JPH09114435A - Data converting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To speedily convent outline data into image data showing gradation information for every pixel, by assuming a pixel corresponding to the boundary between pixel corresponding to the inside of the outline and pixel corresponding to the outside, to be intermediate density. SOLUTION: A CPU 10 reads outline data corresponding to a character code inputted from an input part 112 out of a font memory 16. The direction of a pixel array is set to the lateral direction and a gradation character image A having the periphery of the borderline represented by half-tone is generated from outline data in an outline buffer 141 in a working memory 14 and stored in a gradation buffer A142. The direction of the pixel array is set to the longitudinal direction and a gradation character image B having the periphery of the borderline represented by half-tone is generated and stored in a gradation buffer 143. The gradation character image A and gradation character image B are put together to generate a gradation character image C, which is written in an output image memory 18.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an output device such as a display device or a printing device capable of expressing gradation in pixel units.
It belongs to the technical field of a data conversion device that converts outline-type character shape data into image data in which the outline indicated by the outline is filled, and in particular, converts it into gradation image data in which the vicinity of the outline of the character is expressed in halftone. The present invention belongs to the technical field of a data conversion device.

[0002]

2. Description of the Related Art Conventionally, an output device such as a display or a printer for displaying or printing characters or symbols (hereinafter referred to as a character) is provided with shape data defining a shape of a character stored in advance. A data conversion device for converting into image data representing the information of the pixel is provided, and an image showing the shape of the character is displayed or printed based on the image data obtained by this data conversion device. As a display or printing result by this type of output device, a high quality one without conspicuous jaggies (irregularities of contour lines) is generally required. At the same time, the shape data of the character stored in advance is required to be as small as possible.

Therefore, as an output device for obtaining a high-quality output in which jaggies are not conspicuous with a relatively small amount of data,
There has been proposed a data conversion method that stores outline data that defines the shape data of a character by its contour line and converts the outline data into image data. According to this conversion method, it is possible to obtain image data of various sizes by simply storing shape data of one size in the output device, and to obtain high-quality image data that is relatively inconspicuous. You can

An example of a data conversion device based on this type of conversion system is, for example, Japanese Patent Laid-Open No. 11656/1990 by the present applicant.
As disclosed in Japanese Patent Publication No. 5, it is assumed that the outline data stored in advance is read out, enlarged / reduced and converted according to the output size, and superposed on the pixel screen defining the pixels of the output device. There is a method in which a pixel (for example, a pixel whose center is inside the contour line) determined to be in the outline data when the pixel satisfies a certain criterion is turned on. According to this data conversion device, it is possible to obtain image data having a smooth contour in accordance with the fineness of pixels.

Further, as a data conversion device using this kind of conversion method, an output device capable of expressing gradation in pixel units is used, and binary image data stored in advance, or
There is one that converts the image data obtained from the outline data into a gradation image in which the vicinity of the contour is expressed in halftone. For example, according to a study by the present inventors, binary image data stored in advance is used to generate monotone image data in which ON pixels are set to the maximum density and OFF pixels are set to the minimum density, and each pixel is generated. , The average of the density of the pixel on the monotone image data corresponding to the pixel and the density of the pixel on the monotone image data corresponding to the pixel next to the pixel (either left, right, top or bottom). It is possible to obtain gradation image data with. According to the research conducted by the present inventors, it has been found that with such a configuration, it is possible to obtain a high-quality display / printing result in which the edge portion is blurred and the jaggies are inconspicuous with a relatively small amount of data as in the past. ing.

[0006]

In the output device for displaying, printing, etc., there is a general demand for displaying, printing, etc. of higher quality at a higher speed.

However, the above-mentioned conventional Japanese Unexamined Patent Application Publication No. 2-
In the data conversion device disclosed in Japanese Patent No. 116565,
Since the outline data is converted into binary image data, that is, pixel on / off image data, even if the image data is generated from the outline data, there is no deterioration in quality due to jaggies in pixel units, which is the minimum expression unit of the output device. There is an unavoidable problem. This degradation in quality is due to the large pixel size relative to the character size.
In other words, when the resolution of the output device is low, it occurs remarkably.

Further, since the above-described conventional data conversion apparatus for expressing the vicinity of the contour in halftone converts image data into gradation image data, it is necessary to temporarily generate gradation image data from outline data. In addition, it is necessary to develop the binary image data, and it takes a lot of processing time to obtain the output data. As a result, there is a problem that quick display, printing and the like become difficult.

The present invention has been made in view of the above-mentioned conventional problems, and it is an object of the present invention to provide a data conversion device capable of converting outline data into image data indicating gradation information in pixel units at high speed. To do.

[0010]

In order to solve the above-mentioned problems, a data conversion device according to a first aspect of the present invention is a pixel for an output device capable of gradation-expressing outline data indicating a contour line of a character in pixel units. A data conversion device for converting image data indicating gradation information in units, wherein a pixel corresponding to the inside of the contour line and a pixel corresponding to the outside of the contour line are determined on an output image of the output device. Determination means, and a pixel determined to correspond to the inside has a first density, a pixel determined to correspond to the outside has a second density different from the first density, and corresponds to the inside of the contour line. Image data generating means for setting the pixel corresponding to the boundary between the pixel and the pixel corresponding to the outside of the contour line as the third density.

According to the data converting apparatus of the first aspect, the determining means determines the pixel corresponding to the inside of the contour line and the pixel corresponding to the outside of the contour line on the output image of the output device, and the image is obtained. Pixels that are determined to correspond to the inside by the generation unit have the first density and pixels that have been determined to correspond to the outside have the second density different from the first density, and further correspond to the inside of the contour line. The pixel corresponding to the boundary between the pixel and the pixel corresponding to the outside of the contour line is the third density. Therefore, the outline data can be directly converted into the image data indicating the gradation information.

A data conversion apparatus according to a second aspect is the data conversion apparatus according to the first aspect, wherein the first density is the maximum density of the output device and the second density is the minimum density of the output device. , The third density is an intermediate density of the output device. Therefore, by the image data generating means, for example, a pixel having the highest density such as “black”, a pixel having the lowest density such as “white”, and
For example, a pixel with an intermediate density such as "gray" is obtained,
As a whole, the image data having the intermediate density in the vicinity of the contour line can be obtained by a relatively simple process.

According to a third aspect of the present invention, there is provided the data conversion apparatus according to the first or second aspect, wherein the determination means superimposes the outline data on a pixel coordinate which is a coordinate system defining a pixel of the output device. On the assumption that the pixel has a positional relationship with the outline data that satisfies a certain criterion, it is determined that the pixel corresponds to the inside of the contour line. Therefore, whether each pixel corresponds to the inside or the outside is determined by a relatively simple process.

A data conversion device according to a fourth aspect is the data conversion device according to any one of the first to third aspects, wherein the determination means is a pixel that is a coordinate system that defines the pixels of the output device by the outline data. Assuming that they are superimposed on the coordinates, the positional relationship with the outline data is determined based on the intersection of the scanning line in a certain direction provided on the pixel coordinates and the outline data. Therefore, if scanning lines in a fixed direction are sequentially shifted so as to cover one output screen, it is determined whether or not each pixel corresponds to the vicinity of the contour line for each row of pixels in the fixed direction. The relatively simple determination of the one-dimensional array is sequentially repeated. As a result, a two-dimensional array of pixels that finally covers one output screen, which is one of the first, second, and third densities, can be obtained at high speed by relatively simple processing.

According to a fifth aspect of the present invention, there is provided the data conversion apparatus according to the fourth aspect, wherein the determining means determines two different directions on the output image as the constant direction. Therefore, by the judging means,
The pixel corresponding to the intersection with the contour line in the two directions is set to the third density, and as a result, the determination unit makes a relatively simple determination of the one-dimensional array, and finally the inside of the contour line. Pixels of the third density are arranged so as to surround the area two-dimensionally.

According to a sixth aspect of the present invention, there is provided the data conversion apparatus according to the fifth aspect, wherein the image data generating means is a pixel determined to correspond to the boundary in one of the two different directions. And the pixel determined to correspond to the boundary in the other direction of the two different directions, the matched pixel is defined as the third density, and the boundary in the one direction corresponds to the boundary. When the determined pixel and the pixel determined to correspond to the boundary in the other direction are different from each other, the different pixel is determined in advance as the first pixel.
One of the density and the third density is used. Therefore, if the determination unit determines that the pixels corresponding to the intersections of the contour lines in the two directions match each other, the pixel has the third density, and if the pixels have different pixels, the pixel has the first density or the third density. More preferably, in this different case,
If it is determined in advance that the density is the third density, the determining unit finally arranges the pixels of the third density so as to two-dimensionally and finely surround the inside of the contour line.

A data conversion apparatus according to a seventh aspect is the data conversion apparatus according to any one of the fourth to sixth aspects, wherein the determination means determines as the constant direction two different directions on the output image, or It further comprises an instruction means for instructing whether to make a determination for one direction, and the determination means determines whether to make a determination on the two different directions or on the one direction according to an instruction from the instruction main stage. Characterize. Therefore, depending on the quality of the output image required by the output device, for example, if you want to speed up the process, sacrifice some quality,
Judgment is made only in one direction by the judgment means,
On the contrary, if you want to improve the quality, sacrifice some processing time,
The determination means makes determinations in two directions.

The data converter according to claim 8 is the data converter according to any one of claims 4 to 7, wherein the two different directions are a main scanning direction and a sub-scanning direction of the output device. Characterize. Therefore, the outline data, which is usually defined based on the main scanning direction and the sub-scanning direction, is processed extremely efficiently.

According to a ninth aspect of the present invention, there is provided the data converter according to any one of the first to eighth aspects, wherein the determining means determines the pixel corresponding to the intersection based on a non-zero winding number rule. Is characterized by. Therefore, the pixels corresponding to the intersections are efficiently and sequentially determined by the determination means according to the non-zero winding number rule.

The data converter according to a tenth aspect is the data converter according to any one of the first to eighth aspects, wherein the determining means determines a pixel corresponding to the intersection based on an odd-even rule. And Therefore, the pixels corresponding to the intersections are efficiently and sequentially determined by the determination means according to the odd-even rule.

The data converter according to claim 11 is the data converter according to any one of claims 4 to 10,
The determining means may determine a pixel corresponding to the inside of the contour line and a pixel corresponding to the outside of the contour line for each row of pixels in the certain direction. Therefore, by sequentially shifting the pixel arrangement in a fixed direction so as to cover one output screen, whether each pixel corresponds to the inside or the outside of the contour line for each pixel arrangement in the fixed direction. , Or whether it corresponds to the intersection with the contour line, that is, the relatively simple determination for the one-dimensional array is sequentially repeated by the determining means. As a result, the two-dimensional array of pixels covering one output screen, which has one of the first, second and third densities, is generated by the two-image data generating means.
It can be obtained at high speed by relatively simple processing.

[0022]

Embodiments of the present invention will be described below with reference to the drawings. In the embodiment described below, in a character display device provided with a display device that can express the output density of each pixel as 0 to 15 (the higher the density, the higher the density, and the same hereinafter),
The form which applied this invention to the data converter which produces | generates the character image for output is shown. More specifically, the apparatus shown in the present embodiment is a multi-gradation character image in which outline data defining a shape of a contour line of a character stored in advance is expressed in halftones. It is a data conversion device for converting into a character image.

FIG. 1 shows the configuration of an output device equipped with the data conversion device of this embodiment. In FIG. 1, an output device according to the present embodiment includes a CPU (central processing unit) 10, a program memory 12, a working memory 14, a font memory 16, an output image memory 18, an input unit 112, a display control unit 114, and a CRT (cathode ray). Tube display)
It is configured with 116. These components are:
The output devices are connected to each other via a communication bus 110, and are configured to exchange data with each other.

The CPU 10 performs control for realizing the functions of the apparatus according to the present embodiment, and the program memory 1 including a ROM (read only memory) and the like.
It functions as an example of the determination means and the image data generation means of the present invention according to the program defining the control procedure stored in 2.

The working memory 14 is a RAM.
(Read / write memory) and the like, and processes the program stored in the program memory 12 by C
It stores temporary data when it is executed by the PU 10, and includes a contour buffer 141, a gradation buffer A 142, and a gradation buffer B 143 used in the processing in this embodiment described later.

The font memory 16 is composed of a ROM, a RAM and the like, and stores the shape of the character as outline data in advance. The output image memory 18 is R
It is composed of AM or the like and stores the gradation character image generated by the data conversion processing of the present embodiment. The data format stored in these memories will be described in detail later.

The input unit 112 is a unit for inputting a character code of an output character, an output size and a composition flag, and is composed of, for example, an interface for receiving data transmitted from a host computer. Here, the combination flag is information used in the processing in the present embodiment described later, and is information indicating that the combination flag is on if the flag is on and does not combine if the flag is off. It should be noted that the command for instructing the output size and the composition should be input from the input unit 1 such that it is input from an input device such as a keyboard or mouse.
12 may be configured.

The display control unit 114 reads out the gradation character image stored in the output image memory 18 and displays it on the CRT 116. Note that the processing of displaying an image expressed in gradation on a CRT, that is, the processing of the display control unit 114 and the CRT 116, is a technology that has already been put to practical use in various systems, and is a main part of the present invention. is not. Therefore, detailed description is omitted for the purpose of clarifying the gist of the present invention.

The outline data stored in the font memory 16 will be described below. The outline data represents the shape of the outline of the character with a plurality of straight lines and curves, and is a collection of information of coordinate values that define the straight lines and curves. The outline data of this embodiment is composed of an array of a pair of point data composed of flag data and coordinate value data, and point data. The curve format is quadratic or cubic Bezier curve, 2
Although a B-spline of the next degree is generally used, it is expressed by a cubic Bézier curve in this embodiment. Therefore, hereinafter, all references to a curve are cubic Bezier curves.

The above-mentioned flag data is data indicating the type of information of point data. The types of point data in this embodiment include a starting point of a contour line, an ending point of a straight line, a control point of a curve, and an ending point of a curve. The coordinate value data is data indicating the position of the point data by the x coordinate value and the y coordinate value. Furthermore, the point data described above is data indicating the number of arrays of point data.

The arrangement order of the array of the point data is such that the contour line is traced in one direction. According to this rule, the coordinate value of the starting point of the straight line or the curve can be defined as the straight line, the ending point of the curve, or the starting point of the contour line defined immediately before. In addition, even if the outline data of the character is defined by a plurality of contour lines, the array of point data is such that the flag data of the point data is defined by the start points of the contour lines.
The start of the next contour can be identified so that it fits within one array. In the present embodiment, when the outline data is defined by a plurality of contour lines, the inside of the contour line is the contour line inside the outline data (hereinafter, the outer loop depending on the method of the filled area determination processing described later). Is called), and the inside of the outline is the outside of the outline data (hereinafter referred to as the inner loop), the alignment order of the point data, that is, the rotation direction that follows the outline is counterclockwise and clockwise. Need to be set in different directions. Therefore, in this embodiment, the outer loop is aligned in the counterclockwise direction and the inner loop is aligned in the clockwise direction and stored.

FIG. 2 shows the font memory 16 of this embodiment.
An example of the outline data in is shown. FIG. 2 (a)
A conceptual diagram of the shape represented by the outline data is shown, and a conceptual diagram of the data in the font memory 16 is shown in (b).

In FIG. 2A, the character b is represented by two contour lines, a contour line 2 and a contour line 3, and an area between the contour lines 2 and 3 becomes an image of the character. That is, the shape of the character is obtained by painting this area. Further, the contour line 2 is an outer loop and the contour line 3 is an inner loop. Points 21 to 29 and points 31 to 37 indicate the positions of the point data. The shape of the mark indicating the point data represents the flag data, and the ○ mark indicates the end point of the straight line.
The mark indicates the end point of the curve, the x mark indicates the control point of the curve, and the □ mark indicates the start point of the contour line. In the method of the present embodiment, the point data at the end point of the contour line is not shown because the coordinate value data coincides with the start point of the contour line and cannot be shown separately.

The point data xn and yn (n is a subscript) of FIG. 2B represent coordinate value data, and the coordinate value data of the point n of FIG. 2A are represented by xn and yn. Further, the alphabet represents flag data, where the start point of the contour line is S, the end point of the straight line is L, the control point of the curve is A, and the end point of the curve is C.

The gradation character image stored in the output image memory 18 will be described below. The gradation character image is data in which the shape of the character is represented by information of each pixel of the output device. In addition, the information of each pixel is data that represents the density of the pixel by a numerical value.

FIG. 3 shows an example of the gradation character image of this embodiment. 3A is a conceptual diagram of an image represented by a gradation character image, and FIG. 3B is a conceptual diagram of a gradation character image.

An image of a character as shown in FIG. 3 (a) is expressed as shown in FIG. 3 (b). The numerical value written in the grid representing a pixel represents the density (0 to 15) of that pixel.
The process of converting the outline data of the present embodiment into a gradation character image will be described below with reference to the flowchart of FIG. It should be noted that this process starts after the character code, the output size, and the combination flag are input from the input unit 112.

In FIG. 4, first, the outline data corresponding to the character code input from the input unit 112 is read from the font memory 16 (step S4).
1) The outline data is enlarged / reduced according to the output size (step S42).

Next, the direction of the pixel array is set to the horizontal direction, that is, x
A gradation character image A in which the vicinity of the contour line is expressed in halftone is generated from the outline data in the contour buffer 141 in the working memory 14 by setting in a direction parallel to the axis, and the gradation buffer in the working memory 14 is generated. A14
2 (step S43). The details of the process of step S43 will be described later.

Next, the composition flag input from the input unit 112 is checked to determine whether composition is required (step S).
44). Here, if the synthesis flag is off (NO),
The process of step S45 is executed. If it is on (YES), the processes of steps S46 and S47 are executed.

In step S45, the working memory 1
The gradation character image A stored in the gradation buffer A 142 of No. 4 is written in the output image memory 18. In step S46, the pixel array direction is set to the vertical direction, that is, the direction parallel to the y-axis, and the outline data in the outline buffer 141 of the working memory 14 is used to express the vicinity of the outline in halftone. The tone character image B is generated and stored in the tone buffer B143 in the working memory 14. The details of the process of step S46 will be described later as with the process of step S43.

In step S47, the gradation character image A in the gradation buffer A 142 in the working memory is displayed.
And the gradation character image B in the gradation buffer B 142 are combined to generate a gradation character image C,
Write to the output image buffer. This synthesis is performed by setting the density of each pixel of the gradation character image C to the smaller one of the density of the pixel of the corresponding gradation character image A and the density of the pixel of the corresponding gradation character image B. .

The above processing will be described with reference to FIGS. FIG. 2A represents outline data in the contour buffer 141, that is, outline data read from the font memory 16 (step S41) and transformed into a desired size (step S42). From this data, a gradation character image A, which is a gradation character image in which the pixel arrangement direction is set to the horizontal direction, is generated (step S43). The gradation character image A in the gradation buffer A 142 is shown in FIG. Here, the composition flag is checked (step S4).
4). Since the synthesis flag for this character is ON, a gradation character image B, which is a gradation character image in which the direction of the pixel array is set to the vertical direction, is generated from the outline data in the contour buffer 141 (step S46). The gradation character image B in the gradation buffer B143 is shown in FIG. Next, FIG.
The gradation character images of (a) and (b) are combined by making the density of the corresponding pixel smaller, as the density of the pixel (step S47). The result is the data shown in FIG. 3 (b).
(A). It should be noted that it may be determined in advance that the corresponding higher density is used as the data for that pixel.

Next, steps S43 and S46 described above.
The process of generating the gradation character image of will be described. To simplify the explanation, the process flow is
The direction of the pixel array performed in step S43 is the horizontal direction, that is,
An example of setting the direction parallel to the x axis will be described. It is easy for a person skilled in the art to set the direction of the pixel array in the vertical direction or to set the direction in an arbitrary direction such as an oblique angle of 45 degrees because it is simply the difference in the direction of the outline data on the coordinates representing the pixels. Can be imagined. Therefore, all the cases are explained by describing an example in which the direction of the pixel array is set to the horizontal direction, that is, the direction parallel to the x axis.

First, the data used in the processing will be described with reference to FIG. FIG. 6A shows a state in which the outline data 61 is superimposed on the pixel screen 76 representing the coordinate system of the pixels of the output device. The numerical values shown near the x and y axes in the figure are the coordinates of the pixel, and the straight line indicated by the alternate long and short dash line represents the straight line passing through the center of the pixel. The pixel array in the horizontal direction is an array of pixels having the same y coordinate, and pixels existing on a straight line passing through the center of the pixel described above are the respective pixel arrays.

Further, FIG. 6B shows a conceptual diagram of data called an intersection list of the data of FIG. 6A. This data is generated as temporary data in the gradation character image generation processing described below. The data is composed of pixel array data 63, intersection point data 64 and intersection point data 65.

The pixel array data 63 is information for identifying a plurality of pixel arrays and is the y coordinate value of the pixel array. The intersection point data 64 is the number of the intersection point data 65,
The intersection data 65 represents information on the intersection of the outline data and the center line of the pixel for each intersection.

The intersection data 65 is the x coordinate value of the intersection,
It is composed of direction information and flag information. The intersection data 65 are sorted in ascending order by x-coordinate value.
The x-coordinate value is information indicating the x-coordinate value in the coordinate system of the pixel, which is the intersection or the position of the pixel at both ends of the filled area.

The direction information indicates the vector direction of the outline data at the intersection. The vector direction of each contour line of the outline data in this embodiment is based on the storage order of the point data defining the contour line. As described above, in the present embodiment, the vectors of the contour lines of the outer loop and the inner loop are in the reverse rotation directions.
The outline data in the example of FIG. 6 is represented by the arrow 6 in FIG.
It is assumed that the contour vector is set in the directions indicated by 6 and 67. The direction information is 1 when the outline crosses a straight line representing the center of a pixel in the y coordinate increasing direction (from top to bottom in the figure), and when it crosses in the y coordinate phenomenon direction (from bottom to top in the figure). It is represented by -1.

Further, when the intersections are read out in an aligned manner, the flag information is 1 if the intersections represent the start point of the filled area, 2 if the intersections represent the end point, and 0 if neither. This is information to represent.

Next, the process of generating the gradation character image will be described with reference to the flowchart of FIG. First,
In step S71, the intersection of the outline data and the straight line passing through the center of the pixel is obtained, the above-mentioned intersection list is generated, and stored in the intersection list buffer (not shown) in the working memory 14. In this processing, the x coordinate value of the intersection data 65 in the intersection list stores the x coordinate value of the intersection when the pixel coordinate system is regarded as a continuous space. Also,
All of the flag information is set to 0.

Next, in step S72, both ends of the filled area are determined and flag information of the intersection list is set. This processing can be performed by various existing methods for deriving a filled area, but in this embodiment, two methods described later will be described. Therefore, it is not limited to the two methods. According to the intersection list generated here, the intersection data 65 is read out in the order of arrangement, so that the portion from the x-coordinate value having the flag information 1 to the x-coordinate value having the flag information 2 forms an image of the outline data. That is, it can be recognized that it is inside.

Next, in step S73, the x coordinate value of the intersection point data 65 of the intersection point list is converted from the coordinate value of the intersection point to the coordinate value of the pixel. In the present embodiment, the definition of a pixel to be turned on is a pixel whose center is included inside the contour line. Therefore, the x-coordinate value of the intersection data 65 having the flag information of 1 is the coordinate value of the pixel including the center of the nearest pixel on the right of the intersection, and the x-coordinate value of the flag information of 2 is the left of the intersection. It is set to the coordinate value of the pixel including the center of the nearest pixel.

Next, in step S74, a gradation character image in which the vicinity of the contour line is expressed in halftone is generated in the gradation buffer. More specifically, the intersection point data 65 is sequentially read for each pixel array, the start point and the end point of the area where each pixel is present are halftone density 7, and the pixels between the start point and the end point are each maximum density 15. The expressed character image data is generated and stored in the gradation buffer.

The method of steps S41 to S47 and steps S71 to S74 is executed by the configuration using the instruction means in the present invention.
That is, the processes of steps S71 to S73 are the first and second.
The processing of step S74 corresponds to the processing by the determination means, the processing by the image data generation means, and the input unit 1
The synthesis flag input from 12 corresponds to the instruction by the instruction means.

FIG. 11 shows an example in which data conversion is performed on another character according to the present embodiment. FIG.
11A shows the outline data obtained in steps S41 to S42 described above, and FIG.
The gradation character image A which processed the data of (a) by the process of step S43 mentioned above is shown. In this character image, the gradation character image B that has been subjected to the process of step S46 has only a slight difference from the gradation character image A shown in FIG. The pixel indicated by the arrow in FIG. 11B is a portion different from the gradation character image B, and the numerical value indicates the density in the gradation character image B. Therefore, step S
It is clear that the gradation character image C obtained at 47 has only a slight difference from the gradation character image A. In an apparatus in which high speed is desired even if the quality is deteriorated to some extent, in such a case, that is, the gradation character images A and B are generated, and the gradation character image C obtained by combining them is further generated. When the quality is not so different from that of the gradation character image A or B, the gradation character image A or B can be output from the data converter.

This is because the synthesis flag is turned off and the input unit 1
By inputting information from 12, the optional processing is omitted, that is, when the composition flag is off, the gradation character image A is written as it is in the output image memory 18 (steps S44, S45). A gradation character image can be formed as output data.

In order to reduce the amount of information to be input,
To simplify the process, without using the above composition flag,
It is also possible to form a gradation character image in the output image memory 18. That is, step S44 and step S45 in the flowchart shown in FIG.
It becomes possible by removing the processing of.

Further, when the present invention is applied to an apparatus in which a simple gradation character image is sufficient and requires higher speed processing, steps S41 to S4 described above are used.
The gradation character image A generated by the processes up to 3 can be stored in the output image memory 18 as it is.

Next, two methods that can be applied to the determination of the filled area in step S72 will be described. 2
Each of the two methods is an example in which a rule for determining a filled area on a straight line vector that crosses outline data when converting outline data into binary image data is applied. One of them is the non-zero winding number rule (Non-Zero
Winding Number Rule) and the other is the even-odd rule.
e).

According to the non-zero winding number rule, first, a counter called a winding number is provided and 0 is cleared. Next, check the straight line from the end, and if it intersects with the outline data, increment the winding number if the outline intersects the straight line in the forward direction (here, from left to right with respect to the vector direction of the straight line). If they intersect in the opposite direction, decrement the number of turns. In this way, the non-zero winding number rule is a rule in which the number of windings is checked while setting the number of windings, and the portion where the number of windings is not 0, that is, the portion where the number of windings is non-zero is filled. There are prerequisites to using this rule,
It is necessary to give the outline of the outline data directionality, and it is necessary to reverse the direction in the outer loop and the inner loop. This is mentioned above.

Further, the even-odd rule is to check the straight line vector from the end, and when it intersects with the outline, if it is an odd number of intersections, fill in the subsequent region, and if it is an even number of intersections, It is a rule that determines not to fill.

The known advantages and disadvantages of these two methods are as follows. One point is that the non-zero winding number rule requires more processing time than the odd-even rule and therefore requires a longer processing time, and also has many prerequisites for outline data. Another point is that the non-zero winding number rule can correctly determine a filled area (FIG. 8C) even when a plurality of contour lines define the same area (FIG. 8A). Is not filled (Fig. 8 (b))
That is. It should be noted that this detail is not a main part of the present invention and is a well-known fact, and therefore its explanation is omitted.

Therefore, when the outline data handled in the apparatus does not have the data as shown in FIG. 8A, it is desirable to determine the filled area based on the odd-even rule, and as shown in FIG. 8A. If there is data, the correct filled area cannot be determined without the non-zero winding number rule.

The filled area determination processing according to the present embodiment to which these two methods are applied will be described with reference to the flowcharts of FIGS. 9 and 10. As mentioned earlier, step S
In the process of 71, a list of intersections of straight lines passing through the centers of pixels and outlines has already been generated. It should be noted that the flowchart shows the processing in one pixel array.

First, a method based on the non-zero winding number rule is shown in FIG.
This will be described with reference to the flowchart of. In FIG. 9, first, the crossing point of interest is set to the first crossing point, the crossing counter, the winding number counter, and the previous winding number counter are initialized to 0 (step S91), and the outline intersecting from the direction information of the crossing point data 65 of the crossing point of interest is in order. It is determined whether or not they intersect in the direction (step S92). That is, the direction information is 1
In the case of, it is determined to be the forward direction (YES), the process proceeds to step S93, and the winding number counter is incremented. If the direction information is -1, it is the reverse direction (NO), and the process proceeds to step S94 to decrement the winding number counter.

Next, in step S95, it is determined whether the winding number has changed from 0 to non-zero at the intersection of interest, that is, whether it is the starting point of the filled area. If the previous winding number counter is 0 and the winding number counter is non-zero (YES), the process proceeds to step S96, and 1 is set to the flag information of the intersection point data 65 of the target intersection to indicate the starting point. On the other hand, if the winding number counter is not non-zero in step S95 (NO), the flow proceeds to step S97, and the number of windings is changed from non-zero to zero at the intersection of interest, that is,
It is determined whether it is the end point of the filled area. If the winding number counter is non-zero and the winding number counter is 0 in step S97 (YES), the process proceeds to step S98, 2 is set to the flag information of the intersection data 65 of the target intersection, which indicates the end point, and then step S99. Go to. On the other hand, if the winding number counter does not reach 0 in step S97 (NO),
Without doing anything, the process proceeds to step S99.

In step S99, the intersection counter is incremented, and in step S910, the end of the process is determined by referring to the intersection number data and the intersection counter in the intersection list. If there is an intersection that has not been processed yet (YE
S), the process proceeds to step S911, the value of the winding number counter is set in the previous winding number counter, the target intersection is moved to the next intersection, and the processing from step S92 is repeatedly executed.

Next, a method based on the odd-even rule will be described with reference to the flowchart of FIG. Incidentally, step S51
Although the direction information is set in the intersection data 65 of the intersection list in the processing of No. 5, this is not necessary when the processing of step S52 is performed by the method described below. In FIG.
First, the target intersection is set to the first intersection, and the intersection counter is initialized to 0 (step S101).

Next, it is determined whether the intersection counter is an even number to determine whether the intersection is an odd number, that is, the start point of the filled area (step S102). If it is an even number (YES), the process proceeds to step S103, and the flag information of the intersection data 65 is set to 1, that is, the starting point. On the other hand, if it is not an even number in step S102 (NO), the process proceeds to step S104, and it is determined whether the intersection counter is an odd number to determine whether it is an even-numbered intersection, that is, the end point of the filled area. Here, if it is an odd number (YES), the process proceeds to step S105 to set the flag information of the intersection point data 65 to 2,
That is, after setting the end point, the process proceeds to step S106.
If it is not an odd number in step S104 (NO), the process directly proceeds to step S106.

In step S106, the intersection counter is incremented, and in step S107, it is determined whether all intersections have been processed by referring to the intersection counter and the intersection number data in the intersection list. If there is an unprocessed intersection (YES), the process proceeds to step S108, the target intersection is set to the next intersection, and step S1 is performed.
The processing from 02 onward is repeated.

As described above, according to the present embodiment, the outline data is converted into a gradation image in which halftones are expressed in the vicinity of the outline without temporarily expanding the outline data into a binary image. Processing becomes possible. Further, according to the embodiment in which the pixel corresponding to the intersection with the contour line is obtained for the pixel arrangement in the two directions, it is possible to obtain a more beautiful gradation character image while enabling relatively high-speed processing. Furthermore, according to the mode using the combination flag for instructing whether or not the combination is performed, the redundant processing is omitted, so that the higher-speed processing becomes possible.

In the present embodiment, the gradation character image A generated in step S43 is a gradation character image obtained by setting the pixel array in the horizontal direction,
The gradation character image B generated at 47 has been described as the gradation character image obtained by setting the pixel array in the vertical direction, but it goes without saying that the gradation character image B can be reversed.
The direction of the pixel arrangement can be set in any direction as long as the pixels of the one gradation character image A and the pixel of the gradation image B can be associated with each other.

When the pixels at both ends of the filled area are determined from the intersections in step S73 of the present embodiment, the pixels to be turned on are set so that the center is within the outline. , Any method such as the one entirely inside the outline may be used.

Although the outline data stored in the font memory 16 is used in the present embodiment, the outline data is not limited to this, and the outline data is directly received from the input unit 112 and converted into gradation character data. It can also be changed to convert.

In the present embodiment, the expression form of the curve of the outline data is the cubic Bezier curve, but the present invention is not limited to this, and any curve such as a quadratic Bezier curve or a quadratic B-spline may be used. Alternatively, the format may be one in which all the lines are expressed without using a curve.

In the present embodiment, the outline data stored in the font memory 16 is read out, and the contents of the processes of steps S41 to S42 for modifying the outline data according to the output size are not mentioned in detail, but the known conventional method is used. There is no difference from the data reading process (step S41) and the transformation process (step S42) in the process of converting the outline data stored in the outline font memory into binary image data of a desired size, which is a technique. . That is, in step S42, not only the size conversion but also other geometrical deformation conversions, and deformations for correcting the quantization error at the time of rasterization are performed. The invention can be applied without departing from the spirit of the invention.

In this embodiment, the data conversion device is provided in the display device, but the data conversion device of the present invention is a data conversion device for printing devices such as laser beam printers and ink jet printers capable of expressing gradation. It is also realized as a device.

Besides, the present embodiment can be variously modified without departing from the spirit of the present invention.

[0080]

According to the data converter of the first aspect, the outline data can be directly converted into the image data indicating the gradation information, and the outline data can be converted into the image data at a high speed. it can.

According to the data conversion device of the second aspect, the image data in which the vicinity of the contour line has the intermediate density is obtained by a relatively simple process. As a result, the outline data has the intermediate density in the vicinity of the contour line. Data can be converted at high speed into the created image data.

According to the data conversion apparatus of the third aspect, whether each pixel corresponds to the inside or the outside is determined by a relatively simple process, and as a result, the outline data can be converted into the image data at high speed. Data can be converted.

According to the data conversion apparatus of the fourth aspect, if the scanning lines in a fixed direction are sequentially shifted so as to cover one output screen, the pixel lines in the fixed direction are arranged in sequence.
It is determined whether or not each pixel corresponds to the vicinity of the contour line, and a two-dimensional array of pixels that finally covers one output screen, which is one of the first, second, and third densities, is obtained. , Can be obtained at high speed by relatively simple processing.

According to the data conversion device of the fifth aspect, the pixels of the third density are arranged so as to two-dimensionally surround the inside of the contour line, and as a result, the outline data can be changed to beautiful image data at high speed. Data can be converted.

According to the data conversion apparatus of the sixth aspect, the pixels of the third density are arranged so as to more finely and two-dimensionally surround the inside of the contour line, and as a result, beautiful image data can be obtained from the outline data. Data can be converted at high speed.

According to the seventh aspect of the data conversion apparatus, the determination is made only in one direction or in two directions depending on the quality of the output image and the processing speed required of the output apparatus. As a result, it is possible to convert the outline data into image data suitable for the required quality and processing speed while avoiding redundant processing.

According to the data conversion apparatus of the eighth aspect, since the outline data defined with reference to the main scanning direction and the sub scanning direction is processed very efficiently,
Data can be converted from outline data to image data at extremely high speed.

According to the data converter of the ninth aspect, the pixels corresponding to the intersections are efficiently and sequentially judged by the judging means in accordance with the non-zero winding number rule, so that the data conversion from the outline data to the image data can be carried out at an extremely high speed. be able to.

According to the data converter of the tenth aspect, the pixels corresponding to the intersections are efficiently and sequentially judged by the judging means according to the even-odd rule, so that the data conversion from the outline data to the image data can be carried out at an extremely high speed. it can.

According to the eleventh aspect of the data conversion device, the two-dimensional image data generating means allows the two-dimensional arrangement of the pixels covering one output screen having any one of the first, second and third densities. Such an array can be obtained at a high speed by a relatively simple process, and as a result, data conversion from outline data to image data can be performed extremely quickly.

As a result of the above, according to the present invention, a device for converting the shape data of an outline character at high speed into gradation image data in which the contour neighborhood is expressed in halftone, that is, an outline font is directly gradation-converted. A data conversion device for converting image data can be realized.

[Brief description of the drawings]

FIG. 1 is a block diagram of a data conversion device that performs a gradation character image conversion process according to the present embodiment.

FIG. 2 is a conceptual diagram showing an example of outline data used in the present embodiment.

FIG. 3 is a conceptual diagram showing an example of a gradation character image used in the present embodiment.

FIG. 4 is a flowchart of gradation character image conversion processing according to the present embodiment.

FIG. 5 is a data configuration diagram showing an example of gradation character images A and B according to the present embodiment.

FIG. 6 is a conceptual diagram of intermediate code data in the gradation character image generation processing of the present embodiment.

FIG. 7 is a flowchart of a gradation character image generation process according to the present embodiment.

FIG. 8 is a conceptual diagram illustrating the characteristics of the fill rule used in the present embodiment.

FIG. 9 is a flowchart of a filled area determination process according to the non-zero winding number rule used in the present embodiment.

FIG. 10 is a flowchart of a filled area determination process based on the even-odd rule used in the present embodiment.

FIG. 11 is a conceptual diagram showing another example of outline data and gradation character data A used in the present embodiment.

[Explanation of symbols]

 10 ... CPU 12 ... Program memory 14 ... Working memory 16 ... Font memory 18 ... Output image memory 110 ... Communication bus 112 ... Input section 114 ... Display control section 116 ... CRT

Claims (11)

[Claims] 1. A data conversion device for converting outline data indicating a contour line of a character into image data indicating gradation information for each pixel, which is capable of expressing gradation in each pixel. Determining means for determining a pixel corresponding to the inside of the contour line and a pixel corresponding to the outside of the contour line on the output image of the output image, and the pixel determined to correspond to the inside as the first density and the outside The pixel determined to correspond to the second density is a second density different from the first density, and the pixel corresponding to the boundary between the pixel corresponding to the inside of the contour line and the pixel corresponding to the outside of the contour line is the third density. A data conversion device, comprising: an image data generating unit for obtaining a density. 2. The first density is a maximum density of the output device, the second density is a minimum density of the output device, and the third density is an intermediate density of the output device. The data conversion device according to claim 1. 3. The determining means assumes that the outline data is superimposed on pixel coordinates which is a coordinate system that defines pixels of the output device, and a pixel whose positional relationship with the outline data satisfies a certain criterion is the contour. 3. The data conversion device according to claim 1, wherein it is determined that the line corresponds to the inside of the line. 4. The determining means assumes that the outline data is superposed on pixel coordinates which is a coordinate system defining pixels of the output device, and the positional relationship with the outline data is provided on the pixel coordinates. 4. The data conversion device according to claim 1, wherein the determination is performed based on an intersection of a scanning line in a fixed direction and the outline data. 5. The data conversion device according to claim 4, wherein the determination means determines two different directions on the output image as the fixed direction. 6. The image data generation means determines that a pixel determined to correspond to the boundary in one of the two different directions and a pixel determined to correspond to the boundary in the other direction of the two different directions. If the matched pixel matches the matched pixel, the matched pixel is set to the third pixel.
When the density is determined and the pixel determined to correspond to the boundary in the one direction and the pixel determined to correspond to the boundary in the other direction are different from each other,
The different pixel is defined in advance by the first density or the third density.
The data conversion device according to claim 5, wherein the density is one of the densities. 7. The determination means further comprises an instruction means for instructing whether to determine two different directions or one direction on the output image as the constant direction, the determination means comprising: 7. The data conversion device according to claim 4, wherein the data conversion device determines whether the two different directions or the one direction is determined according to an instruction from the instruction main stage. 8. The data conversion device according to claim 4, wherein the two different directions are a main scanning direction and a sub scanning direction of the output device. 9. The data conversion device according to claim 1, wherein the determination unit determines a pixel corresponding to the intersection based on a non-zero winding number rule. 10. The data conversion device according to claim 1, wherein the determination unit determines a pixel corresponding to the intersection based on an odd-even rule. 11. The determination means determines a pixel corresponding to the inside of the contour line and a pixel corresponding to the outside of the contour line for each array of pixels in the certain direction. The data converter according to any one of items 1 to 10.