[vtkusers] Change display origin from lower left 2 upper left

[Frank Lindseth]

Yes it's possible to manipulate the data sent to the new display- 
system and vtkImageFlip could be used to convert vtkImageData,
but I would prefer (a least for the time being) to use the data as is,  
and instead adapt the new VTK display system to the old one (basically  
flipping the window/viewport y-axis),
it's pretty complicated in terms of view-layout (e.g. view-position  
and width/hight in pixel coord. as well as overlay (e.g. line gong  
from pixel (display/viewport) x1,y1 to x2,y2).

So somthing like:
renWin->SetOriginToUpperLeft();
would be very nice, is my vague recollection of such a method totally  
wrong?

- Frank


On May 7, 2008, at 1:27 PM, Emmanouil Moschidis wrote:

> Hi Frank
> I know that with the vtkImageFlip class has this funtcionality when  
> it comes to  the manipulation of a vtkImageData object. I'm not sure  
> about the viewport though... I'd suppose there is no problem as the  
> origin is defined internally in each object and not by the viewport,  
> am I right?
>
> Frank Lindseth <Frank.Lindseth at sintef.no> wrote:
> Hi all,
>
> Is it possible to change VTK's display/viewport convention from  
> (origin in lower left):
> /\  y
>  |
>  |
> O--------> x
>
> To (origin in upper left):
> O--------> x
>  |
>  |
> \/  y
>
> Any help would be greatly appreciated.
>
>
> Background:
> We would like to replace the old "display system"  in an existing  
> application with a new based on VTK,
> i.e. both display/viewport layout and visualizing exiting data that  
> "assumes" that the display/viewport origin is in the upper left  
> corner,
> converting setup/data coordinates (y) is of course an option, but it  
> would make things a lot easier if VTK used the same origin (as  
> opposed to the lower-left default),
> I'm pretty sure that I was able to set this a long time ago  
> (vtkRenderWindow-method maybe?), but can't find the needed  
> functionality anywhere anymore,
> is it possible?
>
> - Frank
>
>
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------------------------------
Frank Lindseth
Research Scientist (PhD)

SINTEF Health Research
Dept. Medical Technology
N-7465 Trondheim, Norway
Location: Olav Kyrres gt. 9, 4th floor, Trondheim

E-mail: Frank.Lindseth at sintef.no
Telephone: +47 928 09 372
Telefax: +47 930 70 800


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