2.2.2.2.1.3.3 Switch Surface (SWITCH_SURFACE_ORDER)

The Switch Surface Alternate Secondary Drawing Order is used by the server to instruct the client to switch the target drawing surface either to the primary drawing surface (screen desktop) or to an entry in the Offscreen Bitmap Cache. Support for offscreen bitmap caching is specified in the Offscreen Bitmap Cache Capability Set (see [MS-RDPBCGR] section 2.2.7.1.9).


0


1


2


3


4


5


6


7


8


9

1
0


1


2


3


4


5


6


7


8


9

2
0


1


2


3


4


5


6


7


8


9

3
0


1

header

bitmapId

header (1 byte): An Alternate Secondary Order Header, as defined in section 2.2.2.2.1.3.1.1. The embedded orderType field MUST be set to TS_ALTSEC_SWITCH_SURFACE (0x00).

bitmapId (2 bytes): A 16-bit, unsigned integer. The new target drawing surface. If this field has a value less than SCREEN_BITMAP_SURFACE (0xFFFF), it SHOULD<5> identify an entry in the Offscreen Bitmap Cache that contains a bitmap surface that MUST become the new target drawing surface. This value MUST be greater than or equal to 0 and less than the maximum number of entries allowed in the Offscreen Bitmap Cache as specified by the offscreenCacheEntries field of the Offscreen Bitmap Cache Capability Set ([MS-RDPBCGR] section 2.2.7.1.9). Otherwise, if this field has the value SCREEN_BITMAP_SURFACE, the target drawing surface MUST be changed to the primary drawing surface (screen desktop).