drawBitmap没有正确缩放

Question

我有一个应用程序，我正在为学生座位表创建。我希望有一个拖放某些人物图标的背景，并且它在我的Galaxy S上工作正常。但是，在Galaxy Tab上，背景比显示屏缩小得多（见图）。

似乎无论位图有多大，在Galaxy Tab仿真器上它的大小都会缩小到大约2/3。当我使用替代资源作为位图时，它保持大约屏幕大小的2/3。

我的代码如下：

public DrawView(Context context, Long mClassID) {
    super(context);
    setFocusable(true); //necessary for getting the touch events

    mDbHelper = new gradeBookDbAdapter(context);
    mDbHelper.open();
    c = mDbHelper.fetchAllStudentsClassSeating(mClassID);
    int count = 0;
    if (c.getCount() > 0){
    c.moveToFirst();
    do {
          String name = c.getString(c.getColumnIndexOrThrow(gradeBookDbAdapter.KEY_NAME));
          studentId = c.getInt(c.getColumnIndexOrThrow(gradeBookDbAdapter.KEY_ROWID));
          Point point = new Point();
          int X = c.getInt(c.getColumnIndexOrThrow(gradeBookDbAdapter.KEY_X));
          int Y = c.getInt(c.getColumnIndexOrThrow(gradeBookDbAdapter.KEY_Y));
          point.x = (X <= 0)? (10 + count*initsize) : X;
          point.y = (Y <= 0)? 10 : Y;

          studentDesks.add(new StudentDesk(context, c.getCount(), studentId, point, name));
          count++;
       } while (c.moveToNext());
      }
  c.close();
      // import the background for the classroom 
  bkg = BitmapFactory.decodeResource(context.getResources(), R.drawable.classroom);
}

@Override protected void onDraw(Canvas canvas) {
    canvas.drawBitmap(bkg,0,0,null);
    //draw the desks on the canvas
    for (int index = 0; index < studentDesks.size(); index++ ) {
        StudentDesk desk = studentDesks.get(index);
        canvas.drawBitmap(desk.getBitmap(), desk.getX(), desk.getY(), null);
      }

}

// events when touching the screen
public boolean onTouchEvent(MotionEvent event) {
    int eventaction = event.getAction(); 
<snipped>

}

那么我应该做些什么来让背景（bkg）扩展为Galaxy Tab？当我读它时它已经是600x1200，所以为什么它会缩小到它的大小以下 屏幕？