void DragAreaTracker_MouseDown(object sender, MouseButtonEventArgs e)
{
mouse_down_point = e.GetPosition(canvas);
button_left_pressed = e.LeftButton == MouseButtonState.Pressed;
button_right_pressed = e.RightButton == MouseButtonState.Pressed;
if (null == current_annotation)
{
canvas.CaptureMouse();
current_annotation = new DragAreaControl(visible);
Canvas.SetLeft(current_annotation, mouse_down_point.X);
Canvas.SetTop(current_annotation, mouse_down_point.Y);
current_annotation.Width = 0;
current_annotation.Height = 0;
canvas.Children.Add(current_annotation);
if (null != OnDragStarted)
{
OnDragStarted(button_left_pressed, button_right_pressed, mouse_down_point);
}
if (null != OnDragInProgress)
{
OnDragInProgress(button_left_pressed, button_right_pressed, mouse_down_point, mouse_down_point);
}
}
}
private void DragAreaTracker_MouseUp(object sender, MouseButtonEventArgs e)
{
if (null != current_annotation)
{
canvas.Children.Remove(current_annotation);
current_annotation = null;
canvas.ReleaseMouseCapture();
Point mouse_up_point = e.GetPosition(canvas);
OnDragComplete?.Invoke(button_left_pressed, button_right_pressed, mouse_down_point, mouse_up_point);
}
}