Struct HistoryService 

pub struct HistoryService { /* private fields */ }

History service for undo/redo operations

Implementations

impl HistoryService

pub fn new() -> Self

Create a new history service with default settings

pub fn with_max_size(max_size: usize) -> Self

Create a history that keeps at most max_size undo steps, dropping the oldest first; 0 keeps every step.

pub fn push_snapshot(&mut self, drawings: Vec<(usize, Drawing)>)

Record the drawings a bulk edit changes or removes, each with its list index before the edit, as one undo step. Undo restores only these drawings.

pub fn push_add(&mut self, drawing: Drawing)

Record that a drawing was added

pub fn push_delete(&mut self, drawing: Drawing, index: usize)

Record that a drawing was deleted from list index index

pub fn push_modify(&mut self, id: usize, old_state: Drawing)

Record that a drawing was modified

pub fn undo(&mut self, drawings: &mut Vec<Drawing>) -> Option<usize>

Undo the last operation

Returns the ID of the affected drawing, if any.

pub fn redo(&mut self, drawings: &mut Vec<Drawing>) -> Option<usize>

Redo the last undone operation

Returns the ID of the affected drawing, if any.

pub fn can_undo(&self) -> bool

Check if undo is available

pub fn can_redo(&self) -> bool

Check if redo is available

pub fn undo_count(&self) -> usize

Get the number of undo operations available

pub fn redo_count(&self) -> usize

Get the number of redo operations available

pub fn clear(&mut self)

Clear all history

pub fn shift_bar_indices(&mut self, from: f32, delta: f32)

Shift the bar indices at or after from in history (for bars inserted in front of them)

pub fn prune(&mut self, existing_ids: &HashSet<usize>)

Prune undo history entries for drawings that no longer exist.

Only the undo stack is pruned against the live id set. The redo stack is intentionally left intact: a redo entry legitimately references a drawing that is absent from the live set. After an Add is undone, the drawing is removed from the live set but its re-adding command sits on the redo stack; pruning the redo stack against live ids would silently drop that entry and lose the redo. The redo stack is the authoritative record of what redo would restore, so it is the wrong place to enforce live-id membership.

pub fn last_undo_description(&self) -> Option<&'static str>

Get description of the last undoable action (for UI)

pub fn last_redo_description(&self) -> Option<&'static str>

Get description of the last redoable action (for UI)

Trait Implementations

impl Clone for HistoryService

fn clone(&self) -> HistoryService

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for HistoryService

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for HistoryService

fn default() -> HistoryService

Returns the “default value” for a type.