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fix: add bounds checking and content splitting for multi-page songs (Closes #17)

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The PDF renderer now tracks y-position against the bottom margin and
splits song sections across pages when content exceeds available space.
Footer elements (notes, bottom metadata, reference footer) render on the
last page with proper space reservation.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
This commit is contained in:
shahondin1624
2026-03-17 14:17:46 +01:00
parent 0fb2771279
commit f35813560b
3 changed files with 536 additions and 32 deletions
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250
renderer-pdf/src/main/kotlin/de/pfadfinder/songbook/renderer/pdf/PdfBookRenderer.kt
View File

@@ -63,7 +63,7 @@ class PdfBookRenderer : BookRenderer {
renderSongPage(
cb, chordLyricRenderer, fontMetrics, config,
pageContent.song, pageContent.pageIndex,
contentTop, leftMargin, contentWidth
contentTop, leftMargin, contentWidth, marginBottom
)
}
is PageContent.FillerImage -> {
@@ -91,6 +91,166 @@ class PdfBookRenderer : BookRenderer {
document.close()
}
/**
* Computes the index of the first section that should be rendered on page 1.
* All sections before this index render on page 0; sections from this index
* onward render on page 1.
*
* If all sections fit on page 0, returns song.sections.size (i.e., nothing on page 1).
*/
private fun computeSplitIndex(
song: Song,
fontMetrics: PdfFontMetrics,
config: BookConfig,
contentWidth: Float,
availableHeightOnPage0: Float
): Int {
var consumed = 0f
// Header: title
consumed += config.fonts.title.size * 1.5f
// Top metadata
val renderMetaAtBottom = config.layout.metadataPosition == "bottom"
if (!renderMetaAtBottom) {
val metaParts = buildMetadataLines(song, config)
if (metaParts.isNotEmpty()) {
consumed += config.fonts.metadata.size * 1.8f * metaParts.size
}
}
// Key/capo
if (song.key != null || song.capo != null) {
consumed += config.fonts.metadata.size * 1.8f
}
consumed += 4f // gap before sections
for ((index, section) in song.sections.withIndex()) {
val sectionHeight = calculateSectionHeight(section, fontMetrics, config, contentWidth)
if (consumed + sectionHeight > availableHeightOnPage0) {
// This section doesn't fit on page 0
return index
}
consumed += sectionHeight
// Add verse spacing
consumed += config.layout.verseSpacing / 0.3528f
}
return song.sections.size
}
/**
* Calculates the height in PDF points that a section will consume when rendered.
*/
private fun calculateSectionHeight(
section: SongSection,
fontMetrics: PdfFontMetrics,
config: BookConfig,
contentWidth: Float
): Float {
var height = 0f
val metaSize = config.fonts.metadata.size
// Section label
if (section.label != null || section.type == SectionType.CHORUS) {
val labelText = section.label ?: when (section.type) {
SectionType.CHORUS -> "Refrain"
SectionType.REPEAT -> "Wiederholung"
else -> null
}
if (labelText != null) {
height += metaSize * 1.5f
}
}
// Empty chorus (reference)
if (section.type == SectionType.CHORUS && section.lines.isEmpty()) {
height += metaSize * 1.8f
return height
}
// Repeat start marker (contributes no extra height - drawn at current y)
// Lines
val chordSize = config.fonts.chords.size
val lyricSize = config.fonts.lyrics.size
val chordLineHeight = chordSize * 1.2f
val lyricLineHeight = lyricSize * 1.2f
val chordLyricGap = config.layout.chordLineSpacing / 0.3528f
for (line in section.lines) {
if (line.imagePath != null) {
// Inline image: 40mm max height + gaps
val maxImageHeight = 40f / 0.3528f
height += maxImageHeight + 6f
} else {
val hasChords = line.segments.any { it.chord != null }
var lineHeight = lyricLineHeight
if (hasChords) {
lineHeight += chordLineHeight + chordLyricGap
}
height += lineHeight + 1f // 1pt gap between lines
}
}
// Repeat end marker
if (section.type == SectionType.REPEAT) {
height += metaSize * 1.5f
}
return height
}
/**
* Calculates the space (in PDF points) that must be reserved at the bottom of
* the last page of a song for notes, bottom-position metadata, and reference footer.
*/
private fun calculateFooterReservation(
song: Song,
fontMetrics: PdfFontMetrics,
config: BookConfig,
contentWidth: Float
): Float {
var reserved = 0f
val metaFont = fontMetrics.getBaseFont(config.fonts.metadata)
val metaSize = config.fonts.metadata.size
// Notes
if (song.notes.isNotEmpty()) {
reserved += 4f // gap before notes
val noteLineHeight = metaSize * 1.5f
for ((idx, note) in song.notes.withIndex()) {
val wrappedLines = wrapText(note, metaFont, metaSize, contentWidth)
reserved += noteLineHeight * wrappedLines.size
if (idx < song.notes.size - 1) {
reserved += noteLineHeight * 0.3f
}
}
}
// Bottom metadata
if (config.layout.metadataPosition == "bottom") {
val metaParts = buildMetadataLines(song, config)
if (metaParts.isNotEmpty()) {
reserved += 4f
for (metaLine in metaParts) {
val wrappedLines = wrapText(metaLine, metaFont, metaSize, contentWidth)
reserved += metaSize * 1.5f * wrappedLines.size
}
}
}
// Reference footer
if (config.referenceBooks.isNotEmpty() && song.references.isNotEmpty()) {
val lineHeight = metaSize * 1.4f
reserved += lineHeight * 2 // two rows (headers + numbers)
reserved += lineHeight * 1.5f // separator line gap
reserved += lineHeight * 0.5f // bottom gap
}
return reserved
}
private fun renderSongPage(
cb: PdfContentByte,
chordLyricRenderer: ChordLyricRenderer,
@@ -100,12 +260,28 @@ class PdfBookRenderer : BookRenderer {
pageIndex: Int, // 0 for first page, 1 for second page of 2-page songs
contentTop: Float,
leftMargin: Float,
contentWidth: Float
contentWidth: Float,
bottomMargin: Float
) {
var y = contentTop
val renderMetaAtBottom = config.layout.metadataPosition == "bottom"
// Calculate the footer reservation for the last page
val footerReservation = calculateFooterReservation(song, fontMetrics, config, contentWidth)
// Compute the split index to determine which sections go on which page.
// Page 0 gets sections 0..<splitIndex, page 1 gets sections splitIndex..<size.
// Footer space is reserved on the last page only.
val availableOnPage0 = contentTop - bottomMargin -
(if (song.sections.size > 0) footerReservation else 0f)
val splitIndex = computeSplitIndex(song, fontMetrics, config, contentWidth, availableOnPage0)
val isTwoPageSong = splitIndex < song.sections.size
val isLastPage = if (isTwoPageSong) pageIndex == 1 else pageIndex == 0
// Bottom boundary for content on this page
val yMin = bottomMargin + (if (isLastPage) footerReservation else 0f)
if (pageIndex == 0) {
// Render title
val titleFont = fontMetrics.getBaseFont(config.fonts.title)
@@ -125,6 +301,7 @@ class PdfBookRenderer : BookRenderer {
val metaFont = fontMetrics.getBaseFont(config.fonts.metadata)
val metaSize = config.fonts.metadata.size
for (metaLine in metaParts) {
if (y - metaSize * 1.8f < yMin) break
cb.beginText()
cb.setFontAndSize(metaFont, metaSize)
cb.setColorFill(Color.GRAY)
@@ -143,24 +320,31 @@ class PdfBookRenderer : BookRenderer {
if (infoParts.isNotEmpty()) {
val metaFont = fontMetrics.getBaseFont(config.fonts.metadata)
val metaSize = config.fonts.metadata.size
cb.beginText()
cb.setFontAndSize(metaFont, metaSize)
cb.setColorFill(Color.GRAY)
cb.setTextMatrix(leftMargin, y - metaSize)
cb.showText(infoParts.joinToString(" | "))
cb.endText()
y -= metaSize * 1.8f
if (y - metaSize * 1.8f >= yMin) {
cb.beginText()
cb.setFontAndSize(metaFont, metaSize)
cb.setColorFill(Color.GRAY)
cb.setTextMatrix(leftMargin, y - metaSize)
cb.showText(infoParts.joinToString(" | "))
cb.endText()
y -= metaSize * 1.8f
}
}
y -= 4f // gap before sections
}
// Determine which sections to render on this page
// For simplicity in this implementation, render all sections on pageIndex 0
// A more sophisticated implementation would split sections across pages
val sections = if (pageIndex == 0) song.sections else emptyList()
val sections = if (pageIndex == 0) {
song.sections.subList(0, splitIndex)
} else {
song.sections.subList(splitIndex, song.sections.size)
}
for (section in sections) {
// Safety check: stop rendering if we've gone below the boundary
if (y < yMin) break
// Section label
if (section.label != null || section.type == SectionType.CHORUS) {
val labelText = section.label ?: when (section.type) {
@@ -171,6 +355,7 @@ class PdfBookRenderer : BookRenderer {
if (labelText != null) {
val metaFont = fontMetrics.getBaseFont(config.fonts.metadata)
val metaSize = config.fonts.metadata.size
if (y - metaSize * 1.5f < yMin) break
cb.beginText()
cb.setFontAndSize(metaFont, metaSize)
cb.setColorFill(Color.DARK_GRAY)
@@ -185,6 +370,7 @@ class PdfBookRenderer : BookRenderer {
if (section.type == SectionType.CHORUS && section.lines.isEmpty()) {
val metaFont = fontMetrics.getBaseFont(config.fonts.metadata)
val metaSize = config.fonts.metadata.size
if (y - metaSize * 1.8f < yMin) break
cb.beginText()
cb.setFontAndSize(metaFont, metaSize)
cb.setColorFill(Color.DARK_GRAY)
@@ -209,6 +395,7 @@ class PdfBookRenderer : BookRenderer {
// Render lines
for (line in section.lines) {
if (y < yMin) break
val imgPath = line.imagePath
if (imgPath != null) {
// Render inline image
@@ -223,21 +410,23 @@ class PdfBookRenderer : BookRenderer {
if (section.type == SectionType.REPEAT) {
val metaFont = fontMetrics.getBaseFont(config.fonts.metadata)
val metaSize = config.fonts.metadata.size
cb.beginText()
cb.setFontAndSize(metaFont, metaSize)
cb.setColorFill(Color.DARK_GRAY)
cb.setTextMatrix(leftMargin, y - metaSize)
cb.showText(":\u2502")
cb.endText()
y -= metaSize * 1.5f
if (y - metaSize * 1.5f >= yMin) {
cb.beginText()
cb.setFontAndSize(metaFont, metaSize)
cb.setColorFill(Color.DARK_GRAY)
cb.setTextMatrix(leftMargin, y - metaSize)
cb.showText(":\u2502")
cb.endText()
y -= metaSize * 1.5f
}
}
// Verse spacing
y -= config.layout.verseSpacing / 0.3528f
}
// Render notes at the bottom (with word-wrap for multi-paragraph notes)
if (pageIndex == 0 && song.notes.isNotEmpty()) {
// Render notes on the last page
if (isLastPage && song.notes.isNotEmpty()) {
y -= 4f
val metaFont = fontMetrics.getBaseFont(config.fonts.metadata)
val metaSize = config.fonts.metadata.size
@@ -261,8 +450,8 @@ class PdfBookRenderer : BookRenderer {
}
}
// Render metadata at bottom of song page (if configured)
if (renderMetaAtBottom && pageIndex == 0) {
// Render metadata at bottom of song page (if configured) - on the last page only
if (renderMetaAtBottom && isLastPage) {
val metaParts = buildMetadataLines(song, config)
if (metaParts.isNotEmpty()) {
y -= 4f
@@ -284,15 +473,12 @@ class PdfBookRenderer : BookRenderer {
}
// Render reference book footer on the last page of the song
if (config.referenceBooks.isNotEmpty() && song.references.isNotEmpty()) {
val isLastPage = (pageIndex == 0) // For now, all content renders on page 0
if (isLastPage) {
renderReferenceFooter(
cb, fontMetrics, config, song,
leftMargin, contentWidth,
config.layout.margins.bottom / 0.3528f
)
}
if (config.referenceBooks.isNotEmpty() && song.references.isNotEmpty() && isLastPage) {
renderReferenceFooter(
cb, fontMetrics, config, song,
leftMargin, contentWidth,
bottomMargin
)
}
}

209
renderer-pdf/src/test/kotlin/de/pfadfinder/songbook/renderer/pdf/PdfBookRendererTest.kt
View File

@@ -417,4 +417,213 @@ class PdfBookRendererTest {
baos.size() shouldBeGreaterThan 0
}
// --- Content splitting tests ---
private fun createLongSong(title: String = "Long Song"): Song {
// Create a song with many sections that will exceed one A5 page
val sections = (1..20).map { i ->
SongSection(
type = SectionType.VERSE,
label = "Verse $i",
lines = (1..4).map {
SongLine(
listOf(
LineSegment(chord = "Am", text = "Some text with chords "),
LineSegment(chord = "G", text = "and more text here")
)
)
}
)
}
return Song(title = title, sections = sections)
}
@Test
fun `render splits content across pages for two-page song`() {
val song = createLongSong()
val layout = LayoutResult(
tocPages = 0,
pages = listOf(
PageContent.SongPage(song, 0),
PageContent.SongPage(song, 1)
),
tocEntries = emptyList()
)
val baos = ByteArrayOutputStream()
renderer.render(layout, BookConfig(), baos)
baos.size() shouldBeGreaterThan 0
val bytes = baos.toByteArray()
val header = String(bytes.sliceArray(0..4))
header shouldBe "%PDF-"
}
@Test
fun `render does not overflow below bottom margin for very long song`() {
// Create an extremely long song
val sections = (1..40).map { i ->
SongSection(
type = SectionType.VERSE,
label = "Verse $i",
lines = (1..6).map {
SongLine(
listOf(
LineSegment(chord = "C", text = "A long line of text that should be rendered properly "),
LineSegment(chord = "G", text = "with chords above each segment")
)
)
}
)
}
val song = Song(title = "Very Long Song", sections = sections)
val layout = LayoutResult(
tocPages = 0,
pages = listOf(
PageContent.SongPage(song, 0),
PageContent.SongPage(song, 1)
),
tocEntries = emptyList()
)
val baos = ByteArrayOutputStream()
renderer.render(layout, BookConfig(), baos)
baos.size() shouldBeGreaterThan 0
}
@Test
fun `render places metadata at bottom of last page for two-page song`() {
val config = BookConfig(
layout = LayoutConfig(metadataPosition = "bottom")
)
val song = createLongSong().copy(
composer = "Bach",
lyricist = "Goethe"
)
val layout = LayoutResult(
tocPages = 0,
pages = listOf(
PageContent.SongPage(song, 0),
PageContent.SongPage(song, 1)
),
tocEntries = emptyList()
)
val baos = ByteArrayOutputStream()
renderer.render(layout, config, baos)
baos.size() shouldBeGreaterThan 0
}
@Test
fun `render places notes on last page of two-page song`() {
val song = createLongSong().copy(
notes = listOf("This is a note that should appear on the last page")
)
val layout = LayoutResult(
tocPages = 0,
pages = listOf(
PageContent.SongPage(song, 0),
PageContent.SongPage(song, 1)
),
tocEntries = emptyList()
)
val baos = ByteArrayOutputStream()
renderer.render(layout, BookConfig(), baos)
baos.size() shouldBeGreaterThan 0
}
@Test
fun `render places reference footer on last page of two-page song`() {
val config = BookConfig(
referenceBooks = listOf(
ReferenceBook(id = "mo", name = "Mundorgel", abbreviation = "MO"),
ReferenceBook(id = "pl", name = "Pfadfinderlied", abbreviation = "PL")
)
)
val song = createLongSong().copy(
references = mapOf("mo" to 42, "pl" to 17)
)
val layout = LayoutResult(
tocPages = 0,
pages = listOf(
PageContent.SongPage(song, 0),
PageContent.SongPage(song, 1)
),
tocEntries = emptyList()
)
val baos = ByteArrayOutputStream()
renderer.render(layout, config, baos)
baos.size() shouldBeGreaterThan 0
}
@Test
fun `render handles short song that fits on one page without splitting`() {
// A simple short song should still work correctly after split logic is added
val song = Song(
title = "Short Song",
sections = listOf(
SongSection(
type = SectionType.VERSE,
lines = listOf(
SongLine(listOf(LineSegment(chord = "Am", text = "One line")))
)
)
)
)
val layout = LayoutResult(
tocPages = 0,
pages = listOf(PageContent.SongPage(song, 0)),
tocEntries = emptyList()
)
val baos = ByteArrayOutputStream()
renderer.render(layout, BookConfig(), baos)
baos.size() shouldBeGreaterThan 0
}
@Test
fun `render two-page song with bottom metadata and references`() {
val config = BookConfig(
layout = LayoutConfig(
metadataPosition = "bottom",
metadataLabels = "german"
),
referenceBooks = listOf(
ReferenceBook(id = "mo", name = "Mundorgel", abbreviation = "MO")
)
)
val song = createLongSong().copy(
composer = "Bach",
lyricist = "Goethe",
notes = listOf("Play softly", "Repeat last verse"),
references = mapOf("mo" to 55)
)
val layout = LayoutResult(
tocPages = 0,
pages = listOf(
PageContent.SongPage(song, 0),
PageContent.SongPage(song, 1)
),
tocEntries = emptyList()
)
val baos = ByteArrayOutputStream()
renderer.render(layout, config, baos)
baos.size() shouldBeGreaterThan 0
}
}