Transparency Flattening Components and Deployment

This article applies to the Windows version of Datalogics Adobe PDF Library (APDFL) 21. Feature availability, component filenames, file sizes, and deployment requirements may differ on other platforms or in other APDFL versions.

Description

Transparency flattening prepares PDF artwork containing transparent objects and effects for workflows that require content without live transparency. It combines those effects into a representation suitable for the intended output.

This feature is useful when preparing documents for older printing equipment or processing systems that require flattened artwork. It helps applications meet the output requirements of those systems.

Samples

The installed sample is located at:
CPlusPlus\Sample_Source\ContentModification\FlattenTransparency\FlattenTransparency.cpp

It uses PDFlattenerConvertEx2 to flatten the supplied FlattenTransparency.pdf document, with configurable rasterization and compression settings.

Public sample (github): FlattenTransparency

Files

Paths are relative to the SDK root. Sizes are uncompressed file lengths, rounded to two decimal places. Sizes and savings may vary by SDK build.

DL210PDFlattener.ppi provides transparency flattening. No additional exclusive runtime dependency was identified for omission with this plug-in.

Omitting the Feature When Unused

If transparency flattening is unused, omit DL210PDFlattener.ppi to save 0.30 MB.

The plug-in can be omitted when no retained workflow requires transparency flattening. PDFs containing transparency can still be opened, rendered, saved, and reopened without it. Those operations produced matching rendered pixels, text counts, and transparency status in the omission tests.

The positive flattening test processed one page and removed its live transparency. The resulting PDF remained usable without the plug-in.

Application considerations

Remove unconditional PDFlattener initialization and conversion calls when the feature is omitted. For optional installation, check gPDFlattenerHFT after InitPDFlattenerHFT before invoking PDFlattenerInitialize or conversion APIs, and guard termination. The installed sample assumes the plug-in is available.

Transparency flattening is distinct from annotation flattening. The installed Annotations\FlattenAnnotations sample used core PDF APIs and removed 76 annotations in testing with DL210PDFlattener.ppi absent.

Review printing, PostScript output, and PDF/A or PDF/X conversion settings for indirect flattening requirements. This investigation does not establish that every such output configuration is independent of the plug-in. Retain APDFL core dependencies and required font, CMap, Unicode, and color-profile resources. Validate the final product's retained workflows in an isolated deployment.

How to Get Additional Help

Contact Datalogics Tech Support 

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