Abstract: As various objects, images, etc. are selectively enlarged or reduced in size on a screen using a zooming operation, at least three marks are displayed to provide a visual indication of the limits for zoom-in and zoom-out operations. The first and second marks indicate limits for enlarging and decreasing a picture, respectively, while the third mark indicates a position of the current screen display with respect to the displayed limits for the zoom-in and zoom-out operations.

Abstract: A graphical universe that is larger than a display screen is displayed on a screen using a panning operation. To view portions of the graphical universe, a cursor positioned on the display screen using an input device is utilized to fix a reference location for the panning operation. By moving the cursor on the display screen, a line between the cursor and the reference location is provided. The direction of the line indicates direction of the panning operation, while the length of the line determines speed of the panning operation.

Abstract: Various objects, images, pictures, etc. are selectively enlarged or reduced on a screen using a zoom operation. To view an object, for example, on the screen with less details or more details than the current display of the object, a cursor positioned on the screen display using an input device is utilized to fix a reference location located on a circle of a predetermined diameter. By moving the cursor on the screen display, a line between the cursor and the reference location is provided. The direction of the line indicates direction of the zoom operation: if the line is inside the circle, the object is zoomed-out, and if the line is outside the circle, the object is zoomed in. The length of the line determines speed of the zoom operation.