On 9/25/2010 11:16 AM, Wolfgang Hugemann wrote: >> Is it Windows or convert that is expanding your glob for you? In that >> same directory, try >> >> echo *.jpg >> >> and see how many files are listed. > I can't tell; I just note that it's working. The command line above does > not work under Windows; it will just echo the exact string, i.e. > "*.jpp". But you can do things like 'dir *.jpg' and Windows will list > all files with the extension "jpg".
So if it were the Windows shell doing the expansion, it would happen even for the echo command, is the point, and such does happen on Unix. On Windows, each command or program that wants to deal with glob expansion has to do it itself. Some do, some don't. >> So is the difference in the image blob, or in the EXIF tags (which might >> get stripped on the way in to the PDF?)? How different is the size (a >> few bytes? 10%? or ?)? > The difference in size is only very slight, about 1%, and it is not due > to excessive data being stripped off. The image content is actually > slightly different. I compared the two images via > > convert original.jpg extracted.jpg -compose difference -composite > comparison.png > > and then counted the colours. A difference in color count does indicate a difference in image content (although the same color count would not prove identical image content). So you have proven that ImageMagick is expanding and recompressing the images in this particular case, which is typical of its processing style. >>> I suspect that ImageMagick somehow re-encoded the JPEGs before it wrapped >>> them into the PDF. >> You might be right, because IM tends to decompress images to full >> bitmaps before doing pretty much anything to them. >> >>> Is there a way to tell ImageMagick to leave the JPEGs as they are and just >>> to wrap them into a PDF? > It would be great if there would be a "preserve" option or alike. When > combining several JPEGs to a PDF, there really is no use in re-encoding > the JPEGs if you apply no modifications to them. Not only is there no benefit to the re-encoding, there are actually two problems that result: it takes more processor power, and every re-encoding loses a bit of quality. > I checked with Adobe Acrobat and it does the trick of merging several > JPEGs to one PDF, with the extracted JPEGs being exactly identical to > their originals. There also seems to be other proprietary software that > does the trick of bulk-converting JPEGs to PDF, but no freeware tool. > The populat PDFsam does not take other formats than PDF as input. _______________________________________________ Magick-users mailing list [email protected] http://studio.imagemagick.org/mailman/listinfo/magick-users
