Computer graphics processing and selective visual display system – Display peripheral interface input device – Light pen for fluid matrix display panel
Patent
1995-01-18
1998-09-01
Saras, Steven J.
Computer graphics processing and selective visual display system
Display peripheral interface input device
Light pen for fluid matrix display panel
345125, G09G 534
Patent
active
058016759
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a procedure for scrolling of some raster-lines in a window of a screen, operated in the graphic-mode, of a personal computer, which has a processor and a program memory allocated to it as well as a video card, connected with the processor via an external bus, such video card having a video memory (RAM), whose memory contents can be presented on the screen, where one first line of the raster scan lines to be scrolled, to be moved in a raster scan line within the window, is marked with a source-pointer and such raster scan line within a window, in which this line is to be moved into, is marked with a destination pointer, after that a scroll is performed and repeated until all lines to be scrolled are in the raster scan lines of the window.
2. Description of the Prior Art
The scrolling is performed, to scroll the information contained in certain lines to another determined position, meaning to certain other raster scan lines of the window on the screen. These lines can be already displayed raster-lines, which are at another position within the window, they can also be lines especially, which are not presented on the screen of the window yet, but are i.e. on another text page.
A procedure of the above-mentioned kind is known from the European patent 71 725. With the procedure known the line having the source-pointer is moved in the raster-line, which is marked with the destination pointer, positioned in the window. After that the following line is moved in the following raster-line and so on until all lines, which need to be scrolled, were moved (scrolled) in raster-lines of the window.
With the procedure known the processing-speed and the transfer-width, which computers offer, equipped with modern processors of type x386 and higher, are not fully used on one hand, on the other the image structure in the window is performed relatively sharp, because line after line is moved and added. A relatively keen-edged transition is produced. Attention has to be paid to the fact that with a scrolling procedure as mentioned above and known from the stated printed patent specification, the scrolling, meaning the movement of individual raster-lines, does not occur synchronically to the line frequency of the screen, whereby during the actual transfer procedure unwanted images are produced on the screen, mostly a flickering and snow. In the stated printed patent specification it is already suggested in a preferred embodiment not to present the environment in which the movement during the transfer procedure (scrolling) is produced, just leaving it black or fill it up with a colour on purpose. As soon as the scroll-procedure is finished this blanking or the filling with a colour attribute is stopped and the raster-lines are presented.
It is the object of the invention to more fully use the possibilities of modern processors of mentioned type, meaning x386 and higher, than before and speed-up the scrolling process accordingly, project it, however otherwise that the transition between already scrolled raster-lines and raster-lines not yet scrolled are presented more smoothly, so that sharper contrast differences do not occur.
SUMMARY OF THE INVENTION
The object is solved according to the invention, by the fact that at the same time with the first line also at least the subsequent third line is scrolled in corresponding raster-lines of the screen window, that after that the second and at least the fourth line of the area to be scrolled is scrolled from lines in raster-lines of the screen window and so on until all lines to be scrolled were scrolled in raster-lines of the window.
According to the invention the scrollings are performed with the maximum capacity the processor has to offer. With the mentioned processors of type x386 and higher, two word-scrollings are performed. Altogether always two uneven-numbered or two even-numbered lines are scrolled at least, preferably four or more. By that the number of scrollings per clock is at least double as
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Bauer Wulf
Paley Greg
Award Software Int. Inc.
Lezdey John
Saras Steven J.
Vobis Microcomputer AG
Wu Xu-Ming
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