Border margin = style.getMarginWidth(parent_width, parent_width, c.getCtx());
Border margin = master.getMarginWidth(c, parent_width);
    public BlockFormattingContext(Box master, Context c) {        int parent_width = (int) c.getExtents().getWidth();        CalculatedStyle style = c.getCurrentStyle();        Border border = style.getBorderWidth(c.getCtx());        //note: percentages here refer to width of containing block        Border margin = style.getMarginWidth(parent_width, parent_width, c.getCtx());        padding = style.getPaddingWidth(parent_width, parent_width, c.getCtx());        insets = new Border(margin.top + border.top + padding.top,                padding.right + border.right + margin.right,                padding.bottom + border.bottom + margin.bottom,                margin.left + border.left + padding.left);        this.master = master;        master.setBlockFormattingContext(this);        left_floats = new ArrayList();        right_floats = new ArrayList();        offset_map = new HashMap();        abs_bottom = new ArrayList();    }