label_printer/library_bridge.go

package main

import (
	"fmt"
    _ "time"
	"image"
	_ "image/gif"
	_ "image/jpeg"
	_ "image/png"
	"log"
	"os"
    "unsafe"
    "bytes"

	_ "github.com/jbuchbinder/gopnm"
	_ "golang.org/x/image/webp"

	"git.sr.ht/~guacamolie/faxmachine/escpos"
	"git.sr.ht/~guacamolie/faxmachine/escpos/protocol"

)

import "C"

var err error

func printer_init(path string, speed int) (*escpos.Printer) {
    p, err := escpos.StartUSBPrinter(path, protocol.TMT88IV, escpos.FlagNone)
    if err != nil {
        log.Fatalf("failed to start printer: %v", err)
    }

    if err := p.EnableASB(protocol.ASBReportAll); err != nil {
        p.Close()
        log.Fatalf("failed to enable ASB: %v", err)
    }

    go func() {
        for status := range p.ASBStatus() {
            log.Printf("received ASB status: %#v\n", status)
        }
    }()

	if err := p.SetPrintSpeed(speed); err != nil {
		log.Fatalf("failed to set print speed: %v\n", err)
	}

    return p
}

func printer_close(p *escpos.Printer) {
	if err = p.Wait(); err != nil {
		log.Fatalf("failed to print: %v\n", err)
	}
	if err = p.Close(); err != nil {
		log.Fatalf("failed to close printer: %v\n", err)
    }
    fmt.Print("printer closed\n");
}

//export cut
func cut(path *C.char) {
    fmt.Print("Starting cut\n");
    p := printer_init(C.GoString(path), 1)

	if err = p.CutPaper(); err != nil {
		log.Fatalf("failed to cut paper: %v", err)
	}

    printer_close(p)
    //time.Sleep(1000 * time.Millisecond)
}

//export print_text
func print_text(path *C.char, str *C.char) {
    p := printer_init(C.GoString(path), 1)

	fmt.Fprint(p, C.GoString(str))
	fmt.Fprint(p, "\n")

    printer_close(p)
}

//export print_image
func print_image(path *C.char, data *C.uchar, size C.int) {
    p := printer_init(C.GoString(path), 1)

	go func() {
		for status := range p.ASBStatus() {
			log.Printf("received ASB status: %#v\n", status)
		}
	}()

    byteData := C.GoBytes(unsafe.Pointer(data), C.int(size))
    imgReader := bytes.NewReader(byteData)
	img, _, err := image.Decode(imgReader)
	if err != nil {
		log.Fatalf("failed to get decode image: %v\n", err)
	}
	if err := p.PrintImage(img); err != nil {
		log.Fatalf("failed to print image: %v\n", err)
	}

	if len(os.Args) > 2 && os.Args[2] != "" {
		fmt.Fprintf(p, "\n%s\n", os.Args[2])
	}

	if err := p.Wait(); err != nil {
		log.Fatalf("failed to print: %v\n", err)
	}

}


func main() {}