Monkeybread Software - DynaPDF Manual

DynaPDF Manual - Page 771

Function Reference

Page 771 of 839

PDF supports the following application events which can be used to control the visibility of an OCG

or layer:

• Export

• Print

• View

Each event has corresponding categories or members in the Content Usage dictionary as well as

additional categories, which can be combined with three events, e.g. the viewer language or the

current user.

A viewer, that supports these application events, will change the visibility state according to the

settings in the Content Usage dictionary.

Remarks:

Note that application events are not supported in all viewer applications. If a watermark should

appear when printing, for example, then it is usually best to set the state of such a layer to visible,

and to make it invisible in the View event. A viewer that supports application events will hide the

layer at viewing time but still print it. A viewer that does not support application events will always

display the layer.

If the initial state of the layer would be invisible, then it would also stay invisible at printing time if

the viewer does not support application events but layers.

Return values:

If the function succeeds the return value is 1. If the function fails the return value is 0.

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