Image Number 17 for United States Patent #6078306.
Data representing bitmapped graphics and/or text characters is stored in a video buffer or memory of a computer. A window is designated that includes contiguous rows and columns of data to be scrolled. The data in the window is vertically scrolled by columns. One column can be scrolled at a time, or two or more adjacent or alternating columns can be scrolled at a time. The column scrolling method is faster than scrolling by rows when the number of rows in the window is small and/or the number of rows to scroll is high. Program instructions for implementing the scrolling are preferably stored in a Basic Input-Output System (BIOS) Read-Only Memory (ROM) chip to provide a built-in, backward compatible low resolution display capability, e.g. a Color Graphics Adapter (CGA) text display, for a newer computer or other data processing device.
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