A multiple window display system includes a display device and a screen ownership area pointing to the identity of the window which is to contribute the data for each display area of the display device. An ordered list is maintained of the active windows in the priority order thereof. Means are provided to regenerate the screen ownership area from the ordered list, on each change made to the list, in terms of list position per device display area, by overwriting, progressing through the list in ...

The window handler circuit is inserted between an image memory (7) having as many pages as there are possible windows and a screen controller capable of reading from any of the pages of the image memory. The handler comprises two auxiliary memories (3, 4) each of which stores bit maps in which a logic one bit indicates that the corresponding window includes an image element in the same line or the same column as the case may be as the screen position currently being scanned. A battery (5) of AND...

A method and apparatus for automatically changing the display in overlapping rectangular viewport areas of a display screen of a digital display apparatus and in which each viewport area is assigned a different priority level. The method includes the steps of (a) storing in a random access store indications of the position and size of each viewport area, together with an indication of the priority level of the viewport area and (b) constructing a first matrix of (2n+1).sup.2 elements, where n is...

A first method manages a display screen window of an application program that is halted and includes the following steps: in responsive to an application program being halted, (a) copying the informational content of a window of the halted application program; (b) creating a second window, referred to as a shadow window, to be in registration with the window of the halted application program such that the window of the halted application program is hidden from the view of an observer of the disp...

A method displaying a plurality of screen image data sequentially one after another on a screen and a data processing apparatus. A mark or area is set on a screen. The mark or area is used to instruct to change a screen image data to be displayed. An operator moves a cursor on the screen to designate the mark or are so that a screen image data to be next displayed is selected from a plurality of screen image data. The selected screen image data is displayed on the screen.

An object-oriented window manager provides coordination between window displays generated by separate application programs by computing and storing the visible area of each application window each time displayed windows are changed. Each application program directly communicates with the screen buffer memory in order to redraw portions of the screen corresponding to its display area using the visible area computed by the window manager. Each application program communicates with the object-orien...

Processes and apparatuses for characterizing the spatial relationship of two displayed objects. Differences between pairs of coordinates of the two objects are generated. The differences are sequentially stored as binary values in the lower half of a data register and shifted left one bit to preserve the most significant bit of each difference in the upper half of the register. The spatial relationship between the two objects is characterized by accessing a lookup table using a table index, wher...

A data processor having a page turning function, for managing a plurality of data sets each containing a plurality of data units of different kinds, has an extraction portion, a decision portion, and an output control portion. The extraction portion is used to extract a data unit in a page ahead of the present page in response to a next page instruction, or in a page behind the present page in response to a previous page instruction, and the decision portion is used to determine whether or not t...

A view system provides an extensible mechanism for associating a logical set of windows and manipulating them as a unit. For example, operations can be applied across address spaces to all the members of the group. A group is constructed by inserting a reference to each view in the group in a layer object. The layer object, in turn, can be inserted into a data hierarchy structure in a hierarchy object. The data hierarchy structure defines front to back display levels on a display and defines whi...

An apparatus for displaying the display outputs of a plurality of simultaneously active computer processes in corresponding windows on a single screen includes a microcomputer, a display screen and display system software. The software represents a plurality of virtual terminals, one corresponding to each active process, for emulating the operation of real terminals communicating with the processes. Each virtual terminal maintains a display list comprising a set of instructions defining a displa...