package main import ( "errors" "html/template" "image" "image/color" "image/draw" "image/png" "io" "log" "net/http" "os" "strconv" "time" "github.com/boombuler/barcode" "github.com/boombuler/barcode/qr" "janouch.name/sklad/bdf" ) // scaler is a scaling image.Image wrapper. type scaler struct { image image.Image scale int } // ColorModel implements image.Image. func (s *scaler) ColorModel() color.Model { return s.image.ColorModel() } // Bounds implements image.Image. func (s *scaler) Bounds() image.Rectangle { r := s.image.Bounds() return image.Rect(r.Min.X*s.scale, r.Min.Y*s.scale, r.Max.X*s.scale, r.Max.Y*s.scale) } // At implements image.Image. func (s *scaler) At(x, y int) color.Color { if x < 0 { x = x - s.scale + 1 } if y < 0 { y = y - s.scale + 1 } return s.image.At(x/s.scale, y/s.scale) } // ----------------------------------------------------------------------------- func decodeBitfieldErrors(b byte, errors [8]string) []string { var result []string for i := uint(0); i < 8; i++ { if b&(1<= bounds.Min.X; x-- { // TODO: Anything to do with the ColorModel? r, g, b, a := src.At(x, y).RGBA() pixels[off] = r == 0 && g == 0 && b == 0 && a != 0 off++ } data = append(data, 'g', 0x00, 90) for i := 0; i < 90; i++ { var b byte for j := 0; j < 8; j++ { b <<= 1 if pixels[i*8+j] { b |= 1 } } data = append(data, b) } } return } func printLabel(src image.Image) error { data := []byte(nil) // Raster mode. // Should be the only supported mode for QL-800. data = append(data, 0x1b, 0x69, 0x61, 0x01) // Automatic status mode (though it's the default). data = append(data, 0x1b, 0x69, 0x21, 0x00) // Print information command. dy := src.Bounds().Dy() data = append(data, 0x1b, 0x69, 0x7a, 0x02|0x04|0x40|0x80, 0x0a, 29, 0, byte(dy), byte(dy>>8), byte(dy>>16), byte(dy>>24), 0, 0x00) // Auto cut, each 1 label. data = append(data, 0x1b, 0x69, 0x4d, 0x40) data = append(data, 0x1b, 0x69, 0x41, 0x01) // Cut at end (though it's the default). // Not sure what it means, doesn't seem to have any effect to turn it off. data = append(data, 0x1b, 0x69, 0x4b, 0x08) // 3mm margins along the direction of feed. 0x23 = 35 dots, the minimum. data = append(data, 0x1b, 0x69, 0x64, 0x23, 0x00) // Compression mode: no compression. // Should be the only supported mode for QL-800. data = append(data, 0x4d, 0x00) // The graphics data itself. data = append(data, genLabelData(src, 6)...) // Print command with feeding. data = append(data, 0x1a) // --- // Linux usblp module, located in /drivers/usb/class/usblp.c // (at least that's where the trails go, I don't understand the code) f, err := os.OpenFile("/dev/usb/lp0", os.O_RDWR, 0) if err != nil { return err } defer f.Close() // Flush any former responses in the printer's queue. for { dummy := make([]byte, 32) if _, err := f.Read(dummy); err == io.EOF { break } } // Clear the print buffer. invalidate := make([]byte, 400) if _, err := f.Write(invalidate); err != nil { return err } // Initialize. if _, err := f.WriteString("\x1b\x40"); err != nil { return err } // Request status information. if _, err := f.WriteString("\x1b\x69\x53"); err != nil { return err } // We need to poll the device. status := make([]byte, 32) for { if n, err := f.Read(status); err == io.EOF { time.Sleep(10 * time.Millisecond) } else if err != nil { return err } else if n < 32 { return errors.New("invalid read") } else { break } } printStatusInformation(status) // Print the prepared data. if _, err := f.Write(data); err != nil { return err } // TODO: We specifically need to wait for a transition to the receiving // state, and try to figure out something from the statuses. // We may also receive an error status instead of the transition to // the printing state. Or even after it. start := time.Now() for { if time.Now().Sub(start) > 3*time.Second { break } if n, err := f.Read(status); err == io.EOF { time.Sleep(100 * time.Millisecond) } else if err != nil { return err } else if n < 32 { return errors.New("invalid read") } else { printStatusInformation(status) } } return nil } // ----------------------------------------------------------------------------- var font *bdf.Font // TODO: By rotating the label we can make it smaller, as an alternate mode. func genLabel(text string, width int) image.Image { // Create a scaled bitmap of the QR code. qrImg, _ := qr.Encode(text, qr.H, qr.Auto) qrImg, _ = barcode.Scale(qrImg, 306, 306) qrRect := qrImg.Bounds() // Create a scaled bitmap of the text label. textRect, _ := font.BoundString(text) textImg := image.NewRGBA(textRect) draw.Draw(textImg, textRect, image.White, image.ZP, draw.Src) font.DrawString(textImg, image.ZP, text) // TODO: We can scale as needed to make the text fit. scaledTextImg := scaler{image: textImg, scale: 3} scaledTextRect := scaledTextImg.Bounds() // Combine. combinedRect := qrRect combinedRect.Max.Y += scaledTextRect.Dy() + 20 combinedImg := image.NewRGBA(combinedRect) draw.Draw(combinedImg, combinedRect, image.White, image.ZP, draw.Src) draw.Draw(combinedImg, combinedRect, qrImg, image.ZP, draw.Src) target := image.Rect( (width-scaledTextRect.Dx())/2, qrRect.Dy()+10, combinedRect.Max.X, combinedRect.Max.Y) draw.Draw(combinedImg, target, &scaledTextImg, scaledTextRect.Min, draw.Src) return combinedImg } var tmpl = template.Must(template.New("form").Parse(`

`)) func handle(w http.ResponseWriter, r *http.Request) { if err := r.ParseForm(); err != nil { http.Error(w, err.Error(), 500) return } var params = struct { Width int Text string }{ Text: r.FormValue("text"), } var err error params.Width, err = strconv.Atoi(r.FormValue("width")) if err != nil { params.Width = 306 // Default to 29mm tape. } label := genLabel(params.Text, params.Width) if r.FormValue("print") != "" { if err := printLabel(label); err != nil { log.Println("print error:", err) } } if _, ok := r.Form["img"]; !ok { w.Header().Set("Content-Type", "text/html") tmpl.Execute(w, ¶ms) return } w.Header().Set("Content-Type", "image/png") if err := png.Encode(w, label); err != nil { http.Error(w, err.Error(), 500) return } } func main() { var err error fi, err := os.Open("../../ucs-fonts-75dpi100dpi/100dpi/luBS24.bdf") if err != nil { log.Fatalln(err) } font, err = bdf.NewFromBDF(fi) if err != nil { log.Fatalln(err) } if err := fi.Close(); err != nil { log.Fatalln(err) } log.Println("Starting server") http.HandleFunc("/", handle) log.Fatal(http.ListenAndServe(":8080", nil)) }