RFC 191 Charles Irby NIC 7136 Augmentation Research Center Category D.6, I.1 Stanford Research Institute 13-JUL-71
This document will discuss only those facits of display use which have been implemented and are currently operational, namely only those dealing with textual display.
A "processor dsplay" is a display with Processing power which can be controlled by character strings.
The currently implemented characteristics are character size,
horizontal spacing between characters, and font of the
characters (e.g. blinking, italics, intensity, etc.).
The position of items in the display area are given relative to the 0,0, which is the lower left corner of the display area. The horizontal coordinate increases to the right and the vertical coordinate increases toward the top.
When in display mode, the teletype simulation display area is suppressed and the coordinates of the cursor are input with each character. When in teletype simulation mode, all user owned display areas are suppressed and the coordinates of the cursor are not input with each character.
The NLS subsystem deals only with the cursor and the display areas it has requested from the system for output to the user. The display area formatters assumes that the display has 64K by 64K addressable points (with 0,0 at upper left), several different character sizes and fonts, and 7-bit ASCII.
NLS allows the user to specify arguments to commands by
selecting items from the current display image. This is
accomplished through the use of a data structure, which
describes the current display image, to map the cursor
coordinates, which are input with each character, into the proper selection.
splits a file-viewing display area horizontally (into an upper and lower segment) at the selected location moving the image of the original display area to the upper or lower segment depending on whether the cursor is above or below the bugged position when the final Command Accept is input.
No display area will be created which is smaller then 2 lines by 20 columns (using the character size of the original display area).
splits a file-viewing display area vertically (into a left and right segment) at the selected location moving the image of the original display area to the left or right segment depending on whether the cursor is to the left or right of the selected position when the final CA is input.
No display area will he created which is smaller then 2 lines by 20 columns (using the character size of the original display area).
The current character size of the display area which
currently contains the cursor is displayed, and the user may type a number (0, 1, 2, 3) for a new character size. The final Command Accept causes the character size to be changed. The horizontal and vertical increment are
automatically adjusted. Different display areas may
simultaneously have different character sizes.
Clear display area
The selected display area is cleared, i.e. the image is
erased, the return and file return rings are released, and
the association of a file with that display area is
removed. The display area itself is not deleted.
For example, If one executes a Jump command, the position of the cursor when the final Command Accept is entered determines in which display area the new image is to appear.
Also, If one changes viewspecs using the leftmost two buttons of the mouse, the viewspecs of the display area containing the cursor when the buttons go down are used as the initial values and are displayed in the viewspec area. When the buttons are released, the display area containing the cursor receives the new viewspecs.
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