Sebastian Unterschütz
350 lines
9.9 KiB
Go
350 lines
9.9 KiB
Go
package main
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import (
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"fmt"
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"strconv"
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"strings"
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"github.com/go-pdf/fpdf"
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)
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// InlineSpan represents a run of text with consistent inline formatting.
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// Used to pass parsed inline Markdown nodes from the parser to the renderer.
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type InlineSpan struct {
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Text string
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Bold bool
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Italic bool
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Code bool // inline code (`…`)
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}
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// RenderHeader renders a section heading per IHK/DIN 5008 rules:
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// - Font: Helvetica Bold, 14pt
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// - Before: 2 blank lines if not at the top of the page
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// - After: 1 blank line
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// - Level 1 headings always start on a new page
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//
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// The heading is also recorded in the TOC.
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func (r *IHKRenderer) RenderHeader(level int, title string) {
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if level == 1 {
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// Major sections start on a new page per IHK convention.
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r.pdf.AddPage()
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} else if !r.isAtPageTop() {
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// IHK: two blank lines before a heading that is not at the page top.
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r.pdf.Ln(dinSpaceBeforeHeading)
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}
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r.RecordHeader(level, title)
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r.pdf.SetFont("Helvetica", "B", dinFontHeading)
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r.pdf.MultiCell(0, dinLineHtHeading, r.tr(title), "", "L", false)
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// IHK: one blank line (Leerzeile) after every heading.
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r.pdf.Ln(dinSpaceAfterHeading)
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}
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// RenderParagraphSpans renders a paragraph from pre-parsed inline spans.
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//
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// Plain paragraphs (no inline formatting) use MultiCell with Blocksatz (justified)
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// alignment as required by IHK. Paragraphs with mixed bold/italic use Write()
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// which produces left-aligned output — an inherent fpdf limitation for mixed fonts.
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func (r *IHKRenderer) RenderParagraphSpans(spans []InlineSpan) {
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if len(spans) == 0 {
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return
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}
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hasFormatting := false
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for _, s := range spans {
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if s.Bold || s.Italic || s.Code {
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hasFormatting = true
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break
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}
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}
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if !hasFormatting {
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// All plain text: collect and render justified (Blocksatz).
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text := ""
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for _, s := range spans {
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text += s.Text
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}
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r.pdf.SetFont("Helvetica", "", dinFontBody)
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r.pdf.MultiCell(0, dinLineHtBody, r.tr(text), "", "J", false)
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} else {
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// Mixed formatting: render span-by-span using Write().
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for _, span := range spans {
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style := fontStyle(span.Bold, span.Italic)
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if span.Code {
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r.pdf.SetFont("Courier", style, dinFontBody)
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} else {
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r.pdf.SetFont("Helvetica", style, dinFontBody)
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}
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r.pdf.Write(dinLineHtBody, r.tr(span.Text))
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}
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r.pdf.Ln(dinLineHtBody)
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}
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r.pdf.Ln(dinSpaceAfterParagraph)
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}
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// RenderListItem renders a single list item with a bullet prefix.
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// ordered: true → bullet "•"; false → numbered with index.
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// indent: nesting depth (0 = top level).
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func (r *IHKRenderer) RenderListItem(spans []InlineSpan, ordered bool, index, indent int) {
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r.pdf.SetFont("Helvetica", "", dinFontBody)
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lm, _, _, _ := r.pdf.GetMargins()
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// 3 mm base indent + 5 mm per nesting level (reduced from previous 8 mm per level)
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indentMM := 3.0 + float64(indent)*5.0
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prefix := "• "
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if ordered {
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prefix = strconv.Itoa(index) + ". "
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}
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prefixW := r.pdf.GetStringWidth(prefix) + 1.0
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// textX is where the item text starts; wrapped lines must align here too.
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textX := lm + indentMM + prefixW
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textW := r.usableWidth() - indentMM - prefixW
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// Temporarily move the left margin to textX so that MultiCell wraps
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// continuation lines flush with the text, not back to the page margin.
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r.pdf.SetLeftMargin(textX)
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defer r.pdf.SetLeftMargin(lm)
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// Render bullet/number; CellFormat advances X to textX automatically.
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r.pdf.SetX(lm + indentMM)
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r.pdf.CellFormat(prefixW, dinLineHtBody, r.tr(prefix), "", 0, "L", false, 0, "")
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hasFormatting := false
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for _, s := range spans {
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if s.Bold || s.Italic || s.Code {
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hasFormatting = true
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break
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}
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}
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if !hasFormatting {
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text := ""
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for _, s := range spans {
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text += s.Text
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}
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r.pdf.MultiCell(textW, dinLineHtBody, r.tr(text), "", "L", false)
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} else {
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for _, span := range spans {
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style := fontStyle(span.Bold, span.Italic)
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if span.Code {
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r.pdf.SetFont("Courier", style, dinFontBody)
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} else {
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r.pdf.SetFont("Helvetica", style, dinFontBody)
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}
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r.pdf.Write(dinLineHtBody, r.tr(span.Text))
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}
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r.pdf.Ln(dinLineHtBody)
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}
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}
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// RenderTable renders a data table with a header row (grey background) and
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// a auto-repeat header on page breaks. Each table is numbered and recorded
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// in the Tabellenverzeichnis per IHK section 2.4.
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//
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// data[0] is the header row; data[1:] are body rows.
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func (r *IHKRenderer) RenderTable(data [][]string, caption string) {
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if len(data) == 0 {
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return
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}
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r.tableCount++
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label := fmt.Sprintf("Tab. %d", r.tableCount)
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if caption != "" {
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label += ": " + caption
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}
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r.RecordTable(label)
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header := data[0]
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numCols := len(header)
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uw := r.usableWidth()
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colW := uw / float64(numCols)
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// renderHeaderRow draws the (grey) header row, optionally with a "(Fortsetzung)" suffix.
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renderHeaderRow := func(continued bool) {
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title := label
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if continued {
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title += " (Fortsetzung)"
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}
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r.pdf.SetFont("Helvetica", "B", dinFontCaption)
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r.pdf.CellFormat(0, dinLineHtCaption+2, r.tr(title), "", 1, "L", false, 0, "")
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r.pdf.SetFillColor(230, 230, 230)
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r.pdf.SetFont("Helvetica", "B", dinFontCaption)
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for _, col := range header {
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r.pdf.CellFormat(colW, dinLineHtCaption+2, r.tr(col), "1", 0, "C", true, 0, "")
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}
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r.pdf.Ln(-1)
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}
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renderHeaderRow(false)
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r.pdf.SetFont("Helvetica", "", dinFontCaption)
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r.pdf.SetFillColor(255, 255, 255)
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_, pageH := r.pdf.GetPageSize()
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_, _, _, bm := r.pdf.GetMargins()
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rowH := dinLineHtCaption + 2
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for i := 1; i < len(data); i++ {
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if r.pdf.GetY()+rowH > pageH-bm {
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r.pdf.AddPage()
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renderHeaderRow(true)
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r.pdf.SetFont("Helvetica", "", dinFontCaption)
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}
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for _, col := range data[i] {
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r.pdf.CellFormat(colW, rowH, r.tr(col), "1", 0, "L", false, 0, "")
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}
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r.pdf.Ln(-1)
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}
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r.pdf.Ln(dinSpaceAfterParagraph)
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}
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// RenderImage embeds an image with a caption below it.
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// The image is scaled to fit the printable width and the remaining page height.
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// If the image does not fit on the current page, a new page is started.
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// The caption is recorded in the Abbildungsverzeichnis.
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func (r *IHKRenderer) RenderImage(path string, caption string) {
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r.pdf.Ln(dinSpaceAfterParagraph)
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info := r.ensureImageRegistered(path)
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if info == nil {
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r.pdf.SetFont("Helvetica", "I", dinFontCaption)
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r.pdf.CellFormat(0, dinLineHtCaption, r.tr("[Bild nicht gefunden: "+path+"]"),
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"1", 1, "C", false, 0, "")
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return
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}
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imgW := info.Width() * ptToMM
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imgH := info.Height() * ptToMM
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uw := r.usableWidth()
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captionH := dinLineHtCaption + 4
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// Scale to available width
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displayW := uw
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displayH := imgH * (displayW / imgW)
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_, pageH := r.pdf.GetPageSize()
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_, _, _, bm := r.pdf.GetMargins()
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availH := pageH - r.pdf.GetY() - bm - captionH
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if displayH > availH {
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if availH < 20 {
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// Almost no space left — start a new page
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r.pdf.AddPage()
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availH = pageH - r.pdf.GetY() - bm - captionH
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}
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// Scale down to fit height
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displayH = availH
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displayW = imgW * (displayH / imgH)
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if displayW > uw {
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displayW = uw
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displayH = imgH * (displayW / imgW)
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}
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}
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lm, _, _, _ := r.pdf.GetMargins()
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posX := lm + (uw-displayW)/2
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currentY := r.pdf.GetY()
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r.pdf.ImageOptions(path, posX, currentY, displayW, displayH, false,
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fpdf.ImageOptions{ReadDpi: true}, 0, "")
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r.pdf.SetY(currentY + displayH + 2)
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// Figure caption and TOC registration
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r.figureCount++
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label := fmt.Sprintf("Abb. %d", r.figureCount)
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if caption != "" {
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label += ": " + caption
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}
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r.RecordFigure(label)
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r.pdf.SetFont("Helvetica", "I", dinFontCaption)
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r.pdf.CellFormat(0, captionH, r.tr(label), "", 1, "C", false, 0, "")
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r.pdf.Ln(dinSpaceAfterParagraph)
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}
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// Code block layout constants.
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const (
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codeFont = 9.0 // pt — Courier, smaller than body text
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codeLineHt = 4.5 // mm ≈ 9 pt × 1.3 line spacing
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codeGutterW = 11.0 // mm — column reserved for line numbers
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)
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// RenderCodeBlock renders a fenced code block with a line-number gutter.
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//
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// Layout:
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//
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// ┌──────┬──────────────────────────────────┐
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// │ 1 │ package main │
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// │ 2 │ │
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// │ 3 │ func main() { … } │
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// └──────┴──────────────────────────────────┘
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//
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// The language label is shown in small italic text above the block.
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// Lines that exceed the printable width are clipped — code should be
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// formatted to reasonable lengths before conversion.
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func (r *IHKRenderer) RenderCodeBlock(lang, code string) {
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lines := strings.Split(strings.TrimRight(code, "\n"), "\n")
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if len(lines) == 0 {
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return
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}
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r.pdf.Ln(dinSpaceAfterParagraph)
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// Language label — top-right, italic, grey
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if lang != "" {
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r.pdf.SetFont("Helvetica", "I", dinFontCaption)
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r.pdf.SetTextColor(100, 100, 100)
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r.pdf.CellFormat(0, dinLineHtCaption, r.tr(lang), "", 1, "R", false, 0, "")
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r.pdf.SetTextColor(0, 0, 0)
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}
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lm, _, _, bm := r.pdf.GetMargins()
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_, pageH := r.pdf.GetPageSize()
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uw := r.usableWidth()
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codeW := uw - codeGutterW
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r.pdf.SetFont("Courier", "", codeFont)
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for i, line := range lines {
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// Start a new page if this line would fall below the bottom margin.
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if r.pdf.GetY()+codeLineHt > pageH-bm {
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r.pdf.AddPage()
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}
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// Gutter: darker grey, right-aligned line number.
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r.pdf.SetFillColor(218, 218, 218)
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r.pdf.SetX(lm)
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r.pdf.CellFormat(codeGutterW, codeLineHt,
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fmt.Sprintf("%4d ", i+1), "", 0, "R", true, 0, "")
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// Code line: lighter grey, left-aligned, small leading space.
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r.pdf.SetFillColor(246, 246, 246)
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r.pdf.CellFormat(codeW, codeLineHt,
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r.tr(" "+line), "", 1, "L", true, 0, "")
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}
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// Reset colours so subsequent content is unaffected.
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r.pdf.SetFillColor(255, 255, 255)
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r.pdf.Ln(dinSpaceAfterParagraph)
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}
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// fontStyle returns the fpdf font style string for a given bold/italic combination.
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func fontStyle(bold, italic bool) string {
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switch {
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case bold && italic:
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return "BI"
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case bold:
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return "B"
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case italic:
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return "I"
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default:
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return ""
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}
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}
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