proposal for vanilla.ScrollView to support embedded vanilla.Group

embedGroupInScrollview.py

from vanilla import *
import vanilla

from vanilla.vanillaBase import VanillaError

class ScrollView(vanilla.ScrollView):
    
    def __init__(self, posSize, nsView, hasHorizontalScroller=True, hasVerticalScroller=True,
                    autohidesScrollers=False, backgroundColor=None, clipView=None, 
                    drawsBackground=True):
        
        # set a flag if the scrollview is using a vanilla.Group
        isScrollViewWithGroup = False
        # only support vanilla.Group object
        if isinstance(nsView, Group):
            l, t, w, h = nsView.getPosSize()
            # only support when the widht and height is a fixed
            if w <= 0 or h <= 0:
                raise VanillaError("Embedded Group must have fixed width and height")
            # store the group
            isScrollViewWithGroup = nsView
            # get the nsView from the group
            nsView = nsView.getNSView()
            
        super(self.__class__, self).__init__(posSize, nsView, hasHorizontalScroller, hasVerticalScroller, autohidesScrollers, backgroundColor, clipView, drawsBackground)
        
        if isScrollViewWithGroup:
            # when it is a group set the parent frame...
            isScrollViewWithGroup._setFrame(((0, 0), (0, 0)))

w = Window((400, 400), minSize=(100, 100))

g = Group((0, 0, 300, 1000))

g.l = List((10, 10, -10, 100), ["a", "b", "c"])

g.c = CheckBox((10, 130, -10, 22), "Hello")

w.s = ScrollView((0, 0, -0, -0), g)


w.open()