Add support for rotated appendices: implement 90° CCW image rotation for portrait pages, enhance table rendering logic, and update diagram handling directives.

pdf_pages.go

@@ -2,7 +2,12 @@ package main
 
 import (
 	"fmt"
+	"image"
+	"image/draw"
+	_ "image/jpeg"
+	"image/png"
 	"log"
+	"os"
 	"sort"
 
 	"github.com/go-pdf/fpdf"
@@ -142,7 +147,7 @@ func (r *IHKRenderer) RenderAppendices() {
 	r.pdf.SetFont("Helvetica", "", dinFontBody)
 	for i, app := range r.appendices {
 		r.pdf.CellFormat(0, dinLineHtBody,
-			r.tr(fmt.Sprintf("Anlage %d: %s", i+1, app.Title)), "", 1, "L", false, 0, "")
+			r.tr(fmt.Sprintf("Anlage %s: %s", toRoman(i+1), app.Title)), "", 1, "L", false, 0, "")
 	}
 
 	// Save portrait dimensions and standard margins for post-landscape restoration.
@@ -164,12 +169,16 @@ func (r *IHKRenderer) RenderAppendices() {
 
 		r.pdf.SetFont("Helvetica", "B", dinFontBody)
 		r.pdf.CellFormat(0, dinLineHtBody,
-			r.tr(fmt.Sprintf("Anlage %d: %s", i+1, app.Title)), "", 1, "L", false, 0, "")
+			r.tr(fmt.Sprintf("Anlage %s: %s", toRoman(i+1), app.Title)), "", 1, "L", false, 0, "")
 		r.pdf.Ln(dinSpaceAfterHeading)
 
 		switch app.Kind {
 		case AppendixKindImage:
-			r.renderAppendixImage(app.Path)
+			if app.Rotated {
+				r.renderAppendixImageRotated(app.Path)
+			} else {
+				r.renderAppendixImage(app.Path)
+			}
 		case AppendixKindTable:
 			r.renderTableBody(app.TableData, "")
 		case AppendixKindCode:
@@ -215,6 +224,91 @@ func (r *IHKRenderer) renderAppendixImage(path string) {
 		fpdf.ImageOptions{ReadDpi: true}, 0, "")
 }
 
+// renderAppendixImageRotated places an image on a portrait page rotated 90° CW.
+// The image is pre-rotated in memory so that a wide (landscape-ratio) diagram
+// fills the page height. The reader tilts the page 90° CW to read it normally.
+func (r *IHKRenderer) renderAppendixImageRotated(path string) {
+	rotatedPath, err := rotateImageCW(path)
+	if err != nil {
+		log.Printf("warning: could not rotate image %q: %v — falling back to normal", path, err)
+		r.renderAppendixImage(path)
+		return
+	}
+
+	r.renderAppendixImageWithPath(rotatedPath)
+}
+
+// rotateImageCW decodes a PNG/JPEG from disk, rotates it 90° clockwise, writes
+// the result to a temp file, and returns the temp file path.
+// The caller owns the temp file (it is left on disk; fpdf reads it lazily).
+func rotateImageCW(src string) (string, error) {
+	f, err := os.Open(src)
+	if err != nil {
+		return "", err
+	}
+	defer f.Close()
+
+	img, _, err := image.Decode(f)
+	if err != nil {
+		return "", err
+	}
+
+	b := img.Bounds()
+	// 90° CW: new width = old height, new height = old width.
+	rotated := image.NewRGBA(image.Rect(0, 0, b.Max.Y-b.Min.Y, b.Max.X-b.Min.X))
+	draw.Draw(rotated, rotated.Bounds(), image.White, image.Point{}, draw.Src)
+	for y := b.Min.Y; y < b.Max.Y; y++ {
+		for x := b.Min.X; x < b.Max.X; x++ {
+			// 90° CW: new(newW-1-y, x) = old(x, y)
+			rotated.Set(b.Max.Y-1-y, x-b.Min.X, img.At(x, y))
+		}
+	}
+
+	tmp, err := os.CreateTemp("", "ihk_rotated_*.png")
+	if err != nil {
+		return "", err
+	}
+	defer tmp.Close()
+
+	if err := png.Encode(tmp, rotated); err != nil {
+		os.Remove(tmp.Name())
+		return "", err
+	}
+	return tmp.Name(), nil
+}
+
+// renderAppendixImageWithPath is identical to renderAppendixImage but accepts
+// an arbitrary path (used for pre-rotated temp files).
+func (r *IHKRenderer) renderAppendixImageWithPath(path string) {
+	info := r.ensureImageRegistered(path)
+	if info == nil {
+		r.pdf.CellFormat(0, dinLineHtBody, r.tr("[Image could not be loaded: "+path+"]"),
+			"1", 1, "C", false, 0, "")
+		return
+	}
+
+	_, pageH := r.pdf.GetPageSize()
+	lm, _, _, bm := r.pdf.GetMargins()
+	uw := r.usableWidth()
+	availH := pageH - r.pdf.GetY() - bm - 10
+
+	imgW := info.Width() * ptToMM
+	imgH := info.Height() * ptToMM
+
+	displayW := uw
+	displayH := imgH * (displayW / imgW)
+	if displayH > availH {
+		scale := availH / displayH
+		displayH = availH
+		displayW = displayW * scale
+	}
+
+	posX := lm + (uw-displayW)/2
+	r.pdf.ImageOptions(path, posX, r.pdf.GetY(), displayW, displayH, false,
+		fpdf.ImageOptions{ReadDpi: true}, 0, "")
+	r.pdf.SetY(r.pdf.GetY() + displayH + 2)
+}
+
 // RenderAbbreviations renders the list of abbreviations from the YAML config.
 // It is placed after the TOC and uses Roman page numbering.
 func (r *IHKRenderer) RenderAbbreviations() {