Method of displaying thick line and information unit and display system used therefor

• US 5,204,945 A
• Filed: 11/06/1990
• Issued: 04/20/1993
• Est. Priority Date: 11/08/1989
• Status: Expired due to Term

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Fujita, Ryo, Hara, Hideyuki, Sakaibara, Toru
• Primary Examiner(s): Harkcom, Gary V.
• Assistant Examiner(s): NGUYEN, PHU K
• Application Number:
  US07/609,615
• Time in Patent Office: 896 Days
• Field of Search: 395/133, 395/134, 395/141, 395/143, 395/157, 340/747, 340/728, 340/729, 340/734, 340/730
• US Class Current: 345/628
• CPC Class Codes: G09G 5/20 Function-generator circuits, e.g. circle generators line or curve smoothing circuits

Abstract

The display system and a thick line display method realizes a high-speed and accurate display of a thick line without any disorder even if a display range is to be processed by two or more clip frames when the thick line is to be displayed by parallel setting a reference line component and at least one additional line component which is obtained by parallel moving the reference line component in a display system such as an information processing unit that displays graphs. For this purpose, a clip frame showing a display range is expanded by a predetermined width equal to or larger than the total width of additional line components to be set at least at one side of the reference line component and the additional line component is obtained in that expanded frame, and the line component within the clip frame of the additional line component and the reference line component within the clip frame are displayed.

Claims

1. A method of displaying a thick line for displaying the thick line by parallel setting a reference line component and at least one additional line component which is obtained by parallel moving said reference line component, comprising:

a step of expanding a clip frame showing a display range by a predetermined width to be equal to or larger than the total width of the at least one additional line component to be set at least at one side of the reference line component and obtaining the at least one additional line component in the expanded clip frame; and

a step for displaying line components within said clip frame of the at least one additional line component obtained and the reference line component within said clip frame.

2. A method of displaying a thick line for displaying the thick line by parallel setting a reference line component and at least one additional line component which is obtained by parallel moving said reference line component, comprising:

a step for carrying out a first clipping processing to the reference line component such that a first clip frame showing a display range is expanded by a predetermined width equal to or larger than a total width of the at least one additional line component to be set at least at one side of the reference line component to obtain a second clip frame and obtaining line components in the second clip frame;

a step for obtaining the at least one additional line component in addition to the reference line component after the above processing;

a step for obtaining a pixel which constitutes the reference line component that has been first clipping processed and the at least one additional line component obtained;

a step for carrying out a second clipping processing to a picture element obtained to obtain a pixel within the first clip frame; and

a step for displaying the pixel obtained within the first clip frame.

3. A display system comprising:

means for displaying a thick line by parallel setting a reference line component and at least one additional line component which is obtained by parallel moving said reference line component;

means for carrying out a first clipping processing to the reference line component such that a first clip frame showing a display range is expanded by a predetermined width equal to or larger than a total width of the at least one additional line component to be set at least at one side of the reference line component to obtain a second clip frame and obtaining line components in the second clip frame;

means for obtaining a pixel which constitutes the reference line component that has been the first clipping processed and the at least one additional line component obtained;

means for carrying out a second clipping processing to the pixel obtained to obtain a pixel within the first clip frame; and

means for displaying the pixel obtained within the first clip frame.

4. A display system comprising:

means for displaying a thick line by parallel setting a reference line component and at least one additional line component having start and end points obtained by parallel moving start and end points of said reference line;

means for carrying out a first clipping processing to the reference line component such that a first clip frame showing a display range is expanded by a predetermined width equal to or larger than a total width of the at least one additional line component to be set at least at one side of the reference line component to obtain a second clip frame and obtaining start and end points of line components within the second clip frame;

means for obtaining the start and end points of the at least one additional line component next to the reference line component obtained by the first clipping processing;

means for generating a pixel of the reference line component and the at least one additional line component from the start and end points of the reference line component obtained by the first clipping processing and the at least one additional line component obtained;

means for discriminating whether coordinates of the pixel generated are within the first clip frame or not; and

means for displaying the pixel when the coordinates of the pixel discriminated are within the first clip frame.

5. A display system according to claim 4, wherein;

said display system includes a frame memory for storing a display image, said discrimination means compares the write address of the generated pixel in the frame memory with the address area of the frame memory corresponding to said first clip frame, and said display means writes the generated pixel in the frame memory when the write address is within said address area.

6. An information processing unit which provides a multi-window environment and has means for displaying a thick line by parallel setting a reference line component and at least one additional line component having start and end points obtained by parallel moving start and end points of said reference line component, to realize a clipping processing of the thick line which is displayed in one window by dividing the one window into two or more clip frames and by clipping processing each of the clip frames, said information processing unit comprising for each clip frame:

means for carrying out a first clipping processing to the reference line component of the thick line such that a first clip frame showing a display range is expanded by a predetermined width equal to or larger than a total width of the at least one additional line component to be set at least at one side of the reference line component and obtaining line components in the second clip frame;

means for obtaining a pixel which constitutes the reference line component that has been the first clipping processed and the at least one additional line component obtained;

means for carrying out a second clipping processing to the picture element obtained to obtain a pixel within the first clip frame; and

means for displaying the pixel obtained within the first clip frame.