[ https://issues.apache.org/jira/browse/PDFBOX-4847?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Tilman Hausherr updated PDFBOX-4847: ------------------------------------ Fix Version/s: 2.0.21 3.0.0 PDFBox > [PATCH] Allow to access raw image data and fix ICC profile embedding in > PNGConverter > ------------------------------------------------------------------------------------ > > Key: PDFBOX-4847 > URL: https://issues.apache.org/jira/browse/PDFBOX-4847 > Project: PDFBox > Issue Type: New Feature > Components: PDModel, Writing > Affects Versions: 2.0.19 > Reporter: Emmeran Seehuber > Priority: Minor > Labels: feature, patch > Fix For: 3.0.0 PDFBox, 2.0.21 > > Attachments: color_difference.png, pdfbox-rawimages.patch > > > This patch was primary thought to add access to raw image data (i.e. without > any kind of color conversion/reduction). While implementing and testing it I > also found a bug with ICC profile embedding in the PNGConverter. > This patch does those things: > - add a method getRawRaster() to PDImage. This allows to read the original > raster data in 8 or 16 bit without any kind of color interpretation. The user > must know what he wants to do with this himself (E.g. to access the raw data > of DeviceN images). > - add a method getRawImage(). Tries to return the raster obtained by > getRawRaster() as a BufferedImage. This is only successful if there is a > matching java ColorSpace for the colorspace of the image. I.e. only for > ICCBased images. In theory this also should work for PDIndexed sRGB images. > But I have to find a PDF with such an image first to test it. > - add a -noColorConversion switch to the ExtractImage utility to extract > images in their original colorspace. For CMYK images this only works when a > TIFF encoder (e.g. from TwelveMonkeys) is in the class path. > - add support to export PNGs with ICC profile data in ImageIOUtil. > - fix a bug in PNGConverter which does not correctly embed the ICC profile > from the png file. > - the PNGConverterTest tests the raw images; While reading PNG files to > compare it also ensures that the embedded ICC profile is correctly respected. > The default PNG reader at least till JDK11 does *not* respect the embedded > ICC profile. I.e. the colors are wrong. But there is a workaround for this in > the PNGConverterTest (which I have in production for years now). See the > screenshot for the correct color display of the png_rgb_romm_16.png testfile > (left side; macOS Preview app) and the wrong display (right side; Java; > inside IDEA). > > Access to the raw image allows beside finding bugs like in the PNGConverter > it also to do all kind of funny color things. E.g. a future patch could be to > allow using the raw images to print PDFs. If the PDF you want to print has > images with a gamut > sRGB (i.e. all modern cameras) and the target printer > has also a gamut > sRGB (i.e. some ink photo printer) you will for sure see a > difference in the resulting print. Such a mode would be rather slow, as the > current sRGB image handling is optimized for speed and using the original raw > images would need on demand color conversions in the printer driver. But you > get „high quality“ out of it (at least in respect to colors). > I don’t think this is in time for the 2.0.20 release. -- This message was sent by Atlassian Jira (v8.3.4#803005) --------------------------------------------------------------------- To unsubscribe, e-mail: dev-unsubscr...@pdfbox.apache.org For additional commands, e-mail: dev-h...@pdfbox.apache.org