package bookpipeline import ( "bytes" "compress/zlib" "errors" "fmt" "html" "image" "image/jpeg" "image/png" "io/ioutil" "os" "github.com/jung-kurt/gofpdf" "golang.org/x/image/draw" "rescribe.xyz/utils/pkg/hocr" ) // TODO: maybe set this in Fpdf struct const pageWidth = 5 // pageWidth in inches const scaleSmaller = 3 // amount the width and height are divided by // pxToPt converts a pixel value into a pt value (72 pts per inch) // This uses pageWidth to determine the appropriate value func pxToPt(i int) float64 { return float64(i) / pageWidth } type Fpdf struct { fpdf *gofpdf.Fpdf } // Setup creates a new PDF with appropriate settings and fonts func (p *Fpdf) Setup() error { p.fpdf = gofpdf.New("P", "pt", "A4", "") // Even though it's invisible, we need to add a font which can do // UTF-8 so that text renders correctly. // We embed the font directly in the binary, compressed with zlib c := bytes.NewBuffer(dejavucondensed) r, err := zlib.NewReader(c) defer r.Close() if err != nil { return errors.New(fmt.Sprintf("Could not open compressed font", err)) } var b bytes.Buffer _, err = b.ReadFrom(r) if err != nil { return errors.New(fmt.Sprintf("Could not read compressed font", err)) } p.fpdf.AddUTF8FontFromBytes("dejavu", "", b.Bytes()) p.fpdf.SetFont("dejavu", "", 10) p.fpdf.SetAutoPageBreak(false, float64(0)) return p.fpdf.Error() } // AddPage adds a page to the pdf with an image and (invisible) // text from an hocr file func (p *Fpdf) AddPage(imgpath, hocrpath string, smaller bool) error { file, err := ioutil.ReadFile(hocrpath) if err != nil { return errors.New(fmt.Sprintf("Could not read file %s: %v", hocrpath, err)) } h, err := hocr.Parse(file) if err != nil { return errors.New(fmt.Sprintf("Could not parse hocr in file %s: %v", hocrpath, err)) } imgf, err := os.Open(imgpath) defer imgf.Close() if err != nil { return errors.New(fmt.Sprintf("Could not open file %s: %v", imgpath, err)) } img, imgtype, err := image.Decode(imgf) if err != nil { return errors.New(fmt.Sprintf("Could not decode image: %v", err)) } b := img.Bounds() if smaller { r := image.Rect(0, 0, b.Max.X/scaleSmaller, b.Max.Y/scaleSmaller) smimg := image.NewRGBA(r) draw.ApproxBiLinear.Scale(smimg, r, img, b, draw.Over, nil) img = smimg } var buf bytes.Buffer if imgtype == "jpeg" { err = jpeg.Encode(&buf, img, &jpeg.Options{Quality: jpeg.DefaultQuality}) } else { err = png.Encode(&buf, img) } if err != nil { return err } p.fpdf.AddPageFormat("P", gofpdf.SizeType{Wd: pxToPt(b.Dx()), Ht: pxToPt(b.Dy())}) _ = p.fpdf.RegisterImageOptionsReader(imgpath, gofpdf.ImageOptions{ImageType: imgtype}, &buf) p.fpdf.ImageOptions(imgpath, 0, 0, pxToPt(b.Dx()), pxToPt(b.Dy()), false, gofpdf.ImageOptions{}, 0, "") p.fpdf.SetTextRenderingMode(3) for _, l := range h.Lines { for _, w := range l.Words { coords, err := hocr.BoxCoords(w.Title) if err != nil { continue } p.fpdf.SetXY(pxToPt(coords[0]), pxToPt(coords[1])) p.fpdf.CellFormat(pxToPt(coords[2]), pxToPt(coords[3]), html.UnescapeString(w.Text) + " ", "", 0, "T", false, 0, "") } } return p.fpdf.Error() } // Save saves the PDF to the file at path func (p *Fpdf) Save(path string) error { return p.fpdf.OutputFileAndClose(path) }