main.go

package main

import (
	"fmt"
	"os"

	unicommon "github.com/unidoc/unidoc/common"
	pdfcore "github.com/unidoc/unidoc/pdf/core"
	"github.com/unidoc/unidoc/pdf/creator"
	"github.com/unidoc/unidoc/pdf/extractor"
	pdf "github.com/unidoc/unidoc/pdf/model"
	pdfmodel "github.com/unidoc/unidoc/pdf/model"
)

func main() {
	unicommon.SetLogger(unicommon.NewConsoleLogger(unicommon.LogLevelDebug))

	if len(os.Args) < 2 {
		fmt.Printf("Syntax: go run main.go input.pdf\n")
		os.Exit(1)
	}

	inputPath := os.Args[1]

	fmt.Printf("Input file: %s\n", inputPath)
	err := extractText(inputPath)
	if err != nil {
		fmt.Printf("Error: %v\n", err)
		os.Exit(1)
	}
}

func extractText(inputPath string) error {
	f, err := os.Open(inputPath)
	if err != nil {
		return err
	}

	defer f.Close()

	pdfReader, err := pdf.NewPdfReader(f)
	if err != nil {
		return err
	}

	numPages, err := pdfReader.GetNumPages()
	if err != nil {
		return err
	} else if numPages < 1 {
		return nil
	}

	page, err := pdfReader.GetPage(1)
	if err != nil {
		return err
	}

	e, err := extractor.New(page)
	if err != nil {
		return err
	}

	creator := creator.New()

	newpage := pdf.NewPdfPage()
	newpage.MediaBox = page.MediaBox
	creator.AddPage(newpage)

	texts, _, _, err := e.ExtractPageText()
	if err != nil {
		return err
	}

	comps := texts.TextComponents()
	count := 0
	for _, m := range comps {
		// Only parse first 1000 characters for brevity
		if count > 1000 {
			continue
		}
		count++

		p := creator.NewParagraph(m.Text)

		// Add font to page
		if newpage.HasFontByName(pdfcore.PdfObjectName(m.Font.BaseFont())) == false {
			fmt.Printf("%s font not found in page, adding it\n", pdfcore.PdfObjectName(m.Font.BaseFont()))
			newpage.AddFont(pdfcore.PdfObjectName(m.Font.BaseFont()), m.Font.ToPdfObject())
		}

		font, found := newpage.Resources.GetFontByName(pdfcore.PdfObjectName(m.Font.BaseFont()))
		if found {
			newFont, err := pdfmodel.NewPdfFontFromPdfObject(font)
			if err != nil {
				fmt.Println("error is: ", err)
			} else {
				p.SetFont(newFont)
				fmt.Println("font set:", newFont.BaseFont())
			}
		}

		yPos := page.MediaBox.Height() - (m.Y + m.Height)
		p.SetPos(m.X, yPos)

		// p.SetFontSize(m.Font)
		// p.SetWidth(m.Width)
		// p.SetFont(m.Font)

		// p.SetLineHeight(m.Height)
		creator.Draw(p)
	}

	err = creator.WriteToFile("new.pdf")
	if err != nil {
		return err
	}

	return nil
}