zitadel/internal/qrcode/qr_svg.go

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package qrcode
import (
"errors"
"image/color"
"github.com/ajstarks/svgo"
"github.com/boombuler/barcode"
)
// QrSVG holds the data related to the size, location,
// and block size of the QR Code. Holds unexported fields.
type QrSVG struct {
qr barcode.Barcode
qrWidth int
blockSize int
startingX int
startingY int
}
// NewQrSVG contructs a QrSVG struct. It takes a QR Code in the form
// of barcode.Barcode and sets the "pixel" or block size of QR Code in
// the SVG file.
func NewQrSVG(qr barcode.Barcode, blockSize int) QrSVG {
return QrSVG{
qr: qr,
qrWidth: qr.Bounds().Max.X,
blockSize: blockSize,
startingX: 0,
startingY: 0,
}
}
// WriteQrSVG writes the QR Code to SVG.
func (qs *QrSVG) WriteQrSVG(s *svg.SVG) error {
if qs.qr.Metadata().CodeKind == "QR Code" {
currY := qs.startingY
for x := 0; x < qs.qrWidth; x++ {
currX := qs.startingX
for y := 0; y < qs.qrWidth; y++ {
if qs.qr.At(x, y) == color.Black {
s.Rect(currX, currY, qs.blockSize, qs.blockSize, "class=\"color\"")
} else if qs.qr.At(x, y) == color.White {
s.Rect(currX, currY, qs.blockSize, qs.blockSize, "class=\"bg-color\"")
}
currX += qs.blockSize
}
currY += qs.blockSize
}
return nil
}
return errors.New("can not write to SVG: Not a QR code")
}
// SetStartPoint sets the top left start point of QR Code.
// This takes an X and Y value and then adds four white "blocks"
// to create the "quiet zone" around the QR Code.
func (qs *QrSVG) SetStartPoint(x, y int) {
qs.startingX = x + (qs.blockSize * 4)
qs.startingY = y + (qs.blockSize * 4)
}
// StartQrSVG creates a start for writing an SVG file that
// only contains a barcode. This is similar to the svg.Start() method.
// This fucntion should only be used if you only want to write a QR code
// to the SVG. Otherwise use the regular svg.Start() method to start your
// SVG file.
func (qs *QrSVG) StartQrSVG(s *svg.SVG) {
width := (qs.qrWidth * qs.blockSize) + (qs.blockSize * 8)
qs.SetStartPoint(0, 0)
s.Start(width, width)
}