ripping your s apart

RIPPING YOUR PDF FILES APART

What you need to know about what goes on inside your PDF files

Mark Stephens

Thursday, 29 March 12

Mark’s Bio


Mark’s Bio

Working with Java and PDF since 1997


Mark’s Bio

Working with Java and PDF since 1997Founded IDRsolutions 1999


Mark’s Bio

Working with Java and PDF since 1997Founded IDRsolutions 1999Speaker at Seybold, Javaone, Business of Software


Mark’s Bio

Working with Java and PDF since 1997Founded IDRsolutions 1999Speaker at Seybold, Javaone, Business of SoftwareMA degree in Mediaeval History from St Andrews (how useless is that)


Mark’s Bio

Working with Java and PDF since 1997Founded IDRsolutions 1999Speaker at Seybold, Javaone, Business of Software

Ask me about Java, PDF, business or anything which happened before 1500 AD

MA degree in Mediaeval History from St Andrews (how useless is that)


BUT FIRST SOME KITTENS...

The support team at IDRsolutions are waiting for your call (maybe)


The PDF reference guide


Loading page 1124 of a file

WordRead pages 1-1123 (time passes - scroll bar shrinks)Found it (eventually)



PDFRead the metadata refs table(s) - where do I find all the objectsSkip to page 1124




PDFRead the metadata refs table(s) - where do I find all the objectsSkip to page 1124


PDF (in detail)Read the refs table(s) - where do I find all the objectsRead the Root object - points to the Pages objectRead object for page 1124 (tells me the linked font, image, content objects)Draw it


Your PDF file is a Tree

A root linked to all the branches


The PDF reference guideLike you have never seen it before...



You can use vi or emacs if you preferThursday, 29 March 12

The PDF reference guideEnd of the file


The PDF root objectLike you have never seen it before...


PDF files on the webIsn’t having the marker at the end a problem??


PDF files on the webNot if you create it properly


Key takeaways from the PDF structure



We do not need to load the whole file



We do not need to load the whole file It is equally fast to load any part of it



We do not need to load the whole file It is equally fast to load any part of itIt is very easy to replace objects with new versions



We do not need to load the whole file It is equally fast to load any part of itIt is very easy to replace objects with new versionsThere are certain key locations - like at the end of a file



We do not need to load the whole file It is equally fast to load any part of itIt is very easy to replace objects with new versionsThere are certain key locations - like at the end of a fileYou should not edit it in a text editor



We do not need to load the whole file It is equally fast to load any part of itIt is very easy to replace objects with new versionsThere are certain key locations - like at the end of a fileYou should not edit it in a text editorIf you want to use PDF files across the Internet, there is a special mode to make these load the most important parts first.



We do not need to load the whole file It is equally fast to load any part of itIt is very easy to replace objects with new versionsThere are certain key locations - like at the end of a fileYou should not edit it in a text editorIf you want to use PDF files across the Internet, there is a special mode to make these load the most important parts first.Lots of features need you to setup the PDF file correctly.


Those PDF objects in more detail

All PDF objects have:-1. An ID number2. (Optional) A set of dictionary key pairs3. (Optional) A block of binary data.


PDF images are not Tiff, Png or JPeg


A word on colour


A word on colour

DeviceRGBCalRGB

DeviceCMYKICC

SeparationDeviceN

DeviceGrayCalGray

LabPattern


PDF pages are ‘drawn’



0 0 0 1k set cmyk color of text to black



0 0 0 1k set cmyk color of text to blackBT start of some text



0 0 0 1k set cmyk color of text to blackBT start of some text/T1_01Tf Use the font defined as T1_0 elsewhere



0 0 0 1k set cmyk color of text to blackBT start of some text/T1_01Tf Use the font defined as T1_0 elsewhere0 Tc 0 Tw 0 Ts 100 Tz 0 Tr set other text properties



0 0 0 1k set cmyk color of text to blackBT start of some text/T1_01Tf Use the font defined as T1_0 elsewhere0 Tc 0 Tw 0 Ts 100 Tz 0 Tr set other text properties 7.5003 0 0 7.5003 272.1643 540.2979 Tm position onscreen



0 0 0 1k set cmyk color of text to blackBT start of some text/T1_01Tf Use the font defined as T1_0 elsewhere0 Tc 0 Tw 0 Ts 100 Tz 0 Tr set other text properties 7.5003 0 0 7.5003 272.1643 540.2979 Tm position onscreen(L*) Tj draw the text L*



0 0 0 1k set cmyk color of text to blackBT start of some text/T1_01Tf Use the font defined as T1_0 elsewhere0 Tc 0 Tw 0 Ts 100 Tz 0 Tr set other text properties 7.5003 0 0 7.5003 272.1643 540.2979 Tm position onscreen(L*) Tj draw the text L*/T1_1 1Tf change font



0 0 0 1k set cmyk color of text to blackBT start of some text/T1_01Tf Use the font defined as T1_0 elsewhere0 Tc 0 Tw 0 Ts 100 Tz 0 Tr set other text properties 7.5003 0 0 7.5003 272.1643 540.2979 Tm position onscreen(L*) Tj draw the text L*/T1_1 1Tf change font0.856 0 Td move to a different location onscreen



0 0 0 1k set cmyk color of text to blackBT start of some text/T1_01Tf Use the font defined as T1_0 elsewhere0 Tc 0 Tw 0 Ts 100 Tz 0 Tr set other text properties 7.5003 0 0 7.5003 272.1643 540.2979 Tm position onscreen(L*) Tj draw the text L*/T1_1 1Tf change font0.856 0 Td move to a different location onscreen( = 100) Tj draw the text = 100



0 0 0 1k set cmyk color of text to blackBT start of some text/T1_01Tf Use the font defined as T1_0 elsewhere0 Tc 0 Tw 0 Ts 100 Tz 0 Tr set other text properties 7.5003 0 0 7.5003 272.1643 540.2979 Tm position onscreen(L*) Tj draw the text L*/T1_1 1Tf change font0.856 0 Td move to a different location onscreen( = 100) Tj draw the text = 100 -0.324 -1.133Td move to a different location onscreen



0 0 0 1k set cmyk color of text to blackBT start of some text/T1_01Tf Use the font defined as T1_0 elsewhere0 Tc 0 Tw 0 Ts 100 Tz 0 Tr set other text properties 7.5003 0 0 7.5003 272.1643 540.2979 Tm position onscreen(L*) Tj draw the text L*/T1_1 1Tf change font0.856 0 Td move to a different location onscreen( = 100) Tj draw the text = 100 -0.324 -1.133Td move to a different location onscreen[(whit)6(e)] Tj draw the text white (put a gap between t and e)


PDF myth - files are cross platform

Only if you create them properly...


Obfuscation for idiots!

No-one will be able to guess the secret password


20 seconds later...

And the password is....


Lastly a plea

Not all PDF creation tools are equal


In summary


ripping your s apart

Technology

scroll bar

metadata refs

1997founded

dictionary

pdf reference

pdf reference

pdf root objectlike

pdf pages