| 摘要 |
A method and system for undoing interactive editing operations enables efficient undoing of multiple non-invertable editing operations such as digital painting strokes. During the editing process, a plurality of prior states of the data object being edited at uneven intervals are stored. To undo an editing operation, the object being edited is restored to a stored prior state that came before the operation to be undone was performed. Previously performed editing operations between the restored state and the operation to be undone are then reapplied to the data object to recreate the state of the object right before the operation to be undone was performed. A balance between the speed of the multiple-undo operation and the amount of memory required to store selected prior states is achieved by storing prior states at intervals that increase generally exponentially with a base of two. An efficient mechanism is provided for updating the list of stored prior states during the editing process.
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