JPH0423305B2 - - Google Patents

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 an outline line in a strip of thick lines, etc. Since it is difficult to distinguish between the inside and outside of the polygon, conventional methods have been to draw the shape in memory and then analyze it, which requires a lot of processing time. It was hot. 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 device 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 digital images using an information processing device such as a computer graphics device. This relates to the control when carrying out such operations.

[Prior Art] FIG. 4 is a diagram explaining the principle of a drawing method for a painted polygon, in which 50 is a polygon with a painted surface;
1 and 52 respectively indicate horizontal scanning, and 1 to 52 indicate horizontal scanning.
The number 4 means that the horizontal scanning line is a polygon 50 when scanning.
represents the order in which they intersect with the contour line.

In FIG. 4, if we pay attention to the point 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 polygon 50.
, and in the horizontal scanning line 52, the intersection 1
It can be seen that the section from 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 to the even-numbered intersection with the outline of the polygon.

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

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

If an attempt is made to fill in the interior of a polygon drawn in this manner, it is impossible to do so using the method described above with reference to FIG. For example, the fifth
As shown in the figure, when the contour line of a polygon has a width, and if the inner and outer surfaces are respectively contour lines, then in the polygon 53 and the horizontal scanning line 54, the section between the second and third intersection points is inside the polygon 53, but in the horizontal scanning line 55, the section between the second and third intersections 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 thick lines with a certain width, the width of each side causes overlaps between the sides, etc. Since the shape of the sides becomes complicated, 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 processing took 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 device 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 the means described in the claims. That is, the present invention includes an input device that generates coordinate information of an image;
A control unit reads the input locus information and controls generation of a figure, and the figure input from the input device has a band-shaped outline drawn by a locus of large pixels formed by a collection of a plurality of pixels. A coordinate input unit that detects and outputs the coordinates of the polygon formed by the locus of a specific pixel among the plurality of pixels when the polygon is a polygon, and a boundary point detection unit that determines the intersection of the output of the coordinate input unit and the scanning line. and an internal area determination unit that identifies whether the intersection on the scanning line is an odd number or an even number, and thereby determines whether the corresponding part is inside or outside the polygon. , a filling unit that draws a horizontal line segment in the entire area within the area determined to be inside the polygon, and a large pixel that is a set of a plurality of pixels based on the coordinate information input from the input device. a figure generator that draws a polygon by moving the specific one pixel along the locus of the pixels so that the position of the specific one pixel coincides with the position of the specific one pixel; and a figure generator that holds the figures necessary for display. This is a drawing device for drawing a filled polygon, which is equipped with an image memory.

[Embodiment] FIG. 1 is a block diagram showing an embodiment of 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 is an internal region determination section. Department,
Reference numeral 6 represents 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 typically a tablet, mouse, trackball, or the like. 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 locus of multiple pixels, the coordinate input unit 3 detects the coordinates of the polygon that is drawn as a locus of one specific pixel among the multiple pixels. , and the intersection of this and the horizontal scanning line is detected by the boundary point detection unit 4. Then, the interior region determination unit 5 determines the interior of the polygon by identifying whether the intersection is an odd number or an even number, and a filling unit 6 fills the corresponding section by drawing a horizontal line segment. Do this. As a result, the inside of the polygon drawn as a locus of one specific pixel is filled. Thereafter, the figure generation unit 7 matches the trajectory of the specific pixel along the polygon drawn by using the plurality of pixels of the thick outline forming the original polygon as the trajectory of the specific one pixel. By moving the polygon in this manner and drawing the outline of the polygon, the surface painting of the entire polygon is completed.

By controlling these processes as shown in the flow chart 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 multiple pixels (pixels of size dx x dy dots) as shown in (a) is, for example,
At this time, the locus of the pixel at point A shown in (a) becomes as shown in the solid line in (b), but the relationship is as shown in the dotted line in (b). If we extract this, we will obtain a simple polygon as shown in (c), so we will find the intersection points of this polygon with each horizontal scanning line, and calculate the interval between the odd-numbered intersection and the even-numbered intersection. Fill in each with a straight line. As a result, the diagonal lined area with coarse spacing downward to the right in (d) is filled in. Next, by moving the plurality of pixels shown in (a) to draw the outline of the polygon, the portion shown in (d) with diagonal lines at small intervals is filled in.

[Effects of the Invention] According to the present invention as described above, when drawing a digital image, there is an advantage that filling of a polygon whose contour line is expressed by a plurality of dots can be quickly processed using simple logic. There is. Also,
Even if the polygon has a complicated shape, it can be easily processed and there will be no unpainted areas, so the effect is great.

[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 flowchart showing an example of surface painting processing, and Fig. 3 explains the surface painting of a polygon with a thick outline according to the present invention. FIG. 4 is a diagram for explaining the principle of a drawing method for a filled polygon, and FIG. 5 is a diagram for explaining internal determination of a polygon whose outline has a width. DESCRIPTION OF SYMBOLS 1... Input device, 2... Control unit, 3... Coordinate input unit, 4... Boundary point detection unit, 5... Internal area determination unit, 6... Filling unit, 7... Figure generation unit, 8...
...Image memory, 9...Display control section, 10...Display section, 50, 53...Polygon to be painted, 5
1, 52, 54, 55...horizontal scanning lines.

Claims (1)

[Scope of Claims] 1. An input device 1 that generates coordinate information of an image; a control unit 2 that reads the input coordinate information and controls generation of figures; and a plurality of figures input from the input device. Coordinates for detecting and outputting the coordinates of a polygon formed by the trajectory of a specific pixel among the plurality of pixels when the polygon has a band-like outline drawn by the locus of large pixels from a collection of pixels. an input section 3; a boundary point detection section 4 for determining the intersection of the output of the coordinate input section and the scanning line; an internal area determining unit 5 that determines whether the portion to be processed is inside or outside the polygon; a filling unit 6 that draws a horizontal line segment throughout the area that is determined to be inside the polygon; Based on the coordinate information input from the input device, a large pixel which is a set of a plurality of pixels is arranged so that the position of the particular one pixel among the plurality of pixels coincides with the locus of the particular one pixel. 1. A drawing device for a covered polygon, comprising: a figure generation unit 7 which draws a polygon by moving the polygon; and an image memory 8 which holds figures necessary for display.