A display screen control method for a display device capable of supporting a logical screen larger in size than its physical screen is provided. This method enables a desired area to be displayed on the display device by a single operation. According to the method, a first rectangle similar to the logical screen is displayed on the physical screen, a second rectangle similar to the window area which was displayed within a view port in the physical screen is displayed in the first rectangle. The second rectangle is moved to a desired position within the first rectangle by a position indicating means such as a pointing device whereby the area the operator wishes to view is displayed in one quick operation.

A word processing apparatus with a function of an image-format control includes an image data storage for storing image data imputted in a certain format, an reading unit for reading the image data from the image data storage, a display device for displaying a region on a screen, a magnification/reduction control unit for calculating a virtual print size of the read image data, comparing the virtual print size with the size of the region, and magnifying or reducing the size of the read image data when those compared sizes are not equal so as to put the image within the region.

An automotive navigator using a microcomputer displays a car position by a cursor on a road map displayed on a CRT screen. The navigator uses a cassette tape which stores a plurality of road map data and several kinds of reduced map data and expanded map data. It also uses a group of manual switches including a switch for changing the displayed area, a switch for selecting an expanded map or reduced map and a switch for moving the cursor position. Necessary data are displayed on the screen by the state of each switch. A region corresponding to the cursor position is displayed by the expanded map.

Apparatus for displaying an image defined by digital data representing the color content of the pixels of the image comprises a monitor; a first store for storing digital data representing an image at low resolution and a second store for storing digital data representing a magnified portion of the image at high resolution. A microcomputer is connected to the stores and to the monitor and an indicator assembly is acutable by an operator to select an area of an image displayed by the monitor. The microcomputer is responsive to a "magnify" signal from the indicator assembly to cause the monitor to display a portion of the selected after magnification, the portion being displayed within the selected area. The microcomputer suppresses pixels of the orginally displayed image within the remaining portion of the selected area, the degree of magnification being such that the magnified portion substantially fills the selected area.

A character graphic information display device is adapted to decode into the character graphic picture images with the standard density the high density of character graphic information which has been transmitted so as to display it on the display portion after passing through the memory and the processing circuit; the desired region may be displayed on the whole display portion as the high density picture images by the operation of the keypad. Also order to obtain other regions as the high density picture images, the other high density picture images are continuously displayed only by the movement of the cursor in the condition of the high density picture face.