Method and apparatus for displaying hardware dependent graphics in an object-oriented operating system

• US 5,734,852 A
• Filed: 03/08/1996
• Issued: 03/31/1998
• Est. Priority Date: 12/02/1993
• Status: Expired due to Term

• Current Assignee: Apple Inc.
• Original Assignee: Object Technology Licensing Corporation (Apple Inc.)
• Inventors: Zias, Jeff A., Marsh, Donald M.
• Primary Examiner(s): Black, Thomas G.
• Assistant Examiner(s): HO, RUAY L
• Application Number:
  US08/608,327
• Time in Patent Office: 753 Days
• Field of Search: 395/326, 395/327, 395/328, 395/329, 395/330, 395/331, 395/332, 395/333, 395/334, 395/335, 395/500, 395/800
• US Class Current: 715/744
• CPC Class Codes: G06F 3/14 Digital output to display device ; Cooperation and interconnection of the display device with other functional units
• CPC Class Codes: G06F 9/4411 Configuring for operating with peripheral devices; Loading of device drivers
• CPC Class Codes: G06F 9/451 Execution arrangements for user interfaces
• CPC Class Codes: G09G 5/14 Display of multiple viewports

Abstract

Screen objects used by the application programs to draw or paint on the display screen are created in accordance with a predefined class structure which represents a generic display system. Developers of specialized hardware develop specialized classes based on the predefined structure to handle specific command sets and protocols. When the system is initially powered up or reconfigured, the screen objects are created from the generic and specialized classes as necessary by examining the actual display hardware present in the system. When the specialized classes are used to create the screen objects, the screen objects receive the specialized command sets and protocols necessary to interact with display hardware which have been provided by the hardware developers.

Claims

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

a processor for executing each of the plurality of application programs;

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

a hardware configuration system coupled to the display device, the hardware configuration system operating during computer system initialization for identifying the predefined characteristics of the display device; and

a hardware access system cooperating with the hardware configuration system, the hardware access system for instantiating a display device driver object having a plurality of commands and attributes specific to the predefined characteristics of the display device.

2. A computer system according to claim 1 wherein the hardware access system comprises a plurality of object classes, each of the object classes having a plurality of predefined command sets and defining a plurality of predefined data structures, each of the plurality of command sets and data structures representative of the characteristics of at least one of a plurality of different display devices, wherein the hardware access system selects, during computer system initialization and based on the predefined characteristics of the display device, predetermined ones of the predefined command sets and data structures in order to instantiate the display device driver object.

3. A computer system according to claim 1 wherein the operating system comprises apparatus, responsive to commands generated by the one application program, the apparatus for creating a system window object which creates a specific window area on the display device and which comprises commands for drawing in a screen buffer corresponding to the specific window area.

4. A computer system according to claim 3 wherein the operating system further comprises a window server apparatus responsive to the system window object and to the device driver object, the window server apparatus for creating a screen device object which incorporates the commands and attributes of the display device driver object wherein the screen device object specifically controls for the display device in the specific window area.

5. A computer system according to claim 4 wherein the operating system further comprises apparatus responsive to the screen device object for creating a screen buffer object comprising a screen buffer with specific commands and device characteristics for controlling the display device in the specific window area.

6. A computer system according to claim 3 wherein the computer system comprises a memory and wherein the one application program has exclusive access to an exclusive portion of the memory and wherein the system window object is created in the exclusive memory portion.

7. A computer system according to claim 6 wherein the memory further has a common portion which is accessible by each of the plurality of application programs and the display device driver object is created in the common portion of the memory.

8. A computer system according to claim 7 wherein the screen buffer object is created in the exclusive memory portion.

9. A computer system according to claim 1 wherein the hardware configuration system comprises a device memory, located in the display device, for storing the predefined characteristics of the display device.

10. A computer system according to claim 9 wherein the hardware access system comprises means for reading the predefined characteristics from the device memory.

11. A computer system for controlling a display device having predefined characteristics and for displaying on the display device, a plurality of window areas on a desktop background each of the plurality of window areas having displayed therein screen information generated by one of a plurality of application programs, the computer system comprising:

a processor for executing the one application program such that the one application program generates screen information to be displayed on the display device;

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

a device memory located in the display device, the device memory having predefined characteristics of the display device stored therein;

a hardware access system having apparatus for reading the device memory during initialization of the computer system and having a plurality of predefined display device driver object classes incorporating commands and defining a plurality of data structures for controlling the operation of a plurality of different display devices, the hardware access system being responsive to predefined characteristics read from the device memory for instantiating a display device driver object from one of the plurality of predefined display device driver object classes, the display device driver object including commands and data structures specific to the predefined characteristics;

apparatus, responsive to commands generated by one of the plurality of application programs, the apparatus for creating a system window object which generates a specific window area on the display device wherein the system window object comprises commands for drawing in a screen buffer; and

a window server system, responsive to the system window object and to the device driver object, for creating a screen buffer.

12. A computer system according to claim 11 wherein:

the device memory contains a display device identification code; and

the hardware access system comprises predefined commands and defines a plurality of data structures representative a plurality of different display devices and in response to a display device identification code read from the device memory, the hardware access system selects a set of the predefined commands and data structures in order to create the display device driver object.

13. A computer system according to claim 11 wherein the computer system comprises a memory and wherein the one application program has exclusive access to an exclusive portion of the memory and wherein the system window object is created in the exclusive portion of the memory.

14. A computer system according to claim 13 wherein the memory further has a common portion which is accessible by each of the plurality of application programs and the display device driver object is created in the common portion of the memory.

15. A computer system according to claim 14 wherein the screen buffer is created in the exclusive portion of the memory.

16. A computer system for controlling a display device having predefined characteristics, the computer system for generating on the display device 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 processor for executing each of the plurality of application programs to display screen information on the display device;

a memory, coupled to the processor, the memory having a common memory portion and a plurality of exclusive memory portions, one of the plurality of exclusive memory portions being accessible by the one application program;

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

a device memory located in the display device, the device memory having stored therein predefined characteristics of the display device;

a hardware access system having predefined display device driver classes, each of the display device driver classes including commands and defining data attributes for controlling the operation of a plurality of different display devices, the hardware access system operable during computer system initialization for instantiating a display device driver object in the common memory portion from one of the predefined display device driver classes based on the predefined characteristics of the display device being read from the device memory; and

apparatus responsive to parameters generated by one of the plurality of application programs, the apparatus for creating a system window object in the one exclusive memory portion, which system window object creates a specific window area on the display device and which system window object comprises commands for drawing in a screen buffer corresponding to the specific window area.

17. A computer system according to claim 16 wherein the computer system further comprises:

apparatus for creating a window server object in the common memory portion of the memory; and

a first data stream object for transferring the parameters from the system window object to the window server object.

18. A computer system according to claim 17 wherein the window server object comprises apparatus responsive to the parameters transferred from the system window object for creating an internal window object wherein the internal window object is responsive to the window parameters and to the display device driver for creating the screen buffer.

19. A computer system according to claim 18 wherein the computer system further comprises a second data stream object for transferring the screen buffer from the window server object to the system window object.

20. A method for controlling a display device in a computer system, the display device having predefined characteristics, the computer system for generating on the display device a plurality of window areas displayed on a desktop background, each of the plurality of window areas having displayed therein screen information generated by one of a plurality of application programs, the method comprising the steps of:

A. examining the display device during computer system initialization to identify the predefined characteristics of the display device; and

B. using the predefined characteristics identified in the examining step to create a display device driver object having specific commands and data attributes for controlling the display device.

21. A method according to claim 20 wherein:

step A comprises the step of;

A1. reading a display device identification code from the display device; and

step B comprises the steps of;

B1. compiling a set of predefined commands and defining a data structure for each of a plurality of different display devices;

B2. selecting a set of the predefined commands and a data structure based on the display device identification code read from the display device; and

B3. creating the device driver object using the set of predefined command and the data structure selected in step B2.

22. A method according to claim 21 further comprising the steps of:

C. receiving parameters generated by one of the plurality of application programs; and

D. creating a system window object using the parameters received in step c wherein the system window object creates a specific window area on the display device and which comprises commands for drawing in a screen buffer corresponding to the specific window area.

23. A method according to claim 22 further comprising the step of creating a screen device object which incorporates the specific commands and data attributes for controlling the display device in the specific window area using the system window object and the device driver object.

24. A method according to claim 23 further comprising the step of creating a screen buffer object comprising a screen buffer with specific commands and data attributes corresponding to device characteristics for controlling the display device in the specific window area using the screen device object.

25. A method according to claim 24 wherein the computer system comprises a memory and wherein the one application program has exclusive access to an exclusive portion of the memory and including the step of creating the system window object in the exclusive memory portion.

26. A method according to claim 25 wherein the memory further has a common portion which is accessible by each of the plurality of application programs and step of creating the device driver object further comprises the step of creating the device driver object in the common portion of the memory.

27. A method according to claim 26 wherein the step of creating the screen buffer object includes the step of creating the screen buffer object in the exclusive portion of the memory.

28. A method according to claim 20 including the step of reading the predefined characteristics from a device memory located in the display device.

29. A method for controlling a display device in a computer system, the display device having predefined characteristics for displaying a plurality of window areas on a desktop background, each of the plurality of window areas having displayed therein screen information generated by one of a plurality of application programs, the computer system having a memory with a common memory portion and a plurality of exclusive memory portions, one of the plurality of exclusive memory portions being accessible by the one application program, the method comprising the steps of:

A. storing the predefined characteristics of the display device in a device memory located in the display device;

B. storing, in the common memory portion, a set of predefined display device driver classes incorporating commands and defining data structures for controlling the operation of a plurality of different display devices;

C. reading the predefined characteristics of the display device from the device memory during computer system initialization;

D. creating, from one of the predefined display device driver classes, a display device driver object in the common memory portion using the predefined characteristics of the display device read from the device memory;

E. receiving window parameters from one of the plurality of application programs; and

F. creating a system window object in the one exclusive memory portion, which system window object creates a specific window area on the display device and which system window object comprises commands for drawing in a screen buffer corresponding to the specific window area.

30. In a computer system which includes a display system having a display device and a plurality of different video display hardware circuits, each of the plurality of video display hardware circuits including a configuration memory and operating in accordance with a specific protocol and in response to a particular set of commands, apparatus to create a specialized video device driver object, the apparatus comprising:

a display device IO access manager for identifying each of the plurality of video display hardware circuits physically installed on the computer system and for identifying hardware capabilities of each of the plurality of video display hardware circuits physically installed on the computer system;

means for providing a specialized video device driver class; and

means for dynamically constructing a specialized video device driver object from the specialized video device driver class by obtaining video display hardware circuit parameters from the configuration memory of the video display hardware circuit, wherein the video display hardware circuit parameters are used to construct the specialized video device driver object with predetermined hardware capabilities.

31. The apparatus of claim 30 further comprising a hardware configuration system for communicating with the video display hardware circuits, the hardware configuration system comprising:

first configuration programs means for querying a memory for display driver information; and

second configuration programs means for modifying display driver information to allow a user to change video display hardware circuit parameters.

32. The apparatus of claim 31 wherein the means for dynamically constructing comprises a hardware access system for communicating with the video display hardware circuits and for obtaining specific hardware device characteristics and parameters by querying the configuration memory of each of the plurality of video display hardware circuits.

33. A computer system for executing an application program, the computer system having a display system coupled thereto, the display system including a display device and a plurality of different video display hardware circuits, each of the video display hardware circuits including a configuration memory and operating in accordance with a specific protocol and in response to a particular set of commands, the computer system comprising:

(a) a view system for managing a plurality of window areas associated with the application program, the view system comprising;

(a1) means for interfacing with the application program;

(a2) means for creating window areas associated with the application program, each of the window areas having a particular boundary; and

(a3) means for maintaining a plurality of screen buffer objects controlled by the application program, each of the plurality of screen buffer objects for displaying data on the display device;

(b) a graphic system for facilitating the display of graphical images on the display device, the graphic system in communication with said view system and comprising means for interfacing with the application program;

(c) a hardware configuration system for communicating with the video display hardware circuits, the hardware configuration system comprising;

(c1) first configuration program means for querying display driver information; and

(c2) second configuration program means for modifying display driver information to allow a user to change hardware specific information;

(d) a hardware access system for communicating with the video display hardware circuits and for obtaining specific hardware device characteristics and parameters by querying the configuration memory of each of the plurality of video display hardware circuits;

(e) a window server, in communication with said view system, the window server for determining the visible area of each of the plurality of window areas managed by the view system and for communicating the visible area of each window to the application program executing on the computer system; and

(f) means for passing information obtained from the configuration memories of the plurality of video display hardware circuits by the hardware access system to the window server.

34. The system of claim 33 wherein the view system further comprises:

(a4) means for destroying window areas associated with the application program; and

(a5) means for repainting window areas associated with the application program.

35. The system of claim 33 wherein the window server comprises:

(e1) means for determining a visible area of each window based on the ordering of the plurality of windows, and for determining the extent to which a first window of the plurality of windows overlaps a second window of the plurality of windows;

(e2) means for maintaining an ordering of window layers;

(e3) means for ensuring that all windows are presented on the display in an appropriate order;

(e4) means for maintaining an update area for each window wherein the update area for each window describes a part of the window that has been damaged due to window manipulations;

(e5) means for notifying the view system when one of the plurality of window update areas becomes non-empty; and

(e6) means for communicating with the hardware access configuration system and the hardware access system to maintain information about the actual display device on which a screen background is provided.

36. The system of claim 33 wherein the means for passing comprises:

a device driver object; and

a display device object, wherein the device driver object and the display device object are created for a particular type of hardware and are used to create the screen buffer objects that are used by the view system to draw on the display devices and wherein commands and methods which are specific to specialized hardware are passed to the screen buffer objects and are then available in the view system for use by the application program.

37. The system of claim 36 wherein the hardware specific information corresponds to hardware specific attributes of the displays wherein at least one of the hardware specific attributes of the displays is provided as:

a bit depth attribute;

a monitoring attribute; and

a positioning attribute.

38. The system of claim 36 wherein the means for creating windows is provided as a system window object instantiated from a pre-defined window class, wherein the system window object creates a corresponding window.

39. A method of creating a window area on a display device, the method comprising the steps of:

(a) querying a configuration memory of a video display hardware circuit to obtain specific hardware device characteristics and parameters of the video display hardware circuit;

(b) passing information obtained from the configuration memory of the video display hardware circuit to a window server;

(c) passing window parameters from an application program to a view system;

(d) creating a system window object via the view system using the window parameters passed thereto from the application program;

(e) storing the system window object in an allocated storage area of the view system;

(f) sending the window parameters used in creating each window object from the view system to the window server;

(g) sending the specific hardware device characteristics and parameters of the video display hardware circuit to a view system;

(h) in response to the incoming window parameters, creating the window area on the display device via the window server;

(i) returning the visible area of the window area to the view system by means of a data stream;

(j) communicating the visible area of each window to the application program; and

(k) in response to the specific hardware device characteristics and parameters, drawing in the window area on the display device.

40. The method of claim 39 wherein the passing step further comprises the steps of:

passing the size of the window;

passing the extent of the window;

passing the front-to-back location of the window in relation to at least one other window;

passing a task associated with the window that receives events;

passing a parameter which indicates whether the window should be initially visible; and

passing a parameter which indicates the kind of window.

41. The method of claim 39 wherein the step of creating a system window object further comprises the step of creating a plurality of system window objects via the view system, each of the system window objects generating a window.

42. The method of claim 41 wherein the step of creating a system window object includes the step of internally representing, in window server, each window screen area as an internal window object and the method further comprises the step of:

creating the internal window object using the window parameters sent from the view system to the window server.

43. The method of claim 42 further comprising the step of storing the internal window object in a storage area of the window server.

44. The method of claim 43 wherein in response to requests from the view system, the method further comprises the step of performing manipulations of the windows via the internal window object.

45. The method of claim 44 further comprising the step of creating internal window objects from pre-defined classes corresponding to generic display systems.

46. The method of claim 44 further comprising the step of implementing windows which are to incorporate specialized hardware capabilities of display devices by creating subclasses of the classes used to create the internal window objects.

47. The method of claim 46 further comprising the steps of:

identifying actual hardware devices of the computer system; and

selecting subclasses which correspond with the actual hardware devices identified in the identifying step.

48. The method of claim 47 further comprising the steps of:

providing, in the window server, a display device object for each display device displaying a window on the screen background, wherein each display device object includes information describing specialized hardware capabilities of the underlying hardware;

creating, via the display device object, the internal window objects for windows which appear on the corresponding display device; and

transferring the specialized hardware capabilities from the display device object to the internal window object at the time the internal window object is created.

49. The method of claim 48 further comprising the step of creating, for each video display device, a device driver object, wherein each device driver object is created by a display device IO access manager which is provided as part of the hardware access system and wherein each device driver object is specific to the type of hardware to which the display device IO access manager is assigned.

50. The method of claim 49 wherein the step of creating the device driver object, includes the step of the display device IO access manager directly interacting with a particular piece of hardware.

51. The method of claim 50 wherein the step of creating internal window objects, includes the steps of:

creating graph device objects; and

creating screen device objects, wherein the graph device objects and the screen device objects are used by the view system and the application program to draw graphics on the display device and to perform non-window operations.

52. The method of claim 51 wherein the non-window operations correspond to sprite control operations and cursor control operations.

53. The method of claim 52 further comprising the step of streaming the graph device object and screen device object to the view system.