Jeremias That is certainly a good start in terms of information to digest.
I'll give it some time to sink in, and I'll try to browse through the code a bit the coming week to see how familiar I can get with it in that time. Thanks, Peter Jeremias Maerki-2 wrote: > > Ok, so here's a rough overview what needs to be done. No guarantee for > completeness or accuracy. > > 1. Implementation of the rgb-icc() function. > > See also: > http://www.antennahouse.com/xslfo/axf4-extension.htm#rgb-icc > http://www.renderx.com/reference.html#Color_Specifiers > > Whether the #CMYK pseudo-profile is really needed or if ICC colors are > sufficient, I cannot say at this time. In the end, the function needs to > generate a java.awt.Color (or descendant if necessary). I'm not sure if > the rgb-icc() function can sufficiently be mapped into FOP's function > infrastructure because it uses a non-constant number of parameters. > > 2. Internal representation of colors > > Thanks to Max Berger FOP already uses java.awt.Color throughout the > layout engine so we don't have to worry much anymore how the color > information is transported to the renderers. However, I can't tell if > Java's color infrastructure is up to the task of transporting the color > information as we need it for CMYK support. > > 3. org.apache.fop.image package > > This package is in need of a redesign for various reasons, one of them > being that it doesn't use RenderedImage/BufferedImage internally to > represent decoded images. Instead it uses byte arrays with decoded RGB > data. In order to properly support CMYK not only for JPEGs, the > refactoring will need to be done if we want a clean solution. > > 4. Improving the renderers to implement CMYK > > I assume the PDF renderer is the most important here. It needs to be > able to deal with the additional color types. But the other renderers at > least shouldn't fail when they encounter non-RGB data. The PDF library > is another place to look out for color stuff (like the PDFColor class). > PDF profiles like PDF/A-1b and PDF/X-3:2003 will also need to be > verified to work again after CMYK support is there. Having CMYK support > enables the implementation of other PDF/X standards. > > 5. SVG support > > As XSL-FO, SVG is primarily operating in the sRGB space, but has > extensions for ICC color (icc-color() function in SVG). I'm not sure > about the status of ICC color support in Batik, so this has to be > investigated. At any rate, there will need to be some changes to handle > CMYK requirements for SVG graphics. Otherwise, you will only get > RGB/sRGB colors in the PDF. > > That's quite a bit to do. I guess it would make sense to start a Wiki > page to write down all the info around the topic, gather knowledge, to > track progress and to coordinate. > > As for estimates, that's actually quite difficult at this time, without > further investigation. Point 1 shouldn't be all that hard, maybe a day > or so. Point 2 is probably ignorable except if AWT cannot hold the color > information like we need it. Point 3 is larger, probably 4 to 5 days. It > will take some more investigation and design. I've got a idea how this > should look like but so far I haven't written it down. I've only done > some requirements gathering on > http://wiki.apache.org/xmlgraphics-fop/ImageSupport. > Point 4 is probably not that difficult but a lot of tedious work which > involves a lot of testing and reading specifications. I assume it's > another 3 to 4 days. Point 5 is difficult to estimate at this time. > > Add at least a couple of days if you're not familiar with color handling > and the PDF specification. > > The good news is that all this doesn't require knowledge about the > layout engine which simplifies getting into this a lot!!! But of course, > there's still a lot to learn about colors, PDF and PDF profiles. > > Point 3 is on my middle-term radar, as is the rest but with lower > priority. So it's most likely I can help with the image package, but not > immediately. Ideas and guidance, sure, but not code at this time. > > On 20.09.2006 22:48:20 Peter Coppens wrote: >> >> FOP fans, >> >> I could also use cmyk support in fop. My options are to buy some xsl fo >> implementation that supports it or trye to contribute to fop (assuming >> the >> community lets me) >> >> Could someone give me a very rough estimate on how much work it would >> require, including getting acquainted with the fop architecture. >> >> Thanks, >> >> Peter >> >> >> >> Jeremias Maerki-2 wrote: >> > >> > >> > On 31.03.2006 21:48:43 Max Berger wrote: >> >> I know I have no vote in this, but I do disagree. >> > >> > Every opinion is always welcome. >> > >> >> 1) I still believe that PDF is a print medium and should therefore >> >> default to CMYK colorspace. If supported correctly by software, the >> >> colors should show up right on the screen. >> > >> > One use case of PDF is as a print medium, but it's not the only one. If >> > we're talking about producing documents for offset printing, then yes, >> I >> > agree with you. Fact is that most PDF-producing software packages I >> know >> > produce RGB (either uncalibrated DeviceRGB or sRGB). This applies to >> > OpenOffice, Acrobat Distiller with its default settings, GhostScript. >> > The list probably goes on. >> > >> > Supporting CMYK in FOP means some additional work which I don't have >> > time for (and don't really have a need myself). The client that has >> > asked me to implement PDF/A-1 is happy with sRGB since it's only about >> > patent documents. If someone (you?) implements an option to generate a >> > full CMYK PDF, then I'm all for adding that since it has been requested >> > a number of times. But doing that per default would be a change in >> > long-standing standard FOP behaviour which I don't support. >> > >> >> 2) If you want to embedd the sRGB profile, I would recommend using the >> >> profiles found at the International Color Consortium: >> >> http://www.color.org >> >> >> >> especially >> >> >> >> http://www.color.org/srgbprofiles.html >> >> >> >> unfortunately I was unable to find the exact licensing terms. >> > >> > That's exactly why I didn't use them. Licensing terms are not clear. On >> > the other side, Adobe & Co. are distributing the sRGB profile from >> > srgb.com, not from color.org. It's also unclear to me which of the two >> > variants (withBPC/noBPC) would have to be used. >> > >> >> just my 2 cts. >> >> >> >> Max >> >> >> >> >> >> Jeremias Maerki wrote: >> >> > I'm near the end of my work for basic PDF/A-1b support. PDF/A-1b >> >> > mandates the use of an OutputIntent if uncalibrated color spaces >> (like >> >> > DeviceRGB) are used. That means that in each PDF which has PDF/A-1b >> >> > enabled an ICC color profile will be embedded and used in the >> >> > OutputIntent object. Since we don't support ICC-based colors, yet, >> I've >> >> > hard-coded sRGB into PDF/A-1b support (XSL-FO supports sRGB and >> >> > ICC colors, XSL 1.0, 5.9.9). But that means I need to embed the sRGB >> >> > IEC61966-2.1 color profile. The JRE provides such a color profile >> but >> >> > does this is a weird way: the profile alone is about 140KB. That's >> why >> >> > I'd like to use the standard sRGB profile from HP. Info on that >> file: >> >> > >> >> > Obtained from: http://www.srgb.com/usingsrgb.html >> >> > >> >> > The file "sRGB Color Space Profile.icm" is: >> >> > Copyright (c) 1998 Hewlett-Packard Company >> >> > >> >> > To anyone who acknowledges that the file "sRGB Color Space >> Profile.icm" >> >> > is provided "AS IS" WITH NO EXPRESS OR IMPLIED WARRANTY: >> >> > permission to use, copy and distribute this file for any purpose is >> >> hereby >> >> > granted without fee, provided that the file is not changed including >> >> the HP >> >> > copyright notice tag, and that the name of Hewlett-Packard Company >> not >> >> be >> >> > used in advertising or publicity pertaining to distribution of the >> >> software >> >> > without specific, written prior permission. Hewlett-Packard Company >> >> makes >> >> > no representations about the suitability of this software for any >> >> purpose. >> >> > >> >> > I need to get the license approved by the VP legal affairs but I >> don't >> >> > expect any problems. >> >> > >> >> > Anyone against me including this color profile (3144 bytes, >> >> uncompressed) >> >> > in the org.apache.fop.pdf package? >> >> > >> >> > Jeremias Maerki >> > >> > >> > >> > Jeremias Maerki >> > >> > >> > >> >> -- >> View this message in context: >> http://www.nabble.com/Including-an-sRGB-color-profile--tf1373500.html#a6416371 >> Sent from the FOP - Dev mailing list archive at Nabble.com. > > > > Jeremias Maerki > > > -- View this message in context: http://www.nabble.com/Including-an-sRGB-color-profile--tf1373500.html#a6459632 Sent from the FOP - Dev mailing list archive at Nabble.com.
