title: Rotation of view in android-gpuimage
body: <p>I am trying to rotate the image in from android-gpuImage but the rotation is not working. Here is the code</p>
  
  <pre><code>protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
  
      setContentView(R.layout.activity_document_edit);
  
      mGPUImageView = (GPUImageView) findViewById(R.id.gpuimage);
  
      Intent photoPickerIntent = new Intent(Intent.ACTION_PICK);
      photoPickerIntent.setType("image/*");
      startActivityForResult(photoPickerIntent, REQUEST_PICK_IMAGE);
  
      seekBar = (SeekBar) findViewById(R.id.seekBar);
      seekBar.setOnSeekBarChangeListener(this);
      findViewById(R.id.btn_rotate).setOnClickListener(this);
      findViewById(R.id.button_save).setOnClickListener(this);
  
      GPUImageFilter filter = new GPUImageBrightnessFilter();
      switchFilterTo(filter);
      mGPUImageView.requestRender();
  
  }
  </code></pre>
  
  <p>OnClick method for the rotation button:</p>
  
  <pre><code>@Override
  public void onClick(View v) {
      switch (v.getId()) {
          case R.id.btn_rotate:
              rotationAngle -= 90f;
              if (rotationAngle &lt;= -360f)
                  rotationAngle = 0f;
              mGPUImageView.setRotationX(rotationAngle);
              mGPUImageView.requestRender();
              break;
      }
  }
  </code></pre>
  
  <p><code>OnActivityResult</code> i have loaded the image that user selects from the image piker intent. And on click of the button I tried to rotate the <code>mGPUImageView</code> But the view shows blank.</p>
  
  <p>Below is the image when I tried to rotate the <code>mGPUImageView</code></p>
  
  <p><a href="https://i.stack.imgur.com/3OUo7.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/3OUo7.png" alt="View with image loaded"></a></p>
  
  <p>and when I rotated:</p>
  
  <p><a href="https://i.stack.imgur.com/z90LH.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/z90LH.png" alt="enter image description here"></a></p>
  
  <p>How can I implement the rotation. Please help.</p>