JPH026110B2 - - 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 graphic enlargement/reduction drawing processing method. B. Summary of the Invention The present invention provides a graphic display device that draws substantive figures corresponding to graphic information of a segment buffer overlappingly at different scales. By setting the center of the symbol as the reference point, and converting the actual data of the symbol by converting the coordinate values of the reference point for global scale conversion and as the distance from the reference point for individual scale conversion, the symbol can be placed on a line segment. This method eliminates deviations in the relative positional relationship between each figure in the overlapping drawing of figures. 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. 2, this system has a graphing CRT display device 1 with a computer 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 method 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. 2 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 provided 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 figure 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. This will be explained with reference to FIG. The figure shows a case where the frame buffer 6 has three bit planes #1, #2, and #3.
The on/off state of the bits corresponding to the graphic information of the segment buffer ₅₁ is developed as a combination of bit planes #1 to #3. The display on the CRT monitor 3 is then raster scanned on the frame buffer 6, and each bit plane #1 to
Each beam output of R (red), G (green), and B (blue) is given to the CRT monitor 3 according to the display color table defined in the lookup table 7 using the bit-on combination value of #3 as an address. The table below shows an example in which the strength (difference in display color) of each beam in the lookup table 7 is associated with the bit combinations of each bit plane #1 to #3 of the frame buffer 6. 8 types of colors are specified for each pixel by #3, and 512 ( ²⁹ ) colors can be selected by applying 3 bits to each of the R, G, and B beams of the lookup table 7.

[Table] Returning to FIG. 2, the host computer system 2 uses the host computer 8 as the 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 Problem to be solved by the invention In the configuration shown in FIG.
Although the size data of the graphic information registered in the CRT monitor ₁ is kept constant, there are many display requests to enlarge or reduce the cut out graphic information and draw it on the CRT monitor 3. To enlarge or _reduce the figure display, set a window (display area) with widths _W Enlarge or reduce all characters, etc., uniformly. In such general scale display processing, figures with high and low importance are displayed at the same scale, making the displayed figures difficult to see and unfavorable for the operator's accurate figure recognition and judgment. Become. To solve this problem, it is possible to perform processing and display in which the degree of magnification is increased as the degree of importance increases. This process is achieved by setting display size data for each figure information, and when bit-developing this figure information on the frame buffer 6, referring to the display size table and changing the display size magnification for each figure. . In this way, a window (display area) is added to the figure display.
If the scale of each figure can be changed independently from the scale of There is a problem with the disc shifting. When the display processor 4 performs symbol drawing processing, it multiplies the lower left reference point of the symbol definition space by the overall scale conversion rate (reduction scale), and also applies an independent scale to the actual data of the symbol. Since the distance from the reference point is multiplied by the individual scale conversion rate to achieve this, the symbol reference point position is correct, but
This is due to the fact that the individual coordinates representing the symbol entity deviate from the overall scale coordinates. E. Means and Effects for Solving the Problems In view of the above problems, the present invention provides coordinate values of each line segment information for drawing a symbol to draw a figure at different individual scale conversion rates (reduction scales). The center of the defined space is set as a reference point and the distance from the reference point is set, and the actual data of the symbol is an overall scale conversion rate that is multiplied by the coordinate value of the reference point and an individual scale conversion rate that is multiplied by the distance between the reference point and each line segment information. We will perform a drawing process to calculate values using , and convert only the coordinate values of the reference point by global scale conversion, and convert the coordinate values of each line segment information centered on the reference point by individual scale conversion. F. Embodiment FIG. 1 shows the correspondence between the segment buffer coordinate space and the display image of a CRT monitor in the processing method of the present invention. The graphical information registered in segment buffer 5 ₁ includes line segment information defined by points l1 (X _s , Y _s ) and l2 (X _R , Y _R ) in the segment buffer coordinate space, and The display processor 4 superimposes the figures of the two pieces of information on the frame buffer 6 and develops them in bits with the rectangular symbol information defined by the line segment information connecting points a, b, c, and d, respectively. A case will be described below in which drawing is performed with a conversion rate α, an individual scale conversion rate 1 for the substance data of line segment information, and an individual scale conversion rate β for the substance data of symbols. That is, a case will be explained in which only the overall scale conversion rate is applied to the line segment information. First, regarding the line segment information, by multiplying the points l1 (X _s , Y _s ), l2 (X _R , Y _R ) by the overall scale conversion rate α, and then by the individual scale conversion rate 1, respectively l ₁ (X _s , Y _s ) → L1 (αX _s , αY _s ) l ₂ (X _R , Y _R ) → L2 (αX _R , αY _R ) ......The scale conversion of (1) is performed, and the magnification rate is α×1. point at
It is drawn as a line segment between L1 and L2. Next, regarding symbol information, as _shown in FIG. _5A , entity data a- Coordinate points a, b, c, and d of b, b-c, c-d, and d-a are defined using the center point p (X _p , Y _p ) of the symbol definition space as a reference point. That is, the points a to d have the following coordinates. a(X ₁ , Y ₁ ) b(X ₁ , Y ₁ ) c(X ₂ , Y ₂ ) d(X ₂ , Y ₂ ) ......(2) However, in the example where the symbol is shown in Figure 5 A, X ₁ , Y ₁ will be a negative value. To convert the overall scale of symbol information with such entity data coordinates, the definition space reference point p (X _p ,
The _drawing reference point P is determined from p(X _p , Y _p )→P(αX _p , αY _p ) (3) by multiplying Y p ) by the overall scale conversion rate α. The drawing reference point P at this time is in a proportional relationship with the positions of the points L1 and L2 of the line segment information. Next, for individual scaling of symbol information,
Drawing reference point P obtained by the above-mentioned overall scale conversion
Rendering coordinate data A, B, C, D using (αX _p , αY _p ) as the reference and the value obtained by multiplying the symbol entity coordinate points a, b, c, d by the individual scale conversion rate β as the distance from the drawing reference point P. seek. This data A, B,
C and D are as follows. A(αX _p +βX ₁ , αY _p +βY ₂ ) B(αX _p +βX ₁ , αY _p , βY ₁ ) C(αX _p +βX ₂ , αY _p +βY ₁ ) D(αX _p +βX ₂ , αY _p +βY ₂ )... ...(4) In this way, the individual scale conversion of the symbol is performed using the drawing reference point P as the center of the symbol definition space, and for the actual symbol data A to D, the individual scale conversion rate β of the symbol is multiplied from the reference point P. Because it is calculated in addition to the coordinate data of the reference point P, the reference point P of the symbol (the center of the symbol definition space) can only be multiplied by the overall scale conversion rate α, and the drawing using the entity data A to D is based on the position with the line segment. No deviation occurs. Regarding this point, to explain the conventional individual scale conversion and drawing processing, regarding the symbol definition, the symbol definition space is limited to the first quadrant as shown in Figure 5B, and the lower left (point 0) is the reference point. The entity data a to d are defined, or as shown in FIG. 5A, the definition is performed using the center point P as a reference point. However, in conventional symbol drawing processing, the coordinates defined in FIG. 5a are also converted so that the lower left of the symbol definition space becomes the reference point, and processing similar to the definition in FIG. 5B is performed. In other words, the conventional symbol definition as shown in FIG. 5A is unrelated to drawing processing,
It is simply a function that makes it easier to input the coordinates for defining a symbol (if the figure is symmetrical from the center position, the value can be obtained by simply reversing the sign). Regarding the entire scale conversion for such a symbol, the same scale conversion is performed for the line segment and reference point determined by points L1 and L2 as in the above embodiment. However, in symbol individual scale conversion, when multiplied by the conversion rate β, the entity data A to D become the coordinate values shown in (4) above, but the distances from the point (0, 0) X ₁ , X ₂ ,
Since Y ₁ and Y ₂ are multiplied by β, a positional deviation from the line segment display occurs. This explanation will be made using FIG. 6. FIG. 6A is an explanatory diagram of the present proposal, and FIG. 6B is an explanatory diagram of the conventional method. In the figure, L1, L2, and P indicate the positions after being multiplied by the overall scale conversion rate α. Also (X _Q ¹ , Y _Q ¹ ), (X _Q ² , Y _Q ² ), (X _Q ³ , Y _Q ³ )
The rectangles shown by indicate that the area occupied by the symbol definition space in the whole changes depending on the individual scale conversion rate of the symbol, and let the individual scale conversion rates be β ₁ , β ₂ , and β ₃ . In FIG. 6A, since the center of the symbol definition space is multiplied by the overall scale conversion rate, no misalignment with the line segment occurs regardless of the value of the individual scale conversion rate β. This concept is illustrated by drawing circles within the three symbol definition spaces in the figure. The center of every circle is the line segment L1−L2
It is above. Next, in Figure 6B, the lower left point P of the symbol definition space is multiplied by the overall scale conversion rate,
Using this point as a reference, the symbol display area is determined by the individual scale conversion rate β. In the example shown in the figure, circle 1 with conversion rate β ₁ has the center line segment L1
-L2, but in circles 2 and 3 due to the conversion rates β ₂ and β ₃ , the centers are away from the line segment L1-L2, causing a positional shift between the symbol and the line segment. Note that in the embodiment, it is clear that the individual scale conversion rates of the symbols are changed to individual conversion rates in the vertical and horizontal directions so that positional deviation does not occur. G. Effects of the Invention As described above, according to the present invention, the coordinate value of each line segment information with the center of the symbol definition space as the reference point is converted to the distance from the reference point by an individual scale conversion rate in symbol scale conversion drawing processing. Since only the coordinate values of the reference point are converted for the overall scale conversion, even if the scale conversion rate differs for each figure, the relative positional relationship of each figure is displayed without any deviation, making it easier to recognize the figure. It has the effect of making it easier.

[Brief explanation of drawings]

Fig. 1 is a correspondence diagram of segment buffer coordinate space and CRT monitor display area for explaining the processing method of the present invention, Fig. 2 is a configuration diagram of a graphic display device, and Fig. 3 is a diagram of the graphic information handled in Fig. 2. Segment structure diagram,
Figure 4 is a diagram for explaining the processing of bit development and color display of graphical information in a graphic CRT display device, Figures 5A and 5B are diagrams for explaining coordinate values in the symbol definition space, and Figure 6A and Figure 6B
FIG. 2 is an explanatory diagram of conventional positional deviation with respect to the present invention. 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.

Claims (1)

[Claims] 1 The graphic information registered in the segment buffer is expanded into bits in the frame buffer and displayed on the CRT monitor, and the display processor processes multiple graphic information in the graphic display area set within the coordinate space of the segment buffer. In a graphic display device that cuts out graphic information according to the overall scale conversion rate and scales and displays each of the extracted graphic information according to the individual scale conversion rate, the coordinate values of each line segment information for drawing a symbol are defined as the definition of the symbol. The center of the space is set as a reference point and the distance from the reference point is set, and the actual data of the symbol is the overall scale conversion rate multiplied by the coordinate value of the reference point and the individual scale conversion rate multiplied by the distance between the reference point and each line segment information. A graphic display device characterized in that a value is obtained by calculation using a computer.