| 摘要 |
A display scrolling system for a personal digital assistant (PDA) which includes a display screen disposed on a top surface of the PDA and a mouse integrated into the bottom surface of the PDA. Documents to be displayed on the screen are stored in a memory of the PDA. The PDA is placed on a work surface such that the mouse is manipulated by rolling the PDA across the surface. The work surface is regarded by the PDA as a virtual display of the document to be displayed on the display screen. As the PDA is rolled across the surface, the mouse generates translation information to a memory controller, which determines the location of the PDA with respect to the virtual document and generates viewport coordinates, which define a portion of the document to be displayed on the display screen. The viewport coordinates are input to a memory controller, which generates memory addresses to the memory indicating the location in the memory of the document portion defined by the viewport coordinates. The addressed document portion is output from the memory to the display screen for display. In this manner, the display screen serves as a window or viewport through which portions of a document corresponding to the virtual display may be viewed.
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