title: Pyqtgraph. Draw text label next to the rectangle
body: <p>I am trying to draw a grid of rectangles with text labels on each rectangle. I am using this code:</p>
  
  <pre><code>import pyqtgraph as pg
  
  win = pg.GraphicsWindow()
  vb = win.addViewBox(col=0, row=0)
  
  board = ['1234',
           'abcd',
           'efgh']
  
  def draw_board(board):
      for j, row in enumerate(board):
          for i, cell in enumerate(row):
              r = pg.QtGui.QGraphicsRectItem(i, -j, 0.9, 0.9)
              r.setPen(pg.mkPen((0, 0, 0, 100)))
              r.setBrush(pg.mkBrush((50, 50, 200)))
              vb.addItem(r)
  
              t = pg.TextItem(cell, (255, 255, 255), anchor=(i, -j))
              vb.addItem(t)
  
      pg.QtGui.QApplication.exec_()
  
  draw_board(board)
  </code></pre>
  
  <p>For some reason labels seem to be drawn in a completely different coordinate system that even uses different scale. What is the easy way to put my labels in the middle of the respective rectangles? </p>