Feasible, yes. Trivial, no. And it assumes you've done the entire design up front...
On 11/1/11 2:04 PM, "Giampaolo Capelli" <[email protected]> wrote: >How to get back to the pdf domain, once I have pixel values? >Is it feasible? > >Thanks > > >-----Messaggio originale----- >Da: Leonard Rosenthol [mailto:[email protected]] >Inviato: martedì 1 novembre 2011 18:47 >A: Post here >Oggetto: Re: [iText-questions] R: R: R: R: R: image in Flatedecode stream >without metadata in dictionary > >Such approaches have been used in the past. There are pros and cons to >it... > >Leonard > > >On 11/1/11 1:35 PM, "Giampaolo Capelli" <[email protected]> wrote: > >>Hi 1T3XT, >>thank you for the tips. >> >>I'm thinking of a computer vision approach to solve my problem: >>if I switch to the raster domain, that is rendering the pdf syntax into a >>raster image, >>then I will be able to apply some computer vision techniques to recognize >>the shapes (blobs), >>and to get their convex hulls (or bounding boxes). >> >>It would be possible, for example, to work on a black/white version of >>the >>rendered image, then to apply a threshold on its pixels and to apply some >>algorithm to label the connected components and so on. >> >>Once I'll have shapes (blobs), I will be able to get their bounding >>boxes, >>widths, heights and positions espressed in pixel values. >> >>The last step would be to convert such values back to the pdf domain. >> >>Do you think this makes sense? >> >> >>-----Messaggio originale----- >>Da: 1T3XT BVBA [mailto:[email protected]] >>Inviato: martedì 1 novembre 2011 17:34 >>A: Post all your questions about iText here >>Oggetto: Re: [iText-questions] R: R: R: R: image in Flatedecode stream >>without metadata in dictionary >> >>On 1/11/2011 17:09, Giampaolo Capelli wrote: >>> In the attachment >>> >>> I'm providing an example of a pdf file where I see 4 "conceptual >>> images", in the psychological visual sense (I understood that they are >>> not images from the pdf point of view). >>> >>> My aim is to edit the pdf file adding a (rectangular) border to such >>> "conceptual images". >>> >>> Is there an easy way to do it with iText, or should I handcraft some >>> sort of low level parsing myself? >>Please take a look at the screen shot in attachment. It's a screen shot >>of >>RUPS, which is a tool that takes X-Ray photos of PDFs: it shows an >>"internal >>view" of your PDF. >> >>Look at the /Resources Dictionary. It doesn't contain an /XObjects entry. >>This means that there are NO Image XObjects (this you already knew), but >>NO >>Form XObjects either (we assumed there were Form XObjects, but that must >>have been a misunderstanding)! >> >>Where are the four images? Well... as far as the PDF is concerned, there >>are >>no FOUR images. As you rightly point out, they are only there in the >>psychological, visual sense (you've phrased that very well). >> >>As far as the PDF is concerned, there's only ONE sequence of PDF syntax: >>the page content stream (object 5 in the PDF), which is the /Contents >>entry >>of the page dictionary (object 4). All the paths and shapes on that page >>are >>constructed using operators such as moveTo (m), lineTo (l) and curveTo >>(c). >> >>I don't know any software (not iText, not any other software) that is >>intelligent enough to find out which paths and shapes belong to which >>"conceptual" of "visual" image. I don't know any way to automate the >>detection of these images. >> >>----- >>Nessun virus nel messaggio. >>Controllato da AVG - www.avg.com >>Versione: 10.0.1411 / Database dei virus: 2092/3989 - Data di rilascio: >>01/11/2011 >> >> >>------------------------------------------------------------------------- >>- >>---- >>RSA® Conference 2012 >>Save $700 by Nov 18 >>Register now >>http://p.sf.net/sfu/rsa-sfdev2dev1 >>_______________________________________________ >>iText-questions mailing list >>[email protected] >>https://lists.sourceforge.net/lists/listinfo/itext-questions >> >>iText(R) is a registered trademark of 1T3XT BVBA. >>Many questions posted to this list can (and will) be answered with a >>reference to the iText book: http://www.itextpdf.com/book/ >>Please check the keywords list before you ask for examples: >>http://itextpdf.com/themes/keywords.php > > >-------------------------------------------------------------------------- >-- >-- >RSA® Conference 2012 >Save $700 by Nov 18 >Register now >http://p.sf.net/sfu/rsa-sfdev2dev1 >_______________________________________________ >iText-questions mailing list >[email protected] >https://lists.sourceforge.net/lists/listinfo/itext-questions > >iText(R) is a registered trademark of 1T3XT BVBA. >Many questions posted to this list can (and will) be answered with a >reference to the iText book: http://www.itextpdf.com/book/ >Please check the keywords list before you ask for examples: >http://itextpdf.com/themes/keywords.php >----- >Nessun virus nel messaggio. >Controllato da AVG - www.avg.com >Versione: 10.0.1411 / Database dei virus: 2092/3989 - Data di rilascio: >01/11/2011 > > >-------------------------------------------------------------------------- >---- >RSA® Conference 2012 >Save $700 by Nov 18 >Register now >http://p.sf.net/sfu/rsa-sfdev2dev1 >_______________________________________________ >iText-questions mailing list >[email protected] >https://lists.sourceforge.net/lists/listinfo/itext-questions > >iText(R) is a registered trademark of 1T3XT BVBA. >Many questions posted to this list can (and will) be answered with a >reference to the iText book: http://www.itextpdf.com/book/ >Please check the keywords list before you ask for examples: >http://itextpdf.com/themes/keywords.php ------------------------------------------------------------------------------ RSA® Conference 2012 Save $700 by Nov 18 Register now! http://p.sf.net/sfu/rsa-sfdev2dev1 _______________________________________________ iText-questions mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/itext-questions iText(R) is a registered trademark of 1T3XT BVBA. Many questions posted to this list can (and will) be answered with a reference to the iText book: http://www.itextpdf.com/book/ Please check the keywords list before you ask for examples: http://itextpdf.com/themes/keywords.php
