bleh/main.go
2025-06-20 08:04:27 -03:00

334 lines
8.7 KiB
Go

// catprinter_ble.go
// A Go reimplementation of the CatPrinterBLE utility
// using Go's BLE stack and Image processing libraries
package main
import (
"context"
"fmt"
"image/color"
"github.com/disintegration/imaging"
"log"
"os"
"os/signal"
"time"
ble "github.com/go-ble/ble"
"github.com/go-ble/ble/linux"
)
var (
mainServiceUUID = ble.MustParse("ae30")
printCharacteristic = ble.MustParse("ae01")
notifyCharacteristic = ble.MustParse("ae02")
dataCharacteristic = ble.MustParse("ae03")
targetPrinterName = "MXW01"
scanTimeout = 10 * time.Second
printCommandHeader = []byte{0x22, 0x21}
printCommandFooter = byte(0xFF)
)
func min(a, b int) int {
if a < b {
return a
}
return b
}
func reverseBitsInByte(b byte) byte {
b = (b&0xF0)>>4 | (b&0x0F)<<4
b = (b&0xCC)>>2 | (b&0x33)<<2
b = (b&0xAA)>>1 | (b&0x55)<<1
return b
}
func dumpCharacteristics(client ble.Client, svc *ble.Service) {
chars, err := client.DiscoverCharacteristics(nil, svc)
if err != nil {
log.Fatalf("Error discovering characteristics: %v", err)
}
log.Printf("Discovered %d characteristics:", len(chars))
for _, c := range chars {
props := ""
if c.Property&ble.CharRead != 0 {
props += "Read "
}
if c.Property&ble.CharWrite != 0 {
props += "Write "
}
if c.Property&ble.CharWriteNR != 0 {
props += "WriteWithoutResponse "
}
if c.Property&ble.CharNotify != 0 {
props += "Notify "
}
if c.Property&ble.CharIndicate != 0 {
props += "Indicate "
}
log.Printf(" UUID: %s, Properties: %s", c.UUID, props)
}
}
func parseNotification(data []byte) {
if len(data) < 10 || data[0] != 0x22 || data[1] != 0x21 {
fmt.Println("Invalid notification header")
return
}
cmd := data[2]
switch cmd {
case 0xA1: // GetStatus
battery := data[9]
temp := data[10]
statusOk := data[12] == 0
statusCode := data[6]
errCode := data[13]
statusMsg := "Unknown"
if statusOk {
switch statusCode {
case 0x0:
statusMsg = "Standby"
case 0x1:
statusMsg = "Printing"
case 0x2:
statusMsg = "Feeding paper"
case 0x3:
statusMsg = "Ejecting paper"
}
} else {
switch errCode {
case 0x1, 0x9:
statusMsg = "No paper"
case 0x4:
statusMsg = "Overheated"
case 0x8:
statusMsg = "Low battery"
}
}
fmt.Printf("Status: %v (%s), Battery: %d, Temp: %d\n", statusOk, statusMsg, battery, temp)
default:
fmt.Printf("Unhandled command: 0x%02X\n", cmd)
}
}
const (
linePixels = 384
bytesPerLine = linePixels / 8
)
// Convert image to 1bpp, dithered, and packed bytes
func loadImageMono(path string) ([]byte, int, error) {
img, err := imaging.Open(path, imaging.AutoOrientation(true))
if err != nil {
return nil, 0, fmt.Errorf("image open error: %v", err)
}
ratio := float64(img.Bounds().Dx()) / float64(img.Bounds().Dy())
height := int(float64(linePixels) / ratio)
img = imaging.Resize(img, linePixels, height, imaging.Lanczos)
img = imaging.Grayscale(img)
img = imaging.AdjustContrast(img, 10)
pixels := make([]byte, (linePixels*height)/8)
for y := 0; y < height; y++ {
for x := 0; x < linePixels; x++ {
gray := color.GrayModel.Convert(img.At(x, y)).(color.Gray)
if gray.Y < 127 {
idx := (y*linePixels + x) / 8
bit := 7 - (x % 8)
pixels[idx] |= 1 << bit
}
}
}
return pixels, height, nil
}
func sendImageToPrinter(client ble.Client, dataChr, printChr *ble.Characteristic, path string) error {
pixels, height, err := loadImageMono(path)
if err != nil {
return err
}
fmt.Printf("Sending image: %dx%d lines\n", linePixels, height)
cmd := buildCommand(0xA2, []byte{80}) // intensity 80
err = client.WriteCharacteristic(printChr, cmd, true)
if err != nil {
return fmt.Errorf("intensity set failed: %v", err)
}
lines := height
param := []byte{
byte(lines & 0xFF), byte(lines >> 8),
0x30, // reserved
0x00, // 1bpp mode
}
cmd = buildCommand(0xA9, param)
err = client.WriteCharacteristic(printChr, cmd, true)
if err != nil {
return fmt.Errorf("print command failed: %v", err)
}
for y := 0; y < lines; y++ {
slice := pixels[y*bytesPerLine : (y+1)*bytesPerLine]
reversed := make([]byte, bytesPerLine)
for i := 0; i < bytesPerLine; i++ {
reversed[i] = reverseBitsInByte(slice[i])
}
err := client.WriteCharacteristic(dataChr, reversed, true)
if err != nil {
return fmt.Errorf("line %d write failed: %v", y, err)
}
time.Sleep(6 * time.Millisecond)
}
cmd = buildCommand(0xAD, []byte{0x00}) // flush
err = client.WriteCharacteristic(printChr, cmd, true)
if err != nil {
return fmt.Errorf("flush failed: %v", err)
}
return nil
}
func main() {
if len(os.Args) < 2 {
fmt.Println("Usage: catprinter-ble <image_path>")
return
}
imagePath := os.Args[1]
ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt)
defer stop()
d, err := linux.NewDevice()
if err != nil {
log.Fatalf("Failed to open BLE device: %v", err)
}
ble.SetDefaultDevice(d)
log.Println("Scanning for printer...")
var adv ble.Advertisement
ctxScan, cancel := context.WithTimeout(ctx, 10*time.Second)
err = ble.Scan(ctxScan, false, func(a ble.Advertisement) {
if a.LocalName() == targetPrinterName {
adv = a
cancel()
}
}, nil)
if err != nil && err != context.Canceled {
log.Fatalf("Scan error: %v", err)
}
if adv == nil {
log.Println("Printer not found.")
return
}
log.Println("Connecting...")
client, err := ble.Dial(ctx, adv.Addr())
if err != nil {
log.Fatalf("Connect failed: %v", err)
}
defer client.CancelConnection()
mtu, err := client.ExchangeMTU(100)
if err != nil {
log.Printf("MTU negotiation failed, continuing with default MTU. Reason: %v", err)
} else {
log.Printf("Negotiated ATT MTU: %d", mtu)
}
services, err := client.DiscoverServices([]ble.UUID{mainServiceUUID})
if err != nil || len(services) == 0 {
log.Fatalf("Service discovery failed: %v", err)
}
svc := services[0]
chars, err := client.DiscoverCharacteristics(nil, svc)
if err != nil {
log.Fatalf("Char discovery failed: %v", err)
}
var printChr, dataChr *ble.Characteristic
for _, c := range chars {
switch c.UUID.String() {
case printCharacteristic.String():
printChr = c
case dataCharacteristic.String():
dataChr = c
}
}
if printChr == nil || dataChr == nil {
log.Fatalf("Required characteristics missing")
}
err = sendImageToPrinter(client, dataChr, printChr, imagePath)
if err != nil {
log.Fatalf("Failed to print image: %v", err)
}
log.Println("Done!")
}
func buildCommand(cmdId byte, payload []byte) []byte {
cmd := append([]byte{}, printCommandHeader...)
cmd = append(cmd, cmdId)
cmd = append(cmd, 0x00) // reserved
cmd = append(cmd, byte(len(payload)&0xFF), byte(len(payload)>>8))
cmd = append(cmd, payload...)
cmd = append(cmd, calculateCRC8(payload))
cmd = append(cmd, printCommandFooter)
return cmd
}
func calculateCRC8(data []byte) byte {
table := [256]byte{
0x00, 0x07, 0x0e, 0x09, 0x1c, 0x1b, 0x12, 0x15,
0x38, 0x3f, 0x36, 0x31, 0x24, 0x23, 0x2a, 0x2d,
0x70, 0x77, 0x7e, 0x79, 0x6c, 0x6b, 0x62, 0x65,
0x48, 0x4f, 0x46, 0x41, 0x54, 0x53, 0x5a, 0x5d,
0xe0, 0xe7, 0xee, 0xe9, 0xfc, 0xfb, 0xf2, 0xf5,
0xd8, 0xdf, 0xd6, 0xd1, 0xc4, 0xc3, 0xca, 0xcd,
0x90, 0x97, 0x9e, 0x99, 0x8c, 0x8b, 0x82, 0x85,
0xa8, 0xaf, 0xa6, 0xa1, 0xb4, 0xb3, 0xba, 0xbd,
0xc7, 0xc0, 0xc9, 0xce, 0xdb, 0xdc, 0xd5, 0xd2,
0xff, 0xf8, 0xf1, 0xf6, 0xe3, 0xe4, 0xed, 0xea,
0xb7, 0xb0, 0xb9, 0xbe, 0xab, 0xac, 0xa5, 0xa2,
0x8f, 0x88, 0x81, 0x86, 0x93, 0x94, 0x9d, 0x9a,
0x27, 0x20, 0x29, 0x2e, 0x3b, 0x3c, 0x35, 0x32,
0x1f, 0x18, 0x11, 0x16, 0x03, 0x04, 0x0d, 0x0a,
0x57, 0x50, 0x59, 0x5e, 0x4b, 0x4c, 0x45, 0x42,
0x6f, 0x68, 0x61, 0x66, 0x73, 0x74, 0x7d, 0x7a,
0x89, 0x8e, 0x87, 0x80, 0x95, 0x92, 0x9b, 0x9c,
0xb1, 0xb6, 0xbf, 0xb8, 0xad, 0xaa, 0xa3, 0xa4,
0xf9, 0xfe, 0xf7, 0xf0, 0xe5, 0xe2, 0xeb, 0xec,
0xc1, 0xc6, 0xcf, 0xc8, 0xdd, 0xda, 0xd3, 0xd4,
0x69, 0x6e, 0x67, 0x60, 0x75, 0x72, 0x7b, 0x7c,
0x51, 0x56, 0x5f, 0x58, 0x4d, 0x4a, 0x43, 0x44,
0x19, 0x1e, 0x17, 0x10, 0x05, 0x02, 0x0b, 0x0c,
0x21, 0x26, 0x2f, 0x28, 0x3d, 0x3a, 0x33, 0x34,
0x4e, 0x49, 0x40, 0x47, 0x52, 0x55, 0x5c, 0x5b,
0x76, 0x71, 0x78, 0x7f, 0x6a, 0x6d, 0x64, 0x63,
0x3e, 0x39, 0x30, 0x37, 0x22, 0x25, 0x2c, 0x2b,
0x06, 0x01, 0x08, 0x0f, 0x1a, 0x1d, 0x14, 0x13,
0xae, 0xa9, 0xa0, 0xa7, 0xb2, 0xb5, 0xbc, 0xbb,
0x96, 0x91, 0x98, 0x9f, 0x8a, 0x8d, 0x84, 0x83,
0xde, 0xd9, 0xd0, 0xd7, 0xc2, 0xc5, 0xcc, 0xcb,
0xe6, 0xe1, 0xe8, 0xef, 0xfa, 0xfd, 0xf4, 0xf3}
crc := byte(0)
for _, b := range data {
crc = table[crc^b]
}
return crc
}