[
https://issues.apache.org/jira/browse/IMAGING-95?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13479142#comment-13479142
]
Gary Lucas commented on IMAGING-95:
-----------------------------------
I'm not part of the Apache Commons Imaging project team, but I am interested in
this issue... Few people would welcome a speed enhancement for TIFF images
with more enthusiasm than I :-)
I tried your patch with a couple of test files I have and didn't see much
different in measured processing time. Unfortunately, I've got all sorts of
security software running on my computer and it makes for a noisy test
environment, so I can't be sure. So I have a couple of questions:
a) Are there specific TIFF formats where you've observed an improvement?
b) Have you tried running before-and-after tests using the
ApacheImagingSpeedAndMemoryTest.java application?
The ApacheImagingSpeedAndMemory.java class is in the Commons Imaging code
distribution under the path src\test\java\org\apache\commons\imaging\examples
There are detailed instructions for using it in the comments inside the code.
It is designed to give reasonably unambiguous timing information about how long
it takes to load an image (it is coded for TIFF images, but can be edited to
process other formats).
> Some tiff processing takes very long
> ------------------------------------
>
> Key: IMAGING-95
> URL: https://issues.apache.org/jira/browse/IMAGING-95
> Project: Commons Imaging
> Issue Type: Bug
> Components: Format: TIFF
> Affects Versions: 1.0
> Reporter: Amit Gupta
> Attachments: tiff_perf_fix2.patch
>
>
> org.apache.commons.imaging.formats.tiff.TiffReader.getTiffRawImageData(ByteSource,
> TiffDirectory) 226635 1
> org.apache.commons.imaging.common.bytesource.ByteSourceInputStream.getBlock(int,
> int) 226588 5616
> org.apache.commons.imaging.common.BinaryFileFunctions.skipBytes(InputStream,
> int) 226526 5616
> org.apache.commons.imaging.common.BinaryFileFunctions.skipBytes(InputStream,
> int, String) 226526 5616
> org.apache.commons.imaging.common.bytesource.ByteSourceInputStream$CacheReadingInputStream.read(byte[],
> int, int) 226526 188656860
> org.apache.commons.imaging.common.bytesource.ByteSourceInputStream$CacheBlock.getNext()
> 64581 188651244
> skip bytes is being called repeatedly again and again, last column is
> invocation count in one call tree. Second column is total number of time
> taken by that method in that call tree..
> and skip method is not overridden
> org.apache.commons.imaging.common.bytesource.ByteSourceInputStream.CacheReadingInputStream
> and default implementation of InputStream tries to use read method (which is
> overridden in CacheReadingInputStream) to skip.
> In case of a tiff, which has large number of strips, skip is repeatedly
> called and use of read is inefficient as it tried to do a System.arraycopy.
> array copy is not needed in case of skip operation, as the bytes were already
> read in block/cached, we can simply jump the pointer (block by block)
--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators
For more information on JIRA, see: http://www.atlassian.com/software/jira
