JPH026111B2 - - Google Patents

Description

[Detailed description of the invention]

A. Field of Industrial Application The present invention relates to a graphic display device using a graphic CRT display device, and particularly to a line segment information creation processing method for drawing thick lines. B. Summary of the Invention The present invention provides a graphic display device that creates display data on a CRT monitor by adjusting scale and line width from graphic information registered in a segment buffer. A table is created in which line width data is registered, and this table is referenced to create center coordinate data of graphic elements according to the scale, and coordinate data is created by translating the center coordinate data by the number of lines corresponding to the line width data. By providing a display processor for graphic information, it is possible to obtain data with the desired line width simply by specifying the scale of the graphic information. C. Conventional technology Graphic CRT display devices have been
It is mainly used for offline work such as creating and modifying figures in fields such as CAD, CAM, and CAE, but recently, its use as a terminal device for online systems has been increasing. The graphic CRT display device used as the terminal device of this online system is required to have the following two points in terms of function and performance compared to conventional ones. (1) High-speed display: Good responsiveness is an essential condition for online systems, and the process from display request to display completion must be performed quickly, and various display updates must also be performed quickly. (2) Wide area support...Some online systems operate on equipment installed over a wide area. be able to display. It has a so-called computer mapping function. In order to meet these demands, a system configuration called an intelligent terminal type has been adopted as a graphic display system. As shown in FIG. 3, in this system, a graphic CRT display device 1 with a computer is used as a terminal side, and a host computer system 2 is connected to this terminal side via a communication line. An online system is constructed by connecting to a terminal device or host computer. In this configuration, a distributed processing system is used in which the host computer system 2 performs a large amount of arithmetic processing or data processing, and the computer in the terminal-side graphic CRT display device 1 performs display processing, thereby improving responsiveness on the terminal side. The load on the host computer system 2 is also reduced. The graphic display process in the configuration shown in FIG. 3 will be described in detail below. The graphic CRT display device 1 performs refresh drawing using a raster scan display method.
It has a CRT monitor 3, a display processor 4 as a control center, and graphic information (information such as line segments, symbols, characters, etc.) to be displayed is stored in a segment buffer ₅₁ . The graphical information stored in the segment buffer ₅₁ includes the individual graphical elements located at the lowest level (data type that specifies the displayed graphic, display position,
A tree structure is formed by SD (display color, etc.) and attribute elements SP, which are located above these graphic elements SD and define the attributes (visible attributes, detection attributes, etc.) of each graphic element. From the graphic information stored in the segment buffer ₅₁ , graphic information in a range (rectangular area determined by coordinate values) required to be displayed is cut out. This cutting process includes a matrix calculation processing unit 5 ₂ that performs parallel translation and rotation transformation of the displayed figure;
A clipping processing unit ₅₃ etc. is prepared to remove the portion that protrudes from the displayable screen frame of the CRT monitor 3, and furthermore, a line segment of the cut out graphic information is transferred from the display position (coordinate position) to the corresponding frame buffer 6. A digital differential analysis (DDA) processing unit ₅₄ is provided which develops bit on/off information. The frame buffer 6 is physically a memory that has bits that correspond one-to-one to each pixel on the screen of the CRT monitor 3. For color display, it has multiple bit planes and uses the lookup table 7. to determine the display color. Returning to FIG. 3, the host computer system 2 uses the host computer 8 as a control center.
As one of the processing functions of online processing, data processed with graphic information is divided into appropriate formats and stored in an auxiliary storage device 9 such as a magnetic disk, and graphic information within the range required by the graphics CRT display device 1 is transferred to the interface. Ace 10, 11, transmission line 1
The received data is transmitted to the graphic CRT display device 1 through the communication line 2, and the received data is stored in the segment buffer ₅₁ in the graphic CRT display device 1. D Problems to be Solved by the Invention In the configuration shown in FIG. 3, among the graphic information registered in the host computer system 2 and the graphic CRT display device 1, line segment information is starting point P ₁ (X ₁ , Y ¹ ), P ₃
(X ₃ , Y ₃ ) and the end point P ₂ (X ₂ , Y ₂ ), P ₄ (X ₄ , Y ₄ ) as coordinate data, and from this coordinate data
The DDA processing section ₅₄ performs bit expansion into data strings necessary for drawing line segments A and B, and the line segments are displayed on the CRT monitor 3 as described above. Such line segment information and display processing is realized by inserting space bits during bit expansion by specifying data types such as broken lines and dashed-dotted lines in addition to solid lines. However, thick lines in line segment information cannot be realized by the same processing as for broken lines and the like. Therefore, in order to display a thick line, the host computer 8 forms line segment information corresponding to the line width of the thick line, and this group of line segment information is registered in the segment buffer ₅₁ of the graphic CRT display device 1 for drawing. It was hot. In this conventional method, complicated coordinate position calculations are required to create a large amount of line segment information in order to display thick lines, which increases the burden on the host computer, adversely affects online processing, and makes high-speed display difficult. Furthermore, the amount of information registered in the segment buffer ₅₁ increases. On the other hand, a part or all of the graphics displayed on the CRT monitor 3 may be scaled. When performing this scaling process, it is necessary to change the number of displayed line segments so that the line width of thick lines also changes according to the scale. Processing for this requires processing that refers to the scale when forming line segment information on the host computer 8 side, and this also increases the burden on the host computer 8. E. Means and Effects for Solving the Problems In view of the above problems, the present invention provides the ability to display graphics corresponding to the graphics information registered in the segment buffer on a CRT.
A table in which line width data determined in association with scale information when displayed on a monitor is registered, and a table in which line width data is registered in correspondence with scale information when displayed on a monitor, and a table that registers line width data corresponding to graphic information of the segment buffer when scale information is given from the host computer side. Create the center coordinate data of the graphic element according to the scale by referring to it, and create the coordinate data by moving the center coordinate data in parallel by the number of lines corresponding to the line width data of the graphic element, and use it as the graphic display data on the CRT monitor. By specifying a scale for graphic information, the display processor creates graphic data with a line width corresponding to the scale scale by referring to a table. F. Embodiment FIG. 1 shows a block diagram of main parts in the processing method of the present invention. Graphic information in the required range is extracted from the host computer side and registered in the segment buffer ₅₁ , as in the past. In the figure, graphic information is shown as , which has graphic elements a ₁ , a 2 , a ₃ , b ₁ , b ₂ , _{b 3 ,} and c ₁ , c ₂ , c ₃ shall be. Further, it is assumed that one graphic type Ki is defined for each of these graphic elements. In developing these graphical information into bits on the frame buffer 6,
A scale M is specified. This scale M is given as a request from the operator or as a reference scale preset to the host computer and its updated scale data. The display processor 4 processes graphic information,
, the table 21 is referred to to create data such as actual line segments and characters. In this table 21, data of the thick line width S of each figure type K according to the scale M is registered. In the figure, M ₁ , M ₂ , and M ₃ are addressed as scale M.
For scale M ₁ , shape type K ₁ has thick line width S ₁ , K ₂
The line width S is set as S ₁ for K 3 and S ₂ for K ₃ . Here, the thick line width S is specified as the width of one line segment, that is, a multiple of one pixel width. For example 5
In the case of a thick line having the line width of the main line, a value of S=5 is registered in the table 21. This line width table is referred to by line segment information among the graphic information, and the line segment information has a graphic type in its graphic element indicating which line the line width table refers to. For example, as shown in the table below, in the line width table, for figure types K ₁ to _{K 3} , the line width of the line to be referenced in the line width table is determined by the scale M determined by the area to be cut out and displayed. The line width table contains data indicating the actual line width.

[Table] By creating the display graphic data with reference to the table 21, the display processor 4 performs the processing with reference to the table 21 based only on the scale M instruction from the host computer side, and each graphic element is A graphic display with an arbitrary line width S is obtained. Here, among the graphic data created by the display processor 4, for thick line figures, the number of lines corresponding to the coordinate data of one line segment which is the center of the thick line and the line width S (see table) for this coordinate data is calculated. Create coordinate data that is translated by one line width Δx in one direction of X and Y. This process will be explained with reference to FIG. In Figure 2, as coordinate data, line segments P ₁₁ (X ₁ , Y ₁ ) and P ₂₁ (X ₂ , Y ₂ ), which are the centers of line segment A, are created according to size S, and line segments P ₃₁ ( _X3 ,
Y ₃ ) and P ₄₁ (X ₄ , Y ₄ ). Creation of coordinate data based on the line width S is determined based on the slope. First, for line segment A, coordinate data P ₁₁ (X ₁ ,
From Y ₁ ) and P ₂₁ (X ₂ , Y ₂ ), it is determined whether the line segment has an inclination of more than or less than 45 degrees with respect to the horizontal. 45 degrees or more | Y ₂ − _{Y 1} | ≧ | X ₂ − _{X 1} | Less than 45 degrees _{| Y 2 −} Y ₁ | < |
If the inclination is less than 45 degrees, create coordinate data by translating the coordinate data of the central line segment A in the Y direction by one line segment width Δy. This line segment width Δy is a reference width that allows the center line segment A to be moved alternately in positive and negative directions by the specified N lengths. On the other hand, when the inclination is 45 degrees or more, coordinate data of the central line segment A is translated by one line segment width Δx in the X direction to create coordinate data. Since the angle of line segment A in Figure 2 is less than 45 degrees, the coordinate data created will be P ₁₂ (X ₁ , Y ₁ + Δy) and P ₂₂ (X ₂ , Y ₂ + Δy) P ₁₃ (X ₁ , Y ₁ −Δy) and P ₂₃ (X ₂ , Y ₂ −Δy) P ₁₄ (X ₁ , Y ₁ +2Δy) and P ₂₄ (X 2 , _{Y 2 +} 2Δy) P ₁₅ (X ₁ , Y ₁ −2Δy) and P ₂₅ (X ₂ , Y ₂ −2Δy), and these coordinate data are used as DDA along with the coordinate data of the central line segment A.
A thick line is drawn on the CRT monitor ₃ by bit expansion. Similarly, line segment B has an inclination of 45 degrees or more, so
If the coordinate data to be created is S=5, the coordinate data of the central line segment P ₃₁ (X ₃ , Y ₃ ), P ₄₁ (X ₄ ,
Coordinate data P ₃₂ (X ₃ − Δx, Y ₃ ) and P ₄₂ (X ₄ − Δx, Y ₄ ) P ₃₃ (X ₃ + Δx, Y _{3 )} and P ₄₃ (X ₄ + Δx, Y ₄ ) P ₃₄ (X ₃ −2ΔX, Y ₃ ) and P ₄₄ (X ₄ −2Δx, Y ₄ ) P ₃₅ (X ₃ +2Δx, Y ₃ ) and P ₄₅ (X ₄ +2Δx, Y ₄ ) Automatically create something with a start and end point. Note that the calculation for creating the coordinate data is not limited to the central line segments A and B, but can be similarly obtained by adding or subtracting Δx and Δy to the created data. For example, after creating line segment data with coordinate data P ₁₂ and P ₂₂ , creating line segment data with coordinate data P ₁₄ and P ₂₄ requires P ₁₂ and P _22.
This is achieved by adding +Δy to the coordinate data with . G. Effect of the Invention As described above, according to the present invention, in order to create graphic data to be displayed on a CRT monitor from graphic information of a segment structure, a table in which line width data is registered in accordance with scale specification is used. The display processor creates coordinate data that is translated by the number of lines corresponding to the line width data with respect to the coordinate data of the center line segment. It is possible to create graphic data having a line width of 200 kHz, reducing the burden on the host computer and display processor for graphic display including thick line display, and reducing the amount of information registered in the segment buffer.

[Brief explanation of drawings]

FIG. 1 is a block diagram of main parts in the processing method of the present invention, FIG. 2 is an enlarged view of the thick line shown in FIG. 1,
Figure 3 is a conventional configuration diagram of a graphic display device, Figure 4 is a segment structure diagram of graphic information handled in Figure 3, and Figure 5 is a diagram of the segment structure of graphic information handled in Figure 3.
The figure is an explanatory diagram of processing for displaying line segments. 1... Graphic CRT display device, 2... Host computer system, 3... CRT monitor,
4...Display processor, ₅₁ ...Segment buffer, ₅₂ ...Matrix calculation processing unit,
5 ₃ ... Clipping processing section, 5 ₄ ... DDA processing section, 6 ... Frame buffer, 7 ... Lookup table, 8 ... Host computer, 9 ...
Auxiliary storage device, 10, 11...interface, 12...transmission line, 21...table.

Claims (1)

[Claims] 1. In a graphic display device that uses a graphic CRT display device with a display processor as a terminal device and constructs an online system together with a host computer to display graphics, graphic information cut out from the host computer side is displayed as a graphic display device.
means for registering in a segment buffer of a CRT display device; a table in which line width data defined in association with scale information when displaying a figure corresponding to the figure information on a CRT monitor is registered; and a side of the host computer. When scale information is given from , the table is referred to for the graphic information of the segment buffer to create center coordinate data of the graphic element according to the scale and the number of lines corresponding to the line width data of the graphic element. 1. A graphic display device comprising: a display processor that creates coordinate data obtained by translating the center coordinate data and uses the data as graphic display data on a CRT monitor.