JPS615285A - Raster scan graphic display unit - 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 (Field of Application) The present invention relates to a raster scan graphic display device, and more particularly to a raster scan graphic display device in which the end points of thick lines are rounded.

(Prior art) Each dot (
In raster scan graphic display devices, which have a mechanism to display thick lines by adding dots (black dots) in the X-axis direction or y-axis direction by the width of the dots (shaded dots), The end points will be angled as shown. If a figure is drawn using a plurality of such thick lines with angles at their end points and the center lines of the thick lines are continuous, the connecting portions between the thick lines will become unnatural. For example, if you use thick lines 18 to 1d as shown in Figure 2 and draw a parallelogram or the number "0" so that their center lines (shown as tangents) are continuous, , its corner part 28-2
A hollow valve is formed at d, resulting in an unnatural shape.

As described above, the conventional raster scan graphic display device has a drawback in that when a figure is drawn using thick lines, the joints of the thick lines become unnatural.

(Objective) An object of the present invention is to eliminate the drawbacks of the prior art described above, provide a raster scan graphic display device that can display high-quality thick lines, and provides an end point dot generation circuit that generates dots that add roundness to the end points of thick lines. Our goal is to provide the following.

(R required) In order to achieve the above object, the present invention provides a mechanism for displaying a thick line by adding dots corresponding to the width in the X-axis direction or Y-axis direction to each dot on the center line of the thick line. In a raster scan graphic display device with
It is equipped with a circle generation circuit that outputs the coordinates of the circumference from the coordinates of the end points of the thick line and the width information, and an end point dot generation circuit that extracts the coordinates included in the circumference from the coordinates of the circumference. It is distinctive in that it is rounded.

(Example) The present invention will be described in detail below with reference to the drawings.

FIG. 3 is a block diagram of one embodiment of the present invention.

In the figure, reference numeral 1 denotes a vector generating circuit which generates a dot array of a line segment connecting the starting point coordinate a and the ending point coordinate S when the starting point coordinate A and the ending point coordinate S are given.

Note that this vector generation circuit is readily known.

2b shows a direction determination circuit. This direction determination circuit 2 calculates the starting point coordinate a that is now input to the circuit 2 (Xr, Y+
), the end point coordinates are (X2, Y2), the coordinates (Xl, Yl) and (x2゜Y2), the X component of the straight line △X (= I XlX21>, the Y component △Y
Calculate (=lYI Y21). And ΔX≧△
In the case of Y, the direction information signal e is set to a high level to indicate that a width dot is to be added in the Y-axis direction, and on the other hand, in the case of △X<△Y, to indicate that a width dot is to be added in the X-axis direction, The direction information signal e is set to a low level, and the direction information signal is outputted to the width dot generation circuit 3.

The width dot generation circuit 3 receives the direction information signal e, the width information W, and the dot coordinates (Ox, DV) from the vector generation circuit 1.
) group as input, and when the direction information signal e is at a high level, each dot coordinate (Dx, , Dy) from the vector generation circuit 1 is input.
±W in the Y-axis direction centered on (Dx, Dy)
/2 dots, that is, dot coordinates (DX, DV-W
/2), (DX.

The dot row between DV+W/2) is turned on and written to the address corresponding to the coordinates of the dot in the video memory 4.

When the direction information signal e is low level, the dot coordinates (Dx
, ay) in the X-axis direction, that is, the dot coordinates (Dx-W/2.Dy).

The dot row between (D'x + W/2. DV) is turned on and written to the address corresponding to the coordinates of the dot in the video memory 4.

A video memory 4 stores, for example, data "1" at an address corresponding to the output signal of the width dot generation circuit 3;
is an indicator.

When the vector generation circuit 1, direction determination circuit 2 and width dot generation circuit 3 are used, the coordinate (Xl).

A line segment of width W can be drawn with the starting point at the coordinates (Xz, Yz) and the ending point at the coordinates (Xz, Yz). This device for creating line segments was invented by the present inventor and a patent application has been filed, and the details thereof are described in detail in the specification of the patent application, so a detailed explanation will be omitted.

6 is a circle generation circuit, which calculates the center of each of the starting point and ending point of the line segment from (Xl, Yz) and (X2, Y2), respectively, from the starting point coordinate a, the ending point coordinate, and the width information W.
Then, draw a circle with a radius of W/2. This circle generating circuit 6
Since this is already known, detailed explanation will be omitted. The circle generating circuit 6 outputs the coordinates (Xc, Yc) of a dot on the circumference.

7 is an end point dot generation circuit, and this 7 has the coordinates (X
c, Yc) is input. The end point dot generation circuit functions to fill in black the inside of the circle formed by the coordinates (X, c, Yc).

By using the circle generating circuit 6 and the endpoint dot generating circuit 7, it is possible to obtain a line segment with rounded endpoints as shown in FIG. 4, for example.

Next, a specific example of the end point dot generation circuit 7 will be explained. Since this circuit is advantageously processed by software using a microcomputer or the like, its functions will be explained with reference to the flowchart of FIG. 5 and FIG. 6.

Step S1: Clear the value C of a certain counter to 0.

Step S2: Coordinates (Xc) of the dot on the circumference.

The maximum value and minimum value are extracted from the X coordinate XC of Y'c). The maximum value is assumed to be Xl1la×, and the minimum value is assumed to be Xl1in (see FIG. 6).

Step S3: Add C to the minimum value X min to obtain Xo.

Step S4: Extract the maximum and minimum values of the Y coordinate, where the X coordinate is Xo, from the above (Xc, Yc). Let the maximum value be Yn+ax and the minimum value Y min (see FIG. 6).

Step S5...Coordinates (Xo, Ymax)
, (Xo.

Ymax -1), (Xo, Ymax -2
> , -...(Xo, Ymin) (6th
Figure number ff1) is output to the video memory 4. This makes the X coordinate within the circumference (Xc, Yc) X. All Y coordinates are extracted.

Step S6... Add 1 to the above C.

Step S7: It is determined whether Xo is equal to Xmax. If no, the process returns to step S3; if yes, the process ends.

Using this example, when drawing a figure similar to that shown in Fig. 2, the figure 7.
As shown in the figure, a good figure with rounded end points 2a to 2d of the thick line is obtained. In addition, when obtaining this figure, the data to be input into the cooking process of this embodiment are the coordinates (Xa, Ya) of the end points of the center lines of the thick lines 1a, lb, lc, and 1d, (Xa
, Ya>, (X6.

Ys ) and (X6.Ye ), and the thick line 18 to 1d
Only the width information is required.

(Effects) As is clear from the above description, according to the present invention, the following effects are achieved.

(1) Since the end points of thick lines can be rounded, especially when creating a figure by combining thick lines, the joints become natural and a high-quality figure can be obtained.

('2J) When you want to display an arbitrary figure by combining thick lines, you only need to input the coordinates of the end points of the center lines of the thick lines forming the figure and the width information of the thick lines, so the operation is easy.

[Brief Description of the Drawings] Fig. 1 is a diagram showing an example of a thick line display created by a conventional thick line display mechanism, and Fig. 2 is a pattern diagram when a parallelogram or "0" is displayed by the conventional mechanism. , FIG. 3 is a block diagram of one embodiment of the present invention, FIG. 4 is a pattern diagram showing an example of a thick line created by this embodiment, and FIG. 5 shows the function of the end point dot generation circuit of FIG. 3. FIG. 6 is an explanatory diagram of the 70-diameter shown in FIG. 5, and FIG. 7 is a diagram of the pattern shown in FIG. 2 formed according to this embodiment. 1... Vector generation circuit, 2... Direction determination circuit, 3
゛...Width dot generation circuit, 4...Video memory, 5...Display device, °6...Circle generation circuit, 7...End point dot generation circuit, Representative Patent Attorney Enter Hiraki Outside 1 Figure 1 Figure 2 Figure 3 Figure 5 Figure 6 Figure 7

Claims (1)

[Claims] (1) For each dot on the thick center line, in the x-axis direction or y-axis direction
In a raster scan graphic display device having a mechanism for displaying a thick line by adding dots equal to the width in the axial direction, a circle generating circuit outputs the coordinates of the circumference from the coordinates of the end points of the thick line and the width information, and A raster scan graphic display device comprising an end point dot generation circuit for extracting coordinates contained within a circumference from coordinates of the circumference, and rounding end points of thick lines.