Download - Multivac!

9.5.2 Generating PDF/A-conforming OutputCreating PDF/A-conforming output with PDFlib is achieved by the following means:> PDFlib will automatically take care of several formal settings for PDF/A, such as PDFversion number and PDF/A conformance keys.> The PDFlib client program must explicitly use certain function calls and options asdetailed in Table 9.9.> The PDFlib client program must refrain from using certain function calls and optionsettings as detailed in Table 9.10.> Additional rules apply when importing pages from existing PDF/A-conforming documents(see Section 9.5.3, »Importing PDF/A Documents with PDI«, page 211).If the PDFlib client program obeys to these rules, valid PDF/A output is guaranteed. IfPDFlib detects a violation of the PDF/A creation rules it will throw an exception whichmust be handled by the application. No PDF output will be created in case of an error.Cookbook Code samples can be found in the Cookbook topics pdf_flavors/starter_pdfa, pdf_flavors/text_to_pdfa, and pdf_flavors/images_to_pdfa.Required operations for PDF/A-1b. Table 9.9 lists all operations required to generatePDF/A-conforming output. The items apply to both PDF/A conformance levels unlessotherwise noted. Not calling one of the required functions while in PDF/A mode willtrigger an exception.Table 9.9 Operations which must be applied for PDF/A-1 level A and B conformanceitemconformance leveloutput condition(output intent)fontsgrayscale colorRGB colorCMYK colorPDFlib function and option requirements for PDF/A conformanceThe pdfa option in PDF_begin_document( ) must be set to the required PDF/A conformance level,i.e. one of PDF/A-1a:2005 or PDF/A-1b:2005.PDF_load_iccprofile( ) with usage=outputintent or PDF_process_pdi( ) with action=copyoutputintent(but not both methods) must be called immediately after PDF_begin_document( )if any of the device-dependent colors spaces Gray, RGB, or CMYK is used in the document. If anoutput intent is used, an ICC profile must be embedded (unlike PDF/X, unembedded standard outputconditions are not sufficient in PDF/A). Use the embedprofile option of PDF_load_iccprofile( ) to embed a profile for a standard output condition.The embedding option of PDF_load_font( ) (and other functions which accept this option) must betrue. Note that embedding is also required for the PDF core fonts.A gray, RGB, or CMYK ICC profile must be set as PDF/A output condition if grayscale color is used inthe document.An RGB ICC profile must be set as PDF/A output condition if RGB color is used in the document.A CMYK ICC profile must be set as PDF/A output condition if CMYK color is used in the document.Prohibited and restricted operations. Table 9.10 lists all operations which are prohibitedwhen generating PDF/A-conforming output. The items apply to both PDF/A conformancelevels unless otherwise noted. Calling one of the prohibited functions whilein PDF/A mode will trigger an exception. Similarly, if an imported PDF document doesnot comform to the current PDF/A output level, the corresponding PDI call will fail.Additional requirements and restrictions for PDF/A-1a. When creating PDF/A-1a, all requirementsfor creating Tagged PDF output as discussed in Section 9.6, »Tagged PDF«,208 Chapter 9: Generating various PDF Flavors