java - 安卓连接蓝牙打印机如何打印图片bitmap?

Question

打印机打印bitmap的指令是 BITMAP x,y,width,height,mode,bitmap data, 那么将图片转为bitmap后, 如何使用呢

Answer 1

BluetoothDevice device = ... // 获取到的蓝牙设备BluetoothSocket socket = device.createRfcommSocketToServiceRecord(UUID.fromString("00001101-0000-1000-8000-00805F9B34FB")); // 创建一个BluetoothSocket来连接设备socket.connect(); // 连接到设备OutputStream outStream = socket.getOutputStream(); // 获取OutputStream来发送数据Bitmap bitmap = ... // 你的Bitmap对象ByteArrayOutputStream blob = new ByteArrayOutputStream();bitmap.compress(Bitmap.CompressFormat.PNG, 0 /* Ignored for PNGs */, blob);byte[] bitmapdata = blob.toByteArray();// 构造打印指令String command = String.format("BITMAP 0,0,%d,%d,1,", bitmap.getWidth(), bitmap.getHeight());byte[] commandData = command.getBytes();// 发送打印指令outStream.write(commandData);outStream.write(bitmapdata);

在打印图片时候，要把Bitmap转换为打印机可以识别的数据格式

把Bitmap转换为点阵图数据：

public byte[] bitmapToBytes(Bitmap bitmap) {    int width = bitmap.getWidth();    int height = bitmap.getHeight();    byte[] imgbuf = new byte[width * height / 8];    int[] pixels = new int[width * height];    bitmap.getPixels(pixels, 0, width, 0, 0, width, height);    for (int y = 0; y < height; y++) {        for (int x = 0; x < width; x++) {            int pixel = pixels[y * width + x];            if (Color.red(pixel) == 0) {                imgbuf[(y * width + x) / 8] |= (0x80 >> (x % 8));            }        }    }    return imgbuf;}

然后，用ESC/POS指令来打印点阵图：

public void printBitmap(OutputStream outStream, Bitmap bitmap) throws IOException {    byte[] imgbuf = bitmapToBytes(bitmap);    int width = bitmap.getWidth();    int height = bitmap.getHeight();    byte[] command = new byte[] { 0x1D, 0x76, 0x30, 0x00,            (byte) (width / 8), (byte) (width / 8 >> 8),            (byte) (height), (byte) (height >> 8) };    outStream.write(command);    outStream.write(imgbuf);    outStream.write(new byte[] { 0x0A, 0x0A });}

最后，用这个方法：

BluetoothDevice device = ... // 获取蓝牙设备BluetoothSocket socket = device.createRfcommSocketToServiceRecord(UUID.fromString("00001101-0000-1000-8000-00805F9B34FB")); // 创建一个BluetoothSocket来连接设备socket.connect(); // 连接到设备OutputStream outStream = socket.getOutputStream(); // 获取OutputStream来发送数据Bitmap bitmap = ... // Bitmap对象printBitmap(outStream, bitmap);