Erweiterung von Kurt Jungs gopdf, das leider nicht weiterentwickelt wird https://github.com/jung-kurt/gofpdf
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// Copyright (c) 2015 Jelmer Snoeck (Gmail: jelmer.snoeck)
//
// Permission to use, copy, modify, and distribute this software for any purpose
// with or without fee is hereby granted, provided that the above copyright notice
// and this permission notice appear in all copies.
//
// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
// FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
// OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
// PERFORMANCE OF THIS SOFTWARE.
// Package barcode provides helper methods for adding barcodes of different
// types to your pdf document. It relies on the github.com/boombuler/barcode
// package for the barcode creation.
package barcode
import (
"bytes"
"errors"
"image/jpeg"
"io"
"strconv"
"sync"
"github.com/boombuler/barcode"
"github.com/boombuler/barcode/aztec"
"github.com/boombuler/barcode/codabar"
"github.com/boombuler/barcode/code128"
"github.com/boombuler/barcode/code39"
"github.com/boombuler/barcode/datamatrix"
"github.com/boombuler/barcode/ean"
"github.com/boombuler/barcode/qr"
"github.com/boombuler/barcode/twooffive"
"github.com/jung-kurt/gofpdf"
"github.com/ruudk/golang-pdf417"
)
// barcodes represents the barcodes that have been registered through this
// package. They will later be used to be scaled and put on the page.
// RubenN: made this a struct with a mutex to prevent race condition
var barcodes struct {
sync.Mutex
cache map[string]barcode.Barcode
}
// barcodePdf is a partial PDF implementation that only implements a subset of
// functions that are required to add the barcode to the PDF.
type barcodePdf interface {
GetConversionRatio() float64
GetImageInfo(imageStr string) *gofpdf.ImageInfoType
Image(imageNameStr string, x, y, w, h float64, flow bool, tp string, link int, linkStr string)
RegisterImageReader(imgName, tp string, r io.Reader) *gofpdf.ImageInfoType
SetError(err error)
}
// printBarcode internally prints the scaled or unscaled barcode to the PDF. Used by both
// Barcode() and BarcodeUnscalable().
func printBarcode(pdf barcodePdf, code string, x, y float64, w, h *float64, flow bool) {
barcodes.Lock()
unscaled, ok := barcodes.cache[code]
barcodes.Unlock()
if !ok {
err := errors.New("Barcode not found")
pdf.SetError(err)
return
}
bname := uniqueBarcodeName(code, x, y)
info := pdf.GetImageInfo(bname)
scaleToWidth := unscaled.Bounds().Dx()
scaleToHeight := unscaled.Bounds().Dy()
if info == nil {
bcode, err := barcode.Scale(
unscaled,
scaleToWidth,
scaleToHeight,
)
if err != nil {
pdf.SetError(err)
return
}
err = registerScaledBarcode(pdf, bname, bcode)
if err != nil {
pdf.SetError(err)
return
}
}
scaleToWidthF := float64(scaleToWidth)
scaleToHeightF := float64(scaleToHeight)
if w != nil {
scaleToWidthF = *w
}
if h != nil {
scaleToHeightF = *h
}
pdf.Image(bname, x, y, scaleToWidthF, scaleToHeightF, flow, "jpg", 0, "")
}
// BarcodeUnscalable puts a registered barcode in the current page.
//
// Its arguments work in the same way as that of Barcode(). However, it allows for an unscaled
// barcode in the width and/or height dimensions. This can be useful if you want to prevent
// side effects of upscaling.
func BarcodeUnscalable(pdf barcodePdf, code string, x, y float64, w, h *float64, flow bool) {
printBarcode(pdf, code, x, y, w, h, flow)
}
// Barcode puts a registered barcode in the current page.
//
// The size should be specified in the units used to create the PDF document.
// If width or height are left unspecfied, the barcode is not scaled in the unspecified dimensions.
//
// Positioning with x, y and flow is inherited from Fpdf.Image().
func Barcode(pdf barcodePdf, code string, x, y, w, h float64, flow bool) {
printBarcode(pdf, code, x, y, &w, &h, flow)
}
// GetUnscaledBarcodeDimensions returns the width and height of the
// unscaled barcode associated with the given code.
func GetUnscaledBarcodeDimensions(pdf barcodePdf, code string) (w, h float64) {
barcodes.Lock()
unscaled, ok := barcodes.cache[code]
barcodes.Unlock()
if !ok {
err := errors.New("Barcode not found")
pdf.SetError(err)
return
}
return convertFrom96Dpi(pdf, float64(unscaled.Bounds().Dx())),
convertFrom96Dpi(pdf, float64(unscaled.Bounds().Dy()))
}
// Register registers a barcode but does not put it on the page. Use Barcode()
// with the same code to put the barcode on the PDF page.
func Register(bcode barcode.Barcode) string {
barcodes.Lock()
if len(barcodes.cache) == 0 {
barcodes.cache = make(map[string]barcode.Barcode)
}
key := barcodeKey(bcode)
barcodes.cache[key] = bcode
barcodes.Unlock()
return key
}
// RegisterAztec registers a barcode of type Aztec to the PDF, but not to
// the page. Use Barcode() with the return value to put the barcode on the page.
// code is the string to be encoded. minECCPercent is the error correction percentage. 33 is the default.
// userSpecifiedLayers can be a value between -4 and 32 inclusive.
func RegisterAztec(pdf barcodePdf, code string, minECCPercent int, userSpecifiedLayers int) string {
bcode, err := aztec.Encode([]byte(code), minECCPercent, userSpecifiedLayers)
return registerBarcode(pdf, bcode, err)
}
// RegisterCodabar registers a barcode of type Codabar to the PDF, but not to
// the page. Use Barcode() with the return value to put the barcode on the page.
func RegisterCodabar(pdf barcodePdf, code string) string {
bcode, err := codabar.Encode(code)
return registerBarcode(pdf, bcode, err)
}
// RegisterCode128 registers a barcode of type Code128 to the PDF, but not to
// the page. Use Barcode() with the return value to put the barcode on the page.
func RegisterCode128(pdf barcodePdf, code string) string {
bcode, err := code128.Encode(code)
return registerBarcode(pdf, bcode, err)
}
// RegisterCode39 registers a barcode of type Code39 to the PDF, but not to
// the page. Use Barcode() with the return value to put the barcode on the page.
//
// includeChecksum and fullASCIIMode are inherited from code39.Encode().
func RegisterCode39(pdf barcodePdf, code string, includeChecksum, fullASCIIMode bool) string {
bcode, err := code39.Encode(code, includeChecksum, fullASCIIMode)
return registerBarcode(pdf, bcode, err)
}
// RegisterDataMatrix registers a barcode of type DataMatrix to the PDF, but not
// to the page. Use Barcode() with the return value to put the barcode on the
// page.
func RegisterDataMatrix(pdf barcodePdf, code string) string {
bcode, err := datamatrix.Encode(code)
return registerBarcode(pdf, bcode, err)
}
// RegisterPdf417 registers a barcode of type Pdf417 to the PDF, but not to the
// page. code is the string to be encoded. columns specifies the number of
// barcode columns; this should be a value between 1 and 30 inclusive.
// securityLevel specifies an error correction level between zero and 8
// inclusive. Barcodes for use with FedEx must set columns to 10 and
// securityLevel to 5. Use Barcode() with the return value to put the barcode
// on the page.
func RegisterPdf417(pdf barcodePdf, code string, columns int, securityLevel int) string {
bcode := pdf417.Encode(code, columns, securityLevel)
return registerBarcode(pdf, bcode, nil)
}
// RegisterEAN registers a barcode of type EAN to the PDF, but not to the page.
// It will automatically detect if the barcode is EAN8 or EAN13. Use Barcode()
// with the return value to put the barcode on the page.
func RegisterEAN(pdf barcodePdf, code string) string {
bcode, err := ean.Encode(code)
return registerBarcode(pdf, bcode, err)
}
// RegisterQR registers a barcode of type QR to the PDF, but not to the page.
// Use Barcode() with the return value to put the barcode on the page.
//
// The ErrorCorrectionLevel and Encoding mode are inherited from qr.Encode().
func RegisterQR(pdf barcodePdf, code string, ecl qr.ErrorCorrectionLevel, mode qr.Encoding) string {
bcode, err := qr.Encode(code, ecl, mode)
return registerBarcode(pdf, bcode, err)
}
// RegisterTwoOfFive registers a barcode of type TwoOfFive to the PDF, but not
// to the page. Use Barcode() with the return value to put the barcode on the
// page.
//
// The interleaved bool is inherited from twooffive.Encode().
func RegisterTwoOfFive(pdf barcodePdf, code string, interleaved bool) string {
bcode, err := twooffive.Encode(code, interleaved)
return registerBarcode(pdf, bcode, err)
}
// registerBarcode registers a barcode internally using the Register() function.
// In case of an error generating the barcode it will not be registered and will
// set an error on the PDF. It will return a unique key for the barcode type and
// content that can be used to put the barcode on the page.
func registerBarcode(pdf barcodePdf, bcode barcode.Barcode, err error) string {
if err != nil {
pdf.SetError(err)
return ""
}
return Register(bcode)
}
// uniqueBarcodeName makes sure every barcode has a unique name for its
// dimensions. Scaling a barcode image results in quality loss, which could be
// a problem for barcode readers.
func uniqueBarcodeName(code string, x, y float64) string {
xStr := strconv.FormatFloat(x, 'E', -1, 64)
yStr := strconv.FormatFloat(y, 'E', -1, 64)
return "barcode-" + code + "-" + xStr + yStr
}
// barcodeKey combines the code type and code value into a unique identifier for
// a barcode type. This is so that we can store several barcodes with the same
// code but different type in the barcodes map.
func barcodeKey(bcode barcode.Barcode) string {
return bcode.Metadata().CodeKind + bcode.Content()
}
// registerScaledBarcode registers a barcode with its exact dimensions to the
// PDF but does not put it on the page. Use Fpdf.Image() with the same code to
// add the barcode to the page.
func registerScaledBarcode(pdf barcodePdf, code string, bcode barcode.Barcode) error {
buf := new(bytes.Buffer)
err := jpeg.Encode(buf, bcode, nil)
if err != nil {
return err
}
reader := bytes.NewReader(buf.Bytes())
pdf.RegisterImageReader(code, "jpg", reader)
return nil
}
// convertTo96DPI converts the given value, which is based on a 72 DPI value
// like the rest of the PDF document, to a 96 DPI value that is required for
// an Image.
//
// Doing this through the Fpdf.Image() function would mean that it uses a 72 DPI
// value and stretches it to a 96 DPI value. This results in quality loss which
// could be problematic for barcode scanners.
func convertTo96Dpi(pdf barcodePdf, value float64) float64 {
return value * pdf.GetConversionRatio() / 72 * 96
}
// convertFrom96Dpi converts the given value, which is based on a 96 DPI value
// required for an Image, to a 72 DPI value like the rest of the PDF document.
func convertFrom96Dpi(pdf barcodePdf, value float64) float64 {
return value / pdf.GetConversionRatio() * 72 / 96
}