Adobe acrobat 7.0.5 sdk User Manual

Getting Started

The following features are new in the PDF 1.6 specification. For complete details, see the 
PDF 1.6 Reference.

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An enhancement to the syntax of DeviceN color spaces to support NChannel color 
spaces, which give applications greater flexibility when representing colors that are not 
available on a target device. 

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Encryption enhancements to support using the AES encryption algorithm and to 
selectively encrypt embedded files. 

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Enhancements to digital signatures related to usage rights and MDP (modification 
detection and prevention). 

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Additional support for embedded file attachments, including cross-document linking to 
and from embedded files. 

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The ability to define user properties that contain non-drawing-related information 
about objects on a page. 

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The ability to accurately specify relationships between the dimensions of objects on a 
page and their real-world counterparts. 

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An increase to the maximum page size of a PDF document, by specifying the size of the 
unit in default user space. 

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The ability to specify objects that should be printed at a specific size, regardless of the 
dimensions of the printed page. 

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New facilities for embedding OpenType fonts in PDF files. 

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Enhancements to markup annotations, including the ability to group them. 

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The ability to specify non-rectangular regions for link annotations. 

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Greater flexibility in specifying the visibility of graphics based on the state of optional 
content groups, and the ability to lock the states of groups. 

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The addition of Tagged PDF attributes relating to the layout of content in columns.

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The ability to incorporate models of three-dimensional graphical data, using the 3DIF 
format, in a PDF file.