JPH02309460A - Method for plotting graphic - Google Patents

Abstract

PURPOSE:To make it unnecessary to use a memory for a temporary storage area and to increase an expansion plotting speed by finding out the expanding center point of a graphic, dividing the graphic into plural parts by straight lines passing the center point and expansively plotting each divided graphic part. CONSTITUTION:In the case of obtaining expanded graphic data A by expanding the original graphic data a in the overlapped state to the original position, the intersecting point, i.e. the expanding center point O, of straight lines p to s connecting respective vertexes of the original graphic data a to respective vertexes of the expanded graphic data A is found out and a two-dimensional coordinate axes (x and Y axes) defining the intersecting point O as its origin is formed. Then, graphic data parts aI to aIV included in the Ith to IVth quadrants are respectively expansively plotted. Consequently, expansive plotting is attained without using a primary storage area and its rapid processing is attained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a graphic drawing method for enlarging and drawing an original graphic on the same display screen.

[Conventional technology]

FIG. 6 is an explanatory diagram of a conventional graphic drawing method.

Now, when drawing the figure data a shown by the solid line in FIG. 6(a) by enlarging it into a figure A as shown by the broken line with its drawing area overlapping, if the figure data a is simply enlarged as it is, the figure Data a, and thus also graphic data A, may be damaged. For this reason, usually, the graphic data a is temporarily transferred to a temporary storage area as shown in FIG. The graphic data a in this temporary storage area is enlarged and transferred to the transfer destination, or the graphic data A is transferred as is, and the graphic data a is enlarged to the graphic data A and drawn.

[Problem to be solved by the invention]

By the way, in the conventional method as described above, the graphic data a
is transferred to the temporary storage area and then transferred again to the destination location, so two processing steps are required, which inevitably reduces execution speed and also reduces the amount of memory available for the temporary storage area. There were problems such as increased usage burden.

The present invention has been made in consideration of such circumstances, and its purpose is to make it unnecessary to use memory for a temporary storage area, and to speed up the execution speed of enlarged drawing. To provide a graphic drawing method.

[Means to solve the problem]

The figure drawing method according to the present invention calculates the enlarged center point of the figure,
The figure is divided into a plurality of parts by a straight line passing through this center point, and each divided figure part is enlarged and drawn.

[Effect]

According to the present invention, it is thereby possible to prevent the original graphic data and the enlarged graphic data from being drawn at the same time, and damage to the graphic data due to enlarged drawing does not occur.

[Examples] The present invention will be specifically described below based on drawings showing examples thereof.

1 to 3 are explanatory diagrams showing the main steps of the method of the present invention. First, when trying to obtain enlarged graphic data A as shown by the broken line by enlarging the original graphic data a shown by the solid line in FIG. 1 while overlapping this position, each vertex of the original graphic data a is A straight line p+q1r connecting the vertices and each vertex of the enlarged figure data A, and a straight line p+q+r+
Find the intersection O of S.

This intersection O is an expansion center point for expanding the original graphic data a to enlarged graphic data A.

Next, as shown in Figure 2, create a two-dimensional coordinate axis (for example, the horizontal axis is the y-axis and the vertical axis is the y-axis) with the intersection point O as the origin, and divide it along the y-axis and the y-axis to create each quadrant r, n. .

Figure data part a l+ a II included in m, ■
l a llI+alV, and looking at each quadrant, for example, the first quadrant, as shown in FIG. obtain.

Similarly, for the n-th, I[I', and IV quadrants, the graphic data portion a1 included in each quadrant. .

a IIl, a IV are enlarged and drawn to produce enlarged figure data portions A,, AH□1. as shown in FIG. Get AH.

FIG. 4 is a flowchart showing the main steps of the method of the present invention, in which a straight line p+q+r+S connecting corresponding vertices of the original graphic data a and the enlarged graphic data A as shown in FIG.
Find the center point O, which is the intersection of
Graphic data portion aI+a! included in each quadrant! l+
Enlarged drawing is performed for each all+aIV (step S3).

FIG. 5 is a flowchart showing details of enlarged drawing,
First, the graphic data parts a+, a included in each quadrant I~■
The maximum and minimum values of the X and Y coordinates of each vertex are determined for ++, a++++a+v (step 511). For example, in the case of quadrant ■ shown in Fig. 3, the X coordinate value XI + Xt + 1 coordinate value:)' +
The maximum value of +y2 is X7. y I and the minimum value is χ2. y
It is 2.

Next, for example, it is determined whether or not X≧χ2 for the maximum value X and the minimum value XZ in the X coordinate value (Step 512)
, when X1≧X2, the process ends, and when x1≧Xt, from the coordinate point (x l+ y +) to (X,.

yz), the graphic is expanded in the vertical direction (step 513). For example, the data of one column or a plurality of parts (for example, vertical scanning lines) of memory cells in the vertical direction is taken as one unit and is enlarged and drawn. 1 is subtracted from the X-axis coordinate value X1 (step 514), and it is determined again in step 512 whether X1≧X2, and the above-described process is repeated.

As a result, from the coordinate point (X+, y+) side to the coordinate point (X2
Enlarged drawing is performed multiple times toward the °y+) side and ends when X1≧X2 is no longer satisfied, in other words, when enlarged drawing is performed to (χz+Y+).

Note that in the above embodiment, a configuration was explained in which the original graphic data a is divided into the y-axis and the y-axis of a two-dimensional coordinate system.
For example, p in FIG. 1 is not limited to this.

It may also be divided by q, r, s straight lines.

Furthermore, in the above-described embodiment, a case has been described in which data in the vertical direction is enlarged and drawn for each unit, but the invention is not limited to this. For example, data in the horizontal direction may be enlarged and drawn for each unit or multiple units. Needless to say, it is a good thing.

Furthermore, one unit is not limited to one column of memory cells, but it goes without saying that one unit may include multiple columns or multiple rows.

[Effects of the Invention] As described above, in the method of the present invention, even when the original graphic data and enlarged graphic data overlap, it is possible to perform enlarged drawing without using a temporary storage area, thereby speeding up the processing. The present invention has excellent effects such as being able to achieve the following.

[Brief explanation of drawings]

1 to 3 are explanatory diagrams showing the main steps of the method of the present invention,
4 and 5 are flowcharts showing the main steps of the method of the present invention, and FIG. 6 is an explanatory diagram showing the main steps of the conventional method. a...Original figure data A...Enlarged figure data p
, q, r, s...straight line In the drawings, the same reference numerals indicate the same or equivalent parts. Agent Masuo Oiwa 1st
Diagram 2 Diagram ■ Diagram 3 Condolence 4 Diagram 5

Claims (1)

[Claims] (1) In a method of drawing enlarged figure data in a state where it overlaps with the original figure data, there is a process of finding an enlargement center point based on the original figure data and the enlarged figure data, and a process through which the enlarged center point is drawn. A figure drawing method comprising the steps of dividing an original figure into a plurality of figure parts along straight lines, and enlarging and drawing each divided figure part.