As title, Enable extend area by scrolling?
The snerio is like that expend by scrolling left, right, top or bottom by scrolling with five finger or with CTRL + arrow key so it create board to extended as they want.
Like in context menu we have option to export image, but it download image without background, make the functionality that download image with background, also add another menu item for this.
As title, add undo and redo functionality, for that you have to save to local-storage so you can save coordinate because if you save image in mobile browser it slow down the performance