JPS61267096A - Smear drawing display unit for polygonal graphic - 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 the Invention The present invention relates to a graphic drawing display function of a raster scan type display device having a graphic display function among graphic drawing display devices. The present invention relates to a display device that performs color filling.

Conventional technology The conventional method for filling in polygonal figures involves first writing the contour line connecting the vertices into a work memory with the same number of dots as the refresh memory, and then setting the vertices within the polygon drawn on the work memory. The outline of the polygon drawn on the work memory is referenced and the specified line type is sequentially written on the refresh memory using a certain processing procedure, and the addresses of branch points that occur during processing are saved in the built-in stack. There is a method in which a specified area on the refresh memory is sequentially filled in again by a certain processing procedure using each branch point saved in the stack as a base point. This method requires a work memory of the same size as the refresh memory, and has the disadvantage that the processing time required to detect a branch point is longer.

Another method is to find the intersection between two sides of the polygon's outline and a straight line in the horizontal axis direction passing through the dividing vertex, divide the polygon into triangular or trapezoidal parts, and then divide the polygon into triangular or trapezoidal parts. There is a method to fill in the interior of a polygon by filling in the . In this method, when cutting out a polygonal figure as shown in FIG. 4(a), in the first division shown in FIG. 4(a), the outline E1 and the vertex T2 to be divided are
When calculating the coordinates of the intersection point C1 with a straight line in the horizontal axis direction passing through the line and the intersection point C2 between the contour E2 and the straight line, the intersection points do not coincide with the contour due to a calculation error, as shown in FIG. 4 (b), for example. , the vertex T1 and the intersection 01'.

The triangle enclosed by C2' may be split.

In such a case, if the image is divided into triangular or trapezoidal parts and each part is filled in, a polygonal figure as shown in FIG. 6 is filled in. (For example, “PIXEL
J, /I61 B, pages 129-133. ) Problems to be Solved by the Invention In such conventional methods, the outline of the polygon becomes discontinuous at the positions where the polygonal figure is divided into triangular or trapezoidal parts, and the outline of the polygon that has been filled in is However, there was a problem in that it was damaged.

In view of the above-mentioned problems, the present invention provides a polygonal figure filling method that uses a new processing method to prevent the outline of the polygon at the divided positions from becoming discontinuous when filling in a polygonal figure whose vertices are specified. This is what we provide.

Means to solve the problem In order to solve the above problem, a polygon figure with specified vertices is surrounded by two sides of the outline of the polygon figure and a straight line in the horizontal axis direction passing through the vertices to be divided. When dividing the polygon into triangular or trapezoidal parts and filling in the triangular or trapezoidal part, specify the vertex coordinates of both ends of the first and second outlines of the outline of the polygonal figure using the horizontal axis coordinate and the vertical axis coordinate, When the coordinates of a straight line parallel to the dividing line are specified as vertical axis coordinates, the horizontal coordinates corresponding to the vertical axis coordinates of the straight line parallel to the dividing line are calculated from the coordinates of the vertices at both ends of the first contour using a straight line approximation formula. a first means for determining the axis coordinates; a second means for determining the horizontal axis coordinates relative to the vertical axis coordinates of a straight line parallel to the dividing line using a straight line approximation formula from the vertex coordinates at both ends of the second contour; The method includes drawing means for drawing a straight line parallel to the dividing straight line, using the calculation results of the outputs of the first and second means as the starting point and end point of the straight line, and filling each triangular or trapezoidal part. It has a function to fill in the inside of a polygon shape.

Effect of the Invention The present invention uses the above-described configuration to fill in a polygonal figure by filling in a divided triangle or trapezoid with line segments in the horizontal axis direction defined from two sides of the polygon's outline. To eliminate discontinuities in the contour of a polygon that has been completed at divided points, and to enable filling drawing without damaging the contour of the polygon.

Embodiment Hereinafter, an embodiment of the method for filling in polygonal figures according to the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the present invention. 1st
In the figure, a CPU 10 sets parameters for each block. Reference numeral 11 denotes a coloring control unit which receives parameters from the CPU 1o and performs coloring processing. 12 is a refresh memory, 13 is a video circuit, and 14 is a raster scan type display device, the filling drawing data calculated by the filling control section 11 is written to the refresh memory 12, and the contents of the refresh memory 12 are stored in the video circuit 13. is converted into a video signal at the display 14
will be displayed.

The processing order of the filling control section 11 will be explained by taking as an example the case where a polygonal figure shown in FIG. 2 is filled. Here, the horizontal axis coordinate is the X coordinate, and the vertical axis coordinate is the Y coordinate.

(1) From the specified number of vertices and vertex coordinates, select the vertices [T1~
To), the line segment connecting them, that is, the edge [E1 to Ecs
) and write the coordinates of the vertices at both ends of the side to a predetermined address in memory. Also, the maximum value of the Y coordinate of the vertex (
YTo) and the minimum value [YT1] are also determined and written to a predetermined address in the memory.

(2) The coordinates of the created edges [E1 to Ee] are successively retrieved from memory, packet sorted in ascending order with respect to the Y coordinate of the starting point of the edge (the point with the smallest Y coordinate among the vertices at both ends of the edge), and The vertex coordinates of are arranged in note order (El, E2; E3.E
4;E5. E6] to a predetermined address in the memory.

(3) Set the parameter P to the minimum value of the Y coordinate [YT1].

(4) The vertex coordinates of both ends of the side whose starting point's Y coordinate is equal to the parameter P are stored in a work area with memory, and the sides in the work area are sorted in ascending order with respect to the X coordinate. (In this example, it is first sorted in the order of [El; E2].) (5) Read the two sides from the work area in the sorted order, and find the intersection point with the straight line parallel to the X axis passing through the vertex [T2]. C
1], [C2] is calculated and written to a predetermined address in the memory. The coordinates of this intersection point will be determined at the time of the next division process (4
) is used when sorting in ascending order regarding the X coordinate.

In this coordinate calculation, in the case of the intersection [C1], the side (E 1
] O both ends (D coordinate (X T1. Y T1) (X
Ts, Y Ts) From [xTl, YT1] as the starting point, the vertex [T2
] is obtained by calculating the X coordinate corresponding to the Y coordinate (Y T2:l ) of a straight line parallel to the X axis passing through the intersection point [
C2], the coordinates of both ends of the side [E2] (X T1
．． Y T1) (X T3.Y T3:I and (Y T
2) Obtain from DDAK.

(6) Fill in the part [triangle A] divided by a straight line parallel to the X-axis passing through the vertex [T2].

This coloring method will be described later.

(7') If there are other sides (other than El and E2) in the work area, return to (5) and repeat the same process sequentially.

(8) If there are no other sides, the divided Y coordinate (Y T2)
The side whose Y coordinate of the end point is equal to is removed from the work area.

(9) The parameter P is the maximum value of the Y coordinate of the vertex (Y Te
3, the process ends, and in other cases, the parameter P is set to the Y coordinate (Y
Set T2:l, return to (4), and repeat the same process sequentially.

In this example, when the parameter P is (Y T2), the edge (E3.E4) is added to the work area in (4), and (E
1;x2;E3;Ii:4). Furthermore, calculate the coordinates of the intersection point [C3] between the side [E1] and the straight line parallel to the X-axis passing through the vertex [T3], and divide the divided part into [
As trapezoid B], fill in the part of [trapezoid B] in step (6). After determining the condition in (7), return to (6) and select edge [E4],
Intersection with a straight line parallel to the X-axis passing through vertex [T3] [C4]
Calculate the dividing part as [triangle C], and in (6)
Fill in part of triangle C. Furthermore, in (8) side 1:
E2. E3: l is removed from the work area and the parameter P is set to (Y T3) according to the condition judgment of (9) (4)
Go back and repeat the same process.

In the above-mentioned filling method, when filling in [triangle A], the coordinates (X
T1. Y T1) t-Start point L,, Vertex t: T5)
2 whose end points are the O coordinates (X Ts, Y Ts) and the coordinates of the vertex [T3] (X Ts, Y T3), respectively.
The start and end points of a straight line (YT1≦Y≦YT2) parallel to the X axis within the filling range are determined by the seed DDA calculation, and drawing data is written to the address of the refresh memory corresponding to the position of this line segment. When filling in the part of [Trapezoid B], start from the vertex [T1] and move to the vertex (T5), as shown in Figure 3).

Two types of DDA calculations are performed with [T3] as the end point, and no drawing data is written between [YT1≦Y≦Y T2], and within the filling range when (Y T2≦Y≦Y T3:l) Find the starting and ending points of a straight line parallel to the X-axis and write the data.

As described above, according to this embodiment, when determining the starting point and end point of a straight line to be filled in by two types of DDA calculations for a triangle or trapezoid obtained by dividing a polygon, a part of the same side of the polygon is By performing the same DDA calculation for a triangle or trapezoid having , it becomes possible to fill in the polygon without destroying the continuity of the outline of the polygon at the dividing position.

In the above example, we started from the smallest Y-coordinate of the vertices of the polygon, but it is also possible to start from the largest Y-coordinate, or the largest and smallest points of X-coordinate. A straight line that is not parallel to the X-axis but parallel to the Y-axis can be processed in the same way.

Effects of the Invention As described above, the present invention provides a triangular or trapezoidal portion in which a polygonal figure with designated vertices is surrounded by two sides of the outline of the polygonal figure and a straight line in the horizontal axis direction passing through the dividing vertex. When dividing the polygon into a triangular or trapezoidal part, specify the coordinates of the vertices at both ends of the first and second contours of the polygonal shape using the horizontal axis coordinates and vertical axis coordinates, and then specify the straight line and the dividing line. When the coordinates of parallel straight lines are specified by the vertical axis coordinates, the horizontal axis coordinates corresponding to the vertical axis coordinates of the straight line parallel to the dividing line are calculated from the coordinates of the vertices at both ends of the first contour using a straight line approximation formula. a second means for determining the horizontal axis coordinates relative to the vertical axis coordinates of a straight line parallel to the dividing line using a straight line approximation formula from the vertex coordinates of both ends of the second contour;
and drawing means for drawing a straight line parallel to the dividing line using the calculation result of the output of the second means as the starting point and end point of the line segment, and by filling in each triangular or trapezoidal part, a polygon is formed. By having a function to fill in the inside of a figure, it is possible to easily configure the inside of a polygonal figure whose vertices are specified in relation to the graphic drawing display function of a raster scan type display device that has a graphic display function among figure drawing display devices. You can fill in the polygon without losing its continuity.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing an example of the filling process order in the above embodiment, FIG. 3 is a diagram showing an example of filling in divided parts of a polygon, FIG. 4 is a diagram showing an example of processing in the conventional coloring method, and FIG. 6 is a diagram showing an example of coloring in the conventional coloring method. 1o...CPU, 11...Coloring control unit, 12...Refresh memory, 13.
...Video circuit, circuit, 14...Raster scan type display. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 2 Figure 3 Figure 1 Figure 4 I Figure 5 Figure 1

Claims (1)

[Claims] The number of vertices of a polygon specified by the central processing unit includes a central processing unit and a raster scan type display unit having a memory that stores drawing data at address positions corresponding to pixels and displays graphics based on the read data; Based on the vertex coordinates, the writing of the figure to be drawn in the corresponding memory is controlled, and the specified polygon figure is drawn between two sides of the polygon figure's outline and a straight line in the horizontal axis direction passing through the vertex to be divided. When dividing the polygon into triangular or trapezoidal parts surrounded by , and filling in the triangular or trapezoidal parts, the coordinates of the vertices at both ends of the first and second outlines of the outline of the polygon are determined by the horizontal axis coordinates and the vertical axis coordinates. When the coordinates of a straight line parallel to the dividing line are specified as vertical coordinates, the coordinates of the vertices at both ends of the first contour are converted to the vertical coordinates of the straight line parallel to the dividing line using a straight line approximation formula. a first means for determining the corresponding horizontal axis coordinate; and a second means for determining the horizontal axis coordinate with respect to the vertical axis coordinate of a straight line parallel to the dividing line by linear approximation from the coordinates of the vertices at both ends of the second contour. , a drawing means for drawing a straight line parallel to the dividing straight line using the calculation results of the outputs of the first and second means as the starting point and end point of the straight line, and filling each triangular or trapezoidal part. What is claimed is: 1. A display device for displaying a polygonal figure by coloring the inside of the polygonal figure.