Wesley Smith

re-re-re-effects-applied-to-selective-parts-of-a-matrix

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 

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 

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.

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.

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.


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 

> 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 

Thanks Joshua but this is wayyyy above my head.

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.


On Oct 31, 2006, at 11:34 AM, Toni Olivier wrote:

> Thanks Joshua but this is wayyyy above my head.

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 

beginner. If you need more info on alpha blending, please check the 

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  
beginner. If you need more info on alpha blending, please check the  
tutorials and search online.

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