title: use Canvas background color is strange on android
body: <p><a href="https://i.stack.imgur.com/HIQh4.jpg" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/HIQh4.jpg" alt="enter image description here"></a></p>
  
  <p>Hello, I want draw Text on GLSurfaceView on android.</p>
  
  <p>so , I use Canvas, Bitmap and Paint</p>
  
  <p>GLText method</p>
  
  <pre><code>public void GLText() {
      Bitmap mBitmap;
      Canvas mCanvas;
      Bitmap.Config config = Bitmap.Config.ARGB_8888;
  
      mBitmap = Bitmap.createBitmap(128, 128, config);
      mCanvas = new Canvas(mBitmap);
      mBitmap.eraseColor(0);
  
      mCanvas.drawColor(0x00ffffff);
  
      Paint Pnt = new Paint();
  
      Pnt.setColor(0xffffffff);
      Pnt.setTextSize(10);
      Pnt.setAntiAlias(false);
      Pnt.setTextScaleX(1);
  
      mCanvas.drawText("test", 0, 20, Pnt);
  
      GLUtils.texImage2D(GL10.GL_TEXTURE_2D, 0, mBitmap, 0);
  
      mBitmap.recycle();
  }
  </code></pre>
  
  <p>and call <code>glText()</code> is <code>onDrawFrame</code>
  onDrawFrame method is always execute.</p>
  
  <p>I want remove background color.
  this picture camera preview display.</p>
  
  <p>thanks.</p>