Graphiy Behavior

This is a collection of Objects handling user interactions with a canvas:

Pan - move the whole canvas horizontally and vertically
Select
- select on click
- select multiple with Ctrl key pressed
- Rectangular selection - group selection by drawing a rectangle
- Lasso selection - group selection by drawing a free form
Drag - drag selected items relative to the canvas with pointer
Zoom - resize canvas and items in it proportionally

TODO

randomize initial position of nodes
fix offset for dragged element when clicking on child of node for each the event is set
Zoom
Rectangular selection
Lasso selection