andriod 藍牙打印問題

用網上的一個gprinter.jar開發藍牙與收銀機的對接打印，出現如下錯誤：x + width must be <= bitmap.width()

zs這一系列的錯誤都源自於矩陣的檢測：

 

 /**
     * Shared code to check for illegal arguments passed to getPixels()
     * or setPixels()
     *
     * @param x left edge of the area of pixels to access
     * @param y top edge of the area of pixels to access
     * @param width width of the area of pixels to access
     * @param height height of the area of pixels to access
     * @param offset offset into pixels[] array
     * @param stride number of elements in pixels[] between each logical row
     * @param pixels array to hold the area of pixels being accessed
    */
    private void checkPixelsAccess(int x, int y, int width, int height,
                                   int offset, int stride, int pixels[]) {
        checkXYSign(x, y);
        if (width < 0) {
            throw new IllegalArgumentException("width must be >= 0");
        }
        if (height < 0) {
            throw new IllegalArgumentException("height must be >= 0");
        }
        if (x + width > getWidth()) {
            throw new IllegalArgumentException(
                    "x + width must be <= bitmap.width()");
        }
        if (y + height > getHeight()) {
            throw new IllegalArgumentException(
                    "y + height must be <= bitmap.height()");
        }
        if (Math.abs(stride) < width) {
            throw new IllegalArgumentException("abs(stride) must be >= width");
        }
        int lastScanline = offset + (height - 1) * stride;
        int length = pixels.length;
        if (offset < 0 || (offset + width > length)
                || lastScanline < 0
                || (lastScanline + width > length)) {
            throw new ArrayIndexOutOfBoundsException();
        }
    }

研究了哈源代碼發現問題出在resizeImage(mBitmap, width, height);這個方法調用裡面，原有方法：

 

 

 public static Bitmap resizeImage(Bitmap bitmap, int w, int h)
  {
    Bitmap BitmapOrg = bitmap;

    int width = BitmapOrg.getWidth();
    int height = BitmapOrg.getHeight();
    int newWidth = w;
    int newHeight = h;

    float scaleWidth = newWidth / width;
    float scaleHeight = newHeight / height;

    Matrix matrix = new Matrix();

    matrix.postScale(scaleWidth, scaleHeight);

    Bitmap resizedBitmap = Bitmap.createBitmap(BitmapOrg, 0, 0, width, 
      height, matrix, true);

    return resizedBitmap;
  }

這裡計算的單位換算 float=int/int>>>float=int*1.0f/int就不會報錯了，否則平板上會報錯