Browse Prior Art Database

Graphics Message Scrolling

IP.com Disclosure Number: IPCOM000045776D
Original Publication Date: 1983-Apr-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 2 page(s) / 28K

Publishing Venue

IBM

Related People

Halliwell, H: AUTHOR

Abstract

In a graphics system, it is often desirable to display on the CRT, outside the sight defined by the drawing boundaries, prompting messages to assist the user. The following description is of a scrolling message system in which the last message is highlighted and the intensity of previous messages is reduced. In this description, it is assumed that only the previous two prompting messages are retained.

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Graphics Message Scrolling

In a graphics system, it is often desirable to display on the CRT, outside the sight defined by the drawing boundaries, prompting messages to assist the user. The following description is of a scrolling message system in which the last message is highlighted and the intensity of previous messages is reduced. In this description, it is assumed that only the previous two prompting messages are retained.

This message-scrolling system does not require any special processing by the host processor. The message is written as a fourth line in a three-line system. The fourth line is tested at each refresh cycle. If a message is found to be assigned to the fourth line, it has a y-coordinate value of zero. The intensity order on the previous third line is changed from the high intensity order to the low intensity order. Then the y-coordinate of each message line is incremented. This is shown in the flow chart above.

The host computer writes the new message to the display buffer which contains the previous first line as identified by the updated y-coordinate. The high intensity order is written with the message.

This method requires only a single write operation, and the remaining two message areas are not affected even though their position is required to change and the intensity of the lower one is changed.

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