private void calcDimensions() {
        w = Math.max(drawable1.getMinWidth(), drawable2.getMinWidth());
        w = Math.max(w, cellWidth);
        h = Math.max(drawable1.getMinHeight(), drawable2.getMinHeight());
        h = Math.max(h, cellHeight);
    }
cellWidth and cellHeight are only suggested values. These are overridden
by the minimum width and height of the drawables if necessary
@param drawable1
@param drawable2
@param cellWidth
@param cellHeight
core/src/com/ray3k/skincomposer/CheckerDrawable.java