JPS61158394A - Fast circle circular arc generation system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method of generating a circle or an arc. This invention relates to a high-speed single-circle-arc generation method that generates a circle or arc that is stored in a circular table and corrected using a circular pattern.

[Conventional technology]

Conventionally, one method for generating 9 circles or circular arcs is the regular polygon approximation method, which determines the value of the radius according to the radius, approximates the circle to a regular polygon, and finds the dot closest to each vertex. It selects and generates a vector. Another method is to calculate the difference between the current coordinate point and the next coordinate point according to the radius and sequentially draw the drawing using hardware.

[Problem that the invention seeks to solve]

This type of generation method for 9 arcs of circles [, Figure 6 (Gi (6)
, (a) have radii of 25 dots and 55 dots, respectively.

This is an example of a small circle of 5 dots. That is, using the above-mentioned correct answer polygon method, the intersection of the 16th equisector and the circumference 1 is calculated to obtain an approximate value by rounding off, and the dot in the area reached is selected.

As a result, in (α) and (6) of the same figure, there is a drawback that the dots 2' protrude outward and the shapes become squares and rhombuses. In the figure (C), since the white dots 2 divided into 16 equal parts by regular n-polygon approximation are too wide, in order to fill in the gaps, diagonal dots 3 are obtained and complemented using a difference calculation method using hardware.

In this case, there arises a drawback that the diagonal dots 3 are not symmetrical horizontally and vertically as shown.

The purpose of the present invention is to eliminate deformation caused by equal division intersection approximation of a small circle with a radius of less than 16 dots, for example, by storing it in a circular table and generating arcs using the next pattern. Our goal is to provide the following.

[Means for solving problems]

In order to achieve the above object, the high-speed two-circle-arc generation method of the present invention has a graphic data memory storing graphic data including at least circle or arc data, and sends the graphic data to a vector generator to perform the required drawing. In the graphic processing device, a circular table is provided in the graphic data memory in which pattern data indicating coordinate points on the circumference of circles or arcs with a predetermined radius or less is stored corresponding to each radius value, and The present invention is characterized in that when the circular table is detected, the circular table is used.

[For production]

As shown, when observed with the human eye, the roundness is greatly impaired. Therefore, pattern data having the coordinates of the dot that is most likely to be a perfect circle is stored in a circular table in the graphic data memory, and the next time a small circle is detected, this data is read out and drawn. Even for small circles, it is possible to always draw an approximate circle that looks like a perfect circle.

In this case, there are not many types of small circles that are normally used, so
The storage capacity of the round table is also not a big burden.

〔Example〕

FIGS. 1(G) and 1(6) are diagrams explaining the principle of an embodiment of the present invention.

The figure shows nine small circles with a radius of 55 dots, and the sixth
This corresponds to the conventional example shown in Figure (6). Each of the points 0 to 25 has a displacement ΔX and ΔY from the center on a circular table, which will be described later. Naturally, each point is placed on a dot, and these points are successively connected by vectors and selected so as to most closely approximate a perfect circle. However, the maximum point between the starting point and the ending point of the vector is one dot, and when the vector is generated by hardware between the three points S, A, and S5+1 as shown in (6) of the same figure, A There is no need for points; it is sufficient to place only 5 and s+1 on the round table. In this way, an approximate circle can be realized with a minimum number of coordinates.

FIG. 2 is an explanatory diagram of an embodiment of a graphic processing apparatus to which the present invention is applied.

In the same figure, the graphic data memory 12. The control memory 13 and the graphic processing section are controlled.

Furthermore, it is connected to a host (upper-level device) via an interface circuit 11.

That is, the processor 10 calculates the intersection point from the center and radius of the circle or arc and the equal division number data from the figure data 11 and 12 in the normal case based on the control memory 130 program. , the obtained values and the selected dot coordinates are sent to the graphic control circuit 14 in the graphic generating circuit 20, a vector between the dot coordinates is generated in the vector generating circuit 15, and this vector data is designated by the address pointer 16. (Sent to memory control circuit 17 along with the address)
, The image is developed on the image screen 18 under this control.

The image signals on this image grid 18 are connected in parallel (P/8).
It is sent to the 0RT 21 via the conversion circuit 19 and displayed on the screen.

The above is a case of a conventional figure that includes two circles, two arcs, etc., but in the present invention, if the radius of one circle is 16 dots or less, the processor 10 detects this and stores the figure data in the figure data memory. In step 12, the coordinate data pattern of the dots indicated by ΔX and ΔY explained in FIG. It is something that generates.

FIG. 5 shows a circular table 12 which is the main part of the present invention in the embodiment shown in FIG. FIG.

In the same figure, the first five areas are the table of contents area (word), and the first area is the length of the circular table starting from ■■
However, it is possible to jump to another area with the final pointer +1. Further, in the second to fourth areas, it is possible to jump to the beginning of the corresponding quadrant of the coordinate data stored below by using the beginning pointer of the 0th quadrant to the 3rd quadrant. The coordinate data corresponds to the first factor -) OlsuL#2. . . , ΔX and ΔY are stored as bit codes.

This coordinate data is read out and sent to the vector generator 15.
Vectors such as -1, 1-2, 2-5 degrees, etc. are generated.

The above is a case in which a perfect circle is generated. Next, a case in which a fan-shaped arc is generated will be explained.

In this case, the starting point and ending point of the arc are generally set on the circular table 1210.
Since it does not necessarily match the m mark, first, the coordinates ΔX, ΔYt-8ijl from the center of the starting point and ending point of the arc are extracted using the □□□ table.

Find the quadrants of the starting point and ending point of this arc, and
A table search for the corresponding quadrant of
and E is detected.

The magnitude relationship of ΔX and ΔY of the circular table is as follows depending on the quadrant.

0th quadrant ΔXs≧ΔXs+t 1st quadrant Δn≧ΔX
ll1+1ΔY%≦ΔYs+t
ΔY co≧ΔYs ten in the second quadrant ΔX%≦ΔX3+1
3rd quadrant ΔX≦ΔXs+1ΔY, ≧ΔY, ten or so
ΔY-≦-hY%+1 Therefore, in the case of a circular arc, a vector is added that connects both ends of the pattern data of the coordinate points of the circular table interposed between the circular arc starting point and the ending point with the circular arc starting point and ending point.

Figure 4 shows the procedure for a circular arc. After drawing the vector from the starting point of the circular arc to the table starting point (S),
Generate an arc from Na S to E using a circular table.

Nai! When the arc is completed, a circular arc of type 1 can be realized by generating a vector from E to the end point of the arc.

FIG. 5 is a flowchart showing the operation of the embodiment of the present invention.

In the same figure, if the radius of the circle is close to the processor, the radius is 1.
If there are 6 pits or less, the following procedure starts.

First, check whether the circle is a perfect circle, and if it is a perfect circle, draw a vector from 0 in the O quadrant of the circular table t21 to the 2nd stroke in the 3rd quadrant, and further draw a vector from this gap to 0. finish.

If it is not a perfect circle, it is an arc, so extract the quadrant of the starting point of the arc and calculate ΔX and Δy'ts from the center of the starting point of the arc.

Then, search the circular table in the corresponding quadrant, extract the table starting point (#S), and change the arc starting point to the table starting point (#S).
).

Next, calculate ΔX and ΔY from the center of the arc end point, search the circular table in the corresponding quadrant, and find the table end point (suE).
Extract. Then, vectors are drawn sequentially from the table start point (S) to the table end point (SE), and further vectors are drawn from the table end point (#Fi) to the arc end point.

〔Effect of the invention〕

As explained above, according to the present invention, pattern data whose coordinates are the dots that are most likely to be a perfect circle are stored in a circular table, without using the method of calculating and rounding off equal division points in a small circle. By reading and plotting, it is possible to easily obtain nine arcs of circles with a small radius and a well-shaped shape at high speed.

[Brief explanation of drawings]

Figure 1 Ca), (6) is a diagram explaining the principle of the present invention, Figure 2
FIG. 3 is a configuration explanatory diagram of an embodiment to which the present invention is applied. FIG. 4 is a detailed explanatory diagram of the main parts of the embodiment, FIG. 5 is a flowchart showing the operation of the embodiment, and FIGS. 6-) to (a) are explanatory diagrams of the prior art). 12 is a graphic data memory, 121 is a circular table, 13 is a control memory, 14 is a graphic control circuit, 15 is a vector generation circuit, 16 is an address pointer, 17 is a memory control circuit, 18 is an image memory, and 19 is a parallel-to-serial conversion circuit. , 20 is a graphic generation circuit, and 21 is a CRT.

Claims (2)

[Claims] (1) In a graphic processing device that has a graphic data memory storing graphic data including at least circle or arc data, and sends the graphic data to a vector generator to create a desired drawing, the graphic data memory stores a predetermined radius or less. A circular table is provided in which pattern data indicated by coordinate points on the circumference of a circle or arc is stored corresponding to each radius value, and the circular table is used when a circle or arc with a small radius is detected. High-speed circle and arc generation method. (2) The scope of the present invention is characterized in that, for the circular arc of the small radius, both ends of the pattern data of the circular table interposed between the starting point and the ending point of the circular arc are connected to the starting point and the ending point. High-speed circle and arc generation method described in Section 1.