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https://issues.apache.org/jira/browse/IMAGING-170?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14802849#comment-14802849
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Gary Lucas commented on IMAGING-170:
------------------------------------
Interesting ideas.
For Remigiusz Malessa: I can see that you wouldn't be interested in the JPEG
compression even if it were easy to implement (it's not hard, just more coding
than I have time to do right now). As you know, JPEG achieves its large
compression ratios by sacrificing some of the less important information in the
image. On the the other hand, the predictor-based LZW is a non-lossy data
compression scheme which preserves the original image with pixel-for-pixel
fidelity. The predictor just improves the compression ratio in cases such as
your photograph of a cameo. I'll take a look at it this weekend and see what I
can do.
As I recall, one of the unit tests built into the Apache Commons Imaging build
process is the "round-trip test" to make sure that the output data matches the
input data. I will have to check and see what's involved in extending it to
also test the predictor.
If I post code, are you set up to build a new Apache Commons Imaging jar using
maven? Also, it there some place you can temporarily post original images for
me to download and test?
For Sebb: I like your idea. It's kind of outside the original concept in the
Apache Commons Imaging design. So it would mean adding some new methods and
perhaps a new class for processing the data. The main value of this feature
would be time to process images. If you were only doing one or two images, it
wouldn't matter much, but if you were doing a large number it would definitely
improve production times. It also has the virtue of guaranteeing that the
image content of the input TIFF file doesn't change. For folks doing archival
and historical work, that feature would be very reassuring.
> TIFF image gains significant size using TiffImageWriterLossless
> ---------------------------------------------------------------
>
> Key: IMAGING-170
> URL: https://issues.apache.org/jira/browse/IMAGING-170
> Project: Commons Imaging
> Issue Type: Bug
> Components: Format: TIFF
> Affects Versions: 1.0
> Environment: System: Fedora release 21, kernel version:
> 3.18.7-200.fc21.x86_64, JAVA: openjdk version "1.8.0_31", IDE: Eclipse Kepler
> 2, Build id: 20140224-0627
> Reporter: Remigiusz Malessa
> Priority: Minor
> Attachments: kwf00346.tif
>
>
> Good afternoon,
> I am posting an issue report as suggested by mr Benedikt Ritter. It's my
> first issue report and I've just recently started using the Commons Imaging,
> so please go easy on me.
> ------------------------------------------------
> Using Commons Imaging I am reading a Tiff image (will attempt to attach it to
> this ticket), then I remove a tag (Focal Plane Resolution Unit) and then I
> save the new TiffOutputSet to the system using TiffImageWriterLossless.
> The original image is 15MB, the new image (with the Tag removed) is 28MB.
> Here's how I do it:
> {code:title=RemoveTag.java|borderStyle=solid}
> import java.awt.image.BufferedImage;
> import java.io.File;
> import java.io.FileOutputStream;
> import java.io.IOException;
> import java.io.OutputStream;
> import java.util.HashMap;
> import java.util.List;
> import java.util.Map;
> import org.apache.camel.Exchange;
> import org.apache.commons.imaging.ImageFormats;
> import org.apache.commons.imaging.ImageReadException;
> import org.apache.commons.imaging.ImageWriteException;
> import org.apache.commons.imaging.Imaging;
> import org.apache.commons.imaging.common.ImageMetadata;
> import org.apache.commons.imaging.formats.tiff.TiffField;
> import org.apache.commons.imaging.formats.tiff.TiffImageMetadata;
> import org.apache.commons.imaging.formats.tiff.write.TiffImageWriterLossless;
> import org.apache.commons.imaging.formats.tiff.write.TiffOutputDirectory;
> import org.apache.commons.imaging.formats.tiff.write.TiffOutputSet;
> File tInputFile = new File("/home/rem/TEMP/tags.original.tif");
> File toutputFile = new File("/home/rem/TEMP/tags.new.tif");
> final BufferedImage image = Imaging.getBufferedImage(tInputFile);
> ImageMetadata tMetadata = Imaging.getMetadata(tInputFile);
> TiffImageMetadata imageMetadata = (TiffImageMetadata) tMetadata;
> outputSet = imageMetadata.getOutputSet();
> TiffOutputDirectory exifDirectory = outputSet.getExifDirectory();
> exifDirectory.removeField(41488);
> ImageFormats format = ImageFormats.TIFF;
> Map<String, Object> params = new HashMap<String, Object>();
> BufferedImage image = Imaging.getBufferedImage(tInputFile);
> byte[] bytes = Imaging.writeImageToBytes(image, format, params);
> TiffImageWriterLossless writerLossLess = new TiffImageWriterLossless(bytes);
> writerLossLess.write(os, outputSet);
> {code}
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