Method, system, and computer program product for determining a structure of a graphics compositor tree

• US 20040222994A1
• Filed: 05/05/2003
• Published: 11/11/2004
• Est. Priority Date: 05/05/2003
• Status: Active Grant

• Current Assignee: RPX Corporation
• Original Assignee: Silicon Graphics Incorporated (Graphics Properties Holdings, Inc.)
• Inventors: Sadowski, Greg, Kunze, Eric
• Granted Patent: US 7,034,837 B2
• Time in Patent Office: Days
• US Class Current: 345/506
• CPC Class Codes: G06T 1/20 Processor architectures; Processor configuration, e.g. pipelining

Abstract

Compositors are identified in a manner that defines the position of the compositor in the compositor tree. Each compositor has its own “unique compositor identifier”. Starting at the most downstream compositor, it transmits its unique compositor identifier to all upstream compositors directly coupled to it. The upstream compositors receive the unique compositor identifier from the most downstream compositor. Each of the upstream compositors appends its unique compositor identifier to the unique compositor identifier received from the most downstream compositor to produce a “compositor tree compositor identifier”. The compositor tree compositor identifier identifies both the compositor and its position in the compositor tree. This enables an application to detect the structure of the compositor tree so that the application can determine a desired tiling configuration that exploits the structure of the compositor tree.

Claims

1. A method of identifying a compositor in a compositor tree, comprising:

(1) receiving, at the compositor, a compositor tree compositor identifier from a downstream compositor; and

(2) appending said received compositor tree compositor identifier with a unique compositor identifier of the compositor.

2. The method of claim 1, wherein said appending step comprises:

(a) affixing a special character to said received compositor tree compositor identifier; and

(b) attaching the unique compositor identifier to said affixed special character.

3. The method of claim 1, wherein said received compositor tree compositor identifier has attached a unique port identifier of a port of the downstream compositor to which the compositor is coupled.

4. The method of claim 1, wherein the unique compositor identifier is a machine readable serial number.

5. The method of claim 1, wherein the unique compositor identifier is assigned to the compositor during an initialization process.

6. The method of claim 5, wherein the initialization process uses a Universal Series Bus.

7. The method of claim 1, further comprising:

(3) detecting, by the compositor, the downstream compositor.

8. The method of claim 7, wherein said detecting step comprises:

(a) causing the compositor to attempt to detect the downstream compositor; and

(b) ceasing to receive the compositor tree compositor identifier if said caused attempt to detect the downstream compositor failed.

9. The method of claim 1, further comprising:

(3) attaching a unique port identifier to said appended compositor tree compositor identifier.

10. The method of claim 1, further comprising:

(3) reading, by a graphics controller, said appended compositor tree compositor identifier.

11. The method of claim 1, further comprising:

(3) transmitting said appended compositor tree compositor identifier to a graphics controller via an Inter Integrated Circuit bus.

12. The method of claim 1, further comprising:

(3) transmitting said appended compositor tree compositor identifier to an upstream compositor.

13. The method of claim 12, further comprising:

(4) detecting, by the compositor, the upstream compositor.

14. The method of claim 13, wherein said detecting step comprises:

(a) causing the compositor to attempt to detect the upstream compositor; and

(b) ceasing to transmit said appended compositor tree compositor identifier if said caused attempt to detect the upstream compositor failed.

15. A method of determining a structure of a compositor tree, comprising:

(1) locating a downstream compositor of the compositor tree; and

(2) counting a number of compositors coupled to said located downstream compositor.

16. The method of claim 15, wherein said located downstream compositor is a most downstream comparator.

17. The method of claim 16, wherein said locating step comprises:

identifying a compositor of the compositor tree having a compositor tree compositor identifier with only one unique compositor identifier.

18. The method of claim 16, wherein said locating step comprises:

(a) identifying compositors of the compositor tree having compositor tree compositor identifiers with more than one unique compositor identifier; and

(b) selecting a compositor of the compositor tree other than said identified compositors.

19. The method of claim 18, wherein said identifying step comprises:

distinguishing compositors of the compositor tree having compositor tree compositor identifiers with a special character.

20. The method of claim 16, wherein said locating step comprises:

(a) identifying compositors of the compositor tree having compositor tree compositor identifiers with a unique port identifier; and

(b) selecting a compositor of the compositor tree other than said identified compositors.

21. The method of claim 15, wherein said counting step comprises:

(a) identifying compositors of the compositor tree having compositor tree compositor identifiers with a parent compositor tree compositor identifier that is identical to a compositor tree compositor identifier of said located downstream compositor; and

(b) tallying a number of said identified compositors.

22. The method of clam 15, further comprising:

(3) ascertaining if a compositor of said counted number of compositors is a graphics pipeline; and

(4) transmitting a compositor tree compositor identifier of said ascertained graphics pipeline to a graphics controller.

23. The method of claim 22, wherein said ascertaining step comprises:

determining if a compositor tree compositor identifier of the compositor has one of an equal number of unique compositor identifiers and a greater number of unique compositor identifiers as compositor tree compositor identifiers of other compositors.

24. The method of claim 22, wherein said ascertaining step comprises:

determining if a compositor tree compositor identifier of the compositor has one of an equal number of special characters and a greater number of special characters as compositor tree compositor identifiers of other compositors.

25. The method of claim 22, wherein said ascertaining step comprises:

determining if a compositor tree compositor identifier of the compositor has one of an equal number of unique port identifiers and a greater number of unique port identifiers as compositor tree compositor identifiers of other compositors.

26. The method of claim 22, further comprising:

(5) distinguishing a compositor of said counted number of compositors; and

(6) counting, for said distinguished compositor, a new number of compositors coupled to said distinguished compositor.

27. The method of claim 26, wherein said distinguishing step comprises:

identifying a compositor tree compositor identifier of said distinguished compositor.

28. The method of claim 27, wherein the compositor tree compositor identifier includes a parent compositor tree compositor identifier and a unique compositor identifier.

29. The method of claim 28, wherein the parent compositor tree compositor identifier is a compositor tree compositor identifier of said located downstream compositor.

30. The method of claim 26, wherein said distinguishing step comprises:

identifying a port on said located downstream compositor to which said distinguished compositor is coupled.

31. The method of claim 30, wherein said identifying step comprises:

finding a unique port identifier of said located downstream compositor within a compositor tree compositor identifier of said distinguished compositor.

32. The method of claim 26, further comprising:

(7) detecting, for said distinguished compositor, an upstream compositor.

33. The method of claim 32, wherein said detecting step comprises:

(a) causing said distinguished compositor to attempt to detect the upstream compositor; and

(b) ceasing to count, for said distinguished compositor, the new number of compositors coupled to said distinguished compositors if said caused attempt to detect the upstream compositor failed.

34. The method of claim 22, further comprising:

(7) repeating steps (3) through (6), wherein said counted number is said counted new number.

35. A method of determining a structure of a compositor tree, comprising:

(1) receiving, from graphics pipelines, compositor tree compositor identifiers; and

(2) deconstructing said received compositor tree compositor identifiers.

36. The method of claim 35, wherein said deconstructing step comprises:

ascertaining a number of stages in the compositor tree.

37. The method of claim 36, wherein said ascertaining step comprises:

counting a number of unique compositor identifiers within said received compositor tree compositor identifiers.

38. The method of claim 36, wherein said ascertaining step comprises:

counting a number of special characters within said received compositor tree compositor identifiers.

39. The method of claim 36, wherein said ascertaining step comprises:

counting a number of unique port identifiers within said received compositor tree compositor identifiers.

40. The method of claim 36, further comprising:

locating a downstream compositor.

41. The method of claim 40, wherein said located downstream compositor is a most downstream compositor.

42. The method of claim 41, wherein said locating step comprises:

distinguishing, within said received compositor tree compositor identifiers, a unique compositor identifier common to said received compositor tree compositor identifiers.

43. The method of claim 40, further comprising:

determining a number of compositors coupled to said located downstream compositor.

44. The method of claim 43, wherein said determining step comprises:

(a) distinguishing, within said received compositor tree compositor identifiers, a unique compositor identifier common to said received compositor tree compositor identifiers;

(b) identifying, within said received compositor tree compositor identifiers, unique compositor identifiers adjacent to said distinguished unique compositor identifier;

(c) segregating said received compositor tree compositor identifiers into groups according to said identified unique compositor identifiers; and

(d) counting said segregated groups.

45. The method of claim 44, further comprising:

(e) truncating said distinguished unique compositor identifier from said received compositor tree compositor identifiers; and

(f) repeating, for a group of said segregated groups, steps (a) through

(e), wherein said received compositor tree compositor identifiers are said truncated compositor tree compositor identifiers.

46. The method of claim 43, further comprising:

identifying a port on said located downstream compositor to which a compositor of said determined number of compositors is coupled.

47. The method of claim 46, wherein said identifying step comprises:

determining a unique port identifier of said located downstream compositor within a compositor tree compositor identifier of the compositor.

48. A system to identify a compositor in a compositor tree, comprising:

a first memory configured to receive a compositor tree compositor identifier of a downstream compositor;

a processor coupled to said first memory, and configured to append said compositor tree compositor identifier of said downstream compositor with a unique compositor identifier of the compositor to produce a compositor tree compositor identifier of the compositor; and

a second memory coupled to said processor, and configured to store said unique compositor identifier.

49. The system of claim 48, further comprising:

a third memory coupled to said processor, and configured to store a special character.

50. The system of claim 49, wherein said processor is further configured to affix said special character to said compositor tree compositor identifier of said downstream compositor, and to attach said unique compositor identifier to said special character.

51. The system of claim 48, further comprising:

a third memory coupled to said processor, and configured to store a unique port identifier of a port of the compositor.

52. The system of claim 51, wherein said processor is further configured to attach said unique port identifier to said compositor tree compositor identifier of the compositor.

53. The system of claim 48, further comprising:

a detector coupled to said processor, and configured to attempt to detect said downstream compositor.

54. The system of claim 48, further comprising:

a detector coupled to said processor, and configured to attempt to detect an upstream compositor.

55. The system of claim 48, further comprising:

means, coupled to said processor, to communicate said compositor tree compositor identifier of the compositor to a graphics controller.

56. The system of claim 48, further comprising:

a transmitter coupled to said processor, and configured to transmit said compositor tree compositor identifier of the compositor to a graphics controller via an Inter Integrated Circuit bus.

57. The system of claim 48, further comprising:

a transmitter coupled to said processor, and configured to transmit said compositor tree compositor identifier of the compositor to an upstream compositor.

58. A system to determine a structure of a compositor tree, comprising:

a memory configured to store compositor tree compositor identifiers of compositors in the compositor tree; and

a processor coupled to said memory, and configured to locate a downstream compositor of the compositor tree, and to count a number of compositors coupled to said downstream compositor.

59. The system of claim 58, wherein said processor is further configured to identify a compositor of the compositor tree having a compositor tree compositor identifier of said compositor tree compositor identifiers with only one unique compositor identifier.

60. The system of claim 58, wherein said processor is further configured to identify compositors of the compositor tree having compositor tree compositor identifiers of said compositor tree compositor identifiers with more than one unique compositor identifier, and to select a compositor of the compositor tree other than said compositors having said compositor tree compositor identifiers with said more than one unique compositor identifier.

61. The system of claim 60, wherein said processor is further configured to distinguish compositors of the compositor tree having compositor tree compositor identifiers of said compositor tree compositor identifiers with a special character.

62. The system of claim 58, wherein said processor is further configured to identify compositors of the compositor tree having compositor tree compositor identifiers of said compositor tree compositor identifiers with a unique port identifier, and to select a compositor of the compositor tree other than said compositors having said compositor tree compositor identifiers with said unique port identifier.

63. The system of claim 58, wherein said processor is further configured to identify compositors of the compositor tree having compositor tree compositor identifiers of said compositor tree compositor identifiers with a parent compositor tree identifier that is identical to a compositor tree compositor identifier of said downstream compositor, and to tally a number of said compositors having said compositor tree compositor identifiers with said parent compositor tree identifier.

64. The system of claim 58, wherein said processor is further configured to ascertain if a compositor of said number of compositors coupled to said downstream compositor is a graphics pipeline.

65. The system of claim 64, further comprising:

a transmitter coupled to said processor, and configured to transmit a compositor tree compositor identifier of said graphics pipeline to a graphics controller.

66. The system of claim 64, wherein said processor is further configured to determine if a compositor tree compositor identifier of said compositor of said number of compositors coupled to said downstream compositor has one of an equal number of unique compositor identifiers and a greater number of unique compositor identifiers as compositor tree compositor identifiers of other compositors of the compositor tree.

67. The system of claim 64, wherein said processor is further configured to determine if a compositor tree compositor identifier of said compositor of said number of compositors coupled to said downstream compositor has one of an equal number of special characters and a greater number of special characters as compositor tree compositor identifiers of other compositors of the compositor tree.

68. The system of claim 64, wherein said processor is further configured to determine if a compositor tree compositor identifier of said compositor of said number of compositors coupled to said downstream compositor has one of an equal number of unique port identifiers and a greater number of unique port identifiers as compositor tree compositor identifiers of other compositors of the compositor tree.

69. The system of claim 64, wherein said processor is further configured to distinguish a compositor of said number of compositors coupled to said downstream compositor, and to count, for said compositor of said number of compositors coupled to said downstream compositor, a new number of compositors coupled to said compositor of said number of compositors coupled to said downstream compositor.

70. The system of claim 69, wherein said processor is further configured to identify a compositor tree compositor identifier of said compositor of said number of compositors coupled to said downstream compositor.

71. The system of claim 69, wherein said processor is further configured to identify a port on said downstream compositor to which said compositor of said number of compositors coupled to said downstream compositor is coupled.

72. The system of claim 71, wherein said processor is further configured to find a unique port identifier of said downstream compositor within a compositor tree compositor identifier of said compositor of said number of compositors coupled to said downstream compositor.

73. The system of claim 69, further comprising:

a detector coupled to said processor, and configured to attempt to detect, for said compositor of said number of compositors coupled to said downstream compositor is coupled, an upstream compositor.

74. A system to determine a structure of a compositor tree, comprising:

a receiver configured to receive, from graphics pipelines, compositor tree compositor identifiers;

a memory coupled to said receiver, and configured to store compositor tree compositor identifiers of compositors in the compositor tree; and

a processor coupled to said memory, and configured to deconstruct said compositor tree compositor identifiers.

75. The system of claim 74, wherein said processor is further configured to ascertain a number of stages in the compositor tree.

76. The system of claim 75, wherein said processor is further configured to count a number of unique compositor identifiers within said compositor tree compositor identifiers.

77. The system of claim 75, wherein said processor is further configured to count a number of special characters within said compositor tree compositor identifiers.

78. The system of claim 75, wherein said processor is further configured to count a number of unique port identifiers within said compositor tree compositor identifiers.

79. The system of claim 75, wherein said processor is further configured to locate a downstream compositor of the compositor tree.

80. The system of claim 79, wherein said processor is further configured to distinguish, within said compositor tree compositor identifiers, a unique compositor identifier common to said compositor tree compositor identifiers.

81. The system of claim 79, wherein said processor is further configured to determine a number of compositors coupled to said downstream compositor.

82. The system of claim 81, wherein said processor is further configured to:

(a) distinguish, within said compositor tree compositor identifiers, a unique compositor identifier common to said compositor tree compositor identifiers;

(b) identify, within said compositor tree compositor identifiers, unique compositor identifiers adjacent to said unique compositor identifier common to said compositor tree compositor identifiers;

(c) segregate said compositor tree compositor identifiers into groups according to said unique compositor identifiers adjacent to said unique compositor identifier common to said compositor tree compositor identifiers; and

(d) count said groups.

83. The system of claim 82, wherein said processor is further configured to:

(e) truncate said unique compositor identifier common to said compositor tree compositor identifiers from said compositor tree compositor identifiers, thereby producing new compositor tree compositor identifiers; and

(f) repeat, for a group of said groups, processes (a) through (e), wherein said compositor tree compositor identifiers are said new compositor tree compositor identifiers.

84. The system of claim 81, wherein said processor is further configured to identify a port on said downstream compositor to which a compositor of said number of compositors is coupled.

85. The system of claim 84, wherein said processor is further configured to determine a unique port identifier of said downstream compositor within a compositor tree compositor identifier of said compositor of said number of compositors.

86. A computer program product for identifying a compositor in a compositor tree, said computer program product having computer program code embodied in a computer useable medium, said computer program code means comprising:

a first program code means for causing said computer system to receive, at the compositor, a compositor tree compositor identifier from a downstream compositor; and

a second program code means for causing said computer system to append the compositor tree compositor identifier with a unique compositor identifier of the compositor to produce a compositor tree compositor identifier of the compositor.

87. The computer program product of claim 86, wherein said first program code means comprises:

a third program code means for causing said computer system to affix a special character to the compositor tree compositor identifier from the downstream compositor; and

a fourth program code means for causing said computer system to attach the unique compositor identifier to the special character.

88. The computer program product of claim 86, further comprising:

a fifth program code means for causing said computer system to detect the downstream compositor.

89. The computer program product of claim 88, wherein said fifth program code means comprises:

a sixth program code means for causing said computer system to cause the compositor to attempt to detect the downstream compositor; and

a seventh program code means for causing said computer system to cease attempting to receive the compositor tree compositor identifier from the downstream compositor if the attempt to detect the downstream compositor failed.

90. The computer program product of claim 86, further comprising:

a third program code means for causing said computer system to attach a unique port identifier to the compositor tree compositor identifier of the compositor.

91. The computer program product of claim 86, further comprising:

a third program code means for causing said computer system to read, at a graphics controller, the compositor tree compositor identifier of the compositor.

92. The computer program product of claim 86, further comprising:

a third program code means for causing said computer system to transmit the compositor tree compositor identifier of the compositor to a graphics controller via an Inter Integrated Circuit bus.

93. The computer program product of claim 86, further comprising:

a third program code means for causing said computer system to transmit the compositor tree compositor identifier of the compositor to an upstream compositor.

94. The computer program product of claim 93, further comprising:

a fourth program code means for causing said computer system to detect the upstream compositor.

95. The computer program product of claim 94, wherein said fourth program code means comprises:

a fifth program code means for causing said computer system to cause the compositor to attempt to detect the upstream compositor; and

a sixth program code means for causing said computer system to cease attempting to transmit the compositor tree compositor identifier of the compositor if the attempt to detect the upstream compositor failed.

96. A computer program product for determining a structure of a compositor tree, said computer program product having computer program code embodied in a computer useable medium, said computer program code means comprising:

a first program code means for causing said computer system to locate a downstream compositor of the compositor tree; and

a second program code means for causing said computer system to count a number of compositors coupled to the downstream compositor.

97. The computer program product of claim 96, wherein said first program code means comprises:

a third program code means for causing said computer system to identify a compositor of the compositor tree having a compositor tree compositor identifier with only one unique compositor identifier.

98. The computer program product of claim 96, wherein said first program code means comprises:

a third program code means for causing said computer system to identify compositors of the compositor tree having compositor tree compositor identifiers with more than one unique compositor identifier; and

a fourth program code means for causing said computer system to select a compositor of the compositor tree other than the compositors of the compositor tree having compositor tree compositor identifiers with more than one unique compositor identifier.

99. The computer program product of claim 98, wherein said third program code means comprises:

a fifth program code means for causing said computer system to distinguish compositors of the compositor tree having compositor tree compositor identifiers with a special character.

100. The computer program product of claim 96, wherein said first program code means comprises:

a third program code means for causing said computer system to identify compositors of the compositor tree having compositor tree compositor identifiers with a unique port identifier; and

a fourth program code means for causing said computer system to select a compositor of the compositor tree other than the compositors of the compositor tree having compositor tree compositor identifiers with the unique port identifier.

101. The computer program product of claim 96, wherein said second program code means comprises:

a third program code means for causing said computer system to identify compositors of the compositor tree having compositor tree compositor identifiers with a parent compositor tree compositor identifier that is identical to a compositor tree compositor identifier of the downstream compositor; and

a fourth program code means for causing said computer system to tally a number of the compositors having the compositor tree compositor identifiers with the parent compositor tree compositor identifier that is identical to the compositor tree compositor identifier of the downstream compositor.

102. The computer program product of claim 96, further comprising:

a third program code means for causing said computer system to ascertain if a compositor of the number of compositors coupled to the downstream compositor is a graphics pipeline; and

a fourth program code means for causing said computer system to transmit a compositor tree compositor identifier of the graphics pipeline to a graphics controller.

103. The computer program product of claim 102, wherein said third program code means comprises:

a fifth program code means for causing said computer system to determine if a compositor tree compositor identifier of the compositor of the number of compositors coupled to the downstream compositor has one of an equal number of unique compositor identifiers and a greater number of unique compositor identifiers as compositor tree compositor identifiers of other compositors of the compositor tree.

104. The computer program product of claim 102, wherein said third program code means comprises:

a fifth program code means for causing said computer system to determine if a compositor tree compositor identifier of the compositor of the number of compositors coupled to the downstream compositor has one of an equal number of special characters and a greater number of special characters as compositor tree compositor identifiers of other compositors of the compositor tree.

105. The computer program product of claim 102, wherein said third program code means comprises:

a fifth program code means for causing said computer system to determine if a compositor tree compositor identifier of the compositor of the number of compositors coupled to the downstream compositor has one of an equal number of unique port identifiers and a greater number of unique port identifiers as compositor tree compositor identifiers of other compositors of the compositor tree.

106. The computer program product of claim 102, further comprising:

a fifth program code means for causing said computer system to distinguish a compositor of the number of compositors coupled to the downstream compositor; and

a sixth program code means for causing said computer system to count, for the compositor of the number of compositors coupled to the downstream compositor, a new number of compositors coupled to the compositor of the number of compositors coupled to the downstream compositor.

107. The computer program product of claim 106, wherein said fifth program code means comprises:

a seventh program code means for causing said computer system to identify a compositor tree compositor identifier of the compositor of the number of compositors coupled to the downstream compositor.

108. The computer program product of claim 106, wherein said fifth program code means comprises:

a seventh program code means for causing said computer system to identify a port on the downstream compositor to which the compositor of the number of compositors coupled to the downstream compositor is coupled.

109. The computer program product of claim 108, wherein said seventh program code means comprises:

an eighth program code means for causing said computer system to find a unique port identifier of the downstream compositor within a compositor tree compositor identifier of the compositor of the number of compositors coupled to the downstream compositor.

110. The computer program product of claim 106, further comprising:

a seventh program code means for causing said computer system to detect an upstream compositor.

111. The computer program product of claim 110, wherein said seventh program code means comprises:

an eighth program code means for causing said computer system to cause the compositor of the number of compositors coupled to the downstream compositor to attempt to detect the upstream compositor; and

a ninth program code means for causing said computer system to cease attempting to count, for the compositor of the number of compositors coupled to the downstream compositor, the new number of compositors coupled to the compositor of the number of compositors coupled to the downstream compositor if the attempt to detect the upstream compositor failed.

112. A computer program product for determining a structure of a compositor tree, said computer program product having computer program code embodied in a computer useable medium, said computer program code means comprising:

a first program code means for causing said computer system to receive, from graphics pipelines, compositor tree compositor identifiers; and

a second program code means for causing said computer system to deconstruct the compositor tree compositor identifiers.

113. The computer program product of claim 112, wherein said second program code means comprises:

a third program code means for causing said computer system to ascertain a number of stages in the compositor tree.

114. The computer program product of claim 113, wherein said third program code means comprises:

a fourth program code means for causing said computer system to count a number of unique compositor identifiers within the compositor tree compositor identifiers.

115. The computer program product of claim 113, wherein said third program code means comprises:

a fourth program code means for causing said computer system to count a number of special characters within the compositor tree compositor identifiers.

116. The computer program product of claim 113, wherein said third program code means comprises:

a fourth program code means for causing said computer system to count a number of unique port identifiers within the compositor tree compositor identifiers.

117. The computer program product of claim 113, further comprising:

a fourth program code means for causing said computer system to locate a downstream compositor of the compositor tree.

118. The computer program product of claim 117, wherein said fourth program code means comprises:

a fifth program code means for causing said computer system to distinguish, within the compositor tree compositor identifiers, a unique compositor identifier common to the compositor tree compositor identifiers.

119. The computer program product of claim 117, further comprising:

a fifth program code means for causing said computer system to determine a number of compositors coupled to the downstream compositor.

120. The computer program product of claim 119, wherein said fifth program code means comprises:

a sixth program code means for causing said computer system to distinguish, within the compositor tree compositor identifiers, a unique compositor identifier common to the compositor tree compositor identifiers;

a seventh program code means for causing said computer system to identify, within the compositor tree compositor identifiers, unique compositor identifiers adjacent to the unique compositor identifier common to the compositor tree compositor identifiers;

an eighth program code means for causing said computer system to segregate the compositor tree compositor identifiers into groups according to the unique compositor identifiers adjacent to the unique compositor identifier common to the compositor tree compositor identifiers; and

a ninth program code means for causing said computer system to count the groups.

121. The computer program product of claim 120, further comprising:

a tenth program code means for causing said computer system to truncate the unique compositor identifier common to the compositor tree compositor identifiers from the compositor tree compositor identifiers, thereby producing new compositor tree compositor identifiers; and

an eleventh program code means for causing said computer system to repeat, for a group of the groups, said sixth program means through said tenth program means, wherein the compositor tree compositor identifiers are the new compositor tree compositor identifiers.

122. The computer program product of claim 119, further comprising:

a sixth program code means for causing said computer system to identify a port on the downstream compositor to which a compositor of the number of compositors is coupled.

123. The computer program product of claim 122, wherein said sixth program code means comprises:

a seventh program code means for causing said computer system to determine a unique port identifier of the downstream compositor within a compositor tree compositor identifier of the compositor of the number of compositors.