Drawing modes are binary raster - operation codes representing all possible boolean combinations of two variables , using the binary operators and , or , and xor ( exclusive or ) , and the unary operation not 繪圖模式是二進制的光柵操作代碼,使用二元操作符and , or和xor ,以及一元操作符not ,表達了兩個變量所有可能的布爾組合。