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-rw-r--r--pdf.go90
1 files changed, 90 insertions, 0 deletions
diff --git a/pdf.go b/pdf.go
new file mode 100644
index 0000000..e7480fe
--- /dev/null
+++ b/pdf.go
@@ -0,0 +1,90 @@
+package bookpipeline
+
+import (
+ "errors"
+ "fmt"
+ "html"
+ "image"
+ _ "image/jpeg"
+ _ "image/png"
+ "io/ioutil"
+ "os"
+
+ //"rescribe.xyz/gofpdf@addtextrenderingmode"
+ "rescribe.xyz/gofpdf"
+ "rescribe.xyz/utils/pkg/hocr"
+)
+
+const pageWidth = 5 // pageWidth in inches
+
+// 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
+// TODO: find a font that's closer to the average dimensions of the
+// text we're dealing with
+// TODO: once we have a good font, embed it in the binary as bytes
+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.
+ p.fpdf.AddUTF8Font("dejavu", "", "DejaVuSansCondensed.ttf")
+ 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) error {
+ file, err := ioutil.ReadFile(hocrpath)
+ if err != nil {
+ return errors.New(fmt.Sprintf("Could not read file %s: %v", hocrpath, err))
+ }
+ // TODO: change hocr.Parse to take a Reader rather than []byte
+ h, err := hocr.Parse(file)
+ if err != nil {
+ return errors.New(fmt.Sprintf("Could not parse hocr in file %s: %v", hocrpath, err))
+ }
+
+ f, err := os.Open(imgpath)
+ defer f.Close()
+ if err != nil {
+ return errors.New(fmt.Sprintf("Could not open file %s: %v", imgpath, err))
+ }
+ img, _, err := image.Decode(f)
+ if err != nil {
+ return errors.New(fmt.Sprintf("Could not decode image: %v", err))
+ }
+ b := img.Bounds()
+ p.fpdf.AddPageFormat("P", gofpdf.SizeType{Wd: pxToPt(b.Dx()), Ht: pxToPt(b.Dy())})
+
+ // TODO: check for errors in pdf as going through
+
+ _ = p.fpdf.RegisterImageOptions(imgpath, gofpdf.ImageOptions{})
+ p.fpdf.ImageOptions(imgpath, 0, 0, pxToPt(b.Dx()), pxToPt(b.Dy()), false, gofpdf.ImageOptions{}, 0, "")
+
+ p.fpdf.SetTextRenderingMode(gofpdf.TextRenderingModeInvisible)
+
+ for _, l := range h.Lines {
+ coords, err := hocr.BoxCoords(l.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(hocr.LineText(l)), "", 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)
+}