Provide access to data offset in WritableRaster in Java 9

[Alan Bateman]

The 2d-dev or awt-dev mailing lists may be a better place to bring this up.

-Alan

On 13/07/2017 17:21, Peter A wrote:
> Apologies since this probably not the correct list, but I was referenced
> here from another Java list.
>
> Background:
> The high level API in a BufferedImage is very very very slow.  To get
> around that problem, in previous versions of Java, the internal rasters
> which were defined in sun.awt.image were accessed.   Doing so enabled
> real-time computer vision in Java.
>
> Problem:
> Accessing the low level Rasters is no longer practical in Java 9.  After
> this problem was reported by one of my users I looked into it and found a
> work around, for most situations.  Unfortunately the higher level
> WritableRaster does not provide access to the offset inside its internal
> data array.   This makes processing of subimages impossible.  My suspicion
> is that it is most likely an oversight because it provides access to every
> other piece of information needed and the raw data.    It would be great
> if getDataOffset() could be moved into WritableRaster or one of its parents
> instead of being hidden in children of WritableRaster.
>
> Just to clarify the raw arrays are stored inside of a DataBuffer and that
> data structure contains an offset. This offset is always set to zero and
> the offset inside of WritableRaster is what is needed,
> e.g. IntegerInterleavedRaster.getDataOffsets().
>
> Thanks,
> - Peter
>