Graphics Characters - Terminal Devices

PRO/5 supports the graphics characters necessary to draw boxes and lines on the display including those characters used to interconnect lines. The 'GS' mnemonic causes the terminal driver to enter a character translation mode where the characters "0"-"9" and ":" are used to select characters that are essential to drawing boxes. The 'GE' mnemonic disables this character translation. In order for the graphics capability to work correctly under the UNIX or XENIX operating system, the proper definition must be placed in the terminal's "termcap" entry.

The graphics attribute may also be set using the 'ATTR' mnemonic.

Clearing Regions

There are several mnemonics used to clear various regions of the terminal display:

Mnemonic

Description

'CS'

Clear screen

'CE'

Clear to end of screen

'CL'

Clear to end of line

'CF'

Clear foreground

All of these mnemonics operate in the current scroll region.

In addition, the 'PS' and 'PE' mnemonics may modify how a clear works: 'CF' is a 'CS' performed in protect mode.

Any of the clear operations reset the current attributes and colors to the values in the default set prior to the clear. The cleared region will contain the default attributes.

Display Editing

Several mnemonics may be used to "edit" the current window/scroll region:

Mnemonic

Description

'LD','LI'

Line delete, insert

'DC','IC'

Character delete, insert

The editing operations reset the current attributes and colors to the values in the default set prior to the edit operation.

Modifying the Input

The terminal driver allows you to modify the input from the terminal in several ways. Among these are:

Mnemonic

Description

'UC','LC'

Disable/enable lower-case input

'CI'

Clear input buffer of characters

'ET','BT'

Disable/enable type ahead

'FL','EL'

Load function/edit keys

Reading The Display

Portions of the current scroll region may be read using one of the following mnemonics:

Mnemonic

Description

'RL'

Read a line

'RP'

Read from cursor to end of screen

'TR'

Read from beginning of scroll region to cursor

The data transmitted is terminated by a carriage return character ($0D$). If graphics mode is on ('GS') during any portion of the transmission, then the character transmitted will be preceded by 3 characters describing the color (foreground and background) and the character's attributes. These characters will have the most significant bit set to help distinguish them from text data. Otherwise, the format is the same as specified in the FIN() data for a terminal.