我有一个 Apex3，我已经能够关注 the documentation 的大部分内容没问题，但是当涉及到图像时，事情变得非常奇怪(缺乏示例 + 在操作方法上缺乏一致性)。

首先，我尝试使用以下命令尝试通过 JPEG 和 0 质量压缩的位图字节 [] 数组压缩的天真方法:

ESC V n1 n2数据

结果不太好。

然后我发现有一个 apex3 的 android 库接受一个位图并打算打印它但是它不起作用只是打印像这样的奇怪符号:

我尝试使用 JD gui 解码 jar 源代码，他们似乎对位图字节做了一些工作，这是他们的代码(建议代码，如 addToDoc(m_Document, ESC + "B"); 只需将代码放入一个 ByteArrayOutputStream 数据)，(反编译 source from here ):

public void writeImage(Bitmap imageObject, int printHeadWidth)
    throws IllegalArgumentException
  {
    if (imageObject == null) {
      throw new IllegalArgumentException("Parameter 'imageObject' was null.");
    }
    if (printHeadWidth < 1) {
      throw new IllegalArgumentException("Parameter 'printHeadWidth' must be greater than 0.");
    }
    int height = imageObject.getHeight();
    int width = imageObject.getWidth();
    

    byte blanklineCount = 0;
    byte[] dataline = new byte[printHeadWidth + 7 >> 3];
    int[] imageData = new int[height * width];
    
    imageObject.getPixels(imageData, 0, width, 0, 0, width, height);
    

    addToDoc(m_Document, ESC + "B");
    for (int row = 0; row < height; row++)
    {
      boolean blankLine = true;
      for (int index = 0; index < width; index += 8)
      {
        byte currentByte = 0;
        int offset = row * width + index;
        if (index >= printHeadWidth) {
          break;
        }
        int value = index + 0 < width ? imageData[(offset + 0)] & 0xFFFFFF : 16777215;
        boolean set = (value >> 0 & 0xFF) + (value >> 8 & 0xFF) + (value >> 16 & 0xFF) < 384;
        currentByte = (byte)(currentByte | (set ? -128 : 0));
        
        value = index + 1 < width ? imageData[(offset + 1)] & 0xFFFFFF : 16777215;
        set = (value >> 0 & 0xFF) + (value >> 8 & 0xFF) + (value >> 16 & 0xFF) < 384;
        currentByte = (byte)(currentByte | (set ? 64 : 0));
        
        value = index + 2 < width ? imageData[(offset + 2)] & 0xFFFFFF : 16777215;
        set = (value >> 0 & 0xFF) + (value >> 8 & 0xFF) + (value >> 16 & 0xFF) < 384;
        currentByte = (byte)(currentByte | (set ? 32 : 0));
        
        value = index + 3 < width ? imageData[(offset + 3)] & 0xFFFFFF : 16777215;
        set = (value >> 0 & 0xFF) + (value >> 8 & 0xFF) + (value >> 16 & 0xFF) < 384;
        currentByte = (byte)(currentByte | (set ? 16 : 0));
        
        value = index + 4 < width ? imageData[(offset + 4)] & 0xFFFFFF : 16777215;
        set = (value >> 0 & 0xFF) + (value >> 8 & 0xFF) + (value >> 16 & 0xFF) < 384;
        currentByte = (byte)(currentByte | (set ? 8 : 0));
        
        value = index + 5 < width ? imageData[(offset + 5)] & 0xFFFFFF : 16777215;
        set = (value >> 0 & 0xFF) + (value >> 8 & 0xFF) + (value >> 16 & 0xFF) < 384;
        currentByte = (byte)(currentByte | (set ? 4 : 0));
        
        value = index + 6 < width ? imageData[(offset + 6)] & 0xFFFFFF : 16777215;
        set = (value >> 0 & 0xFF) + (value >> 8 & 0xFF) + (value >> 16 & 0xFF) < 384;
        currentByte = (byte)(currentByte | (set ? 2 : 0));
        
        value = index + 7 < width ? imageData[(offset + 7)] & 0xFFFFFF : 16777215;
        set = (value >> 0 & 0xFF) + (value >> 8 & 0xFF) + (value >> 16 & 0xFF) < 384;
        currentByte = (byte)(currentByte | (set ? 1 : 0));
        

        dataline[(index >> 3)] = currentByte;
        blankLine &= currentByte == 0;
      }
      if (!blankLine)
      {
        if (blanklineCount > 0)
        {
          addToDoc(m_Document, "A");
          addToDoc(m_Document, blanklineCount);
          blanklineCount = 0;
        }
        addToDoc(m_Document, compressGraphicLine(dataline));
      }
      else
      {
        blanklineCount = (byte)(blanklineCount + 1);
        if (blanklineCount == 255)
        {
          addToDoc(m_Document, "A");
          addToDoc(m_Document, blanklineCount);
          blanklineCount = 0;
        }
      }
    }
    if (blanklineCount > 0)
    {
      addToDoc(m_Document, "A");
      addToDoc(m_Document, blanklineCount);
      blanklineCount = 0;
    }
    addToDoc(m_Document, ESC + "E");
  }
  
  private byte[] compressGraphicLine(byte[] dataline)
  {
    byte count = 0;
    byte currentByte = 0;
    ByteArrayOutputStream rleString = new ByteArrayOutputStream(128);
    

    addToDoc(rleString, "G");
    for (int index = 0; index < dataline.length; index++) {
      if (count == 0)
      {
        currentByte = dataline[index];
        addToDoc(rleString, currentByte);
        count = (byte)(count + 1);
      }
      else if ((count < 255) && (currentByte == dataline[index]))
      {
        count = (byte)(count + 1);
      }
      else
      {
        addToDoc(rleString, count);
        count = 0;
        

        currentByte = dataline[index];
        addToDoc(rleString, currentByte);
        count = (byte)(count + 1);
      }
    }
    if (count > 0) {
      addToDoc(rleString, count);
    }
    if (rleString.size() > dataline.length + 1)
    {
      rleString.reset();
      addToDoc(rleString, "U");
      for (int item = 0; item < dataline.length; item++) {
        addToDoc(rleString, dataline[item]);
      }
    }
    return rleString.toByteArray();
  }

但我不明白为什么它不起作用。

最后我尝试使用 How can I print an image on a Bluetooth printer in Android? 使用与指南相同的算法，但仍然打印随机的奇怪符号。

最佳答案

与其浪费时间去反编译一些 apk，不如看看官方的 SDK？在制造商网页上 Downloads & Drivers有一个链接到 Java SDK其中包括源 Sample.java。在源代码中创建了一个 BufferedImage，所以我猜(我没有这样的打印机)这将为您提供解决问题的切入点。他们很可能在同一页面上提供了 Android 演示的源代码 Printer Demo Source code for Android

编辑 好的。让我们总结一下:您有一张图像并想打印它。在示例 Sample.java 中涵盖了这种情况

  BufferedImage newImage = new BufferedImage(1024, 512, BufferedImage.TYPE_4BYTE_ABGR);
  // some lines and rectangles are drawn in the image
  ...
  // the image is printed, following the SDK javadoc for DocumentLP.writeImage
  // "This will cause the image specified to be printed. Images will be expanded to occupy
  // the entire width of the printer, so the correct current width of the printer must be
  // specified. Images that are too wide will be cropped, and images that are too narrow 
  // will be padded on the right."
  testDoc.writeImage(newImage, m_PrinterWidth);

对我来说，你唯一需要做的事情:

• 创建一个 BufferedImage 对象
• 将文件中的图像绘制到缓冲图像中
• 调用 DocumentLP 对象的 writeImage 方法

编辑2伪代码 fragment

// taken from SDK javadoc
DocumentLP docLP;
docLP = new DocumentLP("$");

// own code
BufferedInputStream bis = new BufferedInputStream(--from your image--);
BufferedImage bufImage = ImageIO.read(bis);

// have a look into Sample.java for the expected value of m_PrinterWidth
testDoc.writeImage(bufImage, m_PrinterWidth);

编辑 3 Android 代码 fragment (取自 datamax o´neil Android SDK

File file = new File(selectedPath);
byte[] readBuffer = new byte[(int)file.length()];
InputStream inputStream= new BufferedInputStream(new FileInputStream(file));
inputStream.read(readBuffer);
inputStream.close();
fileData = readBuffer;

Bitmap m_imageObject = BitmapFactory.decodeByteArray(fileData, 0, fileData.length);
documentLP.clear();
ocumentLP.writeImage(m_imageObject, m_printHeadWidth);

关于java - 打印 POS/ESC Apex3 图像 S.O.S，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/19918941/