6.4.2 GO hooks

• Link – a GO was linked into the page
• Unlink – a GO was unlinked from the page
• Relink – a GO was relinked between groups inside the page
• Select – a GO was selected
• Unselect – a GO was unselected
• Property create – a new property was created for a GO
• Properties changed – one or more properties was changed for a GO
• Property delete – a property was deleted from the GO
• Change – generic information about changes for the Visualization (see The Visualisation).

Like for the object hooks, the GO Link and Unlink hooks are not called recursively.

The Visualization hook

The Visualization needs a special hook go_changed which informs it about various changes. The changes can be distunguished by the data passed as a callback argument of type const struct changed_data_generic*. It is pointer to one of these structures:

transformed_data

After a transformation, the transformation matrices are passed together with bounding boxes before and after the transformation. The change kind is CK_TRANSFORMED.

altered_data

After a bounding box preserving change, which may be for example a change of the color, the data have the CK_ALTERED kind.

changed_data

For any other changes the CK_CHANGED kind is used.