New daemon architecture

internal/mxw01/print.go

@@ -0,0 +1,56 @@
+package mxw01
+
+import (
+	"fmt"
+	"time"
+
+	ble "github.com/go-ble/ble"
+)
+
+func SendImageBufferToPrinter(client ble.Client, dataChr, printChr *ble.Characteristic, pixels []byte, height int, mode PrintMode, intensity byte, attMTU int) error {
+	cmd := BuildCommand(0xA2, []byte{intensity})
+	if err := client.WriteCharacteristic(printChr, cmd, true); err != nil {
+		return fmt.Errorf("intensity set failed: %v", err)
+	}
+
+	param := []byte{byte(height & 0xFF), byte(height >> 8), 0x30, byte(mode)}
+	cmd = BuildCommand(0xA9, param)
+	if err := client.WriteCharacteristic(printChr, cmd, true); err != nil {
+		return fmt.Errorf("print command failed: %v", err)
+	}
+
+	bytesPerLine := LinePixels / 8
+	if mode == Mode4bpp {
+		bytesPerLine = LinePixels / 2
+	}
+
+	// ATT_MTU includes 3 bytes of ATT overhead for Write Command/Request.
+	payloadMTU := 20
+	if attMTU > 3 {
+		payloadMTU = attMTU - 3
+	}
+	if payloadMTU < 1 {
+		payloadMTU = 1
+	}
+
+	for y := 0; y < height; y++ {
+		slice := pixels[y*bytesPerLine : (y+1)*bytesPerLine]
+		for offset := 0; offset < len(slice); offset += payloadMTU {
+			end := offset + payloadMTU
+			if end > len(slice) {
+				end = len(slice)
+			}
+			chunk := slice[offset:end]
+			if err := client.WriteCharacteristic(dataChr, chunk, true); err != nil {
+				return fmt.Errorf("line %d chunk write failed: %v", y, err)
+			}
+			time.Sleep(DefaultSleep)
+		}
+	}
+
+	cmd = BuildCommand(0xAD, []byte{0x00})
+	if err := client.WriteCharacteristic(printChr, cmd, true); err != nil {
+		return fmt.Errorf("flush failed: %v", err)
+	}
+	return nil
+}