaveSize 1
+        song.sections[0].lines[0].imagePath shouldBe "images/landscape.jpg"
+    }
+
+    @Test
+    fun `parse multiple image directives`() {
+        val input = """
+            {title: Song}
+            {start_of_verse}
+            {image: img1.png}
+            Some text
+            {image: img2.png}
+            {end_of_verse}
+        """.trimIndent()
+        val song = ChordProParser.parse(input)
+        song.sections[0].lines shouldHaveSize 3
+        song.sections[0].lines[0].imagePath shouldBe "img1.png"
+        song.sections[0].lines[0].segments.shouldBeEmpty()
+        song.sections[0].lines[1].imagePath.shouldBeNull()
+        song.sections[0].lines[1].segments[0].text shouldBe "Some text"
+        song.sections[0].lines[2].imagePath shouldBe "img2.png"
+    }
 }

parser/src/test/kotlin/de/pfadfinder/songbook/parser/ConfigParserTest.kt

@@ -192,6 +192,53 @@ class ConfigParserTest {
         config.foreword.shouldBeNull()
     }
 
+    @Test
+    fun `parse config with toc highlight column`() {
+        val yaml = """
+            book:
+              title: "Test"
+            toc:
+              highlight_column: "CL"
+        """.trimIndent()
+        val config = ConfigParser.parse(yaml)
+        config.toc.highlightColumn shouldBe "CL"
+    }
+
+    @Test
+    fun `parse config without toc section uses defaults`() {
+        val yaml = """
+            book:
+              title: "Test"
+        """.trimIndent()
+        val config = ConfigParser.parse(yaml)
+        config.toc.highlightColumn.shouldBeNull()
+    }
+
+    @Test
+    fun `parse config with german metadata labels`() {
+        val yaml = """
+            book:
+              title: "Test"
+            layout:
+              metadata_labels: german
+              metadata_position: bottom
+        """.trimIndent()
+        val config = ConfigParser.parse(yaml)
+        config.layout.metadataLabels shouldBe "german"
+        config.layout.metadataPosition shouldBe "bottom"
+    }
+
+    @Test
+    fun `parse config with default metadata settings`() {
+        val yaml = """
+            book:
+              title: "Test"
+        """.trimIndent()
+        val config = ConfigParser.parse(yaml)
+        config.layout.metadataLabels shouldBe "abbreviated"
+        config.layout.metadataPosition shouldBe "top"
+    }
+
     @Test
     fun `parse config ignores unknown properties`() {
         val yaml = """
@@ -204,4 +251,21 @@ class ConfigParserTest {
         val config = ConfigParser.parse(yaml)
         config.book.title shouldBe "Test"
     }
+
+    @Test
+    fun `parse config with custom title font file only`() {
+        val yaml = """
+            book:
+              title: "Fraktur Test"
+            fonts:
+              title: { file: "./fonts/Fraktur.ttf", size: 16 }
+        """.trimIndent()
+        val config = ConfigParser.parse(yaml)
+        config.fonts.title.file shouldBe "./fonts/Fraktur.ttf"
+        config.fonts.title.size shouldBe 16f
+        config.fonts.title.family shouldBe "Helvetica"  // default family as fallback
+        // Other fonts should still use defaults
+        config.fonts.lyrics.file.shouldBeNull()
+        config.fonts.lyrics.family shouldBe "Helvetica"
+    }
 }

parser/src/test/kotlin/de/pfadfinder/songbook/parser/ValidatorTest.kt

@@ -206,4 +206,53 @@ class ValidatorTest {
         errors shouldHaveSize 1
         errors[0].file shouldContain "myfile.chopro"
     }
+
+    @Test
+    fun `missing font file produces validation error`() {
+        val config = BookConfig(
+            fonts = FontsConfig(
+                title = FontSpec(file = "/nonexistent/path/FrakturFont.ttf", size = 14f)
+            )
+        )
+        val errors = Validator.validateConfig(config)
+        errors shouldHaveSize 1
+        errors[0].message shouldContain "title"
+        errors[0].message shouldContain "not found"
+    }
+
+    @Test
+    fun `multiple missing font files produce multiple errors`() {
+        val config = BookConfig(
+            fonts = FontsConfig(
+                title = FontSpec(file = "/nonexistent/title.ttf", size = 14f),
+                lyrics = FontSpec(file = "/nonexistent/lyrics.ttf", size = 10f)
+            )
+        )
+        val errors = Validator.validateConfig(config)
+        errors shouldHaveSize 2
+    }
+
+    @Test
+    fun `config with no font files produces no font errors`() {
+        val config = BookConfig()  // all default built-in fonts
+        val errors = Validator.validateConfig(config)
+        errors.shouldBeEmpty()
+    }
+
+    @Test
+    fun `config with existing font file produces no error`() {
+        // Create a temporary file to simulate an existing font file
+        val tempFile = kotlin.io.path.createTempFile(suffix = ".ttf").toFile()
+        try {
+            val config = BookConfig(
+                fonts = FontsConfig(
+                    title = FontSpec(file = tempFile.absolutePath, size = 14f)
+                )
+            )
+            val errors = Validator.validateConfig(config)
+            errors.shouldBeEmpty()
+        } finally {
+            tempFile.delete()
+        }
+    }
 }

renderer-pdf/src/main/kotlin/de/pfadfinder/songbook/renderer/pdf/PdfBookRenderer.kt

@@ -104,6 +104,8 @@ class PdfBookRenderer : BookRenderer {
     ) {
         var y = contentTop
 
+        val renderMetaAtBottom = config.layout.metadataPosition == "bottom"
+
         if (pageIndex == 0) {
             // Render title
             val titleFont = fontMetrics.getBaseFont(config.fonts.title)
@@ -116,21 +118,23 @@ class PdfBookRenderer : BookRenderer {
             cb.endText()
             y -= titleSize * 1.5f
 
-            // Render metadata line (composer/lyricist)
-            val metaParts = mutableListOf<String>()
-            song.composer?.let { metaParts.add("M: $it") }
-            song.lyricist?.let { metaParts.add("T: $it") }
+            // Render metadata line (composer/lyricist) - at top position only
+            if (!renderMetaAtBottom) {
+                val metaParts = buildMetadataLines(song, config)
                 if (metaParts.isNotEmpty()) {
                     val metaFont = fontMetrics.getBaseFont(config.fonts.metadata)
                     val metaSize = config.fonts.metadata.size
+                    for (metaLine in metaParts) {
                         cb.beginText()
                         cb.setFontAndSize(metaFont, metaSize)
                         cb.setColorFill(Color.GRAY)
                         cb.setTextMatrix(leftMargin, y - metaSize)
-                cb.showText(metaParts.joinToString(" / "))
+                        cb.showText(metaLine)
                         cb.endText()
                         y -= metaSize * 1.8f
                     }
+                }
+            }
 
             // Render key and capo
             val infoParts = mutableListOf<String>()
@@ -205,9 +209,15 @@ class PdfBookRenderer : BookRenderer {
 
             // Render lines
             for (line in section.lines) {
+                val imgPath = line.imagePath
+                if (imgPath != null) {
+                    // Render inline image
+                    y -= renderInlineImage(cb, imgPath, leftMargin, y, contentWidth)
+                } else {
                     val height = chordLyricRenderer.renderLine(cb, line, leftMargin, y, contentWidth)
                     y -= height + 1f  // 1pt gap between lines
                 }
+            }
 
             // End repeat marker
             if (section.type == SectionType.REPEAT) {
@@ -226,21 +236,52 @@ class PdfBookRenderer : BookRenderer {
             y -= config.layout.verseSpacing / 0.3528f
         }
 
-        // Render notes at the bottom
+        // Render notes at the bottom (with word-wrap for multi-paragraph notes)
         if (pageIndex == 0 && song.notes.isNotEmpty()) {
             y -= 4f
             val metaFont = fontMetrics.getBaseFont(config.fonts.metadata)
             val metaSize = config.fonts.metadata.size
-            for (note in song.notes) {
+            val noteLineHeight = metaSize * 1.5f
+
+            for ((idx, note) in song.notes.withIndex()) {
+                val wrappedLines = wrapText(note, metaFont, metaSize, contentWidth)
+                for (wrappedLine in wrappedLines) {
                     cb.beginText()
                     cb.setFontAndSize(metaFont, metaSize)
                     cb.setColorFill(Color.GRAY)
                     cb.setTextMatrix(leftMargin, y - metaSize)
-                cb.showText(note)
+                    cb.showText(wrappedLine)
+                    cb.endText()
+                    y -= noteLineHeight
+                }
+                // Add paragraph spacing between note paragraphs
+                if (idx < song.notes.size - 1) {
+                    y -= noteLineHeight * 0.3f
+                }
+            }
+        }
+
+        // Render metadata at bottom of song page (if configured)
+        if (renderMetaAtBottom && pageIndex == 0) {
+            val metaParts = buildMetadataLines(song, config)
+            if (metaParts.isNotEmpty()) {
+                y -= 4f
+                val metaFont = fontMetrics.getBaseFont(config.fonts.metadata)
+                val metaSize = config.fonts.metadata.size
+                for (metaLine in metaParts) {
+                    val wrappedLines = wrapText(metaLine, metaFont, metaSize, contentWidth)
+                    for (wrappedLine in wrappedLines) {
+                        cb.beginText()
+                        cb.setFontAndSize(metaFont, metaSize)
+                        cb.setColorFill(Color.GRAY)
+                        cb.setTextMatrix(leftMargin, y - metaSize)
+                        cb.showText(wrappedLine)
                         cb.endText()
                         y -= metaSize * 1.5f
                     }
                 }
+            }
+        }
 
         // Render reference book footer on the last page of the song
         if (config.referenceBooks.isNotEmpty() && song.references.isNotEmpty()) {
@@ -255,6 +296,35 @@ class PdfBookRenderer : BookRenderer {
         }
     }
 
+    /**
+     * Build metadata lines based on configured label style.
+     * Returns a list of lines to render (may be empty).
+     */
+    private fun buildMetadataLines(song: Song, config: BookConfig): List<String> {
+        val useGerman = config.layout.metadataLabels == "german"
+        val lines = mutableListOf<String>()
+
+        if (useGerman) {
+            // German labels: "Worte und Weise:" when same person, otherwise separate
+            if (song.lyricist != null && song.composer != null && song.lyricist == song.composer) {
+                lines.add("Worte und Weise: ${song.lyricist}")
+            } else {
+                song.lyricist?.let { lines.add("Worte: $it") }
+                song.composer?.let { lines.add("Weise: $it") }
+            }
+        } else {
+            // Abbreviated labels on a single line
+            val parts = mutableListOf<String>()
+            song.composer?.let { parts.add("M: $it") }
+            song.lyricist?.let { parts.add("T: $it") }
+            if (parts.isNotEmpty()) {
+                lines.add(parts.joinToString(" / "))
+            }
+        }
+
+        return lines
+    }
+
     /**
      * Renders reference book abbreviations and page numbers as a footer row
      * at the bottom of the song page, above the page number.
@@ -437,6 +507,37 @@ class PdfBookRenderer : BookRenderer {
         return lines
     }
 
+    /**
+     * Renders an inline image within a song page at the given position.
+     * Returns the total height consumed in PDF points.
+     */
+    private fun renderInlineImage(
+        cb: PdfContentByte,
+        imagePath: String,
+        leftMargin: Float,
+        y: Float,
+        contentWidth: Float
+    ): Float {
+        try {
+            val img = Image.getInstance(imagePath)
+            // Scale to fit within content width, max height 40mm (~113 points)
+            val maxHeight = 40f / 0.3528f  // 40mm in points
+            img.scaleToFit(contentWidth * 0.8f, maxHeight)
+
+            // Center horizontally
+            val imgX = leftMargin + (contentWidth - img.scaledWidth) / 2
+            val imgY = y - img.scaledHeight - 3f  // 3pt gap above
+
+            img.setAbsolutePosition(imgX, imgY)
+            cb.addImage(img)
+
+            return img.scaledHeight + 6f  // image height + gaps above/below
+        } catch (_: Exception) {
+            // If image can't be loaded, consume minimal space
+            return 5f
+        }
+    }
+
     private fun renderFillerImage(document: Document, imagePath: String, pageSize: Rectangle) {
         try {
             val img = Image.getInstance(imagePath)

renderer-pdf/src/main/kotlin/de/pfadfinder/songbook/renderer/pdf/PdfFontMetrics.kt

@@ -3,15 +3,21 @@ package de.pfadfinder.songbook.renderer.pdf
 import com.lowagie.text.pdf.BaseFont
 import de.pfadfinder.songbook.model.FontMetrics
 import de.pfadfinder.songbook.model.FontSpec
+import java.io.File
 
 class PdfFontMetrics : FontMetrics {
     private val fontCache = mutableMapOf<String, BaseFont>()
 
     fun getBaseFont(font: FontSpec): BaseFont {
-        val key = font.file ?: font.family
+        val fontFile = font.file
+        val key = if (fontFile != null) File(fontFile).canonicalPath else font.family
         return fontCache.getOrPut(key) {
-            if (font.file != null) {
-                BaseFont.createFont(font.file, BaseFont.IDENTITY_H, BaseFont.EMBEDDED)
+            if (fontFile != null) {
+                val file = File(fontFile)
+                if (!file.exists()) {
+                    throw IllegalArgumentException("Font file not found: ${file.absolutePath}")
+                }
+                BaseFont.createFont(file.absolutePath, BaseFont.IDENTITY_H, BaseFont.EMBEDDED)
             } else {
                 // Map common family names to built-in PDF fonts
                 val pdfFontName = when (font.family.lowercase()) {

renderer-pdf/src/main/kotlin/de/pfadfinder/songbook/renderer/pdf/TocRenderer.kt

@@ -3,11 +3,15 @@ package de.pfadfinder.songbook.renderer.pdf
 import com.lowagie.text.*
 import com.lowagie.text.pdf.*
 import de.pfadfinder.songbook.model.*
+import java.awt.Color
 
 class TocRenderer(
     private val fontMetrics: PdfFontMetrics,
     private val config: BookConfig
 ) {
+    // Light gray background for the highlighted column
+    private val highlightColor = Color(220, 220, 220)
+
     fun render(document: Document, writer: PdfWriter, tocEntries: List<TocEntry>) {
         val tocFont = fontMetrics.getBaseFont(config.fonts.toc)
         val tocBoldFont = fontMetrics.getBaseFontBold(config.fonts.toc)
@@ -35,12 +39,25 @@ class TocRenderer(
         }
         table.setWidths(widths)
 
+        // Determine which column index should be highlighted
+        val highlightAbbrev = config.toc.highlightColumn
+        val highlightColumnIndex: Int? = if (highlightAbbrev != null) {
+            // Check "Seite" (page) column first - the current book's page number column
+            if (highlightAbbrev == "Seite") {
+                1
+            } else {
+                val refIndex = refBooks.indexOfFirst { it.abbreviation == highlightAbbrev }
+                if (refIndex >= 0) 2 + refIndex else null
+            }
+        } else null
+
         // Header row
         val headerFont = Font(tocBoldFont, fontSize, Font.BOLD)
-        table.addCell(headerCell("Titel", headerFont))
-        table.addCell(headerCell("Seite", headerFont))
-        for (book in refBooks) {
-            table.addCell(headerCell(book.abbreviation, headerFont))
+        table.addCell(headerCell("Titel", headerFont, isHighlighted = false))
+        table.addCell(headerCell("Seite", headerFont, isHighlighted = highlightColumnIndex == 1))
+        for ((i, book) in refBooks.withIndex()) {
+            val isHighlighted = highlightColumnIndex == 2 + i
+            table.addCell(headerCell(book.abbreviation, headerFont, isHighlighted = isHighlighted))
         }
         table.headerRows = 1
 
@@ -49,31 +66,43 @@ class TocRenderer(
         val aliasFont = Font(tocFont, fontSize, Font.ITALIC)
         for (entry in tocEntries.sortedBy { it.title.lowercase() }) {
             val font = if (entry.isAlias) aliasFont else entryFont
-            table.addCell(entryCell(entry.title, font))
-            table.addCell(entryCell(entry.pageNumber.toString(), entryFont, Element.ALIGN_RIGHT))
-            for (book in refBooks) {
+            table.addCell(entryCell(entry.title, font, isHighlighted = false))
+            table.addCell(entryCell(entry.pageNumber.toString(), entryFont, Element.ALIGN_RIGHT, isHighlighted = highlightColumnIndex == 1))
+            for ((i, book) in refBooks.withIndex()) {
                 val ref = entry.references[book.abbreviation]
-                table.addCell(entryCell(ref?.toString() ?: "", entryFont, Element.ALIGN_RIGHT))
+                val isHighlighted = highlightColumnIndex == 2 + i
+                table.addCell(entryCell(ref?.toString() ?: "", entryFont, Element.ALIGN_RIGHT, isHighlighted = isHighlighted))
             }
         }
 
         document.add(table)
     }
 
-    private fun headerCell(text: String, font: Font): PdfPCell {
+    private fun headerCell(text: String, font: Font, isHighlighted: Boolean): PdfPCell {
         val cell = PdfPCell(Phrase(text, font))
         cell.borderWidth = 0f
         cell.borderWidthBottom = 0.5f
         cell.paddingBottom = 4f
+        if (isHighlighted) {
+            cell.backgroundColor = highlightColor
+        }
         return cell
     }
 
-    private fun entryCell(text: String, font: Font, alignment: Int = Element.ALIGN_LEFT): PdfPCell {
+    private fun entryCell(
+        text: String,
+        font: Font,
+        alignment: Int = Element.ALIGN_LEFT,
+        isHighlighted: Boolean = false
+    ): PdfPCell {
         val cell = PdfPCell(Phrase(text, font))
         cell.borderWidth = 0f
         cell.horizontalAlignment = alignment
         cell.paddingTop = 1f
         cell.paddingBottom = 1f
+        if (isHighlighted) {
+            cell.backgroundColor = highlightColor
+        }
         return cell
     }
 }

renderer-pdf/src/test/kotlin/de/pfadfinder/songbook/renderer/pdf/PdfFontMetricsTest.kt

@@ -6,6 +6,7 @@ import io.kotest.matchers.floats.shouldBeLessThan
 import io.kotest.matchers.shouldBe
 import io.kotest.matchers.types.shouldBeSameInstanceAs
 import kotlin.test.Test
+import kotlin.test.assertFailsWith
 
 class PdfFontMetricsTest {
 
@@ -158,4 +159,73 @@ class PdfFontMetricsTest {
         height shouldBeGreaterThan 3f
         height shouldBeLessThan 6f
     }
+
+    // --- Custom font file tests ---
+
+    private val testFontPath: String
+        get() = this::class.java.getResource("/TestFont.ttf")!!.file
+
+    @Test
+    fun `getBaseFont loads custom font from file path`() {
+        val font = FontSpec(file = testFontPath, size = 12f)
+        val baseFont = metrics.getBaseFont(font)
+        // Custom font should load successfully and have a non-null PostScript name
+        baseFont.postscriptFontName.isNotEmpty() shouldBe true
+    }
+
+    @Test
+    fun `getBaseFont caches custom font by canonical path`() {
+        val font1 = FontSpec(file = testFontPath, size = 12f)
+        val font2 = FontSpec(file = testFontPath, size = 14f)  // different size, same file
+        val first = metrics.getBaseFont(font1)
+        val second = metrics.getBaseFont(font2)
+        first shouldBeSameInstanceAs second
+    }
+
+    @Test
+    fun `getBaseFont throws for missing font file`() {
+        val font = FontSpec(file = "/nonexistent/path/MissingFont.ttf", size = 12f)
+        assertFailsWith<IllegalArgumentException> {
+            metrics.getBaseFont(font)
+        }
+    }
+
+    @Test
+    fun `getBaseFontBold returns same font when file is specified`() {
+        val font = FontSpec(file = testFontPath, size = 12f)
+        val regular = metrics.getBaseFont(font)
+        val bold = metrics.getBaseFontBold(font)
+        // Custom fonts don't have auto-resolved bold variants
+        regular shouldBeSameInstanceAs bold
+    }
+
+    @Test
+    fun `measureTextWidth works with custom font file`() {
+        val font = FontSpec(file = testFontPath, size = 12f)
+        val width = metrics.measureTextWidth("Hello World", font, 12f)
+        width shouldBeGreaterThan 0f
+    }
+
+    @Test
+    fun `measureTextWidth handles German umlauts with custom font`() {
+        val font = FontSpec(file = testFontPath, size = 12f)
+        // These should not throw and should return positive widths
+        val umlautWidth = metrics.measureTextWidth("\u00e4\u00f6\u00fc\u00df", font, 12f)
+        umlautWidth shouldBeGreaterThan 0f
+
+        // Full German words with umlauts
+        val wordWidth = metrics.measureTextWidth("Gr\u00fc\u00dfe aus \u00d6sterreich", font, 12f)
+        wordWidth shouldBeGreaterThan 0f
+    }
+
+    @Test
+    fun `measureTextWidth with custom font returns different width than built-in font`() {
+        val customFont = FontSpec(file = testFontPath, size = 10f)
+        val builtInFont = FontSpec(family = "Courier", size = 10f)  // use Courier for contrast
+        val customWidth = metrics.measureTextWidth("Test text", customFont, 10f)
+        val builtInWidth = metrics.measureTextWidth("Test text", builtInFont, 10f)
+        // They should both be positive but likely different
+        customWidth shouldBeGreaterThan 0f
+        builtInWidth shouldBeGreaterThan 0f
+    }
 }

songbook.yaml

@@ -14,6 +14,11 @@ fonts:
   title:     { family: "Helvetica", size: 14 }
   metadata:  { family: "Helvetica", size: 8 }
   toc:       { family: "Helvetica", size: 9 }
+  # To use a custom font file (e.g. Fraktur/Blackletter for titles):
+  # title:   { file: "./fonts/FrakturFont.ttf", size: 16 }
+  # The file path is relative to the project directory.
+  # Supported formats: .ttf, .otf
+  # Custom fonts are embedded in the PDF and support Unicode (including umlauts).
 
 layout:
   margins: { top: 15, bottom: 15, inner: 20, outer: 12 }