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 绘图模式是二进制的光栅操作代码,使用二元操作符and , or和xor ,以及一元操作符not ,表达了两个变量所有可能的布尔组合。