[OpenJDK 2D-Dev] Provide access to data offset in WritableRaster in Java 9

[Phil Race]

PS when filing the bug a self-contained (fully compilable) code example
showing what you would are trying to do will help.
Yes .. I guess you will need to use the internal API in that case but
it is a lot easier to unambigiously convey reqiurements with code if 
possible.


-phil.

On 07/13/2017 12:18 PM, Phil Race wrote:
> Hello,
>
> Yes this is the right list, and my reply on jigsaw-dev stands  :-
>
> Sounds like you were accessing jdk internals and found that you
> mostly can do away with that except for sub-images.
>
> What you should really do is file an issue at bugs.java.com as 
> client-libs/2d for cat/subcat.
>
> If this had been raised earlier in JDK 9 development - we could have 
> looked into
> it in time. Now it will have to wait for a follow on release.
>
> -phil.
>
> On 7/13/2017 12:13 PM, Peter A wrote:
>> Apologies since this probably not the correct list, but I was 
>> referenced here from another Java list. I've actually been getting 
>> bounced around to a few mailing lists. I'm hopeful that this is the 
>> right now!
>>
>> 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 *almost* found a work around  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 which are no longer accessible.
>>
>> 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
>>
>> -- 
>> "Now, now my good man, this is no time for making enemies."    — 
>> Voltaire (1694-1778), on his deathbed in response to a priest asking 
>> that he renounce Satan.
>
>