/// <summary>
/// Redoes one task on this UndoSystem
/// </summary>
public void Redo()
{
if (_currentTask == _undoTasks.Count)
{
return;
}
// Get the task to undo
IUndoTask task = _undoTasks[_currentTask];
// Fire the WillPerformRedo event handler
WillPerformRedo?.Invoke(this, new UndoEventArgs(task));
// Finish any currently opened group undos
if (InGroupUndo)
{
FinishGroupUndo(_currentGroupUndoTask.DiscardOnOperation);
}
_currentTask++;
task.Redo();
// Fire the UndoPerformed event handler
RedoPerformed?.Invoke(this, new UndoEventArgs(task));
}
public async Task Undo()
{
if (this.UndoStack.Count() > 0)
{
IUndoTask undoTask = this.UndoStack.Pop();
this.RedoStack.Push(undoTask);
await undoTask.UndoAction.Invoke();
this.OnTaskAdded();
}
}
/// <summary>
/// Removes and returns the next redo task from this UndoSystem's undo list.
/// The undo task is not performed, and is not disposed before being returned.
/// If no redo task is available, null is returned
/// </summary>
/// <returns>The next available redo operation if available, null otherwise</returns>
public IUndoTask PopRedo()
{
if (!CanRedo)
{
return(null);
}
IUndoTask task = NextRedo;
_undoTasks.Remove(task);
return(task);
}
/// <summary>
/// Performs the bucket fill operation
/// </summary>
/// <param name="color">The color of the fill operation</param>
/// <param name="point">The point to start the fill operation at</param>
public void PerformBucketOperaiton(Color color, Point point)
{
IUndoTask undoTask = PerformBucketOperaiton(pictureBox.Bitmap, color, point, compositingMode, true);
if (undoTask != null)
{
pictureBox.OwningPanel.UndoSystem.RegisterUndo(undoTask);
// Finish the operation by updating the picture box
pictureBox.Invalidate();
pictureBox.MarkModified();
}
}
/// <summary>
/// Removes and returns the next undo task from this UndoSystem's undo list.
/// The undo task is not performed, and is not disposed before being returned.
/// If no undo task is available, null is returned
/// </summary>
/// <returns>The next available undo operation if available, null otherwise</returns>
public IUndoTask PopUndo()
{
if (!CanUndo)
{
return(null);
}
IUndoTask task = NextUndo;
_undoTasks.Remove(task);
_currentTask--;
return(task);
}
/// <summary>
/// Registers the given UndoTask on this UndoSystem
/// </summary>
/// <param name="task">The task to undo</param>
/// <exception cref="ArgumentNullException">The undo task provided is null</exception>
public void RegisterUndo(IUndoTask task)
{
if (task == null)
{
throw new ArgumentNullException(nameof(task), @"The task cannot be null");
}
// Grouped undos: record them inside the group undo
if (InGroupUndo)
{
_currentGroupUndoTask.AddTask(task);
return;
}
// Redo task clearing
ClearRedos();
// Task capping
if (_undoTasks.Count >= _maxTaskCount)
{
while (_undoTasks.Count >= _maxTaskCount)
{
_undoTasks[0].Clear();
_undoTasks.RemoveAt(0);
}
}
else
{
_currentTask++;
}
_undoTasks.Add(task);
UndoRegistered?.Invoke(this, new UndoEventArgs(task));
}
/// <summary>
/// Creates a new instance of the UndoEventArgs
/// </summary>
/// <param name="task">The task associated with this event</param>
public UndoEventArgs(IUndoTask task)
{
Task = task;
}
/// <summary>
/// Adds a new task on this GroupUndoTask
/// </summary>
/// <param name="task">The task to add to this GroupUndoTask</param>
public void AddTask(IUndoTask task)
{
_undoList.Add(task);
}
public Task AddUndoTask(IUndoTask undoTask)
{
this.UndoStack.Push(undoTask);
this.OnTaskAdded();
return(Task.FromResult(0));
}