print('safety margin', screen_top_y, 'dvpx')

	print('safety margin', safety_margin, 'dvpx')

		local cursor_y = y_of_schema1(node.editor, node.editor.cursor1)
		print('cursor', cursor_y, 'dvpx')
		if Viewport.y < node.y then
			-- node starts within Viewport
			print('node starts within viewport')
			local max_cursor_y = App.screen.height - scale(node.y - Viewport.y) - safety_margin
			if cursor_y > max_cursor_y then
				-- set Viewport.y so cursor_y == max_cursor_y
				-- equation: cursor_y == App.screen.height - (node.y - Viewport.y)*Viewport.zoom - safety_margin
				-- solve for Viewport.y
				Viewport.y = node.y - (App.screen.height - cursor_y - safety_margin)/Viewport.zoom
				print('adjusting Viewport to', Viewport.y)
			end
		else
			-- node extends above Viewport
			print('node extends above viewport')
			local screen_top_y = y_of_schema1(node.editor, node.editor.screen_top1)
			print('screen top', screen_top_y, 'dvpx')
			local max_screen_top_y = cursor_y - safety_margin
			if screen_top_y > max_screen_top_y then
				screen_top_y = max_screen_top_y
				Viewport.y = node.y + screen_top_y/Viewport.zoom
				print('adjusting Viewport to', Viewport.y)
			end
		end