A Dissabte, 23 de maig de 2009, Hal V. Engel va escriure: > On Saturday 23 May 2009 02:55:29 am Albert Astals Cid wrote: > > > According to the PDF spec. the Y white point value should always be > > > 1.0. So it might be possible to just do the correction to X and Z since > > > this would make the code slightly more efficient. Also I now think it > > > would be better to do this in GfxCalGrayColorSpace::getXYZ() and > > > GfxLabColorSpace::setXYZ() instead of in the locations right after > > > calls to these functions. > > > > When i mean no difference i mean "diff" says the files are exactly the > > same, not that i'm not able to see a difference in them. > > > > May it be because i'm not using any color profile? > > > > Albert > > It could be but the current code base defaults to sRGB as the output > profile if one is not specified by the calling app. So if poppler was > built using USE_CMS then by default it should be using sRGB as the output > color space for CIELab, Cal* and ICC objects. > > To confirm that you are using a profile you might consider modifying your > code so that it explicitly sets the output profile by calling > setOutputProfileName() or setOutputProfile() before opening the document. > For additional testing I am attaching a profile intended for testing that > causes the colors to be transformed in a way that is unmistakable because > it transforms blues into reds and reds into blues. Using this profile it > should be easy to confirm that your code is actually using an output > profile and also which parts of the rendered output are using the output > profile. > > No matter what output profile is being used there should be at least some > difference in the resulting RGB values of CIELab and CalGray objects if the > white point of the object is NOT X = Y = Z = 1.0. I have placed printf() > statements in the code to confirm that this is altering the XYZ values of > the CIELab objects in the altona pdf and it is. I have also confirmed > through testing that this makes a visible difference in the rendered output > at least if the white point is significantly different from X = Y =Z = 1.0. > > Also I cleaned up the white point code so that the white point correction > is now taking place in the getXYZ() functions which is where is really > belongs. I have attached a patch with this set of changes.
Ok, i've tested the patch and yes, i need to load a displayProfile, otherwise it seems to do nothing, the problem is that the differences i see are so minor i can't say if it is correct with the patch or without it. Do you have other PDF that shows a more visible difference? Koji is that inside your area of expertice and can say yay/nay to the patch? Anyone else? Albert > > Hal _______________________________________________ poppler mailing list [email protected] http://lists.freedesktop.org/mailman/listinfo/poppler
