GSoC/2019/StatusReports/tusooa

Better undo/redo for krita

This project is divided into two parts.

Snapshot Docker

Implement a docker to allow users create snapshots (shallow copies) of the current state of documents and switch back to them at a later time.

Copy-on-Write Vector Layers

Make vector layers copy-on-write so that the undo/redo system for them can be implemented by replacing the layer with another, rather than store the undo information for each command.

Progress

Done

• Research into solutions for copy-on-write mechanism
• Snapshot Docker
• COW vector layers
  • Make members of KoShapePrivate implicitly-sharable
  • Make KoShape hierarchy implicitly-sharable

Doing

• Create undo commands that switch between states of vector layers

Links

• Phabricator task
• Branch for Snapshot Docker

Blog posts:

• An introduction
• Some Strategies for COW
• An example for the undo system to use clones