A Dijous, 24 de març de 2011, Thomas Freitag va escriure: > On 24.03.2011 21:14, Albert Astals Cid wrote: > > A Dijous, 24 de març de 2011, Thomas Freitag va escriure: > >> I don't know if this patch is useful without the outstanding overprint > >> patch for Splash, but I finished implementation of the two new options: > >> > >> -overprint renders the PDF in in splashCMYK8 first and converts the CMYK > >> Splash bitmap to RGB during writing (compiler switch SPLASH_CMYK must be > >> set on pdftoppm and on poppler library). It's implemented for png, jpeg > >> and tiff, tested for png and jpeg but should work with tiff, too. > >> USE_CMS is not implemented in the moment, the conversion from CMYK to > >> RGB is done with a copy from the GfxState-routines. > > > > Why copy the functions? > > There are "static inline" in the Gfx header files. I could include the > header file in Splash, but that means that we begin to mix splash and > poppler :-(
There is copy in Splash using the error() function already, so it's nothing new :D > > >> -jpegcmyk produces a jpg in CMYK colorspace (compiler switch SPLASH_CMYK > >> must be set on pdftoppm and on poppler library). > >> > >> Because overprint is not implemented yet, the overprint option changes > >> nothing in the moment. So this option can be used as a zero state for > >> overprinting to see which PDF renders differently with the outstanding > >> first implementation of overprinting. > > > > Don't understand this. > > -overprint option(!) simply renders in splashModeCMYK8 and during > writing it is converted to RGB, so the better option would probably be > to render it directly in splashModeRGB8. But overprint functionality(!) > is naturally only defined in a CMYK colorSpace, therefore we need > splashModeCMYK8 for the overprint functionality. But because overprint > (functionality) is not really implemented in splash with this patch, the > output should nearly the same (nearly, because without the option we > directly render in RGB, with the option we render in CMYK and convert > CMYK to RGB afterwards). > What I mean with zero state: I just run the create MD5 script with this > patch to have an initial MD5 value, assuming, that the output is correct > (because nothing is really changed in the underlying functions). > Tomorrow I'll run my roughly tested overprint patch against this and > examine, what pdf have changed. If these changes fit to specifications, > I'll upload the overprint patch to the community. So we add an option that does nothing (to the end user, that's it)? I'd prefer that not to happen. Albert > > Hope, this clearifies it, > Thomas > > > Albert > > > >> Thomas > >> > >> Am 21.03.2011 20:47, schrieb Albert Astals Cid: > >>> A Dilluns, 21 de març de 2011, Thomas Freitag va escriure: > >>>> Hi all! > >>>> 4. Support of overprint in pdftoppm > >>>> To support overprint in pdftoppm we have to enable SPLASH_CMYK in > >>>> pdftoppm and use it for rendering. But all output formats defined in > >>>> pdftoppm uses RGB as output colorspace, and even the main output > >>>> formats ppm and png do not support CMYK colorspace. Therefore we have > >>>> to possibilities to support overprinting in pdftoppm: > >>>> a) The easiest way would be to specify a new output format like i.e. > >>>> jpegcmyk and create a jpeg image in CMYK colorspace where overprinting > >>>> will be supported. > >>>> b) The more interesting way is to add a new parameter -overprint, when > >>>> set use splashCMYK8 as colorMode and when writing the output file > >>>> convert it to RGB. The first implementation could use the poor > >>>> colorspace conversion in Splash to convert the CMYK bitmap to RGB, but > >>>> we should think of use little cms to do that work for us, which of > >>>> course means that compiling pdftoppm will become more complex. > >>>> > >>>> Any suggestions from the community to point 4? > >>> > >>> Both seem interesting :-) > >>> > >>> Albert > >>> > >>>> Thomas > >>>> > >>>> _______________________________________________ > >>>> poppler mailing list > >>>> [email protected] > >>>> http://lists.freedesktop.org/mailman/listinfo/poppler > >>> > >>> _______________________________________________ > >>> poppler mailing list > >>> [email protected] > >>> http://lists.freedesktop.org/mailman/listinfo/poppler > >>> > >>> . > > > > _______________________________________________ > > poppler mailing list > > [email protected] > > http://lists.freedesktop.org/mailman/listinfo/poppler > > > > . > > _______________________________________________ > poppler mailing list > [email protected] > http://lists.freedesktop.org/mailman/listinfo/poppler _______________________________________________ poppler mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/poppler
