ImageGear for C and C++ on Linux v20.0 - Updated
API Reference Guide > PDF Component API Reference > PDF Component Objects Reference > General Objects > HIG_PDF_LAYER > IG_PDF_layer_set_usage_info

This function sets a Usage dictionary entry in a layer object.


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AT_ERRCOUNT ACCUAPI IG_PDF_layer_set_usage_info(
        HIG_PDF_LAYER hLayer,
        HIG_PDF_ATOM hUsageKey,
        HIG_PDF_BASOBJ hUsageInfo


Name Type Description
hLayer HIG_PDF_LAYER Layer object whose usage information is set.
hUsageKey HIG_PDF_ATOM The usage key in the usage dictionary entry. Possible key values are:
  • CreatorInfo
  • Language
  • Export
  • Zoom
  • Print
  • View
  • User
  • PageElement
hUsageInfo HIG_PDF_BASOBJ The usage information to associate with the key.

Return Value:

Error count.

Supported Raster Image Formats:

This function does not process image pixels.


The entry associates usage information with an entry key for retrieval. If a dictionary does not exist, the method creates one.

A Usage dictionary entry provides more specific intended usage information than an intent entry.

The usage value can act as a kind of metadata, describing the sort of things that belong to the layer: for example, text in French, fine detail on a map, or a watermark. The usage values can also be used by the AutoState mechanism to make decisions about what layers should be on and what layers should be off.

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