JPS63234368A - Circle/circular arc generating system for free line width - Google Patents

Abstract

PURPOSE:To produce a circle or a circular arc of the free line width at a high speed by calculating the outside and inside circle/circular arc coordinates from the circle/circular arc graphic data and producing a pixel corresponding a vector which is orthogonal to the circle/circular arc with the due line width. CONSTITUTION:The coordinate value of a point on the most outside circumference of a circle or a circular arc indicated by the graphic data is calculated by a differential analyzer DDT5 of a circular arc generating module 4. While the coordinate value of a point on the most inside circumference is calculated by a line width vector calculation module 6. Then a command is sent to a vector generating processor 9 in a picture data generating processor 7 for each generation of a single point. A pixel train is drawn by the processor 9 and a pixel generator 10 by an extent equal to the line width toward the center of a circle or a circular arc from said generated point. This drawing process is repeated until a circle or a circular arc of line width '1' forming the utmost outside of a desired circle or circular arc is completed. Thus a circle or a circular arc of the free line width can be produced at a high speed.

Description

Detailed Description of the Invention [Summary] When generating a circle or arc with a free line width in graphical display on a graphics display device, a circle or arc with a line width of 1 is generated with a radius of °l. In order to solve the slow processing speed of the method that repeatedly generates data while changing the ratio, we use a digital differential analyzer (ODA) to calculate only the coordinates of the point on the outermost circumference and the line width bone. Find the coordinates of the point on the inner circumference, and calculate the vector of the line width bone length that intersects the point on the inner circumference from the outermost point j of the circumference toward the center. Draw a circle of free line width by generating pixels on the vector.

Or, it is designed to generate a circular arc.

[Industrial application field]

The present invention relates to a method for generating circles/arcs in a graphics display device equipped with a vector generation processor, and in particular, to a circle having a free line width.

Or related to the generation method of circular arcs.

As is well known, graphics display devices are currently manufactured using computer-aided design (CAD)/computer-aided manufacturing (CAM).
), it is used in all industrial fields, and its applications are diverse.

In particular, when creating design drawings using CAD/CAM, the operator interactively operates the graphics display device to enlarge or reduce the screen.
A method is required to quickly generate circles and single arcs with arbitrary line widths.

[Prior art and problems to be solved by the invention] Fig. 3 is a diagram showing a configuration example of the conventional circle/arc generation method, and Fig. 4 is a diagram showing a configuration example of the conventional circle/arc generation method. It is a figure explaining a process.

Conventionally, for example, when generating a circle/arc with a line width of n, the ODA module 5 included in the graphic calculation processor 3 of the graphics display device calculates the coordinates of a point on the circle or arc with a line width of 1. , and for each point,
In the pixel generator 10 of the image data generation processor 7
The process of generating a 1" pixel and writing it to the corresponding address of the image data memory 11 to generate a circle or 9 arc with a line width of 1 is performed by increasing or decreasing the radius of the circle or arc by 1". However, it was repeated 0 times.

In the end, the graphic calculation processor 3 found the position coordinates of all the pixels forming a circle or arc of the desired line width.

The process of this conventional method is shown in Figure 4.
■It is. ■ in this figure is an example of generating an arc with a line width of 5. Here, . and ○ are pixels generated by the pixel generator IO.

Therefore, in the conventional method of repeatedly generating circles or arcs with a line width of 1 using only the graphic processing calculation processor 3, the thicker the line width, the greater the amount of calculation in the graphic processing calculation processor 3. However, there has been a problem in that it takes time to complete the generation of a circle or arc with a desired line width.

In view of the above-mentioned conventional drawbacks, the present invention focuses on the fact that a graphics display device is equipped with a vector generation processor, and an object of the present invention is to provide a method for rapidly generating a circle or arc of a free line width. It is something to do.

[Means for solving problems]

FIG. 1 is a diagram showing an example of the configuration of a free line width circle/arc generation method according to the present invention.

In the present invention, at least a graphic processing calculation processor 3, a command queue 8, and a vector generation processor 9.

In a graphics display device equipped with both an image data generation processor 7 having a pixel generator 10, coordinates of an outer circle/arc and an inner circle/arc are calculated from externally given circle/arc figure data. a first means 4; and a second means for generating pixels perpendicular to the circle/arc and corresponding to the line width vector obtained from the graphic data based on the calculation result of the first means 4. Means 8, 9.1
0, and based on the first means 4 and the second means 8.9.10, a circle/arc having a line width specified by the graphic data is generated.

[Effect]

That is, according to the present invention, in a figure display on a graphics display device, a circle with a free line width,
Or, when generating a circular arc, in order to solve the processing slowness of the method of repeatedly generating circles or circular arcs with a line width of 1 while changing the radius by 1°, we used a digital differential analyzer (ODA). ), the coordinates of the point on the outermost circumference and
Find the coordinates of a point on the circumference that is inside by the line width, and move from the outermost point on the circumference toward the center and intersect with the point on the inner circumference for the line width. Subtract the vector of length,
By generating pixels on the vector, a circle or arc with a free line width is generated. It is limited to the coordinate calculation of each point and the coordinate calculation of a point moved by the line width from that point toward the center of the circumference, and the vector between the two points and the occurrence of pixels on that vector are image data generation It can be executed in parallel by a processor, the amount of processing by the graphic processing calculation processor is reduced, and circles and arcs with arbitrary line widths can be generated at high speed.

〔Example〕

Embodiments of the present invention will be described in detail below with reference to the drawings.

The above-mentioned FIG. 1 is a diagram showing an example of the configuration of the free line width circle/arc generation method according to the present invention, and FIG. 2 is a diagram explaining the process of the circle/arc generation method according to the present invention. The line width vector calculation module 6 and vector generation processor 9 in FIG. 1 are the means necessary to implement the present invention.
Like numbers refer to like objects throughout the design.

Hereinafter, the circle/arc generation method of the present invention with free line width will be explained with reference to FIGS. 1 and 2.

First, when the interface control processor 1 receives an element data output command (command for processing graphic data) from a host computer (not shown), the graphic data added to the command is stored in the graphic data memory 2. At the same time, the graphic calculation processor 3 is activated.

When the graphic calculation processor 3 receives graphic data (see FIG. 2--) instructing generation of a circle or arc from the graphic data memory 2, control is passed to the arc generating module 4t.

Arc generation module 4 smell is ODA module 5
A digital differential analyzer (ODA) 5 calculates the coordinates of the point on the outermost circumference of the circle or arc specified by the above figure data, and a line width vector calculation module 6
Pass the coordinates to .

In the line width vector calculation module 6, the specified line width and
Calculates the coordinates of the innermost point on the circumference that corresponds to the passed coordinates.

The graphic calculation processor 3 is the outermost part.

Every time the innermost point is calculated, the other point is set as the starting point,
A command requesting the generation of a vector as the end point is sequentially sent to the image data generation processor 7.

In the image data generation processor 7, the received vector commands are queued in a command queue 8, and one of them is taken out and sent to the vector generation processor 9.

The vector generation processor 9 generates a vector between the two points, and the pixel corresponding to the vector is transferred to the pixel generator 1.
0 is generated and the pixel data is written to the corresponding address in the image data memory 11.

The image data in the image data memory 11 is displayed on the screen of a display device (CRT) 13 by a CRT control processor 12 .

Below, the line width is 5. The process for generating a circular arc with a radius of 15 (see FIG. 2--) will be explained step by step with reference to FIG.

First, for the circle (line width 5. radius 15. center (p, q)) specified by the graphic data shown in FIG.
A module 5 has a radius of 15. The position coordinates (☆) of a point R1 on the arc with a line width of 1 are calculated using a digital differential analyzer (ODA).

(See Figure 2-■) Next, the line width vector calculation module 6 calculates a line segment drawn from the above point R1 to the center point (ne) and a radius of 11. The positional coordinates (★) of the intersection point S1 with the circle having a line width of 1 are determined by a known similarity calculation.

(See Figure 2-■) The graphic processing calculation processor 3 sends a command to the image data generation processor 7 to generate a vector (pixel string) between R1 and SL, and Generate a vector. (Refer to the second figure - ■) The image data generation processor 7 queues the above command in the command queue 8 and then causes the vector generation processor 9 to process it. The next command is sent to the image data generation processor 7 without waiting for the completion of command processing.

Thereafter, in the same manner, the graphic calculation processor 3 uses the digital differential analyzer (ODA) to calculate points (R2, S2), (R3, S3), . . . on the arc by similarity calculation.
By repeating the calculation of the position coordinates of (Rt l Sl) + '-' + (Rk, sk) and sending the command to the 9 image data generation processor 7 (see Figure 2-〇~■), the target line is Complete the generation of the width arc. (See Figure 2-■) As described above, the present invention allows a graphics display device to generate a circle or an arc with a free line width by using a graphic processing calculation processor that takes the line width into consideration. A circle with a line width of 1 that forms the outermost part of the circle/arc in the case,
Or calculate the coordinates of points on the arc using a digital differential analyzer (ODA).
), find the intersection between the straight line connecting that point and the center point of the circumference and the circle or arc with a line width of 1 forming the second innermost part by similarity calculation, and use the digital differential analyzer (ODA) Each time a point is generated, a command is sent from the graphic processing calculation processor to the vector generation processor in the graphic data generation processor, and from that point, a pixel string corresponding to the line width is generated as a vector toward the center of the circle or arc. The process of repeating drawing by the generation processor and pixel generator is
The target circle.

The feature is that a circle with a line width of 1, or a circle with a line width of 1 forming the outermost part of the circular arc, or a circle with a free line width, or a circular arc, is generated until the circular arc is completed.

〔Effect of the invention〕

As explained above in detail, the free line width circle/
The arc generation method is used to generate a circle or arc with a line width of 1 when displaying a figure on a graphics display device.
In order to solve the slowness of processing in the method of repeatedly generating data while changing it by 1 degree, we used a digital differential analyzer (O
DA), find the coordinates of the point on the outermost circumference and the coordinates of the point on the circumference that is inside by the line width, and move from the point on the outermost circumference toward the center. Then, by drawing a vector with a length equal to the line width that intersects with the point on the inner circumference, and generating pixels on the vector, a circle or arc with a free line width is generated. Because it is a thing,
The processing of the graphic processing calculation processor is limited to the coordinate calculation of each point on a circle or arc with a line width of 1, and the coordinate calculation of a point moved from that point in the direction of the center of the circumference by the line width, The generation of the vector between the two points and the pixels on the vector can be executed in parallel by the image data generation processor, which reduces the processing load of the graphic processing calculation processor and enables high-speed creation of circles and arcs with arbitrary line widths. There are effects that can be generated.

[Brief explanation of drawings]

FIG. 1 is a diagram showing an example of the configuration of a free line width circle/arc generation method according to the present invention. FIG. 2 is a diagram explaining the process of the circle/arc generation method according to the present invention. FIG. 3 is a diagram showing a configuration example of a conventional circle/arc generation method. FIG. 4 is a diagram explaining the process of the conventional circle/arc generation method. It is. In the drawings, 1 is an interface control processor. 2 is a figure data memory. 3 is a graphic calculation processor. 4 is an arc generation module. 5 is the ODA module. 6 is a line width vector calculation module. 7 is an image data generation processor. 8 is the command queue. 9 is a vector generation processor. 10 is a pixel generator, and 11 is an image data memory. 12 is a CR7811m processor. 13 is a display device (CRT).・、○ is a pixel. R1, SL, - are the positions on the circle/arc.

Claims (1)

[Claims] An image data generation processor (7) having at least a graphics processing calculation processor (3), a command queue (8), a vector generation processor (9), and a pixel generator (10). , a first means (4) for calculating the coordinates of an outer circle/arc and an inner circle/arc from externally given circle/arc graphic data; Based on the calculation result of the means (4), a second means (8, 9
, 10), and the first means (4) and the second means (8, 9, 10).
A circle/arc generation method with a free line width, characterized in that a circle/arc with a line width specified by the graphic data is generated based on the figure data.