JPS62202278A - Depicting system for surface coating polygon - Google Patents

Abstract

PURPOSE:To paint out the inner surface of a polygon simply and at a high speed by depicting, the segment between the odd number intersection of respective horizontal scanning lines and the even number intersection as a horizontal line part, shifting a group of plural adjoining picture elements and depicting a polygonal belt-shaped outline. CONSTITUTION:The coordinate information generated by operating an input device 1 is read by a control part 2. Since a thick outline is held, concerning the polygon depicted as the locus of plural picture elements, a border point detecting part 4 detects the intersection between the polygon depicted as the locus of one special picture element in plural picture elements and a horizontal scanning line. An internal area deciding part 5 identifies whether the point is the odd number point or the even number point, the internal part of the polygon is decided and a painting-out part 6 paints out the equivalent section. Thereafter, plural picture elements are shifted, an outline line is depicted, thereby, completing the surface coating of the polygon as a whole.

Description

[Detailed Description of the Invention] [Summary] In a device that draws a digital image using an information processing device such as a computer graphics device, when attempting to fill in the inner surface of a polygon drawn by a belt-shaped outline made of thick lines or the like. , it is difficult to distinguish between the inside and outside of the polygon, so conventional methods have been to draw the shape in memory and then analyze it, which requires a lot of processing time. there were. In order to solve these conventional problems, the present invention uses a polygon, which is the locus of a specific dot among a group of multiple pixels (dots), to generate the outline of a polygon whose inner surface is to be filled. The interior of the polygon is identified and filled by the intersection of the polygon and the horizontal scanning line, and the outline is overwritten using the plurality of dots, making it possible to process at high speed using simple logic. A drawing method is disclosed.

[Industrial Application Field] The present invention relates to the control of a device that draws digital images using an information processing device such as a computer graphics device, and in particular, the present invention relates to the control of a device that draws a digital image using an information processing device such as a computer graphics device. This relates to control when

[Prior Art] FIG. 4 is a diagram explaining the principle of a method for drawing a polygon with a surface color, in which 50 represents a polygon to be painted, 51 and 52 represent horizontal scanning, and 1 to 52 represent horizontal scanning. The number 4 represents the order in which the horizontal scanning line intersects the outline of the polygon 50 during scanning.

In FIG. 4, if we focus on the points where the horizontal scanning line intersects the outline of the polygon, we can see that in the horizontal scanning line 51, the section from intersection point 1 to intersection point 2 is inside the polygon 50, and in the horizontal scanning line 52, It can be seen that the section from intersection 1 to intersection 2 and the section from intersection 3 to intersection 4 are inside the polygon. In other words, the area between the odd-numbered intersections and the even-numbered intersections between the horizontal scanning line and the outline of the polygon may be considered to be inside the polygon.

Therefore, for each horizontal scanning line, the inside of the polygon 50 can be filled in by drawing a line segment in the section from the odd-numbered intersection with the polygon's outline to the even-numbered intersection.

In recent years, with advances in computer graphics, it has become necessary to draw images that are more complex, diverse, and diverse.

Among these, there are cases where polygons are drawn using lines with a certain thickness. This can be drawn by moving a plurality of images (for example, 2×2 dots) at the same time and forming the outline of the polygon based on their loci.

If you try to fill in the interior of a polygon that has been precisely drawn, it is impossible to do so using the method described above with reference to FIG. For example, as shown in FIG. 5, when the contour line of a polygon has a width, and the inner and outer surfaces are respectively contour lines, the second and third intersection points of the polygon 53 and the horizontal scanning line 54 are The section between the intersections is inside the polygon 53, but the section between the second and third intersections on the horizontal scanning line 55 is outside the polygon. That is, processing cannot be performed simply using the odd/even relationship regarding the order of intersections between the horizontal scanning line and the contour line of the polygon.

[Problems to be Solved by the Invention] As mentioned above, in a polygon whose outline is drawn by a thick line with a certain width, there are overlaps between the sides due to the width of each side, etc. Since the shape of the sides becomes complex, it is difficult to logically estimate the boundaries of the sides. Therefore, in the past, when identifying the interior of such a polygon by filling it in, one had to rely on methods such as drawing the polygon in memory and then analyzing it to determine the interior. There was a problem that the processing required a lot of time.

SUMMARY OF THE INVENTION In view of these conventional problems, it is an object of the present invention to provide a drawing method that can quickly fill in a polygon whose outline has a width using simple logic.

[Means for Solving the Problems] According to the present invention, the above object is achieved by drawing a digital image by a trajectory of a group of mutually adjacent pixels in a device that draws a digital image using an information processing device. means for painting the inner surface of a polygon having a band-shaped outline, which when the polygon to be painted is horizontally scanned, a group of adjacent pixels forming the outline of the polygon; A horizontal line segment is drawn between the odd-numbered intersection point and the even-numbered intersection point between the locus drawn by a specific pixel and each horizontal scanning line, and the plurality of adjacent pixels in the group are moved. This is achieved by a patented polygon drawing method characterized by drawing a band-shaped outline of the polygon as a locus.

[Embodiment] FIG. 1 is a block diagram showing an example of an apparatus for implementing the present invention, in which 1 is an input device, 2 is a control section, 3 is a coordinate input section, 4 is a boundary point detection section, and 5 Reference numeral denotes an internal area determination section, 6 a filling section, 7 a graphic generation section, 8 an image memory, 9 a display control section, and 10 a display section.

In FIG. 1, an input device 1 is usually a tablet, a mouse, a trackball, or the like. and,
Coordinate information generated by operating these input devices is read by the control unit 2.

In the case of a polygon that has a thick outline and is drawn as a trajectory of multiple pixels, the boundary point is detected at the intersection of the polygon, which is drawn as a trajectory of one specific pixel among the multiple pixels, and the horizontal scanning line. The interior area determination unit 5 determines the interior of the polygon by identifying whether the intersection is an odd or even numbered intersection, and a filling unit 6 fills out the corresponding section. Do this. Then, by moving a plurality of pixels and drawing an outline, the entire surface of the polygon is painted.

By controlling these processes as shown in the flowchart shown in Figure 2, the same control flow can be achieved regardless of whether the outline of the polygon whose interior is to be filled is a trajectory of one pixel or a trajectory of multiple pixels. It can be processed within.

FIG. 3 is a diagram illustrating the filling of a polygon having a thick outline according to the present invention. In other words, a polygon drawn as a locus of a plurality of pixels (pixels of size dxXdy dots) as shown in (a) becomes, for example, as shown by the solid line in (b), but in this case, the polygon shown in (,) The trajectory of the pixels at point A has a relationship as shown by the dotted line in (b). If this is extracted, a simple polygon as shown in (c) will be obtained, so find the intersection points of this polygon with each horizontal scanning line, and calculate the nearness between the odd-numbered intersection and the even-numbered intersection. − Fill each interval with a straight line. As a result, the diagonally shaded portion of the downward-sloping target interval in (d) is filled in. Next, by moving the plurality of pixels shown in (,) to draw the outline of the polygon, the portion of (cl) with diagonal lines at fine intervals on the lower left is filled in.

[Effects of the Invention] According to the method of the present invention as explained above, when drawing a digital image using an information processing device such as computer graphics, it is possible to draw a polygon whose outline is represented by a plurality of dots. It has the advantage of being able to process quickly due to its simple logic. Furthermore, even if the polygon has a complicated shape, it can be easily processed and no unpainted areas will be left, which is very effective.

[Brief explanation of drawings]

Fig. 1 is a block diagram showing an example of an apparatus for carrying out the present invention, Fig. 2 is a flow diagram showing an example of surface painting processing, and Fig. 3 is a block diagram showing an example of a device implementing the present invention. FIG. 4 is a diagram illustrating the principle of drawing a polygon with a polygon filled with a polygon, and FIG. 5 is a diagram illustrating internal determination of a polygon whose outline has a width. 1...Input device, 2...Control unit, 3.
...Coordinate input section, 4...Boundary point detection section,
5... Internal area determination section, 6... Filling section, 7... Figure generation section, 8... Image memory, 9...... Display control section, 10...
Display section, 50.53...Polygon to be painted, 51.52.54.55...Horizontal scanning line axis plot is a polygon with a wide width. Hunting, trapping, screaming, 5th

Claims (1)

[Claims] A means for painting the inner surface of a polygon having a band-shaped outline drawn by a group of mutually adjacent trajectories of a plurality of pixels in a device that draws a digital image using an information processing device, the polygon to be painted When scanned in the horizontal direction, the odd-numbered intersections and even-numbered intersections between each horizontal scanning line and the locus drawn by a specific pixel among a group of mutually adjacent pixels forming the outline of the polygon. A drawing method for a covered polygon, characterized in that the spaces between the pixels are drawn as horizontal line segments, and the plurality of pixels adjacent to each other in the group are moved to draw a band-shaped outline of the polygon as a locus thereof.