ref_iface_IVDXFilterPreview_UndoSystem - shekh/VirtualDub2 GitHub Wiki

VirtualDub Plugin SDK 1.2

IVDXFilterPreview interface

IVDXFilterPreview:: UndoSystem

Deinitializes the filter system in preparation for a complex update.

void UndoSystem();

Thread safety

This method is not thread-safe.

Errors

Errors may not be returned from this function (see SetError()).

Remarks

UndoSystem() is used to temporarily take down the filter system when changes must be made that can't be done while the filter is initialized. The pattern for making such a change is as follows:

Call UndoSystem() to stop the filter system.
Change filter parameters.
Call RedoSystem() to restart the filter system.

In cases where the filter system doesn't need to be stopped before making the changes, it is OK to simply make the changes and call RedoSystem().

If the filter system is not currently running or preview is not enabled, calls to UndoSystem() are ignored.