在[MS-RDPEGDI]中对Operation Code的描述太过玄妙了，用S、D、P还有AND，OR，NOT 和 XOR 来表示Operation的具体动作。每次看都感觉一脸懵逼。这回是解决一个Customer Issue，发现以前没有实现的一个Operation。看了文档感觉解读不能，看FreeRDP的源代码，最后只能找到API级别的，内部如何实现的无从得知，这样也就没法在前端实现了。于是搜索了一大圈，找到了微软在Gdiplus.cs这个文件中的枚举类型和注释。解释的清晰明了，早这样写不就好了........
不过根据微软的特点，这个链接大概率的在若干年后就会失效。所以我还是把需要的这部分粘贴过来。而且这些Code我已经重新排过版了，每一个都按照顺序对应了[MS-RDPEGDI]中的Operation Code。
BLACKNESS = 0x00000042, /* dest = BLACK */ ==== 0x00
NOTSRCERASE = 0x001100A6, /* dest = (NOT src) AND (NOT dest) */ ==== 0x11
NOTSRCCOPY = 0x00330008, /* dest = (NOT source) */ ==== 0x33
SRCERASE = 0x00440328, /* dest = source AND (NOT dest ) */ ==== 0x44
DSTINVERT = 0x00550009, /* dest = (NOT dest) */ ==== 0x55
PATINVERT = 0x005A0049, /* dest = pattern XOR dest */ ==== 0x5A
SRCINVERT = 0x00660046, /* dest = source XOR dest */ ==== 0x66
SRCAND = 0x008800C6, /* dest = source AND dest */ ==== 0x88
MERGEPAINT = 0x00BB0226, /* dest = (NOT source) OR dest */ ==== 0xBB
MERGECOPY = 0x00C000CA, /* dest = (source AND pattern) */ ==== 0xC0
SRCCOPY = 0x00CC0020, /* dest = source */ ==== 0xCC
SRCPAINT = 0x00EE0086, /* dest = source OR dest */ ==== 0xEE
PATCOPY = 0x00F00021, /* dest = pattern */ ==== 0xF0
PATPAINT = 0x00FB0A09, /* dest = DPSnoo */ ==== 0xFB
WHITENESS = 0x00FF0062, /* dest = WHITE */ ==== 0xFF
End
