Precision automatic scrolling for an image display system

• US 5,493,641 A
• Filed: 05/22/1995
• Issued: 02/20/1996
• Est. Priority Date: 12/19/1991
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Brown, Jerry R.
• Primary Examiner(s): Herndon, Heather R.
• Assistant Examiner(s): Vo, Cliff N.
• Application Number:
  US08/446,359
• Time in Patent Office: 274 Days
• Field of Search: 395/133, 395/138, 395/147, 395/153, 395/157, 395/158, 395/161
• US Class Current: 715/784
• CPC Class Codes: G06F 3/04845 for image manipulation, e.g. dragging, rotation, expansion or change of colour
• CPC Class Codes: G06F 3/0485 Scrolling or panning

Abstract

A system and method of precision automatic scrolling for use in an image display system. Upon selecting a displayed entity having an off-screen end or other point which is desired to be brought into view, the entity'"'"'s definitional vector coordinate characteristics are compared to the coordinates of the selection point on the display screen. The results of the comparison provide the XY coordinates of the entity which are furthest from the point of selection. The resulting XY coordinates are then made the new center point of the area in view. The current level of magnification is maintained during this operation. The present system and method thus eliminates the need for manual panning/scrolling or demagnification to bring the desired endpoint into view. The present system and method can also be applied to locate and display a nearest endpoint or a closest point of intersection between two entities.

Claims

1. A method for processing an image for display on a video screen comprising the steps of:

selecting a first point within a component of the image on said video screen, said component having a first portion currently visible in a first display frame currently displayed on said video screen and a second portion which may not be currently visible in said first display frame;

using vector format comparing first coordinates indicative of said first point with definitional characteristics of the component so as to determine second coordinates of a second point on said component furthest from said first point; and

responsive to results of said comparing, displaying a second display frame including said second point.

2. The method of claim 1 wherein said displaying comprises the further step of altering a display attribute of said component.

3. The method of claim 1 comprising the further step of, after said selecting, obtaining said definitional characteristics of said component defined in graphics primitive form from an image database.

4. The method of claim 1 wherein said displaying comprises the step of displaying in said second display frame a view of said image centered around said second point.

5. The method of claim 4 wherein said displaying comprises the step of displaying said second display frame next subsequent to said first display frame.

6. The method of claim 1, wherein said first point and said second point are displayed at a same level of magnification.

7. The method of claim 1, wherein said first display frame and said second display frame are displayed at a same level of magnification.

8. A method for processing an image for display on a video screen comprising the steps of:

selecting a first point within a component of the image on said video screen, said component having a first portion within a first display frame currently visible on said video screen and a second portion which may not be currently visible in said first display frame;

selecting a vector function to determine a second point on said image, said second point being within said second portion of said image;

responsive to said selecting a vector function, processing first coordinates indicative of said first point and definitional characteristics of said component so as to determine second coordinates of said second point on said component; and

responsive to said processing, displaying in a second display frame an area of said component including said second point.

9. The method of claim 8 wherein said displaying comprises the further step of altering a display color attribute of said component.

10. The method of claim 8 comprising the further step of, after said selecting of said first point and said vector function, obtaining said definitional characteristics of said component defined as a graphic primitive from an image database.

11. The method of claim 8 wherein said selecting of said vector function comprises the step of selecting from a group of functions including determining a point on said component furthest from said first point and determining a closest point of intersection between said component and another component, relative to said first point.

12. The method of claim 8 wherein said processing comprises the step of determining a closest point of intersection between said component and another component, relative to said first point.

13. The method of claim 8 wherein said displaying comprises the step of displaying an area of said component centered around said second point.

14. The method of claim 13 wherein said displaying comprises the step of displaying said second display frame next subsequent to said first display frame.

15. The apparatus of claim 13 wherein said first display frame and said second display frame are displayed at a same level of magnification.

16. A system for processing an image displayed on a video screen comprising:

means for selecting a first point within a component of the image on said video screen, said component may or may not have a portion currently visible on said video screen;

using vector format means for comparing first coordinates indicative of said first point with a definitional characteristics of said component;

means, coupled to said vector format means for comparing, for determining second coordinates of a second point on said component furthest from said first point; and

means, connected to receive said second coordinates from said means for determining, for displaying an area of said component centered around said second point.

17. The system of claim 16 further comprising means, coupled to said means for displaying, for altering a display color attribute of said component.

18. The system of claim 17 further comprising database means, coupled to said vector format means for comparing and said means for selecting, for storing said definitional characteristics of said component defined in a graphics primitive form.

19. The system of claim 16, wherein said displaying comprises the displaying of said image centered around said second point.

20. The system of claim 19, wherein said displaying comprises the displaying of said second point next subsequent to said first point display.

21. The system of claim 16, wherein said vector format means comprises means for selecting from a group of functions including determining a point on said component furthest from said first point and determining a closest point of intersection between said component and another component, relative to said first point.

22. The system of claim 16, wherein said vector format means comprises means for determining a closest point of intersection between said component and another component, relative to said first point.

23. The system of claim 16, wherein said first point and said second point are displayed at a same level of magnification.