qr_labels/main.go

package main

import (
	"fmt"
	"image/color"

	"codeberg.org/go-pdf/fpdf"
	"github.com/yeqown/go-qrcode/v2"
	"github.com/yeqown/go-qrcode/writer/standard"
)

// 1

var cols = 4
var rows = 5
var qrSize = 40
var fontSize = 20

func main() {
	qrc, err := qrcode.New("https://nanocat.net")
	if err != nil {
		fmt.Printf("could not generate QRCode: %v", err)
		return
	}

	b := newBWC()
	qrBytes := standard.NewWithWriter(&b,
		// standard.WithQRWidth(uint8(qrSize)),
		standard.WithBorderWidth(0),
		standard.WithBuiltinImageEncoder(standard.PNG_FORMAT),
		standard.WithCircleShape(),
		standard.WithFgGradient(&standard.LinearGradient{
			Stops: []standard.ColorStop{{
				T: 0.0,
				Color: color.RGBA{
					R: 255,
					G: 0,
					B: 0,
					A: 0,
				},
			}, {
				T: 1.0,
				Color: color.RGBA{
					R: 0,
					G: 255,
					B: 0,
					A: 0,
				},
			}},
			Angle: 45,
		}), standard.WithLogoImageFileJPEG("cat-pet-animal-domestic-104827.jpeg"),
	)

	// save file
	if err = qrc.Save(qrBytes); err != nil {
		fmt.Printf("could not save image: %v", err)
	}
	// dim := qrc.Dimension()

	pdf := fpdf.New("P", "mm", "A4", "")
	pdf.SetMargins(0, 0, 0)
	pageWidth, pageHeight := pdf.GetPageSize()

	// register the qr
	pdf.RegisterImageOptionsReader("qr", fpdf.ImageOptions{
		ImageType:             "png",
		ReadDpi:               false,
		AllowNegativePosition: false,
	}, b)

	info := pdf.GetImageInfo("qr")
	// panic(info.Height())

	pdf.AddPage()
	pdf.SetFont("Arial", "B", float64(fontSize))

	text := "foobar"
	textWidth := pdf.GetStringWidth(text)

	colWidth := pageWidth / float64(cols)
	rowHeight := pageHeight / float64(rows)

	for rowIdx := range rows {
		for colIdx := range cols {
			topLeftX := colWidth * float64(colIdx)
			topLeftY := rowHeight * float64(rowIdx)

			// if rowHeight*0.8 < float64(qrSize) {
			// 	panic("row too small for qr")
			// }
			// if colWidth*0.6 < float64(qrSize) {
			// 	panic("col too small for qr")
			// }

			// label at the top
			pdf.Text(
				topLeftX+colWidth/2-textWidth/2,
				topLeftY+float64(fontSize),
				text, // +fmt.Sprintf("%d/%d", rowIdx, colIdx)
			)

			info.Height()
			// pdf at the bottom
			pdf.ImageOptions("qr",
				topLeftX+info.Width()-float64(qrSize), //+float64(dim)/2,        // centre
				topLeftY+float64(fontSize)*1.3,        // centre
				float64(qrSize), float64(qrSize),
				false,
				fpdf.ImageOptions{AllowNegativePosition: true}, 0, "")
			// pdf.Image("qr",
			// 	topLeftX+5,                     // centre
			// 	topLeftY+float64(fontSize)*1.3, // centre
			// 	float64(qrSize),
			// 	float64(qrSize),
			// 	false, "tp", 0, "")

		}
	}

	err = pdf.OutputFileAndClose("hello.pdf")
	if err != nil {
		panic(err)
	}
	fmt.Println(pageWidth, pageHeight)
}