Android Zxing調整掃描區域 優化取圖速度（調節掃描框大小）

Zxing 是google提供的二維碼掃描工程

Demo本身默認的掃圖區域最大隻有 360*480    需要拉開很遠的距離才能將整個二維碼掃描到

因此需要我們自己調整取圖大小

 

在CameraManager.java這個類中進行調整

默認的大小是 以下這4個參數 

//  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;

根據屏幕大小調整      大家可以增大這些數值 : 最小的寬 高    ; 最大寬高

 

參數實際在 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;
 }

 

適配不同的屏幕大小可以將代碼改成如下：

public Rect getFramingRect() {
  Point screenResolution = configManager.getScreenResolution();
  if (framingRect == null) {
    if (camera == null) {
      return null;
    }

  //修改之後
  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;
}

寬高 佔據了屏幕的   7/10 
當然...取圖改的這麼大   會多佔一點內存....相應的掃描的時候快得多

以上是實際讀取圖片的大小

實際的界面美化 在ViewfinderView 這個類當中進行繪製

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