Getting Started


Add this package to your dependencies in your pubspec.yaml file:

    box_transform: <latest_version>


Box Transform defines several models to mimic that of Flutter's.

  • The equivalent of Size is Dimension.
  • The equivalent of Offset is Vector2 from the vector_math package.
  • The equivalent of Rect is Box.
  • The equivalent of BoxConstraints is Constraints.


You can call the BoxTransformer.resize method to resize a box. The method takes the following parameters:

handle: The handle that is being dragged. initialRect: The box before resizing started. initialLocalPosition: The position of the mouse pointer before resizing started. localPosition: The current position of the mouse pointer. resizeMode: The resize mode. See Resize Modes for more information. initialFlip: The flip state before resizing started.

Resizing a Box
  final Box rect = Box.fromLTWH(50, 50, 100, 100);

  final ResizeResult result = BoxTransformer.resize(
    handle: HandlePosition.bottomRight, // handle that is being dragged
    initialRect: rect,
    resizeMode: ResizeMode.freeform,
    initialFlip: Flip.none,

  result.rect; // the new rect
You can also use a isolates for these simultaneous resizing operations since this is a pure dart implementation.

You can use BoxTransformer.move to move a box.

Moving a box
  final Box rect = Box.fromLTWH(50, 50, 100, 100);
  final MoveResult result = BoxTransformer.move(
    initialRect: rect,

  result.position; // the new position of the box