calculateSize method
Calculates the size of canvas based on dots count, size and spacing
Implementers can override this function to calculate their own size
Implementation
@override
Size calculateSize(int count) {
var height = dotHeight;
if (type == SwapType.zRotation) {
height += height * .2;
} else if (type == SwapType.yRotation) {
height += dotWidth + spacing;
}
return Size(dotWidth * count + (spacing * count), height);
}