JPH0721397A - Paint-out plotting method for polygon - Google Patents

Abstract

PURPOSE:To provide the paint-out plotting method for polygon capable of making high-speed of plotting time without using a special device for plotting. CONSTITUTION:In the paint-out plotting method for polygon performing the plotting of polygon by painting out the pixel corresponding to the graphic pattern on the display screen with plural pixels arranged, the polygon for plotting is divided along one direction of the display screen and position data on the boundary of the polygon obtained by the division are obtained. In the same division in one direction, a group of position data is formed (S1) by two position data holding between the polygon inside. By making a dot on the pixel which is held between by the group of position data (S3). Thus the plotting of polygon is performed, thus painting-out of polygon is made.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drawing method for displaying a figure on a display device, and more particularly to a polygonal drawing method for displaying a polygon formed by a closed curve.

[0002]

2. Description of the Related Art In general, there is a case where a graphic with a filled inside is drawn on a display device such as a CRT. For example, in numerical control used for industrial machine tools and the like, there is a case in which the validity of a machining program is verified by simulating a cutting situation on the screen of a control device before machining by a machine tool. In the simulation of the cutting situation, when the animation of the tool is displayed, it is often the case that the cutting edge of the tool is normally filled with a single color and drawn.

Conventionally, in this type of drawing, a method of drawing by a special graphic accelerator or calculating a pixel in a closed area surrounded by a line and filling the pixel is adopted.

[0004]

However, the above-described conventional fill-drawing method has the following problems.

(1) The conventional paint-drawing method using a graphic accelerator has a problem in that a special device such as a graphic accelerator is required, and this also causes a problem in that the cost is increased.

(2) Further, in the conventional drawing method in which a pixel in a closed area surrounded by a line representing a figure is calculated and the pixel is filled, among the pixels on the display device every time the figure is moved, There is a problem in that it is necessary to recalculate a pixel that hits a dot in the closed area of the figure, and the drawing process becomes long due to the calculation time.

Further, due to the lengthening of the drawing process, there is a secondary problem that the speed of the animation itself decreases when displaying the animation.

Therefore, the present invention solves the above-mentioned problems of the conventional fill drawing method, and provides a polygon fill drawing method which enables speeding up of drawing time without using a special device for drawing. The purpose is to provide.

[0009]

In order to achieve the above-mentioned object, the present invention provides a graphic by filling the pixels corresponding to a polygonal graphic pattern on a display screen in which a plurality of pixels are arranged. In the polygonal filling drawing method for drawing, the polygon to be drawn is divided along one direction of the display screen, position data at the boundary of the figure obtained by the division is obtained, and in the same division for improvement, Forming a set of position data with two position data that sandwich a polygon inside, and drawing a polygon by hitting dots on the pixels sandwiched by the set of position data to fill the polygon. Is.

Further, the position data specifying a polygon is position data representing a vertex of the polygon and position data on a line segment connecting the vertices, and the position data representing the vertex is included in the position data obtained by the division. Select three adjacent position data in order from one direction, and the center position when the outer product of two adjacent vectors formed by the selected position data is positive or the product of the Y components of the vector is positive The position data on the line segment connecting the vertices is
It is position data when the line segment does not exist in the one-sided improvement, the position data set is formed by this position data, and a polygon is drawn by hitting dots on the pixels sandwiched by the position data set. By doing this, the polygon is filled.

In the present invention, one direction that divides the polygon to be drawn on the display screen may be the X-axis direction or the Y-axis direction.

In the present invention, forming a dot on a pixel means changing the display state such as the density and color of the pixel so as to make a difference in display from other pixels on which no dot is formed. Is caused.

[0013]

According to the present invention, in a polygonal filled drawing method for drawing a polygon by filling the pixels corresponding to the polygon on a display screen having a plurality of pixels arranged, the drawing is first performed. The polygon to be performed is divided along one direction of the display screen, and position data at the boundary of the polygon obtained by the division is obtained. Then, from the position data, in the same division of the one-sided improvement, two position data sandwiching the polygon inside are selected,
A pair of position data is formed by the selected two position data. Then, a polygon is drawn by hitting dots on the pixels sandwiched by the set of position data, whereby the polygon can be filled.

Further, in order to obtain the position data that specifies the polygon, three adjacent position data are selected in order in one direction from the position data obtained by division, and the adjacent position data formed by the selected position data are selected. When the outer product of the two vectors is positive or the product of the Y components of the vector is positive, the central position data is obtained, and this position data is used as position data representing the vertices of the polygon, and the vertices are connected. The position data when the line segment does not exist on a straight line in one direction is obtained, and this position data is used as position data representing a polygonal line segment, and a set of position data is formed from these position data, and the position By drawing a polygon by hitting dots on the pixels sandwiched by the data set,
It is used to fill polygons.

[0015]

Embodiments of the present invention will now be described in detail with reference to the drawings, but the present invention is not limited to the embodiments.

(Structure of Embodiment) FIG. 2 is a diagram showing a state on a display screen when the embodiment is carried out. In FIG. 2, a display device such as a CRT has a plurality of pixels, a pixel corresponding to a polygon is selected from the plurality of pixels, and a dot is applied to the selected pixel to draw the polygon. In the figure, X1 to X3 in the X-axis direction
It is composed of a plurality of pixels which are divided into two and which are also divided into Y1 to Y23 in the Y-axis direction, and a dot is applied to a pixel corresponding to the outline of the figure and a pixel inside the polygon from the pixels. With this, it is possible to perform the target polygonal filled drawing. In the figure, dots are indicated by ●. Note that hitting a dot on a pixel means forming a difference on the display with other pixels on which dots are not hit by changing the display state such as the density and color of the pixel. .

In the polygonal filled drawing method of the present invention, for example, the polygon is divided in the X-axis direction (horizontal line direction), and the shape of the polygon is determined by the set of position data of pixels at both ends of the divided X-axis direction. Specify. For example, in FIG. 2, when the polygon is divided in the X-axis direction, the figure is within the coordinates from Y11 to Y15 on the Y-axis, and in the portion where the Y-axis value is Y11, the X-axis value is from X6. Up to X23, and the position data (X6, Y1
1) and (X23, Y11). Also, the value on the Y-axis is Y
In the portion of 15, the X-axis value is from X12 to X23, and the position data (X12, Y1
5) and (X23, Y15).

Position data sets (X6, Y11) and (X23, Y11), (X) of the pixel position data at both ends in the X-axis direction.
7, Y11) and (X23, Y11), ... (X12,
The polygonal outline is specified by (Y15) and (X23, Y15). In the polygonal filled drawing method of the present invention, the polygonal filled drawing is performed by forming dots on the pixels sandwiched between the pixel represented by the position data and the position data set.

Although the figure is divided in the X-axis direction (horizontal line direction) in the embodiment shown in FIG. 2, it is also possible to divide the figure in the Y-axis direction (vertical line direction). It is also possible to specify a polygonal shape by a set of the position data of the divided pixels at both ends in the Y-axis direction. The direction of division of this polygon and the formation of a set of position data in the direction of division can be set by corresponding the dots of pixels to the scanning direction.

(Apparatus configuration for carrying out the embodiment) FIG. 3
FIG. 1 is a device configuration diagram for implementing a polygonal filled drawing method according to an embodiment.

In FIG. 3, the processor 11 is a ROM
The entire apparatus is controlled according to the system program stored in 12. The software executed by the system program of the ROM 12 has various functions such as graphic storage. EPROM or EEPROM is used for the ROM 12. An SRAM or the like is used as the RAM 13, and temporary data such as input / output signals is stored therein. For the non-volatile memory 14, a CMOS backed up by a battery (not shown) is used. Also,
The non-volatile memory 14 stores various data such as parameters and machining programs to be saved even after the power is turned off.

The graphic control circuit 15 converts the guidance information and the input designated shape into a displayable signal,
It is given to the display device 16. A CRT or a liquid crystal display device is used as the display device 16.

Input to the processor 11, RAM 13, etc. is performed by the MDI 17. As the MDI 17, an input device such as a keyboard or a mouse can be used. It should be noted that the device configuration is based on the ROM 12
By storing a system program for controlling the entire numerical control device in, it can be applied to a normal numerical control device, but is not limited to the numerical control device,
The present invention can be applied to other devices that display graphics.

[Operation of Embodiment] (Drawing Procedure) Next, regarding the procedure of the drawing method of the embodiment of the present invention, the drawing drawing of FIG. 2 and the polygonal filled drawing method of the present invention of FIG. 1 will be described. The procedure will be described with reference to the flowchart. In the following explanation,
A description will be given using the reference numeral of step S.

Step S1: First, position data for drawing a polygon to be displayed on the display device 16 is obtained. This position data is obtained by dividing a polygon in the X-axis direction (horizontal direction) of a polygon as shown in FIG.
It is position data that specifies the pixels at the boundary that form the divided polygon in the X-axis direction, and the shape of the polygon is specified by this.

Further, in this step, the order of the obtained polygon position data is changed, and the polygon position data is sorted in an order suitable for drawing. For example, when the main scanning direction in drawing is the X-axis direction and the sub-scanning direction is the Y-axis direction, first the position data is rearranged so that the position data is in the order of the sub-scanning direction. If there is position data having the same Y value in the rearranged position data, the sorting is performed by arranging in order from the smallest X value so as to be in the main scanning direction.

Then, two sets of position data on the same line in the main scanning direction (having the same Y value) are formed by the sorted position data. In addition, in forming these two sets of position data, if there are three or more position data on the same line in the main scanning direction (having the same Y value), the set of position data is inside the drawing figure. In the case of selecting a combination that sandwiches between the two, and when forming a vertex, one set of position data is formed from the same position data.

By forming this set of position data and designating the set of position data to the display device, all the pixels sandwiched by the set of position data can be designated. Therefore, a plurality of pixels that strike a dot can be specified by a set of position data. This position data set is, for example, the RAM 13 of FIG.
Remember.

Note that this position data is data for specifying the shape of a polygon, and when a figure moves, this position data is changed according to the movement, and the position data during and after the movement is changed. Will ask.

Details of this step will be described later in the section (Procedure for obtaining position data) with reference to the flowchart of FIG.

Step S2: The set of position data obtained in the step S1 is read from the RAM 13. The order of reading the sets of position data can be the order sorted in the process of step S1.

Step S3: A dot is printed on the pixel sandwiched between the sets of position data read out at step S2. This forms part of a polygon. For example, the set of read position data is (X6, Y11), (X2
3, Y11), this set of position data indicates the bottom line of the polygon drawn in FIG. 2 and strikes all dots of the pixels sandwiched by this set of position data. As a result, the bottom line of this polygon can be displayed on the display device 16.

Step S4: By repeating the steps S2 and S3 for all the position data, a polygon can be displayed on the display device 16.

(Procedure for Obtaining Position Data) Next, regarding the details of the process of step S1, a flowchart for obtaining polygonal drawing position data in FIG. 4 and FIGS.
The method for obtaining the drawing position data of the polygon will be described with reference to the drawings.

In the following description of the flow chart,
The case where the drawn polygon has a triangular shape as shown in FIG. 5 will be described. The position data finally obtained from this flow is the position data of the pixel indicated by the diagonal lines in FIG. It seeks a set.

In the following flow chart,
Description will be given using the reference numerals of steps S11 to S21.

Step S11: First, the coordinates of the vertices of the polygon to be drawn are input to a storage device such as the RAM 13.
For example, in the triangular figure shown in FIG. 5, the position data of the vertices indicated by 1 to 3 (or (1) to (3)) is obtained. The position data may be the XY coordinate position data itself, or may be the position data of a pixel corresponding to the XY coordinate position data converted. In the following description, it is assumed that the position data of the vertices of the polygon obtained in this step is the position data of the pixel, and in the case of the position data of the XY coordinates itself, the position data of the corresponding pixel at any stage of this flow. Can be converted to position data.

The position data must be clockwise or counterclockwise with respect to the drawn figure. In FIG. 5, in the case of counterclockwise rotation, the order is 1, 2, 3.
In the case of clockwise rotation, the order is (1), (2), (3). The case of counterclockwise rotation will be described below.

Step S12: A vector v is formed between the position data of the vertices in the obtained order based on the position data obtained in the above step. For example, in FIG. 6, when the vertices are i−1, i, i + 1 counterclockwise,
Form a vector v _i-1 between vertices i-1 and i,
And i + 1 form a vector v _i . The position coordinate of the vertex i is (X _i , Y _i ).

Step S13: vertex i obtained in the above process
By the vector v _i that starts a vector v _i-1 and the vertex i to end point, obtaining an outer product v _i-1 × v _i. In this outer product v _i-1 × v _i , the angle formed by the vector v _i-1 and the vector v _i is θ in FIGS.
Represented by.

Step S14: Outer product v obtained in the above process
_i-1 × v or _i is positive, or it is determined whether a 0 or negative. For example, FIG. 6 shows a case where the outer product v _i-1 × v _i is positive, and FIG. 7 shows a case where the outer product v _i-1 × v _i is negative.

Step S16: If the outer product v _i-1 × v _i is positive, the position data of the vertex i is stored in the RAM, for example.
It is stored in a storage device such as 13 and is set as position data for obtaining the horizontal line of the drawn figure. In FIG.
This stored vertex i is indicated by ●.

Step S15: On the other hand, the outer product v _i-1 × v _i
Is 0 or negative, it is determined whether the product of the Y component of the _i- th vector v _{i and} the Y component of the i−1 th vector v _i−1 is positive or 0 or negative. . If the product of the Y component of the _i- th vector v _{i and} the Y component of the i−1 th vector v _i−1 is positive, the position data of the vertex i is stored in step S16.

On the other hand, when the product is 0 or negative, the position data of the vertex i is not stored and is not set as the position data for obtaining the horizontal line of the drawing figure. this is,
This is because the point i is a point in the middle of the horizontal line and is not necessary as position data for obtaining the horizontal line. In FIG. 7, the vertex i which is not stored is indicated by a white circle.

As shown in FIG. 8, the start point vertex is Y.
In the case of an acute angle with respect to the axial direction, the starting points are set twice so as to be stored as horizontal line information. Whether or not the vertex of the starting point is an acute angle with respect to the Y-axis direction is determined by, for example, the Y component of the i-th vector and i−1.
This can be done depending on whether the product of the nth vector with the Y component is negative. In FIG. 8, the stored vertex i is indicated by ●.

Step S17: The steps S14 to S16 are performed for all the vectors.
As a result, the position data of the vertices, which is necessary as horizontal line information in drawing the polygon, is obtained.

Step S18: Next, position data on the top line segment required as horizontal line information in drawing a polygon is obtained. In the steps S14 to S17, the position data of the vertices necessary as the information of the horizontal line in the drawing of the polygon is obtained, but in this step, the position data necessary as the information of the horizontal line in the line segment connecting the vertices is obtained. Ask for.

Vector v _i obtained in step S13
The straight line corresponding to is defined as i, and it is determined whether or not the straight line i is a horizontal line. When the straight line i connecting the vertices is a horizontal line, the straight line portion of this horizontal line has position data necessary for drawing already set by the vertices at both ends of the straight line. Is not necessary. Therefore, the position data of this straight line i is not set.

On the other hand, if the straight line i connecting the vertices is not a horizontal line, the position data for obtaining the horizontal line is set in the next step S19.

Step S19: The position data of the straight line i is obtained and stored in the storage device.

This straight line i is shown by, for example, a thick solid line in FIG. 9, and the position data on the straight line i is
It is obtained as position data at both ends of a horizontal line in the X-axis direction indicated by a broken line, and is indicated by ● in the figure.
Since the horizontal line portion is not necessary as position data for obtaining the horizontal line as described in the above step,
The position data of this straight line i is not set.

Also in the polygon shown in FIG. 10, similarly, the position data on the straight line i is indicated by ●, and the point represented by the white circle inside the apex in the middle of the horizontal line is the above-mentioned point. As described above, it is not set because it is unnecessary as position data for obtaining the horizontal line.

In the case where the polygon is as shown in FIG. 11, the necessary position data can be obtained by two straight lines other than the horizontal lines that sandwich the polygon. For example, in FIG. 11, when a straight line is represented by i to i + 4 in the clockwise direction, a polygon sandwiched by the straight line i and the straight line i + 1 has a horizontal line for drawing defined by the position data of the straight line i and the straight line i + 1. A horizontal line for drawing is determined by the position data of the straight line i + 2 and the straight line i + 4. The vertex at the intersection of the straight line i + 1 and the straight line i + 2 is not set as position data because the vector outer product is negative and the Y component product is 0 or negative.

Step S20: The steps S18 and S19 are performed for all i. As a result, all position data necessary for drawing can be obtained.

Step S21: The position data input in steps S11 to S20 are sorted in an order suitable for drawing. Since this sort has been described in step S1, the description is omitted here.

A position data set is formed by this sorting, and by specifying the position data set to the display device, all the pixels sandwiched by the position data set can be specified. Yes, multiple pixels that hit a dot can be identified by a set of position data.

[Modification] In the above-described embodiment, the Y-axis direction may be used instead of the X-axis direction as one direction for dividing the polygon.

[0058]

As described above, according to the present invention,
High-speed machine language instructions can be easily used, and high-speed graphic drawing can be performed.

[Brief description of drawings]

FIG. 1 is a flowchart illustrating a procedure of a polygonal filled drawing method according to the present invention.

FIG. 2 is a diagram showing a state on a display screen when implementing an embodiment of the present invention.

FIG. 3 is a diagram showing the configuration of an apparatus for carrying out the polygonal fill drawing method according to the embodiment of the present invention.

FIG. 4 is a flowchart for obtaining polygonal drawing position data according to the present invention.

FIG. 5 is a diagram illustrating a method of obtaining position data for drawing a polygon according to the present invention.

FIG. 6 is a diagram illustrating a method for obtaining polygonal drawing position data according to the present invention.

FIG. 7 is a diagram illustrating a method for obtaining polygonal drawing position data according to the present invention.

FIG. 8 is a diagram illustrating a method of obtaining position data for drawing a polygon according to the present invention.

FIG. 9 is a diagram illustrating a method of obtaining position data for drawing a polygon according to the present invention.

FIG. 10 is a diagram illustrating a method of obtaining position data for drawing a polygon according to the present invention.

FIG. 11 is a diagram illustrating a method of obtaining position data for drawing a polygon according to the present invention.

[Explanation of symbols]

 11 processor 12 ROM 13 RAM 14 non-volatile memory 15 graphic control circuit 16 display device 17 MDI

Claims (3)

[Claims] 1. A filled drawing method for drawing a polygon by filling the pixels corresponding to a graphic pattern on a display screen formed by arranging a plurality of pixels, wherein (a) the polygon is displayed on the display screen. Dividing along one direction, (b) obtaining position data at the boundary of the polygon obtained by the division, (c) in the same division of the one-sided improvement, by two position data sandwiching the polygon inside. A method of drawing a polygon by forming a set of position data, and (d) drawing a polygon by hitting dots on the pixels sandwiched by the set of position data. 2. The position data comprises position data representing vertices of the polygon and position data on a line segment connecting the vertices, and (a) the position data representing the vertices is obtained by the division. If three adjacent position data are selected in the unidirectional order from the position data that are set, and the outer product of two adjacent vectors formed by the selected position data is positive, or the product of the Y components of the vector is positive 2. The position data at the center of the line segment, and (b) the position data on the line segment connecting the vertices is the position data when the line segment does not exist in the one-sided improvement. Polygon fill drawing method. 3. The polygonal solid drawing method according to claim 1, wherein the one direction is an X-axis direction.