See Section 5 for a discussion of the text and graphics screens and their Handlers.
For the text screen and split-screen text window there is a visible cursor on the screen which shows the position of the next input or output operation. The cursor is represented by inverting the video of the character upon which it resides; but the cursor can be made invisible, at the user's option. The graphics screen always has an invisible cursor.
The cursor position is sensed by examining data base variables and can be moved by altering these same variables; in addition, when using the Screen Editor, there are cursor movement control codes that can be sent as data (as explained in Section 5).
B1 CRSINH [02F0,1] -- Cursor display inhibit flag
When CRSINH is zeros all outputs to the text screen will be followed by a visible cursor (inverted character); and when CRSINH is nonzero, no visible cursor will be generated.
CRSINH is set to zero by power-up, the [SYSTEM.RESET] or [BREAK] keys or an OPEN command to the Display Handler or Screen Editor.
Note that altering CRSINH does not cause the visible cursor to change states until the next output to the screen; if an immediate change to the cursor state is desired, without altering the screen data, follow the CRSINH change with the output of CURSOR UP, CURSOR DOWN or some other innocuous sequence.
B2 ROWCRS [0054,1] and COLCRS [0055,2] -- Current Cursor position
ROWCRS and COLCRS define the cursor location (row and column respectively) for the next data element to be read from or written to the main screen segment. When in split-screen mode, the variables TXTROW and TXTCOL define the cursor for the text window at the bottom of the screen as explained in B4 below.
The row and column numbering start with the value zero, and increase in increments of one to the number of rows or columns minus 1; with the upper left corner of the screen being the origin (0,0).
ROWCRS is a single-byte variable with a maximum allowable value of 191 (screen modes 8-11); COLCRS is a 2-byte variable with a maximum allowable value of 319 (screen mode 8).
