| 摘要 |
The simultaneous, real time graphical information is shared between two or more intelligent work stations linked together in conversation via a network. Transmission of the essence of a graphical image is accomplished by fixed and variable length portions. The fixed portion describes the type of command and the size or length of the variable length portion. The variable length portion describes the detailed information need to properly process. Thus, the complete length of data is known a priori. While a network is constipated or congested and a drawing operation is being performed by a user, the communication endpoints are configured as non-blocking, commands are stored in a FIFO (first-in, first-out) queue, and the operating system reports how much of the drawing operation was transferred. After the network becomes unconstipated, writing of any partially written command or stored commands in the queue are completed. The graphical image may be displayed in a window or canvas designated for drawing. By transmitting the parameters defining the object and its commands, the speed of the transmission is increased over pixel-by-pixel transmission.
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