Method and apparatus for visually comparing files in a data processing system

• US 5,142,619 A
• Filed: 08/23/1991
• Issued: 08/25/1992
• Est. Priority Date: 02/21/1990
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Webster, John W. III
• Primary Examiner(s): CLARK, DAVID
• Application Number:
  US07/752,882
• Time in Patent Office: 368 Days
• Field of Search: 395/145-147, 395/149, 395/155, 395/157, 395/151, 340/734, 382/34, 382/57
• US Class Current: 715/803
• CPC Class Codes: G06F 40/194 Calculation of difference between files
• CPC Class Codes: G06F 7/02 Comparing digital values G06F7/06, G06F7/22, G06F7/38 take precedence

Abstract

A method and apparatus for visually comparing two files or portions thereof by visually indicating to the user areas of identity and differences between the items being compared. The items are stored in a video RAM which controls the visual presentation on the screen. The respective pixel settings in the video RAM are exclusively or'"'"'ed and the results are then stored in the video RAM so that the difference between the two items are displayed. A user can edit each item, while the comparison is being made, so that the effect of the editing on the differences, is immediately shown and apparent to the user.

Claims

1. A method of simultaneously presenting to a user on a display, which includes storage which contains representations for display pixels, two files and the differences therebetween, the method comprising the steps of:

storing, in a first area in the display storage, the display pixel representations of one of said files;

storing, in a second area in the display storage, the display pixel representations of the other one of said files;

comparing said pixel representations in said first area with those in said second area on a pixel-by-pixel basis and storing in a third area of said display memory pixel representations of differences therebetween;

responsive to input from the user, editing one of the files, simultaneously updating the differences stored in the third area, and displaying those differences to the user;

wherein the user is continuously presenting with the updated files; and

differences which the user may further edit; and

displaying, on the display, commands available to user which includes the steps of;

displaying, on the display, a command that invokes the comparing step;

displaying, on the display, an ATTACH command; and

responsive to the user invoking the ATTACH command, tying together the contents of the three areas to enable synchronous scrolling.

2. A method of simultaneously presenting to a user on a display, which includes storage which contains representations for display pixels, two files and the differences therebetween, the method comprising the steps of:

storing, in a first area in the display storage, the display pixel representations of one of said files;

storing, in a second area in the display storage, the display pixel representations of the other one of said files;

comparing said pixel representations in said first area with those in said second area on a pixel-by-pixel basis and storing in a third area of said display memory pixel representations or differences between pixels that have been compared;

activating pixels on said display in accordance with said pixel representations in said display storage so as to simultaneously display to a user said two files and all differences therebetween;

responsive to input from the user, editing one of the files, simultaneously updating the differences stored in the third area, and displaying those differences to the user;

wherein the user is continuously presented with the updated files; and

differences which the user may further edit; and

displaying, on the display, a command that invokes the comparing step;

displaying, on the display, commands specifying how the difference is to be applied to the first file or second file; and

selectively either deleting the difference from one of the files, adding the differences to one of the files, or editing the differences in response to the user selecting one of the specifying command.