Zxing调整扫描区域 优化取图速度

Zxing 是google提供的二维码扫描工程
Demo本身默认的扫图区域最大只有 360*480    需要拉开很远的距离才能将整个二维码扫描到
因此需要我们自己调整取图大小
 
在CameraManager.java这个类中进行调整

默认的大小是 以下这4个参数 

//  private static final int MIN_FRAME_WIDTH = 240;
//  private static final int MIN_FRAME_HEIGHT = 240;
//  private static final int MAX_FRAME_WIDTH = 480;
//  private static final int MAX_FRAME_HEIGHT = 360;

根据屏幕大小调整      大家可以增大这些数值 : 最小的宽 高    ; 最大宽高
 
参数实际在 getFramingRect() 方法中起作用
以下是原本Demo中提供的

 /**
   * Calculates the framing rect which the UI should draw to show the user where to place the
   * barcode. This target helps with alignment as well as forces the user to hold the device
   * far enough away to ensure the image will be in focus.
   *
   * @return The rectangle to draw on screen in window coordinates.
   */
  public Rect getFramingRect() {
    Point screenResolution = configManager.getScreenResolution();
    if (framingRect == null) {
      if (camera == null) {
        return null;
      }
      
      //原生
      int width = screenResolution.x * 3 / 4;
      if (width < MIN_FRAME_WIDTH) {
        width = MIN_FRAME_WIDTH;
      } else if (width > MAX_FRAME_WIDTH) {
        width = MAX_FRAME_WIDTH;
      }
      int height = screenResolution.y * 3 / 4;
      if (height < MIN_FRAME_HEIGHT) {
        height = MIN_FRAME_HEIGHT;
      } else if (height > MAX_FRAME_HEIGHT) {
        height = MAX_FRAME_HEIGHT;
      }
      int leftOffset = (screenResolution.x - width) / 2;
      int topOffset = (screenResolution.y - height) / 2;
      framingRect = new Rect(leftOffset, topOffset, leftOffset + width, topOffset + height);
      Log.d(TAG, "Calculated framing rect: " + framingRect);
    }
    return framingRect;
  }

我为了适配不同的屏幕大小将代码改成了

  public Rect getFramingRect() {
    Point screenResolution = configManager.getScreenResolution();
    if (framingRect == null) {
      if (camera == null) {
        return null;
      }
      
    //修改之后  
    int width = screenResolution.x * 7 / 10;
    int height = screenResolution.y * 7 / 10;
    
    int leftOffset = (screenResolution.x - width) / 2;
    int topOffset = (screenResolution.y - height) / 3;
    framingRect = new Rect(leftOffset, topOffset, leftOffset + width, topOffset + height);
      
      
      Log.d(TAG, "Calculated framing rect: " + framingRect);
    }
    return framingRect;
  }

宽高 我占据了屏幕的   7/10 
当然...取图改的这么大   会多占一点内存....相应的扫描的时候快得多
 
以上是实际读取图片的大小
实际的界面美化 在ViewfinderView 这个类当中进行绘制