panel_bounds = function(col, row)
	local panel_width = (App.screen.width - Margin * (Num_panels_horizontal + 1)) / Num_panels_horizontal
	local left = (col - 1) * (Margin + panel_width) + Margin
	local panel_height = (App.screen.height - Margin * (Num_panels_vertical[col]+1)) / Num_panels_vertical[col]
	local top = (row - 1) * (Margin + panel_height) + Margin
	return left,top, panel_width, panel_height
end