## Re: Re: Re: Effects applied to selective parts of a matrix?

Oct 31 2006 | 5:12 pm

• Oct 31 2006 | 6:44 pm
I might also mention that since Jitter Matrix Operators work
exclusively on N-ary cubes (that would be rectangles for the 2D
case), for arbitrary regions of interest (ROI) (say a circle or some
user selected blob of data), you can copy the bounding rectangle of
data you wish to process, process the entire rectangle, write the
arbitrary ROI into the alpha channel, and then alphablend back into
the original submatrix.
I know that this is an unfortunately cumbersome process, but that's
what you have to do currently. Someone with time on their hands could
make a few abstractions/objects roi.prep and roi.apply which would
accomplish the splitting, copying, alphablending stages for you, and
all you'd need to do is put the processing routine between these
objects.
-Joshua
• Oct 31 2006 | 7:32 pm
Quote: wesley.hoke@gmail.com wrote on Tue, 31 October 2006 19:12
----------------------------------------------------
> Have you thought of using the src/dst dim attributes of jit.matrix to
> process a submatrix of a matrix in place?
>
No, but I will look into it - thanks for the suggestion.
• Oct 31 2006 | 7:34 pm
Quote: jkc wrote on Tue, 31 October 2006 20:44
----------------------------------------------------
>
> I might also mention that since Jitter Matrix Operators work
> exclusively on N-ary cubes (that would be rectangles for the 2D
> case), for arbitrary regions of interest (ROI) (say a circle or some
> user selected blob of data), you can copy the bounding rectangle of
> data you wish to process, process the entire rectangle, write the
> arbitrary ROI into the alpha channel, and then alphablend back into
> the original submatrix.
>
> I know that this is an unfortunately cumbersome process, but that's
> what you have to do currently. Someone with time on their hands could
> make a few abstractions/objects roi.prep and roi.apply which would
> accomplish the splitting, copying, alphablending stages for you, and
> all you'd need to do is put the processing routine between these
> objects.
>
> -Joshua
>
----------------------------------------------------
Thanks Joshua but this is wayyyy above my head.
• Oct 31 2006 | 7:45 pm
On Oct 31, 2006, at 11:34 AM, Toni Olivier wrote:
> Thanks Joshua but this is wayyyy above my head.
Perhaps in simpler terms:
If the particular portion of the matrix you want to process in not
rectangular, you can process the bounding rectangle that contains the
entire non rectangular area, and then use alpha blending to composite
back with the original matrix. This isn't exactly easy to do, but
some utility patches could be made to simplify this process for the