JPH0553564A - Half-tone font generation device - Google Patents

Abstract

PURPOSE:To decrease the difference in mean gradation, etc., between generated half-tone fonts, and to improve the quality of a generated half-tone font. CONSTITUTION:A filtering means 108 determines the number N of dots of each character of raster font 112 according to the predetermined number F of dots constituting a filter and the number H of meshes of a half-tone font inputted to the half-tone font generation device 100. A raster font generating means 110 generates the raster font 112 consisting of dots as many as the number NXN determined by the filtering means 108 from the original font 102. Therefore, characteristics such as the number F of dots constituting the filter and a filter function can be made constant and the difference in mean gradation, etc., between half-tone fonts can be decreased.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a CRT (cathode-ray).
tube) A raster font that is used when displaying characters on a screen, such as a halftone font in which each mesh (dot) has a multi-step gradation The present invention relates to a halftone font generation device having a halftone font generation means for generating a halftone font, and more particularly to a halftone font generation device capable of improving the quality of a generated halftone font.

[0002]

2. Description of the Related Art When a character is displayed on a CRT screen, that is, for a human to recognize a character or a number stored in a computer or the like, the character is displayed on the CRT screen or printed on an output sheet. In such cases, the fonts corresponding to the individual characters to be displayed are used to display and print the shape of each character.

For example, conventionally, such a font is
A 16-dot ROM font is used.

This 16-dot ROM font represents each displayed character by dots in 16 rows and 16 columns, and is composed of a total of 256 (= 16 × 16) dots. Hereinafter, such a ROM font is simply referred to as a ROM font.

Since such a ROM font has a limited relatively coarse dot structure, there is no distinction between typefaces such as Gothic typeface and Mincho typeface, and usually only one type of character size is available. There is.

Further, due to the limitation of the number of dots, in such a ROM font, complicated characters such as "roar" are generated.
Is a font in which some lines that make up the shape of the character are thinned out.

Therefore, such a ROM font cannot be said to be of high quality, and when a human reads a display or a print made using such a ROM font,
There is a problem that fatigue increases.

The drawbacks of such a ROM font are listed below.

When the number of dots forming the font is reduced, complicated characters cannot be displayed completely.

A large storage capacity is required in order to use the font data of a required size for each of a plurality of fonts.

When using fonts of different sizes, it is conceivable to enlarge or reduce the font in order to reduce the storage capacity, but in many cases, the quality of the characters is degraded.

When the font data is accessed or the font is enlarged or reduced within the application, the CPU (ce
The load of the ntral processing unit) becomes large, the character quality deteriorates, and the overall execution speed of the application becomes slow.

A font called a halftone font has been conventionally used as a font used for displaying characters on a CRT screen.

This halftone font is a font devised for the purpose of solving the above-mentioned drawbacks of the ROM font.

In this halftone font, the individual dots that make up the font do not have two gradations, white or black, but multi-level gradations with gradations in brightness.

The halftone font can display a curved portion of a character or a portion where lines are complicatedly complicated with a small number of dots due to such multi-step gradation.

Therefore, the CRT of the personal computer
Even on a display screen having a low resolution such as, it is possible to accurately display a complicated character with a small number of dots, or to distinguish and display a font such as Mincho or Gothic.

Further, according to such a halftone font, it is possible to obtain the effect of reducing flicker when displaying characters on the screen of the CRT.

Conventionally, the procedure of generating such a halftone font is generally as follows.

A raster font having a predetermined dot configuration is generated from a vector font in which the character shape is represented by coordinates.

A desired halftone font is generated from the raster font.

[0022]

However, in the conventional halftone font generating apparatus, when generating a halftone font in which the size of one character is different, the average rank between the generated halftone fonts is large. Differences in tone (brightness of each halftone font) may occur.

Therefore, when the halftone font generated by such a halftone font generating device is used for the display and the printing, the display and the printing quality are deteriorated.

The present invention has been made to solve the above-mentioned conventional problems. Even when halftone fonts in which the size of one character is different are generated, the average rank between generated halftone fonts is large. A first object of the present invention is to provide a halftone font generation device capable of reducing a difference in tone (brightness of each halftone font) and the like to improve display and print quality using the halftone font. To aim.

In addition to the first object, it is also possible to provide a halftone font generation device capable of shortening the halftone font generation time when generating a halftone font in which the size of one character is different. Is the second purpose.

[0026]

SUMMARY OF THE INVENTION According to the present invention, a halftone font in which each mesh has a multi-step gradation is used for displaying characters on a CRT screen. In a halftone font generation device having a halftone font generation means for generating from a raster font composed of tonal dots, a predetermined number of dots of the dots constituting the filter used in the halftone font generation means, Filtering means for determining the number of dots of the raster font from the number of meshes of the halftone font to be generated, and the raster font according to the number of dots of the raster font determined by the filtering means. And a raster font generation means for generating By having a fixed value of the number of dots the filter is obtained by achieving the first object.

The second object is achieved by setting the number of dots of the filter to a fixed value that is a power of two.

In the present invention, the mesh is a dot that constitutes a halftone font. Hereinafter, the dot means a dot of a raster font or a dot of a filter described later. On the other hand, the dots of the halftone font are hereinafter referred to as meshes, and are distinguished from the dots of the raster font and the dots of the filter described later.

[0029]

According to the present invention, when generating halftone fonts in which the size of one character is different, the difference in the average gradation (brightness of each halftone font) and the like among the generated halftone fonts is small. It was made by finding the cause of the occurrence.

Normally, when displaying characters on a CRT screen or printing characters with a line printer or the like, characters of various sizes are displayed or printed.

Further, when displaying a large character on a CRT screen, a halftone font having a finer mesh structure is used than when displaying a small character.

This is to improve the aesthetic appearance of the whole when it is displayed or printed. That is, when a large character is viewed by a human, the shape of the character feels rough with the fineness of the mesh configuration of the same halftone font as the small character. Also, if the mesh structure of the halftone font of all characters including small characters is made fine, there is a problem that the display speed and the printing speed are reduced.

Generally, the halftone font generator is
It has a halftone font generating means for generating the halftone font from a raster font composed of dots of two gradations, which is finer than the generated halftone font having a predetermined mesh structure.

Each mesh forming the halftone font corresponds to a plurality of dots of the raster font, which are finer than the mesh structure of the halftone font.

Usually, in the halftone font generating apparatus, a dot structure finer than the mesh structure of the halftone font, which corresponds to each mesh forming the halftone font, is usually called a filter.

Therefore, the halftone font generating means of the normal halftone font generating device counts the number of dots of the black character portion of the raster font corresponding to each mesh forming the halftone font, and calculates the number of dots. In accordance with the above, multi-step gradation values of all meshes of the halftone font for one character are obtained, and the halftone font of the character is generated.

For example, the dots of the black character portion of the raster font corresponding to each mesh of the halftone font and the total number of dots of the raster font per mesh of the halftone font (the number of dots of the black character portion and the white background portion). According to the ratio with the sum of the number of dots), the gradation values of all the meshes of the halftone font for one character are obtained, and the halftone font is generated by this.

It is to be noted that such a multitone gradation value of each mesh of the halftone font is obtained, each mesh of the halftone font and the number of dots of the black character portion of the raster font corresponding to each mesh, Hereinafter, the relationship with the number of dots in the white background portion will be referred to as a filter function. That is, a function for obtaining a multi-step gradation value of each mesh forming the generated halftone font from dots of a raster font having two gradations is hereinafter referred to as a filter function.

The conventional halftone font generator is a halftone font generator which generates halftone fonts having different mesh numbers per character, such as when generating halftone fonts having different character sizes. Even if there is one of the raster fonts that is the original font
The number of dots per character was always constant.

Therefore, the number of dots of a plurality of dots finer than the mesh structure of the halftone font corresponding to each mesh forming the halftone font conventionally generated is the number of meshes per character of the halftone font. Has changed due to changes.

Therefore, in the conventional halftone font generating apparatus, the dot structure of the filter changes when the number of meshes per character of the halftone font is different.

In the halftone font generator,
When the dot configuration of the filter changes, the characteristics of the filter function as described above also change, and the gradation and average gradation of the generated halftone font also change.

Therefore, according to such a conventional halftone font generating apparatus, when generating a halftone font in which the size of one character is different, the average gradation between the generated halftone fonts ( A difference such as the brightness of each halftone font occurs, and the display and print quality using the halftone font deteriorate.

Therefore, the present invention is focused on the filter used in the halftone font generating apparatus.

FIG. 1 is a block diagram showing the gist of the present invention.

In FIG. 1, the halftone font generator 100 generates a halftone font 120 based on an original font 102.

The original font 102 is, for example, a vector font that represents the outline of a character by the coordinate values of lines and curves. Alternatively, the original font 102 is a raster font finer than the raster font 112 described later used in the halftone font generation means 116 described below.

The halftone font 120 is CR
This is a font in which each mesh has multi-level gradation, which is used when displaying characters on the T screen.

In FIG. 1, the halftone font generating apparatus 100 mainly includes a filtering means 10.
8, a raster font generation means 110, and a halftone font generation means 116. The halftone font generation device 100 also has means for storing the number F of dots forming a filter, raster font 112, and other data used during halftone font generation.

The filtering means 108 is responsive to a predetermined number F of dots forming a filter and a halftone font mesh number H input to the halftone font generating apparatus 100 including the filtering means 108. Raster font 1 described later used by the halftone font generation means 116 described below.
The number N of dots per character of 12 is determined by the following equation.

N = F × H (1)

The number H of meshes of the halftone font input to the halftone font generator 100 is
It is input from an application program or the like that requests the halftone font generation device to generate a halftone font. The mesh number H of the halftone font is determined, for example, by the application program according to the size of characters to be displayed or printed.

The number F of dots forming the filter is a predetermined fixed value.

Note that, for example, in the halftone font generation apparatus 100, considering the use of digital processing means such as the use of a microprocessor (MPU), the value of the number of dots F constituting the filter, which is this fixed value, is 2 It is preferable that it is a power of. For example, the value of the number of dots forming this filter is 4 (2 to the power of 2) or 8 (2 to 3).
It is preferably a fixed value such as (power) or 16 (2 to the fourth power).

The digital processing means normally processes every binary number such as 8 digits or 16 digits. Therefore, if the number F of dots forming the filter is a fixed value that is a power of 2, it is possible to efficiently perform processing on the raster font 112 by the halftone font generation means 116 described later, and the halftone font generation time is set. Can be shortened.

The raster font generating means 110 has the number of dots N determined by the filtering means 108.
A raster font 112 of × N is generated.

The halftone font generating means 116
Is a raster font 11 using a predetermined filter function.
Generate a halftone font 120 from 2.

The present invention does not limit the halftone font generating means 116, and does not limit the filter function used in the halftone font generating means 116.

For example, the halftone font generating means 116 counts the number of dots in the black character portion of the raster font 112 corresponding to each mesh forming the halftone font, and according to the number of dots, halftone for one character is generated. The multitone gradation values of all the meshes of the tone font are obtained, and the halftone font 120 of the character is generated. For example, according to the ratio of the number of dots of this black character portion and the total number of dots of the raster font per halftone font mesh (the sum of the number of dots of the black character portion and the number of dots of the white background portion), one character The multitone gradation values of all the meshes of the halftone font are obtained, and the halftone font 120 is generated by this.

Therefore, as described above, according to the halftone font generating apparatus of the present invention, when generating a halftone font in which the size of one character is different, the mesh number of the generated halftone font is changed. Even if it is done, the number of dots of the filter (dot configuration) can be made constant at all times. Therefore, the characteristics of the filter and the filter function used when generating the halftone font can be made constant, and the difference in the average gradation and the like between the generated halftone fonts can be reduced. It is possible to improve display and print quality using a halftone font.

[0061]

Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 2 is an overall configuration diagram of an embodiment of the present invention.

The font accelerator 200 shown in FIG. 2 has the present invention applied to the font generation module 222, as described later with reference to FIG.

The font accelerator 200 shown in FIG. 2 displays on the CRT display device 260a of the personal computer 260 according to the input data 250.

The input data 250 is the document data 25.
0a, graphic data 250b, and typesetting instruction data 250
It consists of c and.

The font accelerator 200 of this embodiment
Is assembled inside the personal computer 260 into a slot which can be inserted from the rear surface of the personal computer 260, into a printed circuit board which can be inserted.

The font accelerator 200 is composed of a typesetting section 210 and a display section 220.

The typesetting section 210 includes a typesetting module 21.
1, a proportional processing module 212, a hyphenation processing module 213, and a prohibition processing module 214. Also, this typesetting section 2
10 also includes a temporary storage unit for storing the layout data 215 output by the typesetting module 211.

FIG. 3 is an image diagram of typesetting according to this embodiment.

In FIG. 3, the typesetting section 2 of FIG.
A typeset image for one page typeset in 10 is shown.

Typesetting unit 2 of font accelerator 200
In accordance with the document data 250a of the input data 250 and the typesetting instruction data 250c, the document 10 first divides the displayed document into constituent elements such as a title 302, a headline 304, and a sentence 306. Next, the typesetting unit 210 sets parameters such as the size of the display area, the display start position, the space between characters, and the width between lines for each of the components of the title 302, headline 304, and sentence 306. Instruct.
Further, at this time, the typesetting unit 210 receives the document data and parameters of the respective divided constituent elements, and performs display processing for each character while performing detailed processing such as prohibition processing, proportional processing, and hyphenation processing. decide.

The typesetting section 210 also uses the graphic data 250b of the input data 250 and the typesetting instruction data 250 described above.
Parameters such as the size of the display area and the display start position of the chart 308 of FIG. 3 are designated according to c.

Therefore, according to the typesetting unit 210 of the font accelerator 200 of this embodiment, the typesetting can be performed only by the character output command from the application, which reduces the load of the application development process and the execution speed of the application. It is possible to improve.

In FIG. 2, the display section 220 is composed of a display module 221 and a font generation module 222. The display unit 220 also includes a predetermined temporary storage unit for storing the display font 223 output by the font generation module 222.

Further, the display unit 220 of this embodiment basically does not always wait for the halftone font, and the halftone of the desired typeface and size of the character to be displayed is displayed from the vector font 230 at each display. A font (display font 223) is generated. For this reason, the storage capacity of the predetermined temporary storage means for storing the display font 223 is relatively compact.

The font accelerator 200 of this embodiment
The present invention described above with reference to FIG. 1 is applied to the font generation module 222 of the display unit 220 of FIG.

FIG. 4 is a block diagram of the font generation module of this embodiment.

In FIG. 4, reference numerals 221 and 222,
223 and 230 are the same as those having the same reference numerals in FIG. 2 described above.

In FIG. 4, the font generation module 222 comprises a filtering means 222a, a raster font generation means 222b, a halftone font generation means 222d, and a filter function means 222e. Also, this font generation module 222
Is also provided with a predetermined storage means for storing the raster font 222c output by the raster font generation means 222b.

FIG. 5 is a diagram showing the relationship among the raster font, halftone font and filter of this embodiment.

In FIG. 5, the filter 322 is a filter used when obtaining the mesh value and gradation value of each mesh of the halftone font.

This filter 322 is composed of F dots × F dots. In this embodiment, even if the mesh structure of the generated halftone font, that is, the number of meshes per font, changes, this filter 322 The dot configuration that constitutes is fixed.

In FIG. 5, the halftone font generated from the raster font data 320 is H
It is composed of H × H meshes. The number of meshes that make up this halftone font depends on the display module 2
It is a variable value according to the command value from 21. That is,
The number of meshes forming the halftone font can be changed according to the size of the characters to be displayed and the typeface.

In the present embodiment, the number of dots F × F forming the filter 322 is fixed as described above, and the number of meshes H × H of the halftone font is determined according to the environment of the application or the like.

Therefore, in this embodiment, the raster font data 32 is generated by the filtering means 222a shown in FIG.
The dot number N × N of 0 is obtained by the above-mentioned equation (1).

For example, when the number of dots F forming the filter 322 having a fixed value is "8" and the number of meshes H of the halftone font is "16" due to the display environment of an application or the like, the raster font The number N of dots forming the data is "128".

Also, the number of dots N which constitutes the raster font data in this way by the filtering means 222a of FIG.
4 is determined, the raster font generation means 222b of FIG. 4 generates a raster font 222c (corresponding to the raster font data 320 in FIG. 5) having a dot number N × N from the vector font 230. ..

The font generation module 22 shown in FIG.
In No. 2, digital processing is performed using a microprocessor (MPU). Further, the value of the number of dots F forming the filter 322, which is the fixed value described above, is "8" (2 to the power of 3) which is a power of 2. Note that this fixed value is preferably a power of 2, and for example, the value of the number of dots F is 4 (2 2) or 16 (2 4).
It is preferably a fixed value such as (power) or 32 (2 to the power of 5).

By thus setting the number of dots F constituting the filter 322 to a power of 2, rasterization of a memory having a word length of 4 bits / word, 8 bits / word, 16 bits / word, 32 bits / word, etc. Font 22
When used as a means for storing 2c, the memory utilization efficiency can be improved.

Further, the halftone font generating means 222
Even when d is a digital processing unit that executes processing in units of word length such as 4 bits / word, 8 bits / word, 16 bits / word, 32 bits / word, the dot number F is set to 2 in this way. By using the power of, the processing efficiency can be improved and the processing speed can be further increased.

FIG. 6 is a flowchart of the halftone font generation processing of this embodiment.

The processing shown in the flowchart of FIG. 6 is executed by the font generation module 222 of the display unit 220 of the font accelerator 200 shown in FIG. 2, that is, the font generation module 222 shown in FIG.

The steps 412 and 416 in FIG. 6 are mainly performed by the raster font generating means 222b shown in FIG.
Run on. Steps 414, 418, 420 of FIG.
Is mainly executed by the halftone font generating means 222d shown in FIG.

The flowchart of the halftone font generation process of FIG. 6 will be described below by taking the character “A” shown in FIG. 7 as an example.

First, in step 412 of FIG. 6, the raster font generating means 222b extracts horizontal line information from the vector font data input from the vector font 230 of FIG.

The horizontal line information extracted in this step 412 becomes the character portions indicated by the symbols a, b, c and d in FIG. 8 in the character "A" shown in FIG.

Subsequently, in step 414, step 4
The remaining portion excluding the horizontal line information extracted in 12 is developed into a halftone font by the halftone font generation means 222d in FIG. That is, this step 41
The character portion of "A" in FIG. 7 which is developed into the halftone font in 4 is the character portion indicated by the symbol e in FIG.

In step 416, the optimum position in the mesh of each horizontal line is determined from the horizontal line information extracted in step 412, and the position of each horizontal line is corrected in the width direction.

The position correction in the width direction of the horizontal line in this step 416 is performed when the horizontal line extends over a plurality of meshes in the width direction, and the brightness of the horizontal line when it becomes a halftone font (contrast to the background). This is to reduce that

The process of step 416 will be described later in detail with reference to FIGS. 9 and 10.

Subsequently, in step 418, step 4
Each horizontal line whose position is corrected in the width direction in 16 is developed into a halftone font.

The development into the halftone font performed in the above step 414 and step 418 will be described later in detail with reference to FIGS.

In FIG. 6, in step 420, the halftone fonts developed in step 414 and step 418 described above are overlapped and the
4 halftone fonts, which are output as the display font 223 of FIG.

FIGS. 9 and 10 are explanatory views of position correction of the horizontal line in the width direction of this embodiment.

That is, FIG. 9 is a model diagram before position correction of the position of a horizontal line in the width direction. On the other hand, FIG. 10 is a model diagram after position correction in the width direction of the horizontal line shown in FIG.

In each of FIGS. 9 and 10, twelve meshes 320a in total are shown. That is, in each of FIGS. 9 and 10, 2 rows ×
Six rows of identical mesh are shown.

In FIG. 9, before correction, that is, before position correction in the width direction, the horizontal line indicated by reference numeral 330a extends over the mesh in the upper row and the mesh in the lower row.

In the present embodiment, the mesh value that determines the gradation value of each mesh of the halftone font is determined according to the number of dots of the character portion of each mesh.

Therefore, as shown in FIG. 9, the center position Ym of the horizontal line portion of the character in the width direction deviates from the center position YFm of the horizontal line in the width direction (vertical direction) of the mesh 320a having the horizontal line. If the horizontal line extends over the mesh 320a of another row, the brightness of the horizontal line (contrast with respect to the background) is reduced.

Therefore, in the present embodiment, the center position Ym in the width direction of each horizontal line portion is made to coincide with the center position YFm in the same direction as the width direction of the horizontal line of the mesh having the horizontal line.
The position of the horizontal line is corrected in the width direction.

In FIG. 9, the symbol W indicates a horizontal line 330a.
Of the horizontal line portion 330a, and the symbol Ys is the coordinate position in the width direction (vertical direction) of the upper left portion of the horizontal line portion 330a.
e is the coordinate position in the width direction (vertical direction) of the lower left portion of the horizontal line portion 330a.

Further, in FIGS. 9 and 10, the origin of coordinates is at the upper left. Also, each coordinate is in units of one dot of the raster font and is an integer.

In FIG. 9, position Ye and position Ys
And the width W, the following equation holds.

Ye = Ys + W-1 (2)

The center position Ym of the horizontal line portion 330a in the width direction can be obtained from the positions Ys and Ye according to the following equation.

Ym = (Ys + Ye) / 2 (3)

Here, the movement (positional correction) in the width direction for the correction of the horizontal line portion 330a is performed by the position Ymo of the widthwise center of the horizontal line portion 330b in FIG. 10 after correction and the mesh 320a having the horizontal line. The position is corrected so that the relationship with the center position YFm is as shown in the following expression.

Ymo = YFm (4)

Therefore, the upper left position Yso and the lower left position Yeo of the horizontal line portion 330b after correction (position correction) in FIG. 10 are as follows.

Yso = Ys + (Ymo-Ym) (5) Yeo = Ye + (Ymo-Ym) (6)

As described above, by correcting the position in the width direction of the horizontal line forming the character described with reference to FIGS. 9 and 10, that is, by performing the processing of step 416 in FIG. 6, the horizontal line forming the character becomes All of them are located at the center of the mesh with each horizontal line (the center of the horizontal line in the width direction), and the brightness (contrast against the background) of each horizontal line part of the halftone font generated by the subsequent processing becomes low. You can prevent it from happening. In particular, in a typeface with fine horizontal lines such as Mincho typeface, the quality of the halftone font effectively generated can be improved.

The amount of movement of the horizontal line when correcting the position in the width direction is the number of dots in the vertical direction of the raster font per mesh, that is, the number of dots F in the vertical direction of one filter, which is one.
This is within the range of / 2 or less, and such position correction of the horizontal line in the width direction does not have a possibility of deforming the shape of the finally generated halftone font character.

FIG. 11 is a graph showing the function of the filter function means used in this embodiment.

The filter function shown in FIG. 11 is a function of the filter function means 222e of the font generation module 222 shown in FIG. The filter function shown in FIG. 11 is a filter function corresponding to the filter 322 of FIG. 5 described above.

In FIG. 11, the mesh value is the number of dots (black dots) corresponding to the character portion among the F × F dots forming the filter 322 of FIG.

Therefore, the maximum value of this mesh value is (F ×
It is the value of F). Further, as shown in FIG. 11, the maximum gradation value of each mesh of the halftone font is 15
However, this value depends on the hardware.

The filter function shown in FIG. 11 has a maximum gradation value of 15 when the mesh value is smaller than the maximum value (F × F) by the parameter Δ.

Therefore, according to the filter function shown in FIG. 11, the average gradation value of the character portion can be increased when developing the halftone font.
The brightness (contrast with respect to the background) of the generated halftone font can be increased, and the quality of the generated halftone font can be improved.

In FIG. 12, the raster font is 256.
FIG. 12 is a diagram showing the value of the parameter Δ of FIG. 11 described above in the case of × 256 dots.

As shown in FIG. 12, the parameter Δ of the filter function is determined according to the number of meshes forming the generated halftone font. Also, this FIG.
As shown in, as the number of meshes forming the halftone font decreases and the size of the filter (corresponding to the size of the mesh) with respect to the size of the entire halftone font increases, the value of the parameter Δ of the filter function increases. Is getting bigger.

13 and 14 are flow charts showing the halftone font expansion processing of this embodiment.

The processing shown in the flow charts of FIGS. 13 and 14 is executed by the halftone font generation means 222d of the font generation module 222 of FIG. 4 described above. The process shown in the flowcharts of FIGS. 13 and 14 corresponds to the process executed in step 414 or 418 of the process shown in the flowchart of FIG.

That is, the processing shown in the flow charts of FIGS. 13 and 14 is the same as that of the raster font 2 output by the raster font generating means 222b in FIG.
22c, a filter dot number F output from the filtering unit 222a, a mesh number H of a halftone font, a dot number N of raster font data, and a filter function unit 222e, a display font 223 is generated, and this is used as a font. Output from the generation module 222.

In FIG. 13, first, step 602
Then, the image value variable, that is, the dot that is the character part of the raster font (black or ON dot,
Hereinafter, 0 is written in a variable used when the number of ON dots) is summed up for one character. This stroke value variable is finally the O of the raster font for one character.
This is the total number of N dots.

At step 604, the maximum value variable, that is, 1
By comparing the mesh values of the respective meshes of characters, 0 is written in the variable used to obtain the maximum value of the number of ON dots in each mesh.

At step 606, the variable i, i row,
When sequentially processing a total of i × j meshes in j columns, 0 is written in a variable for counting rows.

At step 608, the variable j, that is, the i-th row,
Write 0 to the variable used to count the columns when processing the j-th column mesh in sequence.

At step 610, the mesh values SFij,
That is, a total of H × H variables SF00 to SF for writing the number of ON dots of each mesh of total H × H
(H-1) 0 is written in the variable in the i-th row and the j-th column of (H-1).

In step 612, the mesh value, that is, the number of ON dots in the filter of the corresponding mesh of the i-th row and the j-th column is written in the mesh value SFij of the i-th row and the j-th column.

In steps 614 and 616, the maximum value variable is compared with the mesh value SFij. If the mesh value SFij is larger than the value of the maximum value variable, the mesh value is assigned to the maximum value variable. Write the value of SFij.

At step 618, the value of the mesh value SFij is added to the value of the image value variable, and this value is written in the image value variable.

At step 620, the variable j is incremented (the value is increased by "1").

At step 622, it is judged whether the value of the incremented variable j is equal to the number H of columns of the mesh for one character. If they are equal, the process proceeds to step 624. If they are not equal, the process proceeds to step 610. Branch ahead of.

At step 624, the variable i is incremented.

At step 626, it is judged whether the value of the incremented variable i is equal to the value of the number of rows H of the mesh for one character, and if they are equal, step 640 of FIG.
If not, the process branches to the front of step 608.

At step 640, the value of the parameter Δ required when using the filter function is determined by the number H of halftone font meshes to be generated.

The parameter Δ in this step 640
The value of is determined according to a predetermined memory table in which the data corresponding to FIG. 12 described above is written.

In step 642, a correction value used in obtaining the gradation value Pij of each mesh is determined from the value of the mesh value SFij of each mesh according to the number H of halftone font meshes to be generated and the image numerical variable. .

The method of determining the correction value in step 642 is as follows.

First, the image numerical value variable obtained in step 618 and the like and the total number of dots of raster font data (N
XN) and the following equation, the ratio of dots, that is, the ratio of ON dots of all dots for one character of raster font data is obtained.

Dot ratio (%) = (image value / (N × N)) × 100 (7)

The correction value is obtained as follows from the dot ratio obtained by the equation (7).

When dot ratio <6%: correction value = 4 (8a) 6% ≦ dot ratio ≦ 8%: correction value = 2 × (8-dot ratio) (8b) Other than: Correction value = 0 (8c)

After step 642 for performing such processing, in step 644, 0 is written in the variable i for counting the number of rows of the mesh.

Then, in step 646, 0 is written in the variable j for counting the number of mesh columns.

In step 648, the mesh value SFij of the mesh in the i-th row and the j-th column, the maximum value variable, the parameter Δ, and the gradation value Pij of the mesh in the i-th row and the j-th column are calculated according to the following equation. Find the value.

Pij = 16 × SFij / (maximum value−Δ) (9)

In steps 650 and 652, the gradation value P obtained in step 648 according to the equation (9) is calculated.
It is determined whether the value of ij is larger than 0. If the gradation value Pij is larger than 0, the correction value obtained in step 642 described above is added to the gradation value, and this is set as the gradation value Pij. . That is, the correction value is added only to the gradation value Pij of the mesh of the character portion, and the correction value is not added to the gradation value Pij of the mesh of the background portion.

In steps 654 and 656, the gradation value P
It is determined whether ij is larger than 15, and if the gradation value Pij is larger than 15, the value of the gradation value Pij is set to 15.

In step 658, the variable j for counting the number of mesh columns is incremented.

In step 660, it is determined whether the variable j is equal to the number H of columns of the mesh for one character. If the variable j is H, the process proceeds to step 662, and if it is not equal, the process proceeds to the front of step 648. Branch off.

At step 662, the variable i for counting the number of rows of the mesh is incremented.

At step 664, it is judged whether or not the value of the variable i for counting the number of rows of the mesh is equal to the number H of rows of the mesh for one character, and if the variable i is equal to the number H of rows, 13 and all the processes shown in the flowchart of FIG. 14 are terminated. On the other hand, if it is determined in step 664 that the variable i is not equal to the number H of rows, the process branches to the front of step 646.

As described above, by performing the processing shown in the flowcharts of FIGS. 13 and 14, the tone value of each mesh for one character can be obtained from the mesh value of each mesh for one character, A halftone font of the desired character can be generated. Further, not only the filter function described above with reference to FIG. 11 can be used in the generation of this halftone font (step 64).
0, 648 to 656, etc. and Eq. (9)), Eqs. (7) and (8a) to (8c) can be used to perform the above-mentioned correction (equivalent to steps 642, 652, etc.). , The quality of the generated halftone font can be improved.

As described above, in this embodiment, as shown in FIG.
As described above with reference to FIG. 5 and the like, the present invention is applied to the font generation module 222 and the like of the display unit 220.

Therefore, according to this embodiment, even when halftone fonts in which the size of one character is different are generated, the average gradation between the generated halftone fonts (the brightness of each halftone font is different). It is possible to obtain an excellent effect that it is possible to improve the display quality and the print quality using the halftone font by reducing the difference such as the above.

Further, in the present embodiment, as described above, the value of the number F of dots forming the filter 322 is "8" which is a power of 2, and as described above, the raster font 2 is used.
It is possible to improve the memory use efficiency of 22c and the processing efficiency of the halftone font generating means 222d.

[0168]

As described above, according to the present invention,
Even when generating halftone fonts in which the size of one character is different, the average gradation between the generated halftone fonts (brightness of each halftone font)
It is possible to obtain an excellent effect that it is possible to provide a halftone font generating apparatus capable of improving the display quality and the printing quality using the halftone font by reducing the difference between the above.

Further, in the present invention, when the number of dots forming the filter is a power of 2, in addition to the first object, halftone fonts for generating halftone fonts in which the size of one character is different are used. It is also possible to obtain the effect that the font generation time can be shortened.

[Brief description of drawings]

FIG. 1 is a block diagram showing the gist of the present invention.

FIG. 2 is an overall configuration diagram of an embodiment of the present invention.

FIG. 3 is an image diagram of typesetting according to the embodiment.

FIG. 4 is a block diagram of a display unit of the above embodiment.

FIG. 5 is a diagram showing a relationship among a raster font, a halftone font, and a filter in the above embodiment.

FIG. 6 is a flowchart of a halftone font generation process of the above embodiment.

FIG. 7 is a diagram showing a character example targeted by the embodiment.

FIG. 8 is a diagram showing extraction and remaining portion of horizontal line information of the character example.

FIG. 9 is an explanatory diagram (before correction) of position correction in the width direction of the horizontal line in the embodiment.

FIG. 10 is an explanatory diagram (after correction) of position correction of the horizontal line in the width direction in the embodiment.

FIG. 11 is a graph showing the function of the filter function means used in the above embodiment.

FIG. 12 is a diagram showing a relationship between the number of meshes of a halftone font to be generated and the parameter Δ of the filter function means in the embodiment.

FIG. 13 is a first half of a flowchart showing a halftone font developing process in the embodiment.

FIG. 14 is a second half of the flowchart showing the halftone font development processing in the embodiment.

FIG. 15 is a graph of a filter function used in a conventional halftone font generation device.

[Explanation of symbols]

 100 ... Halftone font generation device, 102 ... Original font, 108 ... Filtering means, 110 ... Raster font generation means, 112 ... Raster font, 116 ... Halftone font generation means, 120 ... Halftone font, 200 ... Font accelerator, 210 ... typesetting section, 211 ... typesetting module, 212 ... proportional processing module, 213 ... hyphenation processing module, 214 ... prohibition processing module, 215 ... layout data, 220 ... display section, 221 ... display module, 222 ... font generation module, 222a ... Filtering means 222b ... Raster font generation means, 222c ... Raster font, 222d ... Halftone font generation means, 222e ... Filter function means, 223 ... Display font, 230 ... Vector font data, 250 ... Input data, 250a ... Document data, 250b ... Graphic data, 250c ... Formatting instruction data, 260 ... Personal computer, 260a ... CRT display device, 320 ... Raster font data, 320a ... Halftone font mesh, 322 ... Filter, 330a ... Horizontal line before correction, 330b ... Horizontal line after correction, H ... Number of meshes that make up a halftone font, F ... Number of dots that make up a filter, N ... Make up a raster font Number of dots to be set, Δ ... Parameter of filter function.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical indication H04N 1/23 Z 9186-5C

Claims (2)

[Claims] 1. A halftone font, which is used when displaying characters on a CRT screen or the like, in which each mesh has a multi-step gradation, is a raster composed of dots of two gradations finer than the halftone font. In a halftone font generating device having a halftone font generating means for generating from a font, a predetermined number of dots constituting a filter used in the halftone font generating means and the halftone font for generating are constituted. Filtering means for determining the number of dots constituting the raster font from the number of meshes of the mesh to be formed, and raster font generating means for generating the raster font according to the number of dots of the raster font determined by the filtering means. , And the number of dots of the filter Halftone font generation apparatus being characterized in that a fixed value. 2. The halftone font generation device according to claim 1, wherein the number of dots of the filter is a fixed value that is a power of two.