[vtkusers] using vtkImageBlend to combine two gray image

[贾鹏飞]

Hi All:

  I have two gray images (vtkimagedata version),  they have the same size. I want to combine them together using vtkimageblend.

1st： the following are some codes:

 vtkSmartPointer<vtkImageBlend> imgBlender = vtkSmartPointer<vtkImageBlend>::New();
 imgBlender->SetOpacity( 0, 0.5);
 imgBlender->SetOpacity( 1, 0.5);
 imgBlender->AddInput(AP);
 imgBlender->AddInput( APdrr );

It seems that the result is wrong! the second is in the window, while the first seems not in the proper position, only part of it.

2nd：Then I adjust the opacity 
vtkSmartPointer<vtkImageBlend> imgBlender = vtkSmartPointer<vtkImageBlend>::New();
 imgBlender->SetOpacity( 0, 1);
 imgBlender->SetOpacity( 1, 1);
 imgBlender->AddInput(AP);
 imgBlender->AddInput( APdrr );

then the result only shows the second image, there is not the first image!

can someone give me some suggestions, thanks in advance!