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DynaPDF Manual - Page 170

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Function Reference
Page 170 of 750
The conversion capabilities are very limited if this callback function is not set! If you get an error like
" File uses multiple device color spaces!" then please set this callback function so that ICC profiles
can be loaded if necessary.
PDF/A 1b:
When creating new PDF/A 1a or PDF/A 1b files, the following features are prohibited:
The fill or stroke alpha constant in an extended graphics state must be 1.0 if present (see
CreateExtGState()).
Transparency groups, blend modes, as well as alpha channels in images.
Layers (CreateOCG(), CreateOCMD() and all related functions).
Annotations which are not defined in PDF 1.4. Highlight annotations cannot be used since
these annotations require the blend mode Multiply.
Form fields (form fields will be flattened if present). Note that check boxes use the font
ZapfDingbats which is mostly not present on a Windows system.
Embedded ICC profiles with a major version higher than 2. Version 4 profiles cannot be used
in PDF/A 1 files.
PDF/A files cannot be encrypted. The usage of CloseFileEx() or CloseAndSignFileEx() is not
allowed.
All features which are not defined in PDF 1.4.
PDF/A 2b or 3b
PDF/A 2b or 3b based on PDF 1.7 and hence support more features like transparency or optional
content (layers). The only difference between PDF/A 2b and 3b is that the latter version supports also
embedded files. The following restrictions must be considered:
Annotations which are not defined in PDF 1.7.
Form fields (form fields will be flattened if present).
Overprinting is permitted but the overprinting mode cannot be set to 1 if an ICCBased
CMYK color space is used. Due to implicit color conversion rules this applies also to
DeviceCMYK.
Application events are prohibited in PDF/A 2 and 3 (see AddOCGToAppEvent() for further
information).
Annotation replies are still prohibited (see SetAnnotMigrationState() for further
information).
PDF/A files cannot be encrypted. The usage of CloseFileEx() or CloseAndSignFileEx() is not
allowed.
 

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