[vtkusers] vtkRenderLargeImage and 2D Objects

[Kent Eschenberg]

 "--On 4/4/05 10:57:27 AM <andrew at artwork.com> wrote:
> David,
> Thanks for your response. Bear with me, but I do not
> understan this part of your response:
>>Try using a vtkImageActor to display the output of a
>> jpeg reader as an element of a 3D scene.

If I may jump in ... 3D objects pass through the OpenGL projection matrix 
which can be used to easily change the scale and offset of the 3D scene. 
vtkRenderLargeImage uses this to build up the large image.

2D objects go around this matrix and are displayed more or less directly. 
This adds a little speed and provides a nice one-to-one relationship 
between 2D object pixels and display pixels. I supose vtkRenderLargeImage 
could have been written to also deal with 2D objects -- but it wasn't.

David's suggestion moves your 2D objects over to the 3D world where they 
will be scaled and offset along with the other 3D objects. You might see a 
tiny difference at the pixel level of detail.

Kent