gopdf

gopdf is a simple library for generating PDF document written in Go lang.

A minimum version of Go 1.13 is required.

Features

• Unicode subfont embedding. (Chinese, Japanese, Korean, etc.)
• Draw line, oval, rect, curve
• Draw image ( jpg, png )
  • Set image mask
• Password protection
• Font kerning

Installation

go get -u github.com/signintech/gopdf

Print text

package main
import (
	"log"
	"github.com/signintech/gopdf"
)

func main() {

	pdf := gopdf.GoPdf{}
	pdf.Start(gopdf.Config{ PageSize: *gopdf.PageSizeA4 })
	pdf.AddPage()
	err := pdf.AddTTFFont("wts11", "../ttf/wts11.ttf")
	if err != nil {
		log.Print(err.Error())
		return
	}

	err = pdf.SetFont("wts11", "", 14)
	if err != nil {
		log.Print(err.Error())
		return
	}
	pdf.Cell(nil, "您好")
	pdf.WritePdf("hello.pdf")

}

Set text color using RGB color model

pdf.SetTextColor(156, 197, 140)
pdf.Cell(nil, "您好")

Set text color using CMYK color model

pdf.SetTextColorCMYK(0, 6, 14, 0)
pdf.Cell(nil, "Hello")

Image

package main
import (
	"log"
	"github.com/signintech/gopdf"
)

func main() {
	pdf := gopdf.GoPdf{}
	pdf.Start(gopdf.Config{PageSize: *gopdf.PageSizeA4 })
	pdf.AddPage()
	var err error
	err = pdf.AddTTFFont("loma", "../ttf/Loma.ttf")
	if err != nil {
		log.Print(err.Error())
		return
	}

	pdf.Image("../imgs/gopher.jpg", 200, 50, nil) //print image
	err = pdf.SetFont("loma", "", 14)
	if err != nil {
		log.Print(err.Error())
		return
	}
	pdf.SetXY(250, 200) //move current location
	pdf.Cell(nil, "gopher and gopher") //print text

	pdf.WritePdf("image.pdf")
}

Links

package main

import (
	"log"
	"github.com/signintech/gopdf"
)

func main()  {
	pdf := gopdf.GoPdf{}
	pdf.Start(gopdf.Config{ PageSize: *gopdf.PageSizeA4 })
	pdf.AddPage()
	err := pdf.AddTTFFont("times", "./test/res/times.ttf")
	if err != nil {
		log.Print(err.Error())
		return
	}

	err = pdf.SetFont("times", "", 14)
	if err != nil {
		log.Print(err.Error())
		return
	}

	pdf.SetXY(30, 40)
	pdf.Text("Link to example.com")
	pdf.AddExternalLink("http://example.com/", 27.5, 28, 125, 15)

	pdf.SetXY(30, 70)
	pdf.Text("Link to second page")
	pdf.AddInternalLink("anchor", 27.5, 58, 120, 15)

	pdf.AddPage()
	pdf.SetXY(30, 100)
	pdf.SetAnchor("anchor")
	pdf.Text("Anchor position")

	pdf.WritePdf("hello.tmp.pdf")

}

Header and Footer

package main

import (
    "log"
    "github.com/signintech/gopdf"
)

func main() {
    pdf := gopdf.GoPdf{}
    pdf.Start(gopdf.Config{ PageSize: *gopdf.PageSizeA4 })

    err := pdf.AddTTFFont("LiberationSerif-Regular", "./test/res/LiberationSerif-Regular.ttf")
    if err != nil {
        log.Print(err.Error())
        return
    }

    err = pdf.SetFont("LiberationSerif-Regular", "", 14)
    if err != nil {
        log.Print(err.Error())
        return
    }

    pdf.AddHeader(func() {
        pdf.SetY(5)
        pdf.Cell(nil, "header")
    })
    pdf.AddFooter(func() {
        pdf.SetY(825)
        pdf.Cell(nil, "footer")
    })

    pdf.AddPage()
    pdf.SetY(400)
    pdf.Text("page 1 content")
    pdf.AddPage()
    pdf.SetY(400)
    pdf.Text("page 2 content")

    pdf.WritePdf("header-footer.tmp.pdf")

}

Draw line

pdf.SetLineWidth(2)
pdf.SetLineType("dashed")
pdf.Line(10, 30, 585, 30)

Draw oval

pdf.SetLineWidth(1)
pdf.Oval(100, 200, 500, 500)

Draw polygon

pdf.SetStrokeColor(255, 0, 0)
pdf.SetLineWidth(2)
pdf.SetFillColor(0, 255, 0)
pdf.Polygon([]gopdf.Point{{X: 10, Y: 30}, {X: 585, Y: 200}, {X: 585, Y: 250}}, "DF")

Draw rectangle with round corner

pdf.SetStrokeColor(255, 0, 0)
pdf.SetLineWidth(2)
pdf.SetFillColor(0, 255, 0)
err := pdf.Rectangle(196.6, 336.8, 398.3, 379.3, "DF", 3, 10)
if err != nil {
	return err
}

Draw rectangle with round corner using CMYK color model

pdf.SetStrokeColorCMYK(88, 49, 0, 0)
pdf.SetLineWidth(2)
pdf.SetFillColorCMYK(0, 5, 89, 0)
err := pdf.Rectangle(196.6, 336.8, 398.3, 379.3, "DF", 3, 10)
if err != nil {
	return err
}

Rotation text or image

pdf.SetXY(100, 100)
pdf.Rotate(270.0, 100.0, 100.0)
pdf.Text("Hello...")
pdf.RotateReset() //reset

Set transparency

Read about transparency in pdf (page 320, section 11)

// alpha - value of transparency, can be between `0` and `1`
// blendMode - default value is `/Normal` - read about [blendMode and kinds of its](https://www.adobe.com/content/dam/acom/en/devnet/acrobat/pdfs/PDF32000_2008.pdf) `(page 325, section 11.3.5)`

transparency := Transparency{
	Alpha: 0.5,
	BlendModeType: "",
}
pdf.SetTransparency(transparency Transparency)

Password protection

package main

import (
	"log"

	"github.com/signintech/gopdf"
)


func main() {

	pdf := gopdf.GoPdf{}
	pdf.Start(gopdf.Config{
		PageSize: *gopdf.PageSizeA4,
		Protection: gopdf.PDFProtectionConfig{
			UseProtection: true,
			Permissions: gopdf.PermissionsPrint | gopdf.PermissionsCopy | gopdf.PermissionsModify,
			OwnerPass:   []byte("123456"),
			UserPass:    []byte("123456789")},
	})

	pdf.AddPage()
	pdf.AddTTFFont("loma", "../ttf/loma.ttf")
	pdf.Cell(nil,"Hi")
	pdf.WritePdf("protect.pdf")
}

Import existing PDF

Import existing PDF power by package gofpdi created by @phpdave11 (thank you 😄)

package main

import (
        "github.com/signintech/gopdf"
        "io"
        "net/http"
        "os"
)

func main() {
        var err error

        // Download a Font
        fontUrl := "https://github.com/google/fonts/raw/master/ofl/daysone/DaysOne-Regular.ttf"
        if err = DownloadFile("example-font.ttf", fontUrl); err != nil {
            panic(err)
        }

        // Download a PDF
        fileUrl := "https://tcpdf.org/files/examples/example_012.pdf"
        if err = DownloadFile("example-pdf.pdf", fileUrl); err != nil {
            panic(err)
        }

        pdf := gopdf.GoPdf{}
        pdf.Start(gopdf.Config{PageSize: *gopdf.PageSizeA4})

        pdf.AddPage()

        err = pdf.AddTTFFont("daysone", "example-font.ttf")
        if err != nil {
            panic(err)
        }

        err = pdf.SetFont("daysone", "", 20)
        if err != nil {
            panic(err)
        }

        // Color the page
        pdf.SetLineWidth(0.1)
        pdf.SetFillColor(124, 252, 0) //setup fill color
        pdf.RectFromUpperLeftWithStyle(50, 100, 400, 600, "FD")
        pdf.SetFillColor(0, 0, 0)

        pdf.SetXY(50, 50)
        pdf.Cell(nil, "Import existing PDF into GoPDF Document")

        // Import page 1
        tpl1 := pdf.ImportPage("example-pdf.pdf", 1, "/MediaBox")

        // Draw pdf onto page
        pdf.UseImportedTemplate(tpl1, 50, 100, 400, 0)

        pdf.WritePdf("example.pdf")

}

// DownloadFile will download a url to a local file. It's efficient because it will
// write as it downloads and not load the whole file into memory.
func DownloadFile(filepath string, url string) error {
        // Get the data
        resp, err := http.Get(url)
        if err != nil {
            return err
        }
        defer resp.Body.Close()

        // Create the file
        out, err := os.Create(filepath)
        if err != nil {
            return err
        }
        defer out.Close()

        // Write the body to file
        _, err = io.Copy(out, resp.Body)
        return err
}

Possible to set Trim-box

package main

import (
	"log"

	"github.com/signintech/gopdf"
)

func main() {

    pdf := gopdf.GoPdf{}
    mm6ToPx := 22.68

    // Base trim-box
    pdf.Start(gopdf.Config{
        PageSize: *gopdf.PageSizeA4,
        TrimBox: gopdf.Box{Left: mm6ToPx, Top: mm6ToPx, Right: gopdf.PageSizeA4.W - mm6ToPx, Bottom: gopdf.PageSizeA4.H - mm6ToPx},
    })

    // Page trim-box
    opt := gopdf.PageOption{
        PageSize: *gopdf.PageSizeA4,
        TrimBox: &gopdf.Box{Left: mm6ToPx, Top: mm6ToPx, Right: gopdf.PageSizeA4.W - mm6ToPx, Bottom: gopdf.PageSizeA4.H - mm6ToPx},
    }
    pdf.AddPageWithOption(opt)

    if err := pdf.AddTTFFont("wts11", "../ttf/wts11.ttf"); err != nil {
        log.Print(err.Error())
        return
    }

    if err := pdf.SetFont("wts11", "", 14); err != nil {
        log.Print(err.Error())
        return
    }

    pdf.Cell(nil,"Hi")
    pdf.WritePdf("hello.pdf")
}

Placeholder.

this function(s) made for experimental. There may be changes in the future.

With the placeholder function(s), you can create a placeholder to define a position. To make room for text to be add later.

There are 2 related function(s):

• PlaceHolderText(...) used to create a placeholder to fill in text later.
• FillInPlaceHoldText(...) used for filling in text into the placeholder that was created with PlaceHolderText.

Use case: For example, when you want to print the "total number of pages" on every page in pdf file, but you don't know the "total number of pages" until you have created all the pages. You can use func PlaceHolderText to create the point where you want "total number of pages" to be printed. And then when you have created all the pages so you know the "total number of pages", you call FillInPlaceHoldText(...). This function will take the text (in this case, text is "total number of pages") replace at the point that been created since func PlaceHolderText.

func main(){
    	pdf := GoPdf{}
	pdf.Start(Config{PageSize: *PageSizeA4})
	pdf.AddTTFFont("LiberationSerif-Regular", "LiberationSerif-Regular.ttf")
	pdf.SetFont("LiberationSerif-Regular", "", 14) }

	for i := 0; i < 5; i++ {
		pdf.AddPage()
        	pdf.Br(20)
        	//create PlaceHolder
		err = pdf.PlaceHolderText("totalnumber", 30)
		if err != nil {
			log.Print(err.Error())
			return
		}

	}

    	//fillin text to PlaceHolder
	err = pdf.FillInPlaceHoldText("totalnumber",fmt.Sprintf("%d", 5), Left)
	if err != nil {
		log.Print(err.Error())
		return
	}

	pdf.WritePdf("placeholder_text.pdf")
}

visit https://github.com/oneplus1000/gopdfsample for more samples.