Commands

Editing is done through the QUndoStack mechanism for redo/undo-ing actions. All changes to a transcript, including style changes, should be done through a QUndoCommand.

The qcommands module should contain all available QUndoCommand classes and classes/functions relating to generating any QUndoCommand.

The two main functions are steno_insert and steno_remove, which insert and remove elements from the userData slot of the block in the QTextEdit.

Constructing a new QUndoCommand

Each command has to subclass QUndoCommand

Each subclass of QUndoCommand that acts on the transcript text must have the following parameters, regardless of whether they are used in redo or undo functions. This is to maintain consistency for action generation (future proof).

• cursor: reference to copy of present QTextCursor, such as QTextEdit.textCursor(), should be earliest position if cursor has selection

• document: reference to QTextEdit transcript

• block: integer, blockNumber in editor (do not take direct block reference in case it gets destroyed)

Commands that act only on GUI style or data do not need to.

block_state is an attribute that is set within the QUndoCommands to indicate a block has been changed. For safety, even if an action is undone, the block’s state is not reverted.

The userState attribute of each paragraph in the QtextEdit will be set to 1 (ie, is modified? True) if any QUndoCommand acted on it. Right now, this is to signify that the paragraph has been modified for use in saving the transcript, and it is not reset back to 0 even if the command is undone. This may change in the future.

The QTextBlock where edits are made within the QUndoCommand should be retried with findBlockByNumber and not directly with the current QTextCursor, in both redo and undo. This is especially important in undo. Then the cursor position should be set with position_in_block and block coordinates.