JPH01166275A - Production of paint-out image data utilizing parallel processing - Google Patents

Abstract

PURPOSE:To improve the availability of a memory and to perform paint-out processing at a high speed in an inside or outside area of a contour by carrying out the expansion of picture elements of the contour and the generation of a paint-out instruction flag in parallel with each other. CONSTITUTION:An input device 11 forming an image paint-out data producing device 10 consists of a digitizer or a keyboard and outputs segment data SP on an image to be painted out to a polygon processing circuit 12. A circular pattern is inputted to a circle processing circuit 13 and the coordinate value of segment expressing picture elements received from the circuit 13 is given to a frame memory 15 and a flag storing memory 16 respectively via a selector 14. Furthermore, main and secondary scanning directions on a screen 23a of a CRT 23 are defined by memory spaces stored in both memories 15 and 16. At the same time, color information CI showing a specific color in which a pattern is painted out is outputted from the device 11 and registered in a color information register 18. Then an address is sent to the memory 15 and an address generating circuit 21 is controlled by both memories 15 and 16. Thus the paint-out processing is carried out.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention is based on outline information expressing the position and shape of the outline of a figure on a predetermined screen. The present invention relates to a method for obtaining filled image data in which a region is filled.

(Prior Art and its Problems) Various techniques have been proposed for filling in the internal or external area of a given figure on a bitmap corresponding to the screen of a graphic display. In one of the typical such techniques, as shown in FIG. 31, a contour line search origin (seed) 3 is set in an internal area surrounded by a contour line 2 of a figure 1. Then, starting from this search origin 3, image data is traced up, down, left and right, and the range until reaching the contour line 2 is filled in.

However, in FIG. 31, X indicates the main scanning coordinate, and Y
indicates sub-scanning coordinates.

Another conventional method is the method shown in FIG. 32 (scan line algorithm method).

In this method, first, each vertex 4a to 4f of the contour line 2 is
They are sorted based on their Y coordinates, and thereby the positional relationships of the line segments 5a to 5f forming the contour line 2 are grasped.

Then, while performing main scanning in the X direction, sub-scanning is performed in the (-Y) direction, thereby finding the intersection between each scanning line and the contour line 2.

However, which line segment should be referred to in each main scan can be known from the result of the above sorting. By determining the coordinates of the intersection between each main scanning line and the contour line 2 in this way, the section from one intersection 6a to the next intersection 6b in each scanning line is filled out on the bitmap.

Further, as a modification of such a technique, the figure 1 is divided into a plurality of trapezoids and/or triangles by the dividing line 7 in the main scanning direction shown in FIG. 32, and the internal area of each trapezoid or triangle is filled. Techniques have also been proposed.

(Problems to be Solved by the Invention) Among these conventional techniques, in the technique shown in FIG. 31, image data must be read out pixel by pixel from the image memory to perform a contour line search.

Therefore, there is a problem in that the time required for the filling process is insufficient.

Also, if there is a concave part in figure 1, one search origin 3
It is not possible to fill in all of the internal area of figure 1 starting from .For example, another search origin must be set for shaded area 8 in FIG. 31. In order to indicate that the shaded region 8 could not be executed by searching from the search origin 3, for example, the coordinates of the vertex 4 must be saved in a predetermined stack area. However, since the number of vertices that require such evacuation differs depending on the shape of the figure, it is not possible to specify how much capacity the stack area should have. As a result, the stack area must be set to be relatively large, which results in inefficient use of the storage area.

On the other hand, in the scan line algorithm method, vertices 4a to
4f sorting processing is required, but sorting processing generally takes a considerable amount of time. For this reason, the processing time for the entire filling process also becomes long. Further, the technique of dividing the figure 1 into trapezoids and/or triangles requires a process of determining the coordinates of the vertices of the trapezoids and/or triangles. Therefore, in this case as well, there is a problem that the processing time inevitably increases.

Furthermore, in the scan line algorithm method, the contour line 2
A clockwise or counterclockwise direction is given to the contour line 2, thereby instructing whether to fill in the inner area or the outer area of the contour line 2. For this reason, when a figure whose directionality cannot be specified, as shown in FIG. 33, is given, there is a problem that it becomes difficult to fill it in.

(Object of the Invention) The present invention is intended to overcome the above-mentioned problems in the prior art, and is an image filling data generation method that has short processing time, high memory usage efficiency, and fewer restrictions on the shapes that can be filled. The purpose is to provide

(Means for Achieving the Object) In order to achieve the above-mentioned object, the present invention provides a method for filling in the internal area or external area of a desired figure in a frame memory having a storage space corresponding to a predetermined screen. The method for generating image data includes the first step of inputting contour information representing the position and shape of the contour of the figure on the screen, and the step of inputting contour information representing the position and shape of the contour of the figure on the screen, and the step of inputting contour information expressed in pixels by pixel expansion of the contour. a second step of determining a line and writing the pixel-represented contour line in a bitmap format in the frame memory; and based on the intersecting relationship between the pixel-represented contour line and a scanning line in the storage space of the frame memory. specifies the position of the filled end point pixel in scanning the storage space of the frame memory, and writes a fill instruction flag indicating the position of the filled end point pixel in bitmap format in a flag storage memory having a storage space corresponding to the screen. synchronizing the third step of writing, the reading scan of the fill instruction flag in the flag storage memory, and the fill scan of the inner area or the outer area of the outline in the frame memory based on the fill instruction flag. and a fourth step of generating filled-in image data by performing the filling-in image data.
Step and the third step are executed in parallel.

(Embodiment) A. Outline of the embodiment FIG. 2 is an overall block diagram of an image filling data generation device used in an embodiment of the present invention, and FIG. 1 shows the concept of processing in this embodiment. It is a diagram. In FIG. 2, this image filling data generation device 10 is a CRT.
It is used to perform graphic display processing on the display 23, and has an input device 11 composed of a digitizer, a keyboard, and the like. From this input device 11, for example, a CRT display 23
Outline information expressing the position and shape of the outline C of the figure 50 of FIG. 1(a) on the screen 23a of FIG. 1(a) is arbitrarily input. When the figure 50 is a polygon, this outline information is formed by information specifying the position of each line segment L-L3 forming the outline C on the screen. Specifically, these line segments L are calculated using vector data (line segment data) including the main scanning coordinates (X coordinates) and sub-scanning coordinates (Y coordinates) of both end points of each line segment 1 to L3 on the screen 23a. -13 is specified as follows.

L: Starting point C1 (x, yl).

End point C2 (x, y) L: Starting point C2 (x, y).

End point C3 (X, y) L: Starting point C3 (x, y3).

End point C1 (X, V) 1 However, end points C1 to C3 are polygons (
In the illustrated example, it is the vertex of a triangle), and also serves as a tangential reading point for two consecutive line segments (for example, [ and 12).

Therefore, below, these end points C1 to C3 are also referred to as "vertices" or "connection points." Furthermore, each line segment 1 to L
Line segment LJ: Starting point C5 (X, V5).

End point C (X, V) EE It is expressed by (Figure 3).

The same applies to polygons other than triangles.

The line segment data thus provided, together with a control signal to be described later, is provided to the polygon processing circuit 12 in FIG. 2 as polygon specifying information SP as one form of contour information. The internal structure and operation of this polygon processing circuit 12 will be described in detail later, but its basic functions are pixel expansion of each line segment and identification of a filled area based on this. Among these, the filling area is specified by setting a filling instruction flag for a filling start pixel and a filling end pixel on each scanning line.

FIGS. 1(b) and 1(c) conceptually illustrate such pixel development and specification of a filled area, respectively.

However, the white circles in FIG. 1 indicate pixels obtained by expanding line segments (line segment representation pixels), and the black circles indicate filling end point pixels (general term for filling start pixels and end pixels). The reason why these pixels do not completely lie on the line segment is that the line segment is expanded approximately because the pixel size is not zero. Note that the "line segment expressing pixel" is a form of the "contour line expressing pixel".

The coordinate values (X, 8.Y, 8) of the line segment representation pixel are the second
The frame memory 5 (15a to 15d) with 4 bits per pixel and 1 bit per pixel are connected via the selector 14 in the figure.
The address signal is applied to the bit flag storage memory 16 as respective address signals.

However, in FIG. 2, the coordinate values output from the selector 14 are expressed as (X, Y,). Each of these frame memories 5a to 15d and the flag storage memory 1
6 have the same storage space as the number of pixels for one frame of the screen of the CRT display 23. Also,
In the storage space of these memories 15 and 16, the screen 23a
In correspondence with the scanning direction in , a main scanning direction X and a sub-scanning direction Y are defined.

On the other hand, color information CI indicating with what color the inside of the figure 50 is to be filled is inputted from the input device 11 and registered in the color information register 18 . Then, the X coordinate value X in the frame memory 15.

This color information CI is written in a storage area having the column address and the row address as the Y coordinate value Y and Y coordinate value Y, respectively. In this embodiment, a writing priority condition is adopted, so that even if color information has already been written to a corresponding address in the frame memory 15, new color information CI is written to that address. There is. When it is desired to write third color information determined by the mutual relationship between the already written color information and new color information CI into the frame memory 15, for example, a read modify write (RMW) circuit using an exclusive OR circuit is used. You can use .

Since such writing processing is performed for each line segment expressing pixel, the coordinate value X of the line segment expressing pixel (contour line expressing pixel)
, ,Y, are generated, the spatial pixel distribution (contour expressed by pixels) in FIG. 1(b) is stored in the frame memory 15.
The state expressed on the pit map will be obtained.

In parallel with such layering processing to the frame memory 15, the flag storage memory 16 (in the initial state, all
Cleared by OII. ) is written. This flag F is generated as a 7-lag F8 in the polygon processing circuit 12, and then is given to the exclusive OR gate 17 via the selector 14 (the flag after passing through the selector 14 is expressed as flag F). ing). The other input of the exclusive OR gate 17 is data F read from a storage area of the flag storage memory 16 whose column and row addresses are coordinate values X, Y, respectively. (flag value) is read. Then, the output of this exclusive OR gate 17 is the data F
. is written to the same address where it was stored.

The reason why the RMW format using exclusive OR is used in this writing is as follows. That is, in this embodiment, when the flag Ftfi is ``1'', it is specified that the pixel is a filled end point pixel, but when writing this flag F, it is necessary to satisfy the following three conditions.

(1) Flag value F that has already been written. When is "0", the value of the new flag F1 is written as is.

(2) When the already written flag value Fo is "1" and the new flag F1 is "O", the original flag value F. = ll I II is not erased.

(3) When both flags IF and F1 are "1", the flag value after writing is set to "0" because the filling start pixel and the end pixel overlap.

The exclusive OR circuit 17 is used because the logical operation that satisfies these conditions (1) to (3) is an exclusive OR.

Through the above processing, when writing of the flag F to the flag storage memory 16 is completed, a state in which the spatial pixel distribution shown in FIG. 1(C) is expressed in the bitmap format of the flag storage memory 16 is obtained.

The generation of coordinate values X, Y, and flag F in the polygon processing circuit 12 of FIG. Since writing is performed in parallel, the time required for each of these processes as a whole is short.

After writing to each of the frame memory 5 and flag storage memory 16 is completed, the address generation circuit 21
generates an address signal AD for sequentially accessing each address of the frame memory 5 in scanning line order. The concept of "scanning line sequential" is applicable to such access because the frame memory 5 and storage memory 16 are in a bitmap format that corresponds one-to-one with the screen of the CRT display 23. . therefore,
"Scanning line sequential" here means CRT display 2
This means that the access order corresponds to the scanning order on the screen 23a of No. 3.

This address signal AD is also supplied to flag storage memory 16. At this time, flag storage, memory 16
is in a readout enabled state, and the value of the flag F for each pixel is read out sequentially in scanning line order. However, for a pixel for which reading from the flag storage memory 6 has been completed, the flag for that pixel in the flag storage memory 16 is cleared to 0''.The signal indicating the value of this flag F is as shown in FIG. It is applied to a JK-7 lip 70 tube (JK-FF) 20 connected as shown inside.

Therefore, as shown in FIG. 4, for example, in readout scanning along one scanning line l, pixel P8. When pb is a filled end point pixel, the flag F is set to "1" between these pixels P and P, and the output of the JK-FF 20 is set to "1" between pixels P and P. This JK-FF20
The output of is the write enable signal WE of the frame memory 5.
It becomes. While these accesses continue, color information CI is provided to the frame memory 5 from the color information register 8.

Therefore, by synchronizing reading from the flag storage memory 16 and writing to the frame memory 15, data in the section sandwiched between two filled end point pixels along the X direction on the frame memory 15 is Color information CI is given to the pixel.

Pixels to which color information Cr is newly added through such filling processing are indicated by white circles marked with an X in FIG. 1(d).

The image data (FIG. 1(d)) generated in the frame memory 15 as described above is based on the contour line C in FIG. 1(a).
This is image data with the internal area filled in. Therefore, by sequentially reading out the filled image data from the frame memory 15 in scanning line order and decoding the color code using a color palette circuit 22 composed of a RAM or the like, a color image signal for each pixel can be obtained. If an image is displayed on the CRT display 23 based on the color image signal in synchronization with the electron beam scanning of the screen 23a of the CRT display 23, an image corresponding to FIG. 1(d) is obtained.

The apparatus 10 of FIG. 2 is also provided with a circle processing circuit 13 which is used to fill in the interior or exterior regions of circles rather than polygons. In this circle processing circuit 13, parameters expressing the size and position of a circle on the screen 23a are inputted from the input device @11 as circle specifying information SC. Then, pixel expansion of the circle and flag generation are performed by operations described below. Therefore, from this circle processing circuit 13, the main scanning coordinate value X of the circle-expressing pixel. and sub-scanning coordinate value Y,. and the fill end point instruction flag F. is given to the selector 14.

The selector 14 selects coordinate values xpc, 'l'p input from the circle processing circuit 13 in response to a switching signal SW given from the input device 11 during circle processing. and flag F.

, as coordinate values X, , Y, and flag F, memory 1
5.16 and exclusive OR gate 17, respectively.

The subsequent processing is basically the same as the polygon processing. That is, the line segment representation pixels in the above description may be replaced with circle representation pixels. And polygon processing circuit 1
2 and the circle processing circuit 13 do not operate at the same time; the former operates when polygon specifying information SP is given, and the latter operates when circle specifying information SC is given.

Further, the processing in the elements subsequent to the selector 14 in FIG. 2 is executed regardless of whether the figure is a polygon or a circle. Then, an arbitrary number of figures are written into the memories 15 and 16 in accordance with the input order,
After entering all the shapes (any number of polygons and any number of circles) that should be filled with the same color,
The filling operation shown in FIG. 1(d) is executed. When filling in different colors, the process starting from inputting the figure is repeated.

Therefore, in the following, the polygon processing circuit 12 will be explained in detail first, and the circle processing circuit 13 will be explained later.

Since these circuits 12 and 13 operate substantially independently of each other, only one of them may be provided.

8. Details of 3 Processing Times 12 FIG. 5 is a block diagram showing the internal configuration of the polygon processing circuit 12. The polygon specifying information SP input from the input device 11 in FIG. 2 includes the starting point coordinates (x
, y) and the end point coordinates S (X, V). The input of coordinate values for these line segments is performed along the contour line C in the order of counterclockwise or clockwise rotation. For example, in the example of FIG. 1, first the starting point C1 and the ending point C
2 coordinate values are input, and then the starting point C for line segment L2 is input.
2 and the coordinate values of the end point C3 are input, and finally the values of the start point C3 and the end point C1 of the line segment L3 are input. The polygon processing circuit 12 operates every time the start point coordinates and end point coordinates for each line segment are input. That is, this polygon processing circuit 12 processes each line segment in series. Note that it is arbitrary whether the information about each line segment is input clockwise or counterclockwise, and this does not dictate which area is to be filled.

The polygon specific information SP also includes a start/end signal vS
Contains E. This start/end signal vSE is
Whether the input line segment coordinate values are the first line segment (for example, line segment L1), the last line segment (line segment L3), or an intermediate line segment (line segment L3) along the contour line C. This is a signal for identifying whether it is the minute L2). This start/end signal SE is generated by the operator simultaneously performing a start/end input operation when inputting coordinate values from the input device 11.

The input start point coordinates (x, y), end point coordinates S (x, y), and start/end signal vSEE are registered in registers 101 to 103, respectively. Of these, the register 103 generates a contour start pulse 3 when the start/end signal VSE indicates the "first line segment". Also, when the "last line segment" is specified, the contour end pulse VE
(="H") continues to be generated. When the operator does not perform any input operation to generate the start/end signal VSE, thereby indicating an "intermediate line segment," neither pulses Vs nor vE are generated.

Coordinate values <x5, '/3) and (XE, yE
) is given to the preprocessing section 200 from the registers 101 and 102. The preprocessing unit 200 is provided to perform preprocessing for the straight line generation operation (pixel expansion of a line segment) in the straight line generator 300. In this embodiment, pixel expansion of line segments is performed according to Bresenham's algorithm. Bresenham's algorithm is one of the algorithms used in ODA (digital differential analyzer), and its details can be found in, for example, Bresenhai J, E.: "Algorithm
for ComputerControl of a
Digital Plotter”, IBM 5y
St. J., 4(1):25-30.1965, the outline of which is as follows.

(B-1) Overview of the Presenham algorithm In the Presenham algorithm, as shown in Figure 6, the starting point (x, y) J SS of the line segment L is the center, and the radius is equal to the length of the line segment. Consider a circle C8 with . However, the line segment and the circle C8 are expressed in a two-dimensional rectangular coordinate system, and in correspondence with this example, the main scanning coordinate axis X and the D1 scanning coordinate axis Y form this two-dimensional rectangular coordinate system. has been done.

The two-dimensional plane in Fig. 6 is divided into four quadrants from the first quadrant to the fourth quadrant by the coordinate axes X and Y.
This plane is subdivided into eight partial planes PL, ~PL8 by two straight lines α and β that form an angle of 45° with respect to the X and Y axes. Among these partial planes PL-PL8, seven partial planes PL-PL8 are used for exchanging the X-axis and Y-axis, reversing the sign of the X-axis (X→-X), and/or
Alternatively, by reversing the sign of the Y axis (Y→-Y), it can be made to coincide with the partial plane PL1.

That is, even if, for example, a line segment depends on the partial plane PL3 as shown by the virtual line in FIG. 6, the pixel expansion is performed as if it existed in the partial plane PL1. , by performing the above exchange/inversion operation on the result obtained, it is possible to obtain the pixel expansion result on the partial plane PL3.

Therefore, the pixel expansion of the line segment can be performed on the assumption that the line segment exists on the partial plane PL without losing its membrane properties.

When focusing on the partial plane PL1, the angle θ between the line segment existing in this partial plane PL1 and the X axis is O°≦θ
<Has a value within the range of 45°. In other words, if pixel 51 is a rectangle with length d in both the X and Y directions as shown in FIG. 7, then the Y coordinate on line segment LJ when the X coordinate changes by length d. The change is
The length is less than or equal to d. Therefore, when the line segment is expanded into pixels, the change in the Y coordinate when the X coordinate changes by the length d is limited to 0 pixels or 1 pixel.

Presenham's algorithm is a method of pixel expansion of a line segment according to the above-mentioned principles. (1) Determine which of the partial planes (octants) PL1 to PL8 the line segment L exists in; (1st process), (2) In the direction where the rate of change in the component of the line segment is large (X direction in the above example), change the X coordinate by N l II, and in the direction where the rate of change in the component is small (Y direction) is to perform pixel expansion of the line segment in the partial plane PL1 corresponding to the line segment L while changing the Y coordinate by "0" or 1" (second process), (3) above (1), (2 ) based on the result of line segmentation.

Identifying line segment representation pixels (third process),
Pixel expansion is performed by a combination of three processes.

(B-2) Details of the preprocessing unit 200 The preprocessing unit 200 executes the first process of the Presenham algorithm, and also generates line segment direction identification data ID ( (described later). This pre-processing section 20
The internal structure of 0 is shown in FIG.

In FIG. 8, the coordinate values (x, y), (XE.

Of S yE ), the X coordinates X and XE are given to the subtractor 201, and the Y coordinate values y and y are given to the subtractor 202, respectively. For this reason, the subtractors 201 and 202
From is the component (displacement) in the X and Y directions of the line segment.
: X sE= X EX s ””
(1) VSE= VE V3
”12) are output respectively.These components XSE
” SEs are held in registers 203 and 204, respectively.

The X-direction component X3E is provided to the sign determiner 205. The sign determiner 205 generates an X-direction mode pulse vHX when the sign of the X-direction component xSE is negative. Similarly, the sign determiner 206 determines the sign of the y-direction component "SE, and when the sign is negative, the Y-direction mode pulse VMY
occurs.

When the X-direction mode pulse VHx is generated, the sign of the X-direction component X8E (<0) is inverted in the sign inverter 207 at the next stage, and the X-direction distance dx is defined by the value obtained thereby. When the X-direction mode pulse vHx is not generated, the X-direction path 111dx is defined by the value of the X-direction component xSE itself. Therefore, in this sign inverter 207, the absolute value lX of the X direction component xSE
5El defines the distance dx in the X direction. The same applies to the sign inverter 208 in the Y direction, and from this sign inverter 208, the Y direction distance dV-IV
The value of 3El is output.

By the way, the X direction mode pulse V. Due to the occurrence of X, the line segment becomes the partial plane PL in the left half of FIG.
It is specified that it belongs to one of PL6. Also, when the Y-direction mode pulse ■MY occurs, the line is segmented, and the partial plane PL −PL in the lower half of FIG.
8. Therefore, these pulses v and ■ form part of the HX MY line segment direction determination information for determining the direction of the line segment LJ.

These pulses ``HX = ``MY'' are stored in a register 311.
It is also given in 312. Registers 311 and 312 hold 1N in the initial state, and the pulse vH
When X and vHY are respectively given, their held data is reset to "O". In other words, ff1(
X direction mode data MX and Y direction mode data MY
) indicates the directional mode of the line segment with respect to the X-axis and the Y-axis, according to the relationship shown in FIG.

The values of distances dx and dy output from sign inverters 207 and 208 in FIG. 8 are provided to a comparator 209. Comparator 209 mutually compares the values of these distances dx and dy, and outputs swap mode pulse VH8 when dx<dy. The fact that the condition dx<dy is satisfied means that the line segment LJ is the partial region tii! of FIG. P.L., P.L.
This means that it belongs to one of L, PL, and PL7. In this case, the angle between the line segment LJ and the X-axis is 45° or more. Therefore, when the swap mode pulse VH3 is generated, the swap circuit 210 in FIG. 8 exchanges the values of distances dx and dy with each other, and the resulting values are used to calculate the converted distance ΔX in the X direction and the converted distance ΔY in the Y direction, respectively. Define. Furthermore, when the swap mode pulse VH3 is not generated (that is, when dx≧dy), the converted distances ΔX and ΔY are defined by the distances dx and dy themselves, respectively.

In other words, ΔX=dy, ΔY=dX (when dx<dy)...(3) ΔX=dx, Δ
Y−dV (when dx≧dy) (4).

That is, when dx<dy, the X-axis and Y-axis are exchanged with each other so that the angle between the line segment and the X-axis is always in the range of 0° to 45°. Therefore, by the sign inversion and coordinate exchange as described above, even if the line segment does not exist in the partial plane PL in FIG. 9, the line segment can be treated as if it existed in the partial plane PL1 It becomes possible to perform pixel expansion of .

Swap mode pulse VH3 is also provided to register 313 in FIG. The register 313, like the registers 311 and 312, is set to 1'' in the initial state.Then, the swap mode pulse ■H
When 3 is given, the value held in register 313 (swap mode data MS) is reset to "O". Therefore, if we refer to the X-direction mode data MX, Y-direction mode data MY, and swap mode data MS, which are the values held in the registers 311 to 313, we can see that the line segment is a partial plane ( 8th circle) PL -
You can see which PL8 it belongs to.

FIG. 10 is a flowchart showing the operation of the microcomputer when the preprocessing circuit 200 is configured using software using a microcomputer. The operation in FIG. 10 is the same as the operation of the hardware circuit in FIG. 8, except that each process is performed in series, so a description thereof will be omitted.

Note that the conversion deviation (
The calculation ΔY−ΔX) corresponds to the subtraction (simulation) in the subtracter 107 in FIG.

The preprocessing circuit 200 in FIG. 8 is also provided with a line segment direction identification data generation circuit 250. The line segment direction identification data generation circuit 250 generates line segment direction identification data ID based on the direction of the line segment. This line segment direction identification data 10 is used, as will be described later, in determining whether or not a connection point between two line segments is to be a filled end point.

The value of the line segment direction identification data ID is determined based on the rules shown in FIG. In other words, the circle CB similar to that in Figure 6
When considering, depending on which direction the line segment is facing, the line segment direction identification data ID is set to OII~
Assign a value of “3”.

(1) When the line segment coincides with the vector AR pointing in the positive direction of the X axis: ID = "0", (2) When the line segment has a component in the positive direction of the Y axis (i.e., when belonging to area A): ID-“1”, (3) Line segment is vector A pointing in the negative direction of the X-axis
, when matching: ! D-“2”, (4) line segment,
has a component in the negative direction of the Y axis (i.e. area A
): ID-3".

The line segment direction identification data generation circuit 250 takes the value of the Y direction component "SE" in order to determine whether the line segment satisfies any of the conditions (1) to (4) above. As well as register 311.31 in FIG.
The values of direction mode data MX and MY are taken in from 2. FIG. 12 shows an operation flowchart when the line segment direction identification data generation circuit 250 is configured in software, and since the contents of FIG. 12 are self-evident from the above explanation and FIG. 9, Explanation will be omitted.

(B-3) Details of the linear generator 300 The values of the converted distances ΔX and ΔY output from the preprocessing circuit 200 are respectively latched by the latch circuits 104 and 105 in FIG. 5, and then given to the linear generator 300. . Also,
The subtracter 106 calculates the difference between these converted distances ΔX and ΔY, and outputs the converted deviation (ΔY - ΔX). The value of the converted deviation (ΔY−ΔX) is latched by the latch circuit 107 and then provided to the linear generator 300. By definition, the converted distances ΔX and ΔY are the absolute values lx
1.1y3El and SE ΔX=Max[l x l, lysEl]
...(5) SE △Y=Min[l x l , l y3E1 ]
-(6) There is a relationship of SE. However, Max[...], Min[・
] indicate the maximum value and the R small value, respectively. Further, the conversion deviation (ΔY−ΔX) has a value of zero or a negative value.

The internal configuration of the linear generator 300 is shown in FIG. For the purpose of understanding this internal configuration and operation, we will first define the following.

DX: This is a value that is decremented by 1'° each time processing for one pixel is completed in the decrement counter 301 in FIG. In the initial state, this decrement counter 301 has a converted distance ΔX in the X direction.
The value of is loaded. Therefore, when the processing for N pixels is completed, the result is DX-ΔX-N (7) (see FIG. 15). When the pixel expansion is completed over the entire length of the line segment, DX=O, and a processing completion signal SE1 for the line segment is output.

m: This indicates the cumulative number of times the pixel coordinates have been changed simultaneously in both the X direction and the Y direction up to that point when dividing the line segment and sequentially developing it into pixels. Therefore, for example, regarding line segment LJ in FIG. 7, when pixel development up to pixel 51 is completed, x=x, x3.
Simultaneous pixel coordinate changes in the X and Y directions are to be performed three times x5, so m=3.

n: This indicates the cumulative number of times that pixel coordinates change only in the X direction in pixel development up to that point. In the example of FIG. 7, X=X2. Such a change occurs in X4, resulting in n-2.

As already explained, in Presenham's algorithm, the Y coordinate changes by "OI+" or "1" for each pixel expansion.Also, the line segment changes by 4 with respect to the X axis.
Since the angle is less than 5°, the X coordinate is “1” every time.
“Only change.

Therefore, the total value (m+n) of the above-mentioned number values m and n is equal to the number of line segment representation pixels that have already been obtained (=N).

Xc, Yo: These respectively indicate the pixel occurring at that time (for example, pixel 52 in Figure 14) and the starting point (x,
SS and Y). By the definition of the number of times m and n, X c = m + n = N
= (8) Yc=m
...There is the relationship (9).

With the above preparations, a case will be described in which pixel development has already been completed up to pixel 52 in FIG. 14 and the next line segment representing pixel after pixel 52 is determined. The matter to be determined at this point is whether to use the pixel 54 adjacent in the X direction or the pixel 53 adjacent in the diagonal direction as the next line segment representation pixel. In other words, the distance in the X direction is X. It is necessary to determine whether to increase only the deviation by 1'' or to increase both the deviations X and Yo in the X and Y directions by 1.

This determination is based on Y at the center point 54a of the pixel 54 (FIG. 16).
Difference f between the coordinates and the Y coordinate of the corresponding point 56 on the line segment
If f ≦ 1/2 ... (11) is satisfied, the process proceeds to pixel 54, and f > 1/2 ... (1
This is performed according to the criterion that if the condition 2) is satisfied, the process proceeds to pixel 53. This standard is specified as follows.

Generally, when pixel expansion proceeds in a diagonal direction (that is, in a direction in which the X and Y coordinates increase by "1"), the difference f in the Y coordinates of the corresponding pixel and the corresponding point on the line segment LJ. (16th
In the figure, the difference fo for pixel 52 is depicted. )
changes by (ΔY/ΔX)-1...(13). Also, if the pixel expansion advances in the X direction, the difference f
0 is (ΔY/ΔX)...
(14) changes. Difference f. The initial value of is "0".

Therefore, the determination parameter e is set as: e=ΔX-fo-ΔX/2 (15)
If defined by, the value of this judgment parameter e is (
-Δx/2) as the initial value, it can be obtained by accumulating (ΔY - ΔX) each time the pixel expansion advances in the diagonal direction, and by accumulating ΔY each time the pixel expansion advances in the X direction. . and the difference f at pixel 52. Since the difference f at the pixel 54 and the relationship f = fo + (ΔY/ΔX) - (1G), the judgment condition for equation (12) is (1
5), by using equation (16), e 〉 −Δ
Y...(11). That is, the pixel to proceed to can be determined based on the magnitude relationship between the determination parameter e and (-ΔY). In addition, the number of times m, n
If we use e=m(ΔY−ΔX)+nΔY−(ΔX/
2)...(18) It can also be expressed as follows.

The above principle is schematically shown in FIG.
If ΔY, the pixel expansion proceeds in the diagonal direction, and if e≦ΔY, the pixel expansion proceeds in the X direction.

The straight line generator 300 in FIG. 13 is configured to operate in accordance with the above pixel expansion principle. At the start of operation, register 302 takes the value of the X direction translation distance ΔX and the value of (−ΔX/2) is loaded into it. The value held in this register 302 is the value of the determination parameter e, and the value of this determination parameter e is given to the sign determination circuit 305. The sign determination circuit 305 performs e>−
A pulse signal Sa is generated when 8Y, and a pulse signal Sb is generated when e≦−ΔY.

These pulse signals S and Sb serve as select signals for the selector 303;

occurs, the selector 303 selects one input (ΔY−
ΔX) side. Further, when the pulse signal Sb is generated, the selector 303 switches to the other input ΔY side. The input selected by the selector 303 is then given to an adder 304, where it is added to the value of the determination parameter e. The result of the addition is register 3
02 and held in this register 302. For this reason, register 302. A circuit consisting of an adder 304 and a selector 303 sets the value of the determination parameter e to (18
) has the function of calculating according to the formula.

The pulse signal S, ,S, has an X-direction deviation X. is given to a 7-p counter 306 for determining .

The up counter 306 is configured to increment by '1' even if either the pulse signal S or Sb is generated.This is because each time the pixel expansion advances by one pixel,
X direction deviation X. This is to make sure that it changes. On the other hand, the up counter 307 for determining the Y direction deviation is set to "1" only when the pulse signal Sa is generated.
is incremented by ''. This is only when the pixel expansion progresses in the diagonal direction due to e〉−ΔY.
Y direction deviation Y. This is to change the

X direction deviation X and Y direction deviation Y. The value of is provided to swap circuit 308. The swap circuit 308 converts the X and Y coordinates of the line segment expression pixel found in the partial plane PL1 when the line segment exists in the partial plane P2°PL, PL or PL7 in FIG. This is provided to obtain the line segment representation pixel coordinates corresponding to the line segment itself by exchanging the lines. That is, when the swap mode data MS obtained from the register 313 is O11, the swap circuit 308 adjusts the X direction deviation
and Y direction deviation Y. exchange values with each other. Such exchange is not performed when the swap mode data MS is 1''. Therefore, the X direction deviation dX and Y direction deviation dY, which are the outputs of the swap circuit 308, are d
X=X, dY,=Y.

C (when MS="1") ... (19) dX
=Y, dY, =X.

C (when MS="O") ... is given by (20). The swap/non-swap rules in swap circuit 308 are listed in Table 1.

Table 1 The deviation (jX,.) output from the swap circuit 308.

The value of dY is determined by the starting point coordinates X3. ” is added or subtracted from the value of S. Here, addition/subtraction can be switched using dX, dY,
This is done using the values of the X-direction mode data MX and Y-direction mode data MY according to the rules shown in the column. However, in Table 1, "+" indicates addition, and r-J indicates subtraction. To perform such addition/@calculation switching,
The starting point coordinates (xs) depend on which of the partial planes PL1 to PL8 in FIG. 9 the line segment L belongs to.

This is because the direction in which the line segment extends from ) is different. For example, in the partial plane PL3, the X coordinate of the line segment representation pixel is obtained by subtracting the X direction deviation dX from the X direction starting point coordinate XS, so (x
-dX, ) is calculated.

The main scanning coordinate value XPS and the n1 scanning coordinate I Y ps outputted from the computing units 309 and 310 in this way are as follows:
As described above, the signal is applied to the selector 14 in FIG. 2, and is then used as an address signal for the memories 15 and 16.

The straight line generator 300 of FIG. 13 is also provided with a fill flag set circuit 314. This filling flag set circuit 314 operates in such a way that (1) when swap mode data MS is "1" and pulse signal Sa is generated, (2) when swap mode data MS is "On" and pulse signal s8.Sb When any of the following occurs, a flag set pulse F, .1 is generated at .

This flag set pulse Fset is applied to the fill flag 0N10FF circuit 112 in FIG. 5, and is used as a basis for generating the fill instruction flag F8.

Among these, condition (1) is that when the absolute value of the angle between the line segment and the X axis is 45° or less, the sub-scanning coordinate value Y
,. This means that the filling instruction flag F8 is set only when . In other words, in the case of line segment expansion in this embodiment, a plurality of line segment expressing pixels 57a having the same sub-scanning coordinate Y.

57b (Fig. 18A) may be obtained, but if the fill end point indication flag is set for all of these line segment representation pixels 57a and 57b, one line segment, is considered to be a "filled end point" twice.

As a result, for example, filling is completed at the next pixel after the filling start pixel, and desired filling processing is not performed. For this reason, the fill instruction flag F8 is set only for the pixel 57a whose sub-scanning coordinates change from the pixel 59 immediately before. In FIG. 18A, flagged pixels are shown with diagonal lines.

Moreover, the condition (2) above is as shown in FIG. 18B.
When the absolute value of the angle between the line segment LJ and the X axis is 45° or more, a flag is set on all line segment expressing pixels 58. This is because in such a case, a plurality of line segment expressing pixels do not have the same sub-scanning coordinates.

Flowcharts when the above processing is executed by software are shown in FIGS. 19A and 198. However, FIG. 198 is a routine corresponding to step 811 in FIG. 19A.

The line segment expression pixel being processed is the end point of line segment 1-J (that is, 2
If the pixel does not correspond to the connection point of the book line segment), the fill flag 0N10FF circuit 112
is the flag set pulse F. Create CvJ based on 1.

In this state, the fill flag set pulse F. If 1 is given, overfill flag 0N10
The output signal F1 of the FF circuit 112 becomes H''.Furthermore, when the line segment expressing pixel being processed is not the end point of the line segment J,
OR'7'-to111 output signal G3 is also 'H'l' (
The reason will be explained later).

Therefore, the line segment representation pixel being processed is a line segment.

If the pixel corresponds to the upper intermediate point (that is, a point other than [Q), fill flag set pulse F,. If 1 is given, the fill instruction flag FS becomes “1”.
, Therefore, when processing the contour line (polygon) C8 shown in FIG. 20, among the line segment representation pixels shown by black circles, the pixels whose Y coordinates change (shown by squares). The fill instruction flag F8 (F) is “1” in
It is said that Connection points C11-016 of line segments 111-L16
The handling of is explained below.

Whether or not to assign a fill instruction flag to a connection point of a line segment is determined based on the relationship between the scanning direction on the screen 23a and the direction of two line segments that are mutually connected at that connection point. be done. That is, as shown in FIG. 21, the line segment direction identification data IDJI J2 (see FIG. 11) of the first and second line segments L and L connected to each other is any one of "0" to li 311. Depending on whether there is a connection point, it is determined whether to give a fill instruction flag F to the pixel corresponding to the connection point. However, in Figure 21, the inside square is F.

- Indicates a pixel that is "1".

The rules shown in FIG. 21 are also shown in Table 2. However, rlDlJ in Table 2.

rlD2j is line segment direction identification data J of line segments L and L.
I J2 Shows the evening.

Table 2 By applying such rules, e.g.
For the contour line Cb in FIG. 2, only the filling instruction flag F3 for the connection point marked with a square is set to "1". Therefore, for example, when filling in along the scanning line l, filling starts at the connection point C21 and ends at the connection point C24. If connection point 022. The fill flag F of C23 is also “1”
If it were, the filling would be completed once at the connection point C22, and a new filling would be started from the connection point C23. Therefore, determining the value of the flag at the connection point according to the rules shown in FIG. 21 (Table 2) is a useful technique for ensuring the accuracy of the filling process.

By the way, naturally, the connection point is the two line segments L and L
This is a point that belongs to both. For this reason, JI J
2 Add a flag to the connection point by dividing both lines, 1°L
, 2g1l, the flag assignment process will be duplicated. Therefore, in this embodiment, flag assignment is determined only from the line segment 'J2 side starting from the connection point.

For example, at the connection point C15 in FIG.
When performing pixel expansion of C15, it is determined whether to flag this connection point C15. However, when inputting line segment information counterclockwise from line segment L11 on outline C8 in FIG. 20, information on line segment 116 has not yet been input at the time when line segment L11 is input. Therefore, for the connection point C11 (that is, the last connection point formed), a flag value is assigned when performing pixel expansion of the last line segment L16.

In order to process such connection points, the line segment direction identification data ID output from the preprocessing circuit 200 in FIG. 5 is processed by two latch circuits ios and i.

It is given to 9. By applying the contour start pulse Vs from the register 103, the line segment direction identification data ID for the first line segment L11 in FIG. 20 is latched into the latch circuit 108. This latch circuit 108
The line segment direction identification data 10 latched in is expressed as r
It's called FIDJ and it's a ball.

The latch circuit 109 latches the value of the input line segment direction identification data ID every time processing of a new line segment is started. Further, the value of the line segment direction identification data 10 latched in this latch circuit 109 is latched in the next stage latch circuit 110 every time the processing of a new line segment is started. Therefore, each time processing of a new line segment is started, the value of the line segment direction identification data D for each line segment is transferred from the latch circuit 109 to the latch circuit '18110. Therefore, at any given time, the line segment being processed at that time (for example, the line segment L in FIG.
15) line segment direction identification data ID (102) and the line segment direction identification data I of the line segment L14 that was processed immediately before
D(IDI) are output from the latch circuits 110 and 109, respectively.

The rules in Table 2 are stored in advance in the connection information table memory 11 in the form of a lookup table. Then, data ID1. Depending on the value of ID2, the value of flag F is output as signal G1. Fill flag 0
The N10FF circuit 112 is configured so that when a pixel corresponding to the starting point of each line segment is generated, it is set/reset by the signal G1, and the held content is set as the output signal F1. Whether the generated pixel corresponds to the starting point can be determined by determining whether it is the first pixel generated in pixel expansion of each line segment.

Furthermore, in the processing for the last line segment 116, when a pixel corresponding to the end point of this line segment 116 is generated, the connection information table memory 111 stores data ID2 (Era), FID, instead of data IDI, ID2. These data ID2. are imported by referring to Table 2. A flag F8 corresponding to the value of FID is generated as a signal G1. At this time, data 101 (
PID) is not used.

In this process, it can be determined that the last line segment L16 is the last line segment L16 by inputting the contour end pulse VE.

Further, whether the pixel corresponds to the end point can be determined by referring to the processing completion signal SE1 output from the decrement counter 301 in FIG. 13. Therefore, the flag assignment determination regarding the connection point C11 in FIG. 20 is executed at the end of pixel expansion of the entire contour line Ca.

On the other hand, the main scanning coordinate XP output from the straight line generator 300
S and the sub-scanning coordinate Y, 8 are the buffer circuit 113.1
14 and then provided to the selector 14 in FIG. The sub-scanning coordinate YPs is also given to the comparator 115 in FIG. The comparator 115 calculates this sub-scanning coordinate Y,8 and the sub-scanning coordinate y of the end point of the line segment.
, and when they match, it outputs a signal G2 which becomes "y". This signal G2 is given to the OR gate 116 together with the contour end pulse V, and the output of the OR gate 116 is ANDed. The flag F3, which is the output of the AND gate 117, has the following value.

(1) When pixel coordinates for an intermediate point are generated:
Value according to fill set pulse Fset.

(2) When the pixel coordinates for the starting point of each line segment (excluding the first line segment) are generated: the value indicated by the output signal G1 of the connection information table memory 111.

(3) When a pixel coordinate equal to the Y coordinate of the end point of each line segment occurs (at this time, the output signal G2 of the comparator 115 becomes L''): OR gate 11 of AND gate 117
Since the input on the 6 side is 'L', the flag F8 is 0'' (for example, although the flag F3 should be '1' in the black circle on the left side of the connection point C11 in FIG. 20).

(4) When the pixel coordinates corresponding to the end point of the last line segment are generated (at this time, the contour end pulse V[ becomes "H" and the signal S[1 becomes 'H'), and the AND
One input G3 of the AND gate 117 becomes "H" via the gate 118. ): Output G1° (B-4) of the connection point information table memory 111 Summary of processing for polygons As described above, the polygon processing circuit 12 in FIG. and the value of flag F8 to be given to that pixel are sequentially output pixel by pixel. Whether or not to set the flag F8 for each line segment representation pixel is determined based on the intersecting relationship between the scanning line on the screen 23a and the pixel-represented contour line. Depending on the selection by the switching signal SW, the selector 14 outputs these coordinates X, Y and flag F8 as coordinates ps ps x, y and flag F. The subsequent processing is as already explained.

Therefore, for the contour line Ca in FIG. 20, its internal area is filled out on the frame memory 15 by the filling scan l shown by the arrow in FIG. The filled-in image is displayed on the screen 23a of the CRT display 23 in scanning line sequential order.

Details of the 00 yen processing circuit 13 On the other hand, the circle processing circuit 13 shown in FIG. 2 is used to fill in the inner region or the outer region of the contour line expressed by a circle. The circle processing circuit 13 executes ((2) pixel development of the contour line, (2) In parallel with the pixel development, fill-in instruction flag F.
It is common to polygon processing relation 12 in two basic functions: generating C.

However, in this circle processing circuit 13, (1) the coordinate value of the center point of the circle and the value of the radius of this circle are input from the input device 11 as data specifying the position and shape of the contour line; ) Processing is performed under different conditions than for figures whose outlines are polygons in that there are no connection points between line segments as in the case of polygons.

Corresponding to Presenham's algorithm in the case of polygons, in the circle processing circuit 12, Horn,B,P,;"C1rcle Generator for
0isplay DQvices", Compute,
Graphics Image Processin
G, 5.280.1976 (hereinafter referred to as [Hor
n) is called algorithm J. ).

This algorithm is also a type of algorithm for DDA.

Horn's algorithm is similar to Presenham's algorithm to a large extent.

That is, when the circle C3 shown in FIG. 24 is given as an outline, this circle CJ is divided into eight partial planes PL to P
Eight parts (arcs) B-88, each belonging to L8
Divide into. Then, the pixel expansion of the arc B belonging to the partial plane PL1 in the range of 0° to (+45°) from the X axis is performed. The pixel expansion of the other arcs B2 to B8 is performed by reversing the coordinate sign of the pixel expansion of the arc B1 and/or exchanging the X and Y axes. The X direction mode data MX, Y direction mode data MY and swap mode data MS are
Defining and using it as shown in the figure is the same as in polygon processing.

The angle φ between the tangent E1 and the X-axis at any point on the arc B1 is within the range of 45°≦φ≦90''. Therefore, the pixels in FIG. 25 obtained by expanding the arc B1 ( In the chain of circular arc expression pixels) 71, the Y coordinate is sequentially set to “1”.
It can be changed step by step. The change in the X coordinate of the arc expressing pixel 71 is "OF+ or 1". This situation is opposite to the case of polygon processing. The determination parameter e in the case of circle processing is determined according to the following principle.

The determination parameter e must be defined so that it can be determined which of pixels 73 and 74 should be adopted as the next arc expressing pixel at the time when pixel expansion is completed up to pixel 72 in FIG. 26A. It won't happen. So, first of all, the center point of the circle (X,

The coordinates of the center point 72a of the pixel 72 when yJ) is the origin are expressed by (X, Yo) as in the case of a line segment. At this time, the center point 73a of the pixel 73 whose both the X and Y coordinates are changing is expressed by the following coordinates: (X, -1, Y, +1). Also, pixel 7 where only the Y coordinate changes
The center point 74a of 4 is expressed by the coordinates: (Xo, Yo+1). Therefore, the distance R from the point (X, /) to the J point 73a and the distance R3 from the point (x, y,) to the J point 74a can be expressed as follows.

R2'=(X -1) +(Yo+1)...(2
1) R32c"+(Y +1) ・(22)-X
.

Moreover, the distance R1 from the point (X, V,) to the point 72a is R1′o2゜0. (23) =X +Y It is expressed as

Therefore, when proceeding from pixel 72 to pixel 73, the change in the square of the distance from the point (XJ, y, 1) ΔR
2' and the change ΔR3 when proceeding to pixel 74 are (
24), (251), respectively.

ΔR=R2" - R1 = (2Y +11 (2Xo-1) ... (24) ΔR=R-R1 -2Yo+ 1 - (25) Therefore,
The square of the distance between the point (x, y, 1) and the arc representation pixel is (2Y +1) - (2X -1) ... (2
6)C, and each time the pixel expansion advances in the Y direction, (2Yo
+1) -C2D changes.

Needless to say, if any point on the arc B and the center point (x,
The square of the distance to y, 1) is a constant value R1. Therefore, the cumulative value eA obtained by accumulating the values of equations (26) and (27) is an error that indicates how far the arc expressing pixel is from the arc B1.

At pixel 72 in FIG. 26A, the value of this cumulative value eA is e
Suppose that it is Ao. Then, when proceeding to pixel 74, the cumulative r1e A is calculated as e =
eA1=eAo ten (2Yc +i) −(28)
(See Figure 26B).

On the other hand, the error occurring at pixel 74 (formula (27)) and
The difference from the error caused by 3 (formula (2B)) of 0 is Q = 2
Xo-1.(29). Therefore, as seen from Figure 268, if e A1 < Q/2
-(30), then pixel 7
4 is closer to arc B1, e^1 ≧ G/2
... (31), the pixel 73 is closer to the arc B1 (the equal sign is included in equation (31) for convenience). Therefore, it can be seen that if the condition of equation (30) is satisfied, the process should proceed to pixel 74, and if the condition of equation (31) is satisfied, the process should proceed to pixel 73. In addition,(
Substituting equation 29) into equation (31), eAl ≧ Xo-(1/2)...
(32), but considering that the coordinate values can only take integer values, equation (32) becomes eAl ≧ Xc , ・(33
). Therefore, the value of the judgment parameter e is defined by the cumulative value eA of equations (26) and (27), and the value of the parameter eA1 obtained by adding the value of (2Yo+1) to this judgment parameter e and the value of the parameter eA1 at that time Directional deviation X. The pixel to proceed to next can be determined based on the magnitude relationship between the two pixels.

FIG. 27 is a block diagram of the circle processing circuit 13 formed in accordance with the above principle, and FIG. 28 is a flow chart when circle processing is performed by software. In the circle processing circuit 13 of FIG. 27, first, the radius R of the circle C4 is set in the register 4.
02 to the down counter 405. Also, 20'' is loaded into the up counter 406. These counters 405 and 406 are for holding the values of the X direction deviation X and the Y direction deviation Y. Correspondingly, the deviation is X.

The initial values of Y are “R” and “On” respectively, and CJ It is.

On the other hand, a register 404 that holds the value of the determination parameter e
is given "0" as its initial value. That is, since the value of the error eA in the pixel 75 is "0", the initial value of the determination parameter e is set to "OH".

Y direction deviation Y. The value is provided to multiplier 408, where it is multiplied by a constant value “2” from constant setter 410.

Adder 409 adds a constant value "1" from constant setter 407 to the resulting value.

Therefore, one input of adder 412 is (2Yo+1)
becomes. The other input of this adder 412 is given the value of the determination parameter e. Therefore, the output of the adder 412 is the parameter eA defined by equation (28).
It has a value of 1.

The value of parameter eA1 is given to determination circuit 403. This determination circuit 403 determines the deviation X in the X direction from the parameter eA1. It is used to determine the magnitude relationship between e^1≧
When Xc, pulse S. occurs. Also, e^
1. If xo, a pulse S is generated.

Among these pulses S and Sd, pulse S.

is given to selector 416 as a select signal. "0" is given to one input of the selector 416, and the data value (2Xo-1) is given to the other input. Of these, the data value (2Xo-1>) is created using a multiplier 411, a constant setter 410, 414, and a subtracter 415.

When the pulse Sc is generated due to eA1≧Xc, the selector 416 selects the data value <2Xo−1).
is output to the subtracter 417. The other input of this subtracter 417 is given the parameter eA1. Therefore, when pixel expansion should proceed diagonally, the data value (2Xo-1) is subtracted from the parameter "AI," thereby generating an updated determination parameter e. When the pulse SC does not occur, the selector 4
16 outputs "0" to the subtracter 417. Therefore, when pixel expansion should proceed in the Y direction, the parameter eA
The value of 1 itself defines the updated determination parameter e. The updated value of the determination parameter e is given to the register 404.

Therefore, with this configuration, (26), (2
7) The operation of accumulating the value of the expression and the judgment operation using the expressions (28) and (33) are realized.

On the other hand, the pulse S,8 is output by the up counter 40c'
d 6, and the Y direction deviation Y as the count value of the up counter 406, no matter which of these occurs. The value of is incremented by "1".

Further, when the pulse Sc is applied, the down counter 405 decrements by 1'', thereby decreasing the value of the X direction deviation X. by 1''. By this, eA
When 1≧Xc, pixel expansion progresses diagonally and eAl
<When Xc, pixel expansion proceeds in the Y direction.

The counter 419 is a 3-bit counter that has an initial value of ``111'' and decrements by 1'' when a clock signal (not shown) is applied.

This clock signal is generated at a cycle of ⅛ of the update cycle of the value of the determination parameter e. And the count value S. Each bit of register 421, 422, 423
are given to each. Registers 421, 422.42
The held value 3 corresponds to the values of the X-direction mode data MX, Y-direction mode data MY, and swap mode data MS, respectively. Therefore, a set of mode data (MX, M
Y.

MS) is the deviation X. , Yo, (111), (110),..., (000)...(34)
) takes eight values.

The swap circuit 424 and the arithmetic units 425 and 426 are the same as the swap circuit 308 and the arithmetic units 309 and 31 in FIG.
It has the same function as 0. However, arithmetic unit 425.42
6, the coordinates of the center point of circle C (x, y,
1) given J
There is J. Therefore, the arithmetic units 425 and 426 output the X-direction coordinate value X of the arc-expressing pixel. and Y direction coordinate value Y
,. is output.

Until the deviations Coordinate values occur consecutively. Similarly, for the other arc-expressing pixels, one set of coordinate values for a total of eight pixels is generated, one for each of the partial planes PL1 to PL8.

Swap mode data MS and pulse S. is given to the fill flag 0N10FF circuit 427 in FIG. Swap mode data MS is “1”, so that pixels are moved to partial planes P l-1, PL, PLr,
Alternatively, when the existence of the fill instruction flag F is specified in PL8, the fill instruction flag F is output from the fill flag 0N10FF circuit 427, regardless of whether the pulse SC is generated or not. becomes “1”. It is the partial plane PL
This is because the Y coordinate always changes in pixel expansion within 1° PL, PL and PL8.

On the other hand, MS="0", so that the pixels are located in the partial planes PL, PL3 . When instructed to exist in PL6 or PL7, the fill instruction flag F is set only when pulse Sc is generated. becomes “1”.

This means that these partial planes PL , PL , PL
And in PL7, deviations X and Y with respect to the processing result in partial plane PL1. It is related to the exchange that takes place. In other words, when the pixel expansion progresses diagonally in the partial plane P[1, the partial planes PL,2, PL3゜P
A change in the Y coordinate occurs in the pixel development of L and PL7. In this embodiment, in order to set the pixel in which the Y coordinate has changed as the filling end point, the filling instruction flag F is set by generating a pulse S.sub.2. is set to "1".

By repeating the above processing, when the pixel expansion on the partial plane PL1 reaches the position of the straight line α (Fig. 29),
≦Yo. By the way, as mentioned above, the partial plane PL
- Pixel development in PL8 is performed as a set of eight pixels that correspond to each other. Therefore, when the pixel expansion on one partial plane PL1 is completed, the pixel expansion on the remaining partial planes PL to PL8 is also completed. Therefore, comparator 418 outputs "X". and Y.

When Xo≦Yo is established, a processing completion signal SE2 instructing completion of pixel expansion for circle CJ is generated.

The coordinate value X, generated based on the above operations. ,Y
,. Flag F. is given to the selector 14 in FIG. In the case of circle processing, the selector 14 selects these coordinates 1i1X, Y and flag F by the switching signal SW. , the coordinate value x,.

Output as pc pc Y and flag F. The subsequent processing has already been described.

For this reason, for example, for pixel development as shown in FIG. 29, filling by the filling scan l shown in FIG. 30 is performed in the frame memory 15.

Note that in the case of circle processing, a circuit for processing singular points such as connection points is not required. This is because a circle is always convex toward the outside and does not have a concave portion like the polygon shown in FIG. 22, so one scanning line and one circle never intersect more than three times.

Since the flowchart in FIG. 28 is self-evident from the description of FIG. 27, its description will be omitted. However, step 821 in FIG. 28 is replaced by step S1 in FIG. 19B.
1, where (X, V)S is replaced with (x, y).

JD, Modification In the above embodiment, the filled image on the frame memory 15 is used to display on the screen 23a of the CRT display 23, but the filled image data can be displayed on other types of display devices or recording devices. may be provided to the device. It is also possible to provide this filled-in image data to the image processing device.

By modifying the configuration of the polygon processing circuit 12, it is possible to handle contour lines in general formed by connecting a plurality of line elements. A line element may be a curved line. Furthermore, by modifying the configuration of the circle processing circuit 13, it is also possible to handle closed curves in general that do not have connection points, such as ellipses.

Further, by adding a modification such as providing an inverter to the JK-FF 20 shown in FIG. 2, it is also possible to fill in the outside of the contour line.

The term "figure" in this invention is a concept that includes not only geometric figures but also figures forming letters and numbers.

(Effects of the Invention) As explained above, according to the present invention, since the pixel expansion of the outline and the generation of the filling instruction flag are performed in parallel, the filling process of the internal area or external area of the outline is performed. is carried out at high speed.

Furthermore, since a stack area with an uncertain storage capacity is not required, memory usage efficiency is high.

Furthermore, since processing can be performed regardless of whether the outline is traced clockwise or counterclockwise, there are fewer restrictions on the types of figures that can be handled.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the concept of an embodiment of the present invention, Fig. 2 is an overall block diagram of an image filling data generation device 10 used in the embodiment, and Fig. 3 is line segment information expressed in vector format. FIG. 4 is an explanatory diagram of flag reading from the flag storage memory, FIG. 5 is an internal configuration diagram of the polygon processing circuit 12, and FIGS. 6, 7, and 9 are illustrations of line segment pixels. 8 is an internal configuration diagram of the preprocessing circuit 200, FIG. 10 is a flowchart when preprocessing is performed by software, FIG. 11 is an explanatory diagram of line segment direction identification data ID, and FIG. 12 is a flowchart showing the generation operation of line segment direction identification data ID, FIG. 13 is a block diagram showing the internal configuration of the straight line generator 300, FIGS. 14 to 17 are explanatory diagrams of the operation of the straight line generator 300, and FIG. 18A and Fig. 188 is an explanatory diagram of pixels for which a fill instruction flag should be set. Fig. 19A and Fig. 198 are flowcharts when straight line generation is performed by software. Fig. 20 to Fig. 23 are connection point processing and filling processing. FIGS. 24 to 26 are explanatory diagrams of circle processing, FIG. 27 is a block diagram showing the internal configuration of the circle processing circuit 400, and FIG. 28 is a case in which circle processing is performed using software. FIGS. 29 and 30 are explanatory diagrams of filling in circles, FIGS. 31 and 32 are explanatory diagrams of the prior art, and FIG. 33 is a diagram showing an example of a figure whose directionality cannot be specified. 10... Image filling data generation device, 12... Polygon processing circuit, 13... Circle processing circuit, 15... Frame memory, 16... Flag storage memory, 23... CRT display, C , C, C,...contour line, XPS-YPS/Xpc-Ypc/XP/YP...pixel coordinates, FS, Fo, F...filling instruction flag, X...main scanning direction, Y/ ...Sub-scanning direction, l...Scanning line

Claims (2)

[Claims] (1) A method for generating filled image data in which an internal area or an external area of a desired figure is filled in in a frame memory having a storage space corresponding to a predetermined screen, the outline of the figure on the screen a first step of inputting contour line information expressing the position and shape of the line; obtaining a pixel-expressed contour line by pixel-expanding the contour line; and storing the pixel-expressed contour line in the frame memory. a second step of writing in a bitmap format on the pixel, and specifying the position of the filled end pixel in the scanning on the screen based on the intersecting relationship between the contour line expressed in pixels and the scanning line on the screen; a third step of writing a fill instruction flag indicating the position of the fill end point pixel in a bitmap format into a flag storage memory having a storage space corresponding to the screen; and reading the fill instruction flag from the flag storage memory. a fourth step of synchronously performing scanning and filling scanning of an internal area or an external area of the outline in the frame memory based on the filling instruction flag, thereby generating filled image data in the frame memory; A filled-in image data generation method using parallel processing, characterized in that the second step and the third step are executed in parallel. (2) The contour line is a polygon formed by a combination of multiple line segments, and the third step is whether to set a fill instruction flag for the pixels corresponding to the interconnection points of the line segments. is determined based on the relationship between the direction of each of the two line segments connected at the connection point and the scanning direction on the screen,
A filled-in image data generation method using parallel processing according to claim 1.