Object-oriented window area display system

• US 5,522,025 A
• Filed: 10/25/1993
• Issued: 05/28/1996
• Est. Priority Date: 10/25/1993
• Status: Expired due to Term

• Current Assignee: Apple Inc.
• Original Assignee: Taligent, Inc. (HP Inc.)
• Inventors: Rosenstein, Larry S.
• Primary Examiner(s): Bayerl, Raymond J.
• Assistant Examiner(s): dela Torre, Crescelle N.
• Application Number:
  US08/142,894
• Time in Patent Office: 946 Days
• Field of Search: 395/155, 395/157, 395/158, 395/160, 395/161, 395/133, 395/135, 345/119, 345/120, 345/113
• US Class Current: 715/807
• CPC Class Codes: G09G 5/14 Display of multiple viewports

Abstract

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-oriented window manager by creating a window object which provides flexible display capabilities that are transparent to the application program. Several techniques are used to decrease the visible area computation time. First, as mentioned above a copy of the visible area is stored or "cached" in each window object. This copy can be used if the application program needs to redraw the window area and the visible area has not been changed. In addition, the window manager computes the visible area of each application window utilizing a routine that assumes that only a single window has been changed and compares the new visible area of the window to the old visible area to obtain the change area. This change area is then used to recompute the visible area of all windows which lie behind the changed window.

Claims

1. A computer system for controlling a display device to generate a display having a plurality of window areas displayed on a desktop background, each of the plurality of window areas displaying screen information generated by one of a plurality of application programs, the computer system comprising:

a memory;

screen buffer storage apparatus having a plurality of storage areas, each of the plurality of storage areas having a size and storing the screen information for one of the plurality of window areas, the stored screen information being used by the display device to generate the display;

a processor controlled by the plurality of application programs, wherein each of the plurality of application programs comprises means for directly storing the screen information in the storage areas of the screen buffer storage apparatus;

an operating system cooperating with the processor for controlling the display device;

means, responsive to a change in a window area, for communicating the window area change to the plurality of application programs so that the plurality of application programs may respond to the window area change

a window object in the memory and associated with each of the plurality of windows, each window object including window data and window functions and being created by an application program, wherein the window object comprises a mechanism for receiving a request from one of the plurality of application programs and apparatus responsive to a received request for providing a storage area location and size to the one of the plurality of application programs which made the request,

wherein the window data comprises a copy of the storage area size of the associated window and wherein the window object further comprises apparatus responsive to a request from one of the plurality of application programs for determining the validity of the storage area size copy,

wherein the means for communicating comprises apparatus for storing, with each storage area size, a first time stamp indicating the time at which the storage area size was recalculated, and wherein the window object comprises apparatus for storing with the storage area size copy a second time stamp indicating the time at which the storage area size copy was stored in the window object.

2. A computer system according to claim 1 wherein the validity determining apparatus comprises apparatus responsive to a request from an application program for a selected storage area size corresponding to a window for retrieving a first time stamp stored with the selected storage area size from the means for communicating and apparatus responsive to the retrieved first time stamp for comparing the retrieved first time stamp to the second time stamp stored in the window object.

3. A computer system according to claim 2 wherein the validity determining apparatus further comprises means for retrieving the storage area size stored in the means for communicating when the time stamp comparing apparatus indicates that the storage area size stored in the window object is not valid.

4. A computer system for controlling a display device to generate a display having a plurality of window areas displayed on a desktop background, each of the plurality of window areas displaying screen information generated by one of a plurality of application programs, the computer system comprising:

a memory;

screen buffer storage apparatus having a plurality of resizable storage areas, each of the plurality of resizable storage areas having a size and each storing the screen information for one of the plurality of window areas;

a processor controlled by the plurality of application programs to receive screen information from a selected one of the plurality of application programs and to store the received screen information in one of the plurality of resizable storage areas corresponding to the selected one application program;

an operating system cooperating with the processor for controlling the display device;

a means, having a shared data area for storing the storage area sizes and being responsive to a change in a storage area size of one storage area, for changing a storage area size of at least one other storage area;

a window object created in the memory by each of the plurality of application programs, the window object, upon creation, cooperating with the means for changing to create a window area by allocating one of the plurality of storage areas;

wherein the means for changing is created by the operating system;

wherein the window areas are overlapped and visually appear to have a front to back ordering and wherein the means for changing comprises a mechanism for maintaining each of the plurality of windows in an ordered list having a plurality of list positions where each list position corresponds to a position in the front to back ordering;

wherein the means for changing comprise apparatus, responsive to a change in position and size of one of the plurality of window areas, for calculating a changed window area indicating a portion of the one of the plurality of window areas which is modified by the change in position and size, the means for changing further comprising apparatus responsive to the changed window area for recalculating the storage area size of storage areas corresponding to window areas which appear behind the one window area as determined by the ordered list;

wherein the recalculating apparatus recalculates the storage area size by combining the changed area with the stored area sizes corresponding to window areas which appear behind the one window area as determined by the ordered list;

wherein each of the plurality of window objects comprises a cache memory and a plurality of methods for manipulating the window areas;

wherein information is transferred between each window object and the means for changing by means of data stream objects;

wherein each window object comprises a mechanism for receiving a request from one of the plurality of application programs and apparatus responsive to a received request for providing a storage area location and a storage area size to the one of the plurality of application programs which made the request; and

wherein a copy of the storage area size of the associated window is stored in the window object cache memory and the window object comprises apparatus responsive to a request from one of the plurality of applications for determining the validity of the storage area size copy.

5. A computer system according to claim 4 wherein the validity determining apparatus comprises apparatus responsive to a request from an application program for a selected storage area size corresponding to a window for retrieving a first time stamp stored with the selected storage area size from the means for changing and apparatus responsive to the retrieved first time stamp for comparing the retrieved first time stamp to the second time stamp stored in the cache memory.

6. A computer system according to claim 5 wherein the validity determining apparatus further comprises means for retrieving the storage area size stored in the means for changing when the time stamp comparing apparatus indicates that the storage area size stored in the cache memory was stored before the last recalculation by the window manager object.

7. A computer system for controlling a display device to generate a display having a plurality of overlapped windows displayed on a desktop background, each of the plurality of windows having a visible area for displaying screen information generated by one of a plurality of application programs, the computer system comprising:

a memory;

a processor controlled by the plurality of application programs for controlling and coordinating the operation of the computer system;

an operating system cooperating with the processor for controlling the display device;

means, having a shared data area, for storing window visible areas and being responsive to a change in a visible area of one of the plurality of windows for changing the visible areas of others of the plurality of windows; and

a window object in the memory and created by each of the plurality of application programs, each window object being associated with the one of the plurality of windows, and each window object including a cache memory for storing a copy of the visible area of the associated window;

wherein each window object comprises apparatus responsive to a request from one of the plurality of application programs for determining the validity of the window visible area copy;

wherein the means for storing comprises apparatus for storing with each window visible area, a first time stamp indicating a time at which the window visible area was last recalculated, and wherein the window object comprises apparatus for storing in the cache memory a second time stamp indicating the time at which the window visible area copy was stored in the cache memory.

8. A computer system according to claim 7 wherein the validity determining apparatus comprises apparatus responsive to a request from an application program for a selected window visible area for retrieving a first time stamp from the means for storing and apparatus responsive to the retrieved first time stamp for comparing the retrieved first time stamp to the second time stamp stored in the cache memory.

9. A computer system according to claim 8 wherein the validity determining apparatus further comprises means for retrieving the window visible area from the means for storing when the time stamp comparing apparatus indicates that the visible area stored in the cache memory was stored before the last recalculation by the window manager object.

10. A method for an application program to display screen information in one of a plurality of window areas displayed on a desktop background, each one of the plurality of window areas having a changeable visible area, the method comprising the steps of:

A. creating a window manager having a shared data area and being responsive to a change in a visible area of one window for changing the visible areas of at least one other window;

B. causing the application program to request the visible area of the one of a plurality of window areas from the window manager;

B1. creating a window object associated with each of the plurality of windows, each window object including window data and window functions and being created by an application program;

B2. causing the window object to request the visible area,

B2B. maintaining a cache copy of the visible area in the window object;

B2C. checking the cache copy in the window object before requesting a copy of the visible area from the window manager object;

B2D. storing with each window visible area, a first time stamp indicating the time at which the visible area was recalculated;

B2E. storing a second time stamp in the window object indicating the time at which the cache copy was stored in the window object; and

C. causing the application program to display screen information only in the visible area obtained from the window manager.

11. A method according to claim 10 wherein step B2 comprises the steps of:

B2F. retrieving a first time stamp stored with a selected window visible area from the window manager when a request is received from an application program for a window visible area; and

B2G. comparing the retrieved first time stamp to the second time stamp stored in the window object.

12. A method according to claim 11 wherein step B2 further comprises the steps of:

B2H. retrieving the window visible area stored in the window manager when the time stamp comparison of step B2G indicates that the cache copy stored in the window object is not valid.