ghostscript.go

Documentation: github.com/jung-kurt/gofpdf/contrib/ghostscript

     1  package main
     2  
     3  // This command demonstrates the use of ghotscript to reduce the size
     4  // of generated PDFs. This is based on a comment made by farkerhaiku:
     5  // https://github.com/jung-kurt/gofpdf/issues/57#issuecomment-185843315
     6  
     7  import (
     8  	"fmt"
     9  	"os"
    10  	"os/exec"
    11  
    12  	"github.com/jung-kurt/gofpdf"
    13  )
    14  
    15  func report(fileStr string, err error) {
    16  	if err == nil {
    17  		var info os.FileInfo
    18  		info, err = os.Stat(fileStr)
    19  		if err == nil {
    20  			fmt.Printf("%s: OK, size %d\n", fileStr, info.Size())
    21  		} else {
    22  			fmt.Printf("%s: bad stat\n", fileStr)
    23  		}
    24  	} else {
    25  		fmt.Printf("%s: %s\n", fileStr, err)
    26  	}
    27  }
    28  
    29  func newPdf() (pdf *gofpdf.Fpdf) {
    30  	pdf = gofpdf.New("P", "mm", "A4", "../../font")
    31  	pdf.SetCompression(false)
    32  	pdf.AddFont("Calligrapher", "", "calligra.json")
    33  	pdf.AddPage()
    34  	pdf.SetFont("Calligrapher", "", 35)
    35  	pdf.Cell(0, 10, "Enjoy new fonts with FPDF!")
    36  	return
    37  }
    38  
    39  func full(name string) {
    40  	report(name, newPdf().OutputFileAndClose(name))
    41  }
    42  
    43  func min(name string) {
    44  	cmd := exec.Command("gs", "-sDEVICE=pdfwrite",
    45  		"-dCompatibilityLevel=1.4",
    46  		"-dPDFSETTINGS=/screen", "-dNOPAUSE", "-dQUIET",
    47  		"-dBATCH", "-sOutputFile="+name, "-")
    48  	inPipe, err := cmd.StdinPipe()
    49  	if err == nil {
    50  		errChan := make(chan error, 1)
    51  		go func() {
    52  			errChan <- cmd.Start()
    53  		}()
    54  		err = newPdf().Output(inPipe)
    55  		if err == nil {
    56  			report(name, <-errChan)
    57  		} else {
    58  			report(name, err)
    59  		}
    60  	} else {
    61  		report(name, err)
    62  	}
    63  }
    64  
    65  func main() {
    66  	full("full.pdf")
    67  	min("min.pdf")
    68  }
    69
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