Browse Prior Art Database

Shadow Cursor

IP.com Disclosure Number: IPCOM000084008D
Original Publication Date: 1975-Sep-01
Included in the Prior Art Database: 2005-Mar-01
Document File: 2 page(s) / 43K

Publishing Venue

IBM

Related People

Busch, DJ: AUTHOR [+2]

Abstract

The horizontal position of a cursor on a text display system is indicated both by an underscore of the addressed, cursored character and by an underscore on a scale line at the top of the display. The cursor indication at the cursored character, is accomplished upon a compare of the character accessed in a refresh buffer with the stored address of the cursored character. The indication on the scale line is provided in response to the indication beneath the cursored character.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 53% of the total text.

Page 1 of 2

Shadow Cursor

The horizontal position of a cursor on a text display system is indicated both by an underscore of the addressed, cursored character and by an underscore on a scale line at the top of the display. The cursor indication at the cursored character, is accomplished upon a compare of the character accessed in a refresh buffer with the stored address of the cursored character. The indication on the scale line is provided in response to the indication beneath the cursored character.

In this display system a plurality of lines of text characters are displayed by raster scanning with full length vertical display lines. Thus, with each vertical sweep a vertical segment of a single character on each text line is illuminated on the cathode-ray tube screen.

In Fig. 1 text character codes representative of lines to be displayed are stored in display refresh buffer 1. The address in buffer 1 in which the cursored character is stored is written into cursor control byte 2. When it is desired to display an underscore immediately beneath the cursored character as well as a shadow, underscore mark beneath the scale line at the top of the display, an additional bit is set to 1 in byte 2.

At the beginning of the display of the frame, the cursored character address from byte 2 is written into cursor register 4 which is connected to an input of compare 5. As the character codes are sequentially accessed in buffer 1 by memory address register 3, the addresses in buffer 1 of these characters are also input to compare 5.

Assuming that it is desired to d...