Method and apparatus for setting a graphical object's position and orientation with viscous dragging

• US 5,471,571 A
• Filed: 07/17/1992
• Issued: 11/28/1995
• Est. Priority Date: 12/27/1991
• Status: Expired due to Term

• Current Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Smith, Randall B., Tang, John C., Henderson, Jr., D. Austin
• Primary Examiner(s): Nguyen, Phu K.
• Application Number:
  US07/914,304
• Time in Patent Office: 1,229 Days
• Field of Search: 395/133, 395/155, 395/159, 395/137, 395/161, 395/155, 395/136, 395/138, 395/139, 345/157, 345/159, 345/160, 345/121, 345/126
• US Class Current: 345/654
• CPC Class Codes: G06F 3/04845 for image manipulation, e.g. dragging, rotation, expansion or change of colour
• CPC Class Codes: G06F 3/04892 Arrangements for controlling cursor position based on codes indicative of cursor displacements from one discrete location to another, e.g. using cursor control keys associated to different directions or using the tab key arrangements for controlling cursor position based on coordinate signals G06F3/038

Abstract

A method and apparatus for using a cursor movement device such as a mouse device to position and orient a graphical object or cursor on a computer screen. The movement and orientation of the graphical object on the screen depends directly upon the path of motion of the cursor. The actual movement of the graphical object is similar to the dragging of an object through a viscous medium. In this manner, a two dimensional object can be moved and rotated on a planar display device with only two directional inputs. Also, the cursor, itself, can be treated as a graphical object. This allows the user to rotate the cursor to a desired orientation. Furthermore, the orientation of the cursor can be used to select one of a plurality of functions performed by the cursor movement device.

Claims

1. In a computer system, a method of controlling movement of an N-dimensional graphical object on a display having a plurality of coordinate values, comprising:

displaying said graphical object at a selected location and orientation on said display;

positioning a cursor at a desired location on said display with a cursor movement device;

moving said cursor along a desired path of motion on said display with said cursor movement device, where said location and path of motion are defined by N variables; and

modifying said graphical object on said display, such that said location and orientation of said graphical object are modified in dependance on said desired location and said desired path of motion.

2. The method of claim 1, wherein in said modifying step, said location and orientation of said graphical object are modified according to a hypothetical viscous dragging of the graphical object through an imaginary medium.

3. The method of claim 1, wherein in said modifying step, modifying said location and orientation of said graphical object is simulated to dragging a solid object through a viscous medium.

4. The method of claim 3, wherein before said moving step said method further comprising:

determining center of mass coordinate values for said graphical object, such that said orientation of said graphical object is modified by rotating said graphical object around said center of mass coordinates.

5. The method of claim 4, wherein before said moving step said method further comprising:

determining an extent value of said graphical object; and

said maneuvering step comprising;

computing a change in orientation value, Δ

θ

, and a change in position value, Δ

x, such that ##EQU13## where;

P is a vector from an arbitrary origin to a cursor position on said display;

L is said extent value;

r is a vector from said center of mass of said graphical object to said cursor position on said display;

θ

is a vector representing said orientation of said graphical object around said center of mass; and

x is a vector from said origin to said center of mass coordinate values.

6. The method of claim 5, further comprising:

redrawing said graphical object in dependence on said Δ

θ and

Δ

x values.

7. The method of claim 3 wherein said graphical object is a three-dimensional representation on said display.

8. In a computer system, a method of controlling movement of an N-dimensional cursor on a display having a plurality of coordinate values, comprising:

displaying said cursor at a selected location and orientation on said display;

preselecting a center of mass point on said cursor;

positioning said cursor at a desired location on said display with a cursor movement device;

moving said cursor along a desired path of motion on said display with said cursor movement device, where said location and path of motion are defined by N variables, such that said location and orientation of said cursor are modified in dependance on said preselected center of mass point and said path of motion.

9. The method of claim 8, wherein in said computer system, said cursor movement device and said cursor selectively perform a plurality of functions, such that the function performed by said cursor movement device and said cursor is selected in dependence on said orientation of said cursor.

10. The method of claim 8, wherein in said moving step, said location and orientation of said cursor are modified according to a hypothetical viscous dragging of the graphical object through an imaginary medium.

11. The method of claim 8, wherein in said moving step, modifying said location and orientation of said cursor is simulated to dragging a solid object through a viscous medium.

12. The method of claim 11, wherein in said computer system, said cursor movement device and said cursor selectively perform a plurality of functions, such that the function performed by said cursor movement device and said cursor is selected in dependence on said orientation of said cursor.

13. The method of claim 11, wherein before said moving step said method further comprising:

determining center of mass coordinate values for said cursor, such that said orientation of said graphical object is modified by rotating said cursor around said center of mass coordinates.

14. The method of claim 13, wherein before said moving step said method further comprising:

determining an extent value of said cursor; and

said maneuvering step comprising;

computing a change in orientation value, Δ

θ

, and a change in position value, Δ

x, such that ##EQU14## where;

P is a vector from an arbitrary origin to a coordinate value on said cursor on said display;

L is said extent value;

r is a vector from said center of mass of said cursor to said coordinate value on said cursor on said display;

θ

is a vector representing said orientation of said cursor around said center of mass; and

x is a vector from said origin to said center of mass coordinate values.

15. The method of claim 14, further comprising:

redrawing said cursor on said display in dependence on said Δ

θ and

Δ

x values.

16. The method of claim 15, wherein in said computer system, said cursor movement device and said cursor selectively perform a plurality of functions, such that the function performed by said cursor movement device and said cursor is selected in dependence on said orientation of said cursor.

17. A computer system, comprising:

a central processing unit;

a display having a plurality of coordinate values and coupled to said central processing unit, said display capable of displaying an N-dimensional graphical object at a selected location and orientation of said display; and

a cursor movement device coupled to said central processing unit said cursor movement device controlling positioning of a cursor on said display, said cursor movement device positioning said cursor at a desired location on said graphical object and moving said cursor along a desired path of motion on said display, where said location and path of motion are defined by N variables, such that said location and orientation of said graphical object are modified in dependance on said desired location and said desired path of motion.

18. The computer system of claim 17, wherein said location and orientation of said graphical object are modified in dependence on said path of motion according to a hypothetical viscous dragging of the graphical object through an imaginary medium.

19. The computer system of claim 18 wherein said graphical object is a three-dimensional representation on said display.

20. The computer system of claim 17, wherein said location and orientation of said graphical object are modified in dependence on said path of motion simulated to dragging a solid object through a viscous medium.

21. The computer system of claim 20, wherein said cursor movement device is a mouse device.

22. The computer system of claim 20, wherein said cursor movement device is a track-ball device.

23. The computer system of claim 20, wherein said cursor movement device is a stylus in combination with an information input sheet.

24. The computer system of claim 20, wherein said display is a cathode ray tube screen.

25. The computer system of claim 20, wherein said central processing unit determines center of mass coordinate values for said graphical object, such that said orientation of said graphical object is modified by rotating said graphical object around said center of mass coordinates.

26. The computer system of claim 25, wherein said central processing unit determines an extent value of said graphical object and computes a change in orientation value, Δ

θ

, and a change in position value, Δ

x, such-that ##EQU15## where;

P is a vector from an arbitrary origin to a cursor position on said display;

L is said extent value;

r is a vector from said center of mass of said graphical object to said cursor position on said display;

θ

is a vector representing said orientation of said graphical object around said center of mass; and

x is a vector from said origin to said center of mass coordinate values.

27. The computer system of claim 26 wherein said central processing unit redraws said graphical object on said display in dependence on said Δ

θ and

Δ

x values.

28. A computer system, comprising:

a central processing unit;

a display having a plurality of coordinate values and coupled to said central processing unit, said display capable of displaying a cursor at a selected location and orientation of said display; and

a cursor movement device coupled to said central processing unit said cursor movement device controlling positioning of a N-dimensional cursor on said display, said cursor movement device moving said cursor along a desired path of motion on said display, where said location and path of motion are defined by N variables, such that said location and orientation of said cursor are modified in dependance on a preselected center of mass point on said cursor and said path of motion.

29. The computer system of claim 28, wherein said cursor movement device and said cursor selectively perform a plurality of functions, such that the function performed by said cursor movement device and said cursor is selected in dependence on said orientation of said cursor.

30. The computer system of claim 29, wherein said cursor movement device is a stylus in combination with an information input sheet.

31. The computer system of claim 29, wherein said display is a cathode ray tube screen.

32. The computer system of claim 29, wherein said cursor movement device is a mouse device.

33. The computer system of claim 29, wherein said cursor movement device is a track-ball device.

34. The computer system of claim 28, wherein said location and orientation of said cursor are modified according to a hypothetical viscous dragging of the cursor through an imaginary medium.

35. The computer system of claim 28, wherein said location and orientation of said cursor are modified in dependence on said path of motion simulated to dragging a solid object through a viscous medium.

36. The computer system of claim 35, wherein said cursor movement device and said cursor-selectively perform a plurality of functions, such that the function performed by said cursor movement device and said cursor is selected in dependence on said orientation of said cursor.

37. The computer system of claim 36, wherein said cursor movement device is a mouse device.

38. The computer system of claim 36, wherein said cursor movement device is a track-ball device.

39. The computer system of claim 36, wherein said cursor movement device is a stylus in combination with an information input sheet.

40. The computer system of claim 35, wherein said central processing unit determines center of mass coordinate values for said cursor, such that said orientation of said cursor is modified by rotating said cursor around said center of mass coordinates.

41. The computer system of claim 40, wherein said central processing unit determines an extent value of said cursor and computes a change in orientation value, Δ

θ

, and a change in position value, Δ

x, such that ##EQU16## where;

P is a vector from an arbitrary origin to a coordinate value on said cursor on said display;

L is said extent value;

r is a vector from said center of mass of said cursor to said coordinate value on said cursor on said display;

θ

is a vector representing said orientation of said cursor around said center of mass; and

x is a vector from said origin to said center of mass coordinate values.

42. The computer system of claim 41, wherein said central processing unit redraws on said display cursor in dependence on said Δ

θ and

Δ

x values.

43. The computer system of claim 42, wherein said cursor movement device and said cursor selectively perform a plurality of functions, such that the function performed by said cursor movement device and said cursor is selected in dependence on said orientation of said cursor.